Symptoms of Posttraumatic Stress in Parents of Children with Cancer: Are they Elevated Relative to Parents of Healthy Children?

Abstract

Objective To examine posttraumatic stress symptoms (PTSS) in parents of children with cancer as a function of time since diagnosis, treatment status, and relapse history, and as compared to parents of healthy children. Method Participants included parents of 199 children with cancer, comprising a cross-sectional sample of diagnoses and treatment phases, ranging from currently on therapy to long-term survivors, and 108 parents of healthy children obtained via acquaintance control methods. Parents completed a standardized self-report measure of PTSS. Results Within the cancer group, parental report of PTSS differed as a function of treatment status and time since diagnosis. Parents of children on active treatment endorsed similar levels of PTSS as control parents, whereas parents of children off treatment reported significantly lower levels of PTSS than did controls. Similarly, parents of long-term survivors reported significantly lower levels of PTSS than did controls, while parents of recently diagnosed children did not differ from controls on PTSS. In contrast, parents of children who had suffered a relapse reported significantly higher levels of PTSS, and were much more likely to be identified as a posttraumatic stress disorder (PTSD) case. Conclusions As a group, parents of children with cancer did not demonstrate any evidence of increased PTSS relative to parents of healthy children. Time since diagnosis, child treatment status, and relapse history are significant determinants of parent PTSS. Only parents of children who experienced a relapse appear to be at increased risk of PTSD. The current results appear discrepant from the existing literature, and possible explanations for these discrepancies are examined.

Having a child diagnosed with cancer is a potentially traumatic event and has been viewed as one of the most severe stressors that a parent can experience (Kazak, 1998). In the fourth edition of the Diagnostic and Statistical Manual of the American Psychiatric Association (APA, 1994) “learning that one's child has a life-threatening illness” was added to the list of events traumatic enough to lead to posttraumatic stress disorder (PTSD). The diagnosis of PTSD and the presence of posttraumatic stress symptoms (PTSS) have become the focus of a great deal of research within the pediatric cancer population, with many studies reporting on the incidence in parents of children with cancer. In contrast to research examining PTSS in children with cancer, which has shown generally low levels, studies of their parents have found increased levels of PTSD and PTSS (Kazak et al., 2004; Kazak, Boeving, Alderfer, Hwang, & Reilly, 2005; Manne, Du Hamel, Gallelli, Sorgen, & Redd, 1998; Stuber, Christakis, Houskamp, & Kazak, 1996). Studies comparing PTSD/PTSS in parents of children with cancer to parents of healthy children have reported a greater incidence of PTSD and higher levels of PTSS in the cancer group (Barakat et al., 1997; Brown, Madan-Swain, & Lambert, 2003; Pelcovitz et al., 1996).

Much of the existing literature has examined parent PTSS in populations of pediatric cancer survivors who are assessed many years postdiagnosis (Barakat et al., 1997; Brown et al., 2003; Kazak et al., 2004; Manne et al., 1998; Pelcovitz et al., 1996; Stuber et al., 1997). In general, these studies suggest that elevated levels of parent PTSS persist for many years beyond the completion of the child's treatment. Fewer studies have examined PTSS in parents of children still on active treatment. Kazak and colleagues (2005) found that 68% of mothers of children on active treatment for cancer reported PTSS in the moderate to severe range. In comparison to an earlier study of parents of long-term survivors conducted by the same group (Kazak et al., 2004), PTSS levels were much higher in the on treatment group, with symptom scores on the Impact of Events Scale (IES-R, Weiss & Marmar, 1997) >50% higher for parents of those on therapy (Kazak et al., 2005). It should be noted that these data from parents of children on therapy and long-term survivors were obtained in separate studies.

One report examined PTSS in parents of children on treatment and long-term survivors simultaneously in the same study (Phipps, Long, Hudson, & Rai, 2005). The results suggest that time elapsed since child's diagnosis may have an effect on parents’ self-reported PTSS. Parents of children diagnosed within the past 2 years self-reported higher levels of PTSS that appear to be elevated relative to normative values. Parents of long-term survivors (at least 5 years since diagnosis and 2 years since completion of treatment), however, endorsed significantly lower symptom levels that were comparable to normative values. The authors hypothesized that this symptom pattern might suggest that the PTSS experienced during the child's treatment represent the parent's response to concurrent stressors (e.g., seeing their child endure multiple medical procedures, pain, nausea; waiting for results of diagnostic tests such as imaging and bone marrow biopsies; and financial burden of treatment), as opposed to past stressors (e.g., receiving the news of their child's diagnosis).

