Abstract
Purpose
This cross-sectional study compared breastfeeding outcomes among childhood cancer survivors to those of women in the general population and evaluated whether breastfeeding is adversely affected by cancer treatment or endocrine-related late effects.
Methods
A self-reported survey ascertained breastfeeding practices and incorporated items from the questionnaires used in the Infant Feeding Practices Study II (IFPS II) to allow comparison with the general population. Among 710 eligible survivors, 472 (66%) responded. The participants were predominantly non-Hispanic White (84%), married (73%), and had some college or less (60%). The mean maternal age at the time of birth of the first child after cancer treatment was 24 years (SD 24.3 ± 4.8).
Results
Fewer survivors planned to breastfeed than did IFPS II controls (67% vs. 82%, P < .0001), and fewer survivors initiated breastfeeding (66% vs. 85%, P < .0001). The median breastfeeding duration was shorter among survivors, with early undesired weaning occurring sooner in the survivor group (1.4 months, interquartile range (IQR) 0.5–3.5 months) than in the IFPS II group (2.7 months, IQR 0.9–5.4 months). A higher proportion of survivors reported an unfavorable breastfeeding experience (19% vs. 7.5%, P < .0001) and early, undesired weaning (57.5%, 95% CI 51–64) than did IFPS II participants (45.2%, 95% CI 44–47, P = .0164). Among survivors who expressed intention and choose to breastfeed, 46% endorsed disrupted lactation related to physiologic problems with high risk in those overweight/obese.
Conclusions
Survivors are at risk of negative breastfeeding experiences; however, lactation outcomes were not significantly associated with cancer diagnosis, treatments, or endocrine complications.
Implications for Cancer Survivors
Prior research has not examined the association of cancer treatments and clinically validated late effects with lactation outcomes in a clinically diverse childhood cancer survivor cohort. Findings from this study suggest that childhood cancer survivors, especially those who are overweight/obese, are at risk of having negative breastfeeding experiences. Early undesired weaning, physiologic problems related to lactation and misconceptions about breastfeeding, especially fears of passing on cancer through breastmilk, highlight the need for counseling and specialized support to optimize lactation outcomes in this vulnerable population.
Keywords: Breastfeeding, Lactation, Childhood cancer survivors, Cancer treatment, Late effects
Introduction
Advances in pediatric cancer treatment have resulted in a growing population of adult survivors, many of whom experience treatment-related adverse health outcomes. Current estimates predict >500,000 survivors of childhood cancer living in the United States by 2020. As of January 1, 2011, more than 70,000 female childhood cancer survivors of childbearing age survived a minimum of 5 years post treatment [1]. Compared to men treated for childhood cancer, female childhood cancer survivors have a higher risk of diminished health status [2, 3], however, most reach reproductive age and many desire biological parenthood [4]. Prior data on breastfeeding indicates that childhood cancer treatments such as radiation and surgery may result in lactation failure related to direct injury to the mammary glands or anterior pituitary dysfunction [5–7]. Among childhood cancer survivors, growth hormone (GH) deficiency is the most common anterior pituitary deficit observed following cranial radiation [8]. This and other late effects such as hypothyroidism, diabetes, and obesity potentially impact successful lactation [9–11].
Our study aimed to compare breastfeeding outcomes among mothers surviving childhood cancer to mothers in the general population and to evaluate if breastfeeding is adversely affected by cancer treatment or endocrine-related late effects. We hypothesized that female survivors of childhood cancer would have higher frequencies of physiologic-related lactation difficulties than healthy women due to cancer or treatment-related complications.