A recent paper explores the current criteria for PTSD, specifically, the controversy surrounding the A1 criterion that defines what the DSM-IV considers to be a “traumatic stressor.” Gold and colleagues (Gold, Marx, Soler-Baillo, & Sloan, 2005) beg the question, “Is life stress more traumatic than traumatic stress?” in response to findings in which participants who reported not having experienced a “traumatic stressor” consistent with DSM-IV criteria A1 reported higher levels of PTSD symptomatology than participants who had experienced an A1 trauma. Results like these force researchers to question PTSD as an appropriate diagnosis. Consistent with findings suggesting that parents of children with cancer on active treatment report higher levels of PTSS than those whose children have completed treatment (Phipps et al., 2005), perhaps parents are reporting on concurrent life stress associated with their child's cancer treatment rather than PTSS.

Recent research has examined the relative impact of experiencing multiple traumatic stressors compared to a single stressor. Copeland et al. (Copeland, Keeler, Angold, & Costello, 2007) noted that in a large community sample of children and adolescents, although stressors meeting PTSD A1 criteria are quite common, individuals are unlikely to develop PTSS unless they have experienced more than one such stressor. Such findings might be framed to support a type of “two-hit hypothesis,” whereby the initial trauma may not be sufficient to lead to disorder, but produces vulnerability such that the effect of a second trauma will be greater. From this perspective, the initial cancer diagnosis of one's child may not be traumatic enough to lead to PTSD, but the ongoing treatment and stressors related to it may be more likely to lead to PTSS. Further, the initial diagnosis and treatment of one's child may leave a parent with a sensitization such that an additional stressor, such as a relapse or recurrent disease, would be more traumatic and even more likely to lead to trauma-related symptoms. Interestingly, in our review of the current literature, relapse is rarely mentioned, and only as an exclusion criteria (Best, Streisand, Catania, & Kazak, 2001; Kazak et al., 2004; Manne et al., 1998; Manne, DuHamel, & Redd, 2000). To our knowledge, no studies to date have included the experience of a child's relapse as a predictor of parental PTSS.

In reviewing the available studies of PTSS in parents of children with cancer, the lack of control groups is striking, with only three studies including parents of healthy children as comparisons (Barakat et al., 1997; Brown et al., 2003; Pelcovitz et al., 1996), all of which reported higher symptom levels in the cancer group. Most studies focus on within cancer group comparisons, or use historical control data. However, there is a paucity of control data on the common measures of PTSS, such as the IES and IES-R used here. The study of Barakat et al. (1997) was the only to provide a large community sample of parents of healthy children on the IES, and subsequent studies have often used this as a benchmark (Phipps et al., 2005). Reliance on such historical control data is problematic, particularly now that it is over a decade old. Thus, the current study includes a healthy comparison group, using an acquaintance control methodology.

The current study was designed to further examine levels of PTSS in parents of children with cancer. Differences in self-reported PTSS of parents were examined as a function of time elapsed since diagnosis by including discrete groups of patients categorized by length of time since diagnosis. Although time from diagnosis and treatment status (on vs. off therapy) overlap, they are also considered to be distinct factors influencing stress symptoms. Thus, parental PTSS was also explored as a function of whether or not the child was in active treatment. Additionally, to explore the possibility that a second traumatic stressor increases the likelihood of developing PTSS, we examined the impact of a child's relapse. The current study also extends prior research by including a comparison group of parents with healthy children obtained through an acquaintance control methodology. We hypothesized that parents of recently diagnosed cancer patients would report higher levels of PTSS than parents of long-term survivors, and, similarly, that parents of children on active treatment would endorse higher symptom levels than those of children off treatment. Further, we hypothesized that parents of pediatric cancer patients would report higher levels of PTSS than the comparison parents generally, but that this difference would be greater in the parents of children recently diagnosed and in active treatment. Finally, we hypothesized that parents of childhood cancer patients who have experienced a relapse or recurrence would report higher levels of PTSS than parents whose children had not experienced a relapse.

Methods

Participants

Cancer Group

Parents were recruited from outpatient clinics at a major pediatric oncology center as part of a larger study in which their children served as participants as well. Eligible parents had children between the ages of 7 and 18 with a primary diagnosis of malignancy who were English speaking and had no known cognitive deficits. Parents of patients who were at least 1 month from diagnosis were eligible, with no upper limit to time elapsed since diagnosis. Sampling procedures were designed to obtain a broad cross-section of patients in terms of diagnosis and time-elapsed since diagnosis. Patients were recruited in order to obtain relatively equal numbers in four groups according to time since initial diagnosis. Group 1 included parents of children from 1 to 6 months since diagnosis. Group 2 was composed of parents whose children were between 6 and 18 months of receiving their diagnosis. The children of the parents in group 3 were at least 18 months, but <5 years, from diagnosis. Group 4 included parents of survivors, >5 years from their diagnosis. Out of the 339 families we approached, 249 (73%) were initially enrolled. Of these, 35 returned incomplete information and 15 withdrew before completing all materials, leaving a sample of 199 cancer patients and their parents. Of these, 71 patients (36%) were still in active treatment and 128 (64%) were off treatment at the time of their participation in the study. The diagnostic breakdown of the children is generally representative of the population served by the institution, and may be seen in Table I. A total of 30 patients (15.1%) had experienced a relapse. There were no differences in age, gender, race, diagnostic group, or time since diagnosis between the patients of parents who elected to participate and those who declined.

Table I.

Demographic and Medical Variables

	On-Tx Cancer	Off-Tx Cancer	Control
Characteristic	(n = 71)	(n = 128)	(n = 108)
Age [mean (SD)]	11.17 (3.5)	12.95 (3.2)	12.38 (3.0)
Gender [n (%)]
Male	42 (59.2)	62 (48.4)	44 (40.7)
Female	29 (40.8)	66 (51.6)	64 (59.3)
Race [n (%)]
White	52 (73.2)	100 (78.1)	99 (91.7)
Black	17 (23.9)	22 (17.2)	6 (5.6)
Other	2 (2.8)	6 (4.7)	3 (2.7)
SESa [n (%)]
I and II	32 (45.1)	66 (52.0)	79 (73.8)
III	23 (32.4)	30 (23.6)	18 (16.8)
IV and V	16 (22.5)	31 (24.4)	10 (9.3)
Parent education [n (%)]
High school or less	27 (38.0)	49 (39.2)	17 (16.2)
Some college	20 (28.2)	23 (18.9)	27 (25.7)
College graduate	17 (23.9)	31 (24.8)	46 (43.8)
Graduate school	7 (9.9)	23 (18.4)	15 (14.2)
Parent participantb [n (%)]
Mother	60 (84.5)	100 (78.1)	98 (90.7)
Father	8 (11.3)	25 (19.5)	9 (8.3)
Otherc	1(1.4)	3 (2.3)	1 (0.9)
Diagnostic category [n (%)]
ALLd	22 (31.0)	25 (19.5)
Other leukemia	6 (8.5)	5 (3.9)
HD/NHLe	10 (14.1)	20 (15.6)
Solid tumor	21 (29.6)	46 (35.9)
Brain tumor	12 (16.9)	32 (25.0)
Time since diagnosis/(Traumaf) [n (%)]
≥ 1–6 months	40 (56.3)	12 (9.4)	19(19.2)
6–18 months	16 (22.5)	31 (24.2)	23 (23.2)
18 months to < 5 years	15 (21.1)	32 (25.0)	35 (35.4)
>5 years	—	53 (41.4)	22 (22.2)
Relapse [n (%)]	12 (16.9)	18 (14.0)

^aSES per Barratt Simplified Measure of Social Status (Barratt, 2006).

^bTwo cancer patients did not have a parent participate.

^cStepparent or grandparent as custodial guardian.

^dAcute lymphocytic leukemia.

^eHodgkin's disease/non-Hodgkin's lymphoma.

^fTrauma or stressor reported by control parent.

Control Group

Participants in the control group were recruited through an “acquaintance control” methodology. Families of the cancer patients recruited to the study were asked to identify up to three friends from their home neighborhood or school who were within ± 2 years of the age of the patient. Data from those agreeing to participate were obtained through the mail, with telephone assistance where necessary. Using this procedure, 367 potential control families were identified. Of these 367 potential control children and their parents, eight refused participation, five proved ineligible, and 57 had insufficient or incorrect contact information. Survey packets were sent to the remaining 297 potential control families and complete information was received back from 108 (36%) of them.