Methods
In this cross-sectional study, a survey was mailed to mothers to assess their experiences with childbirth and infant feeding practices related to their first child born following treatment for childhood cancer. The protocol was approved by the St. Jude Children’s Research Hospital (SJCRH) Institutional Review Board and the completion/return of the survey implied consent to participate in the study, thereby granting a waiver for a signed consent form. Eligible female survivors of childhood cancer were identified among those returning for annual follow-up in the SJCRH After Completion of Therapy (ACT) Clinic or participating in the St. Jude Lifetime Cohort Study (SJLIFE). Following active cancer treatment, patients are eligible for transfer to the ACT Clinic. Survivors eligible for follow-up in the ACT Clinic must be cancer-free for at least two years post treatment completion and at least five years post diagnosis. ACT patients are evaluated annually until they are 18 years of age and 10 years after diagnosis. SJLIFE is a retrospective cohort study with prospective follow-up and ongoing data accrual. The detailed methods for ascertainment, recruitment and evaluation of this cohort of cancer survivors have been reported previously [12–14]. Specific eligibility criteria for inclusion in the present study included being female, ≥18 years of age, report of a live birth, and ability to read and understand English. Study questionnaires were completed at one time point by participants utilizing a web-based entry or by scannable paper forms. Survivors were queried regarding prenatal plans for infant feeding, initiation and duration of breastfeeding, and reasons for weaning or choosing not to breastfeed specific to their first child post cancer treatment. Additionally, some questions related specifically to cancer treatment and experiences were included (Table 1).
Table 1.
Domains assessed in the lactation outcomes survey
| Domains | Sample questions |
|---|---|
| Intention | Before the birth of your first child following childhood cancer treatment, what method did you PLAN to use to feed your baby? |
| Initiation | Did you ever breastfeed, try to breastfeed, or pump milk for your baby, either in the hospital or birth center or after you went home? |
| Duration | How old was your baby when you completely stopped breastfeeding or pumping milk? |
| Health status | Did you have any breast conditions (scarring, implants, uneven breast size surgeries) before or during this pregnancy? |
| Before delivering your first child after cancer treatment, did anyone tell you that you might not be able to breastfeed due to your cancer treatment? | |
| Did you have any birth complications (breech presentation, placental problems, maternal heart problems, etc.)? | |
| Did you take any medications or herbal remedies to boost milk production? Please comment on any other breastfeeding/pregnancy experiences or difficulties. |
|
| Perceptions and preferences about breastfeeding | How important was it to you to breastfeed your baby? How confident were you that you would be able to breastfeed as long as you planned? Did anyone tell you that you might not be able to breastfeed due to your cancer treatment? |
To determine the prevalence of early, undesired weaning and disrupted lactation associated with physiologic problems among childhood cancer survivors, we utilized a similar methodology to that reported by Stuebe, et al. in the Infant Feeding Practices Study II (IFPS II). IFPS II, conducted by the Food and Drug Administration (FDA) and the Centers for Disease Control and Prevention (CDC), was a longitudinal study that enrolled 4902 women and followed approximately 2,000 mother -infant pairs from the third trimester of pregnancy throughout the first year of life to study a variety of infant feeding practices [15]. Lactation outcomes of interest were compared between survivors and IFPS II who 1) completed the survey (n=4902); 2) reported initiation of breastfeeding (n=2572); and 3) decided not to breastfeed (n=461) (Table 4). Survivors (n=243) and IFPS II participants (n=2335) who expressed intentions to breastfeed and initiated breastfeeding were used in the analysis for early, undesired weaning and disrupted lactation. For the purposes of our comparison, we used the IFPS responses from the questionnaires specifically related to prenatal, neonatal, and infant feeding.
Participants were classified based on breastfeeding and/or pumping milk attempts. We determined “intention to breastfeed” by asking how old each mother anticipated their baby would be when she stopped breastfeeding or pumping milk. “Early weaning” was then defined as less time spent breastfeeding than intended by the mother in her prenatal plan. For the purposes of this study, “expected weaning” was defined as ending breastfeeding at a time equal to, or greater than the response to the prenatal question “How old do you think your baby will be when you completely stop breastfeeding?” The question “Did you breastfeed as long as you wanted to?” was used to determine “undesired weaning.” Analytic categories included 1) Expected/early desired weaning and 2) Disrupted lactation (Figure 1).