Table I displays the medical and demographic information for the children of the parents in both groups. Although the acquaintance control method was used in an attempt to obtain a control group similar to the cancer groups on demographic characteristics, a few significant differences among the cancer and control groups emerged. The children in the two groups did not differ significantly by gender or age, but differed by race, χ²(2, 305) = 11.72, p =.003, with significantly more African American children in the cancer group than in the control group. The groups also differed significantly in socioeconomic status (SES), χ²(2, 304) = 13.65, p =.001, with more SES group I and II children, i.e., higher SES, using the Barratt Simplified Measure of Social Status (Barratt, 2006), an updated adaptation of the widely used Hollingshead index (Hollingshead, 1975), and significantly fewer SES group IV and V children in the healthy control group than in the cancer group.

Measure

Impact of Events Scale, Revised (IES-R)

The original IES was published in 1979 as a short self-report measure assessing aspects of PTSD symptoms in response to specific traumatic events (Horowitz, Wilner, & Alvarez, 1979). The 22-item IES-R measures PTSS in response to a traumatic event that is specified in the instructions (Weiss & Marmar, 1997). It includes three subscales, Intrusion, Avoidance, and Hyperarousal, corresponding to DSM-IV cluster B, C, and D criteria for PTSD, respectively. The IES and IES-R have been used in studies of childhood cancer survivors and their parents (Barakat et al., 1997; Kazak et al., 1997). The internal reliabilities of the Intrusion, Avoidance, and Hyperarousal scales have been reported as.91,.84, and.90, respectively (Weiss & Marmar, 1997). In the current study, parents in the cancer group responded to items in reference to their child's cancer as the stressor. Parents in the control group identified what they consider to be the most major stressor they have experienced, and responded to items based on it. The IES-R total score was found to have high internal consistency for the total sample (α =.948), as well as for the Intrusion subscale (cluster B; α =.899), the Avoidance subscale (cluster C; α =.869), and the Hyperarousal subscale (cluster D; α =.871).

Stressors that parents of the healthy control children reported in reference to the IES-R fell into five general categories. Of the 108 control group parents, 35 (32.4%) indicated death of a relative, friend, or pet; 20 (18.5%) indicated diagnosis of a major illness as their most major stressor; 20 (18.5%) reported interpersonal loss such as divorce or moving away from family; 11 (10.2%) stated that an accident or emergency room visit was the most traumatic stressor they had experienced; 16 (14.8%) indicated another less common stressor; and 6 (5.5%) did not indicate a specific stressor. Time elapsed since the stressor was categorized in the same manner as time from diagnosis in the cancer group, with relatively equal distribution across the four groups, a breakdown comparable to the cancer group as a whole (Table I).

Procedure

Questionnaire packets were administered to cancer group parents during a visit to the hospital after informed consent was obtained according to institutional guidelines. The same packets were mailed to participants in the control group after informed consent was obtained over the phone. One parent of each child participant completed the IES-R. In cases in which both parents were available, they were asked to select which parent would complete the measure. Of the total sample, 258 (84%) mothers, 42 (13.7%) fathers, and 5 (1.6%) other guardians such as an aunt or grandparent completed the measure.

Results

Preliminary Analyses

Within the cancer group, there were no differences in parent-reported PTSS by child's diagnostic category. However, as predicted, differences were observed by time since diagnosis and treatment status, that is, whether or not the parent's child was on active treatment for cancer, and by relapse status. Therefore, subsequent analyses comparing parents of children with cancer to parents of healthy children accounted for these differences, utilizing subgroups within the cancer sample.

There were no significant differences in reported levels of PTSS between mothers and other caretakers, and analyses from the entire sample and sample limited to mothers was comparable. Therefore, data from all caretakers were combined, and parental informant was included as a covariate in all analyses.

Differences in Parent PTSS by Time Since Child's Diagnosis

A significant negative correlation was observed between time since child's diagnosis and parent's reported PTSS as measured by the total score on the IES-R (r = −.28, p <.001). However, examination of the scatterplot suggests that this relationship may not be best characterized as a linear one. Visual inspection of the scatterplot indicates a slight increasing trend during the first 18 months after diagnosis, followed by a declining trend thereafter, particularly beyond 5 years postdiagnosis.