Fig. 1.
Flow diagram of the study cohort
Boxes in grey/black indicate groups used in analysis of comparison of Participants (N=472) and nonparticipants (N=238) (Table 2)
Boxes in blue/white indicate groups used in analysis of comparison of cancer survivors who did (N=304) and did not breastfeed (N=154) (Table 3)
Boxes in black/white indicate groups used in analysis of comparison of expected (N=63)/early desired weaning (N=39) and disrupted lactation (N=124) (Table 5)
Mothers were also asked to respond to a list of 30 reasons for choosing to discontinue breastfeeding, using a Likert scale from “1–Not important at all” to “4–Very important.” These responses were dichotomized into two categories of “Not Important” (“Not at all important” or “Not very important”) and “Important” (“Somewhat important” or “very important”). To assess the prevalence of lactation problems secondary to physiologic causes, we analyzed self-reported reasons for early, undesired weaning. “Disrupted lactation” was defined as early, undesired weaning as well as discontinuing breastfeeding due to any one of eight physiologic reasons (such as difficulties with milk supply, sore, cracked and bleeding nipples, trouble with latching, baby not gaining enough weight, etc.). Disrupted lactation as defined by Stuebe in the IFPS II included endorsement of at least two of three physiologic problems as important reasons for stopping breastfeeding [15]. In the present study, we considered any of eight physiologic reasons to define disrupted lactation. Because depressive symptomology in the postpartum period influences infant feeding outcomes [16], we also analyzed self-reports of depression by asking “Did you suffer any problems following the birth of your baby?” Response options to this question specified postpartum depression and physiologic complications.
Pediatric cancer diagnosis and treatment information were abstracted from the medical records according to a structured protocol [17]. Diagnostic categories used for analysis included central nervous system (CNS) tumor, non-CNS solid malignancy, leukemia, and Hodgkin and non-Hodgkin lymphoma. Treatment modalities examined included brain, neck, chest, abdomen or pelvis radiation as well as surgeries involving the brain, breast and thyroid. Endocrine-related treatment complications were validated by medical record review and defined by the diagnosis of GH deficiency, diabetes mellitus, and/or hypothyroidism prior to and up to one year after the birth of the first child after completion of cancer treatment. In the absence of an established diagnosis and/or ongoing treatment of endocrinopathy, GH deficiency, hypothyroidism and diabetes mellitus were defined by insulin-like growth factor-1 (IGF-1) plasma values < –2 zs for age and sex, free T4 values < 0.9 ng/dL and fasting glucose ≥ 126 mg/dL, respectively [18]. Participant BMI was calculated at a date near the beginning of the pregnancy. We used diagnoses of overweight/obesity recorded within three years prior to the pregnancy or one year after the pregnancy for analysis, using criteria determined per Centers for Disease Control guidelines [19].
Data from the IFPS II were used to compare survivor reports of breastfeeding experiences to the general population. IFPS II recruited participants from a nationally distributed consumer opinion panel of more than 500,000 US households, enrolling 4,902 participants [20]. We included in our analysis some questions replicated in both studies, such as “How did you plan to feed your baby prior to birth?” and “How old was your baby when you stopped breastfeeding?”
Statistical Analysis
Descriptive statistics were used to summarize the demographic and treatment variables for survivors who did (participants) and did not respond (nonparticipants) to the survey and participants who did and did not breastfeed. The Chi-square test was used to compare categorical variables and the t-test was used to compare continuous variables between each of the paired groups. Chi-square test or t-test was also used to compare demographic and breastfeeding outcomes between survivors and mothers in the general population.
The univariate associations between demographic, clinical factors and disrupted lactation were examined by using Chi-square test for categorical variables and t-test for continuous variables. Variables with p-value less than 0.1 were included in a modified Poisson multivariable regression model [21] to estimate relative risk (RR) of disrupted lactation and 95% confidence intervals (CI). Analyses were conducted using Statistical Analysis System software (SAS 9.4, Cary NC).
Results
Surveys were completed by 472 (66%) of 710 eligible female cancer survivors. Table 2 summarizes the demographic and treatment characteristics of participants and nonparticipants. Participants were more likely to be non-Hispanic White, older at time of survey, older and a longer elapsed time from diagnosis at birth of first child after treatment, more likely to have treatment with neck or abdominal irradiation, and more likely to have diagnosis of hypothyroidism. Of interest, when asked to rate the level of concern about passing cancer on to the baby through breast milk, 26.8% of survivors were “a little concerned” or “very concerned.”
Table 2.
Comparison of clinical characteristics of the childhood cancer survivor survey study participants and eligible nonparticipants
| Participants N=472 |
Nonparticipants N=238 |
||
|---|---|---|---|
| Variables | N (%) | N (%) | P value |
| Race | |||
| Non-Hispanic White | 396 (83.9) | 174 (73.1) | <0.001 |
| Other | 76 (16.1) | 64 (26.9) | |
| Age at survey | |||
| Mean ± SD | 38.6 ± 8.0 | 36.7 ± 8.3 | 0.003 |
| Age at birth of first child after treatment | |||
| Mean ± SD | 24.3 ± 4.8 | 22.5 ± 4.4 | <0.001a |
| Time from diagnosis to birth of first child after treatment | |||
| Mean ± SD | 14.9 ± 7.1 | 13.4 ± 6.8 | 0.007a |
| Time since diagnosis to survey | |||
| Mean ± SD | 29.2 ± 8.7 | 27.6 ± 9.4 | 0.03 |
| Marital status | |||
| Married | 342 (72.5) | ||
| Not married | 130 (27.5) | ||
| Educational level | |||
| High school, some college or less | 283 (60.0) | ||
| College or postgraduate | 189 (40.0) | ||
| Household income | |||
| Unknown | 35 (7.4) | ||
| Under $40,000 | 262 (55.5) | ||
| $40,000 or more | 175 (37.1) | ||
| Employment status | |||
| Unknown | 11 (2.3) | ||
| Employed | 279 (59.1) | ||
| Unemployed | 182 (38.6) | ||
| Cancer diagnosis | |||
| Hodgkin/non-Hodgkin lymphoma | 99 (21.0) | 43 (18.1) | 0.72 |
| Leukemia | 172 (36.4) | 86 (36.1) | |
| CNS tumor | 27 (5.7) | 17 (7.1) | |
| Non-CNS solid tumor | 174 (36.9) | 92 (38.7) | |
| Brain radiation | |||
| No | 349 (73.9) | 182 (76.5) | 0.46 |
| Yes | 123 (26.1) | 56 (23.5) | |
| Neck radiation | |||
| No | 285 (60.4) | 167 (70.2) | 0.010 |
| Yes | 187 (39.6) | 71 (29.8) | |
| Chest radiation | |||
| No | 352 (74.6) | 193 (81.1) | 0.052 |
| Yes | 120 (25.4) | 45 (18.9) | |
| Abdomen radiation | |||
| No | 383 (81.1) | 209 (87.8) | 0.024 |
| Yes | 89 (18.9) | 29 (12.2) | |
| Neurosurgery | |||
| No | 432 (91.5) | 219 (92.0) | 0.82 |
| Yes | 40 (8.5) | 19 (8.0) | |
| Thyroidectomy | |||
| No | 465 (98.5) | 236 (99.2) | 0.73b |
| Yes | 7 (1.5) | 2 (0.8) | |
| Breast surgery | |||
| No | 439 (93.0) | 226 (95.0) | 0.31 |
| Yes | 33 (7.0) | 12 (5.0) | |
| Growth hormone deficiency | |||
| No | 463 (98.1) | 236 (99.2) | 0.35b |
| Yes | 9 (1.9) | 2 (0.8) | |
| Hypothyroidism | |||
| No | 420 (89.0) | 227 (95.4) | 0.005 |
| Yes | 52 (11.0) | 11 (4.6) | |
| Diabetes | |||
| No | 467 (98.9) | 235 (98.7) | 1.000b |
| Yes | 5 (1.1) | 3 (1.3) | |
| BMI | |||
| Normal/underweight | 293 (64.0) | ||
| Overweight/obese | 165 (36.0) | ||
T test
Fisher exact test
SD, standard deviation
Table 3 summarizes the clinical characteristics of survivors who did and did not breastfeed. Among participants, 294 (62%) reported a plan to breastfeed and 269 (57%) subsequently initiated breastfeeding (Figure 1). Compared to participants who did not attempt breastfeeding, women who chose to breastfeed were more likely to be non-Hispanic White, younger at time of survey, older and a longer elapsed time from birth of first child after treatment, married, have higher educational attainment and household income, be employed, and not be concerned about passing cancer to their babies through breastmilk. They did not differ by cancer treatment exposures or history of endocrine disorders.