In order to better understand the effects of time since diagnosis on parent-reported PTSS, a series of one-way analyses of covariance (ANCOVAs) were conducted with four levels based on time elapsed since the child's diagnosis of cancer (1–6 months; 6–18 months; 18 months to 5 years; >5 years), with a fifth level comprising the healthy comparison parents. These ANCOVAs were run on the IES-R total score and the three IES-R subscales, controlling statistically for race, SES, and informant (i.e., parent completing the measure). Means on the subscales and the total score for the five groups are presented in Table II. SES was the only significant covariate in these analyses. On the Avoidance and Hyperarousal subscales and on the total score, as SES increased (i.e., with greater education, higher level occupations), the level of self-reported symptoms decreased.

Table II.

Main Effect of Time Since Diagnosis on Parent Self-Report on IES-R

	1–6 months	6–18 months	18 months –5 years	> 5 years	Control
	Mean (SD)	Mean (SD)	Mean (SD)	Mean (SD)	Mean (SD)	F	Effect size f
Intrusion	8.19 (5.7)a	9.42 (6.2)a	9.04 (6.4)a	5.46 (5.9)b	9.64 (6.7)a	4.47*	.24
Avoidance	7.48 (6.6)a	8.13 (6.2)a	7.48 (6.5)a	4.20 (5.7)b	7.98 (6.5)a	3.87*	.23
Hyperarousal	6.56 (5.3)a	7.49 (6.2)a	6.65 (6.3)a	3.44 (5.0)b	6.24 (6.3)a	3.57*	.22
Total	22.23 (15.6)a	25.04 (17.3)a	23.17 (17.8)a	13.10 (15.6)b	23.86 (17.6)a	4.66*	.26

Different subscripts indicate means that are significantly different.

*p <.01.

IES-R total scores differed significantly as a function of these time since diagnosis groupings, F(4, 281) = 4.66, p <.01, effect size f =.22. Post hoc analyses revealed that parents of children who were >5 years since their cancer diagnosis reported the lowest levels of PTSS and differed significantly from all other groups including controls. None of the other groups, including controls, differed significantly from each other. A similar pattern was found on all three subscales as well: Intrusion, F(4, 281) = 4.47, p <.01, effect size f =.24, Avoidance, F(4, 281) = 3.87, p <.01, effect size f =.23, and Hyperarousal, F(4, 281) = 3.57, p <.01, effect size f =.22, and on all subscales, the > 5 years from diagnosis group differed significantly from all other groups, who did not differ from each other. Descriptively, the same pattern was observed on all IES-R subscales and total score, where symptom scores show a small, nonsignificant increase in the 6-month to 18-month postdiagnosis group relative to the 1–6 month group, followed by a small, nonsignificant decrease in the 18-month to 5-year postdiagnosis group, and then a statistically significant decline in the >5 years postdiagnosis group. This is consistent with the correlation findings and the pattern visually observed in the scatterplot previously described.

A similar one-way ANOVA with time since stressor and total IES-R score was run in the control group to determine if PTSS levels differed as a function of time elapsed since the reported stressor. There were no significant differences in PTSS by time since stressor, F(3, 91) =.41, p =.75

Differences in Parent PTSS by Child's Health/Treatment Status

Differences in IES-R scores between parents of children with cancer on and off treatment, and parents of healthy children were tested using one-way ANCOVAs controlling for race, SES, and informant. Means on the subscales and the total score for the three health status groups (on treatment, off treatment, and healthy control) are presented in Table III. SES was a significant covariate in three of these analyses. Specifically, for the Avoidance and Hyperarousal subscales and the total IES-R score, as SES increased, the level of self-reported symptoms decreased.

Table III.

Main Effect of Health Status on Parent Self-Report on IES-R

	On Tx Cancer	Off Tx Cancer	Control
	Mean (SD)	Mean (SD)	Mean (SD)	F	Effect size f
Intrusion	9.34 (6.4)a	7.20 (6.0)b	9.64 (6.7)a	5.47**	.20
Avoidance	8.18 (6.7)a	5.98 (6.2)b	7.98 (6.5)a	4.40*	.18
Hyperarousal	7.43 (6.0)a	5.17 (5.7)b	6.24 (6.3)a	3.47*	.15
Total	24.94 (17.3)a	18.34 (16.6)b	23.86 (17.6)a	5.16**	.19

Different subscripts indicate means that are significantly different.

*p <.05; ** p <.01.