Table 3.
Comparison of clinical characteristics of childhood cancer survivor participants who did and did not breastfeed
| Breastfed |
Did not breastfeed |
||
|---|---|---|---|
| Variable | N=304(%) | N=154 (%) | P value |
| Race | |||
| Non-Hispanic White | 270 (88.8) | 116 (75.3) | <0.001a |
| Other | 34 (11.2) | 38 (24.7) | |
| Age at survey | |||
| Mean ± SD | 38.0 ± 7.9 | 39.8 ± 8.0 | 0.023a |
| Age at birth of first child after treatment | |||
| Mean ± SD | 25.0 ± 4.7 | 22.9 ± 4.6 | <0.0001a |
| Time from diagnosis to birth of first child after treatment (years) | |||
| Mean ± SD) | 15.8 ± 7.2 | 12.9 ± 6.2 | <0.0001a |
| Time since diagnosis to survey (years) | |||
| Mean ± SD | 28.7 ± 8.9 | 29.8 ± 8.3 | 0.23a |
| Marital status | |||
| Married | 248 (81.6) | 83 (53.9) | <0.0001 |
| Not married | 56 (18.4) | 71 (46.1) | |
| Educational level | |||
| High school, some college or less | 161 (53.0) | 113 (73.4) | <0.0001 |
| College or postgraduate | 143 (47.0) | 41 (26.6) | |
| Household income | |||
| Under $40,000 | 154 (54.4) | 106 (71.1) | <0.001 |
| $40,000 or more | 129 (45.6) | 43 (28.9) | |
| Employment status | |||
| Employed | 194 (65.3) | 83 (54.2) | 0.018 |
| Unemployed | 103 (34.7) | 70 (45.8) | |
| Diagnosis | |||
| Hodgkin/non-Hodgkin lymphoma | 65 (21.4) | 33 (21.4) | 0.73 |
| Leukemia | 107 (35.2) | 61 (39.6) | |
| CNS tumor | 19 (6.3) | 7 (4.5) | |
| Non-CNS solid tumor | 113 (37.2) | 53 (34.4) | |
| Brain radiation | |||
| No | 229 (75.3) | 109 (70.8) | 0.29 |
| Yes | 75 (24.7) | 45 (29.2) | |
| Neck radiation | |||
| No | 189 (62.2) | 87 (56.5) | 0.24 |
| Yes | 115 (37.8) | 67 (43.5) | |
| Chest radiation | |||
| No | 222 (73.0) | 118 (76.6) | 0.41 |
| Yes | 82 (27.0) | 36 (23.4) | |
| Abdomen radiation | |||
| No | 244 (80.3) | 126 (81.8) | 0.69 |
| Yes | 60 (19.7) | 28 (18.2) | |
| Neurosurgery | |||
| No | 278 (91.4) | 141 (91.6) | 0.97 |
| Yes | 26 (8.6) | 13 (8.4) | |
| Thyroidectomy | |||
| No | 300 (98.7) | 151 (98.1) | 0.60b |
| Yes | 4 (1.3) | 3 (1.9) | |
| Breast surgery | |||
| No | 281 (92.4) | 144 (93.5) | 0.68 |
| Yes | 23 (7.6) | 10 (6.5) | |
| Growth hormone deficiency | |||
| No | 299 (98.4) | 150 (97.4) | 0.49b |
| Yes | 5 (1.6) | 4 (2.6) | |
| Hypothyroidism | |||
| No | 272 (89.5) | 135 (87.7) | 0.56 |
| Yes | 32 (10.5) | 19 (12.3) | |
| Diabetes | |||
| No | 299 (98.4) | 154 (100.0) | 0.17b |
| Yes | 5 (1.6) | 0 (0.0) | |
| BMI | |||
| Normal/underweight | 194 (65.8) | 95 (62.5) | 0.49 |
| Overweight/obese | 101 (34.2) | 57 (37.5) | |
| Postpartum depression | |||
| No | 222 (75.5) | 121 (82.3) | 0.11 |
| Yes | 72 (24.5) | 26 (17.7) | |
| Concern about passing cancer | |||