Health status had a significant effect on the IES-R total score, with parents of children on active treatment for cancer and parents of healthy control children reporting similar levels of PTSS overall, and parents of children diagnosed with cancer but off active treatment reporting significantly lower levels of symptoms F(2, 281) = 5.16, p <.01, effect size f =.19. There was a similar significant effect of health status on the Intrusion F(2, 281) = 5.47, p <.01, f =.20, Avoidance F(2, 281) = 4.40, p <.05, f =.18, and Hyperarousal subscales F(2, 281) = 3.47, p <.05, f =.15. Again, parents of healthy children and of children on active cancer treatment reported levels of symptoms similar to each other, but significantly higher than those reported by parents of children no longer on treatment.

Differences in Parent PTSS by Child's Experience of Relapse or Recurrence

A similar analytic approach was used to examine the effect of relapse history. Parents of children with cancer were categorized into three groups: those on versus off therapy without a history of relapse, and those with any history of relapse. Prior to creating these categories, it was determined that there were no differences in PTSS reported by parents of children with a history of relapse either on or off therapy. Due to this, and also because these groups were quite small, they were combined for the following analyses. Again, one-way ANCOVAs were run on IES-R scales correcting for race, SES, and informant. Descriptive means are presented in Table IV. SES was again a significant covariate in three of these analyses (Avoidance, Hyperarousal, and Total).

Table IV.

Main Effect of Relapse Status on Parent Self-Report on IES-R

	No Relapse, Off Tx	No Relapse, On Tx	Relapse	Control
	Mean (SD)	Mean (SD)	Mean (SD)	Mean (SD)	F	Effect size f
Intrusion	6.66 (5.7)a	8.95 (6.2)b	11.10 (6.9)b	9.56 (6.7)b	5.94*	.25
Avoidance	5.26 (5.7)a	7.88 (6.4) b	10.14 (7.2) b	7.95 (6.5) b	6.29**	.26
Hyperarousal	4.31 (5.0)a	7.23 (6.0) b	10.03 (6.8)c	6.09 (6.1) b	8.14**	.29
Total	16.23 (15.2)a	24.05 (16.6)b	31.28 (19.6)c	23.59 (17.5)b	7.84**	.29

Different subscripts indicate means that are significantly different.

*p <.01; **p <.001.

Relapse status had a significant effect on the IES-R total score F(3, 281) = 7.84, p <.001, f =.29, with parents of children who have experienced a relapse reporting the highest symptom levels, almost double that of parents of children with no history of relapse and off treatment. Parents of children on treatment with no relapse history and parents of healthy children reported similar, intermediate symptoms levels. Similar significant effects of relapse status were seen on all IES-R subscales, with parents of children having experienced relapse reported levels significantly higher than all other groups (Table IV).

PTSD “Cases” by Child's Health Status and Child's Relapse Status

Although the assessment approach used in the current study does not allow for true diagnostic evaluation of the presence or absence of PTSD, we classified likely “cases” of PTSD using the responses on the IES-R. We applied an approach similar to that used in a recent investigation by Schwartz and Drotar (2006). Participants who indicated a severity score of 3 or higher on each item representing a symptom from Cluster B (IES-R Intrusion subscale), Cluster C (IES-R Avoidance subscale), or Cluster D (IES-R Hyperarousal subscale) were judged as having endorsed that symptom. Those participants that endorsed one or more symptoms from cluster B, three or more from cluster C, and two or more from cluster D were classified as probable “cases” of PTSD. Criteria E is assumed as the IES-R asks the parent to respond based on his or her experiences over the past month. This approached yielded 34 such cases (11.6%). Chi-square analysis revealed no differences in cases among the three groups of parents based on treatment status: those of healthy control children (9.8%), those of children with cancer currently on treatment (13.0%), and those of children with cancer not currently on treatment (12.4%), χ² (2, 292) =.534, p = ns. However, relapse status emerged as a significant predictor of cases, χ² (3, 292) = 7.974, p =.047. Parents of children who experienced a relapse were more likely to be identified as a case (27.6%) than parents of children who had not experienced a relapse and were currently on (10.3%) or off treatment (9.6%), or parents of healthy children (9.8%).

Discussion

Contrary to previous findings and the current hypothesis, we failed to identify increased PTSS in parents of children with cancer. Our results indicate that parents of children in active treatment for cancer report levels of PTSS similar to parents of healthy children, with both of these groups reporting significantly higher PTSS than parents of long-term cancer survivors. Also contrary to the existing literature, we did not find any differences in the number of likely cases of PTSD among the three groups of parents, those of children on active treatment, those of survivors, and those of healthy children. Consistent with the results of Phipps et al. (2005), the current findings indicate that PTSS of parents of children with cancer differs as a function of time elapsed since diagnosis. In general, PTSS decreases as time since diagnosis increases. However, this pattern does not appear to begin until 1–2 years postdiagnosis, and only parents of children >5 years from diagnosis show significantly lower levels of PTSS. The findings regarding on versus off treatment and time from diagnosis suggest that the IES-R survey items might be largely measuring anxiety symptoms reflecting parents’ response to concurrent stressors associated with pediatric cancer treatment, rather than truly posttraumatic symptomatology. Together, the current results suggest that simply having a child with cancer does not lead to increased PTSS in parents, a finding which is at odds with a preponderance of the existing literature. However, a new finding from the current study suggests that such parents may be left vulnerable to a ‘second hit,’ and that experiencing a second major cancer-related event, i.e., a relapse or recurrence, does lead to a significant increase in PTSS.

Because the current data appears inconsistent with previous findings in this area, comparisons were made to descriptive data from previous studies. There has been a paucity of control data on the IES/IES-R, with only one prior study (Barakat et al., 1997) using a community control comparison on the IES. When comparing the mean PTSS scores obtained from mothers on the original IES in the Barakat et al. study to our mean IES-R scores, it appears that the parents of survivors in our study reported relatively similar levels, and were only slightly less distressed than their sample. However, a much greater discrepancy is noted in the comparison of scores reported by the two control groups. The comparison sample in the current study reported greater symptoms of intrusion and avoidance, roughly double that of parents of healthy children in the study of Barakat et al. (1997).

We explored differences in the methodology between our study and the Barakat et al. (1997) study in an attempt to explain the observed differences. The patients in our cancer sample were neither “less sick” nor off of treatment longer than those included in the sample of Barakat et al. In both studies, there were significant demographic differences between cancer and comparison groups, but these differences appear to be more pronounced in the Barakat study. For example, the control group parents were more highly educated than parents in the cancer group. However, whereas 14% of our comparison parents attended graduate school, a much larger percentage (44%) of Barakat's comparison parents received graduate education. This may be crucial given the significant association between SES and PTSS in the current study. The participation rates reported were similar in both studies, and the control participants completed the study measures at home in both investigations. In a more recent study that used the IES-R to identify levels of PTSS in parents of pediatric cancer survivors (Kazak et al., 2004), mean scores reported by both mothers (Total = 28.2) and fathers (Total = 24.2) were much greater than those reported by parents of survivors in the current study.

In regards to parents of patients in active treatment, a study which utilized the IES-R reported scores markedly higher than those obtained from parents of children on active treatment in the current study (mothers, Total = 43.6; fathers, Total = 32.6; Kazak et al., 2005). In contrast, the current findings are nearly identical to those reported by parents of recently diagnosed children in Phipps et al. (2005; Total = 24.8). It is difficult to rectify the discrepant findings between the current investigation and Kazak et al. (2005), given that the populations studied and methods used were similar. Perhaps some of this could be attributed to site effects, with the current findings representing the lower end of the distress continuum and the Kazak et al. (2005) the higher end. Site effects are somewhat obviated in a recent multi-site study reporting on the natural history of adjustment in mothers of children newly diagnosed with cancer (Dolgin et al., 2007). In that study, IES-R scores at study entry (32.0, a mean of two months from diagnosis) were intermediate between those of the current study and those of Kazak et al. (2005). However, in the Dolgin et al. (2007) study, IES-R scores 6 months poststudy entry (27.2), when most patients were still in active treatment, had declined significantly, and were much more comparable to those of the current study.

The finding that parents of long-term cancer survivors reported lower levels of PTSS than did control parents is curious and difficult to explain, but raises some interesting speculations. Is it possible that the defenses of parents whose children are diagnosed with cancer are strongly activated during the early acute phase of diagnosis and treatment as a means of managing high levels of threat, and then stay activated beyond the completion of treatment? In a similar vein, one might apply a stress-inoculation model to understand this finding. Perhaps parents who learn to cope reasonably well with the early challenges of diagnosis and demands of treatment are in some ways better equipped to handle other life stresses as the threats of the acute phase of treatment begin to subside. Anecdotally, we have heard several parents paraphrasing Nietzsche, “that which does not kill me makes me stronger” (Ridley & Norman, 2003), to suggest that, indeed, their experiences with childhood cancer have left them better prepared to face life challenges. Along these lines, Barakat and colleagues (Barakat, Alderfer, & Kazak, 2006) reported that parents of childhood cancer survivors described posttraumatic growth following their child's successful treatment, including improvements in how they think about life and how they treat other people. This is also consistent with studies suggesting the development of greater strengths of character following recovery from serious illness (Peterson, Park, & Seligman, 2006). Alternately, one might also infer that parents of off treatment survivors currently rate themselves as less distressed in comparison to the period of their child's treatment, i.e., there is a frame shift in their reference as they rate their symptoms. These remain speculations, but raise interesting questions for further research.

The current findings regarding relapse history have not been reported previously. Parents of children who had suffered a relapse report higher levels of PTSS than parents of children who had not relapsed, regardless of treatment status. Parents of relapsed patients also show higher levels of likely PTSD cases, nearly three times higher than those without a relapse history. Clearly, a second cancer-related stressor event, such as relapse, produces a much higher risk of PTSS. It is curious that relapse status has not been examined in prior studies, many of which have included relapse as an exclusionary criterion. The current findings are consistent with literature which indicates that PTSS increases with multiple traumas and that a subsequent trauma carries a heightened risk of PTSD (Copeland et al., 2007; Kangas, Henry, & Bryant, 2002). This suggests that the diagnosis of cancer in a child, even when it does not lead to increased symptoms of PTSS, may leave a parent sensitized, and thus at increased sensitivity to subsequent stressors. From this perspective, the event of relapse may be experienced as a second hit in a two-stage process (Knudson, 2001); the first hit (diagnosis) produces vulnerability, and primes the organism such that the second hit (relapse) is more likely to lead to disorder. By the same token, parents who have experienced earlier traumatic events prior to the initial diagnosis of their child are likely to be at higher risk, and likewise, parents of survivors who experience subsequent noncancer-related traumas will be at higher risk of experiencing PTSS.

The current study includes several limitations. First, the design included only self-report survey measures of PTSS and no diagnostic assessment of PTSD. In the absence of diagnostic interview data, we believe our approach to identification of potential ‘cases’ of PTSD in the patient population is a reasonable approximation, and has a strong precedent in the literature (Schwartz & Drotar, 2006; Weathers, Litz, Herman, Juska, & Keane, 1993). An additional limitation of our design is that the cancer and comparison groups completed the PTSS measure in reference to different stressful events. Whereas the diagnosis of a life-threatening illness in a child is considered an event of sufficient magnitude to meet criterion A1 from the DSM-IV, few of the events reported by the control parents appeared to meet this criteria. Yet, if this were to contribute to group differences, one might expect that it would contribute to lower levels of PTSS in the control group, rather than vice-versa. There is also recent evidence to suggest that commonly experienced stress events that do not meet DSM-IV A1 criteria may produce as much, or even more, PTSS as traumatic events consistent with A1 criteria, i.e., that commonly experienced life stressors may be more “traumatic” than traumatic stress (Gold et al., 2005). This raises questions about the validity of the A1 criteria, and more generally, the utility of a PTSD model for promoting understanding of human response to trauma. Although such a discussion is beyond the scope of this paper, a number of recent papers have addressed this controversy (Coyne & Thompson, 2007; Jones & Wessely, 2007; McHugh & Treisman, 2007).

Additional limitations include our use of a one time cross-sectional survey to address the effect of time since diagnosis, recognizing that a longitudinal design is required to make any definitive conclusions regarding the effects of time. Our decision to obtain data from only one parent, which was based on the trend in our institution that typically only one parent is available during children's clinic visits, represents another limitation. However, there were no significant differences in reported levels of PTSS between mothers and other caretakers, analyses from the entire sample and sample limited to mothers was comparable, and parental informant was included as a covariate in all analyses.

The final limitation of our study is that it was conducted at a single site, raising the question of whether these findings are more generalizable, or perhaps are reflective of some unique aspects of a single site. The results highlight the salience of this limitation, as the current findings stand out as somewhat discrepant from much of the existing literature. If our findings are indeed generalizable to the larger population of parents of children with cancer, it would not appear that PTSS is a major issue for this population, except for the small subset of parents whose children have experienced relapse. However, the discrepancy between our current findings and some of the existing literature highlights the need for additional multi-site studies, which should remain a priority for future research.