| Not concerned | 242 (79.9) | 93 (60.8) | <0.0001 |
| Concerned | 61 (20.1) | 60 (39.2) | |
T test
Fisher exact test
SD, standard deviation
Lactation outcomes among survivors and IFPS II participants
Breastfeeding intentions and outcomes differed significantly between childhood cancer survivor respondents and participants in the IFPS II (Table 4). During the prenatal period, fewer survivors planned to breastfeed (67% vs 82%, P<.0001) and fewer attempted to initiate breastfeeding during the post-natal period (66% vs 85%, P<.0001). Reasons for not ever breastfeeding also differed between survivors and IFPS II mothers. The latter were more likely to report “I believe that formula is as good as breastfeeding or that formula is better” (P=0.05), or “I thought breastfeeding would be too inconvenient” (P<.0001). Breastfeeding experience, assistance with breastfeeding, and reasons for deciding to stop breastfeeding were compared between survivors and IFPS II participants. During the first two weeks of breastfeeding, more survivors perceived that they did not have enough milk (32% vs 14%, P<.0001). Significantly more IFPS II mothers answered “Lactation Consultant” (P<.0001) to “Who helped you with breastfeeding?” while more survivors reported receiving help from their doctor (P=.004) and family members (P<.0001). More survivors perceived that their breastfeeding experience was unfavorable (19% vs 7.5%, P<.0001) and responded that they were less likely than IFPS II participants to try breastfeeding again (18% vs 6.2%, P<.0001). In addition, more survivors reported having trouble “getting milk to flow” (P<.0001), that baby had trouble sucking or latching on (P=0.003), and problems with sore, cracked, or bleeding nipples (P<.0001) than the IFPS II participants. The rates of unplanned or emergency cesarean deliveries was higher in survivors compared to the IFPS II cohort (30.6% vs 12%, P<.0001).
Table 4.
Comparison of lactation outcomes among survivors and Infant Feeding Practices Study II participants
| Responses from all participants |
Survivors (N=472) N (%) |
IFPS II (N=4902) N(%) |
P value |
| Prenatal breastfeeding intentions | |||
| Plan to breastfeed | 310 (66.7) | 3984 (81.6) | <0.0001 |
| Plan to formula feed only | 150 (32.3) | 706 (14.5) | |
| Don’t know | 5 (1.1) | 191 (3.9) | |
| Breastfeeding initiation | |||
| Yes | 304 (66.4) | 2572 (84.8) | <0.0001 |
| No | 154 (33.6) | 461 (15.2) | |
| Method of delivery | |||
| Vaginally and not induced | 146 (31.9) | 1157 (38.2) | <0.0001 |
| Vaginally and induced | 130 (28.4) | 1017 (33.6) | |
| Planned cesarean (C-section) | 42 (9.2) | 489 (16.2) | |
| Unplanned or emergency cesarean | 140 (30.6) | 363 (12.0) | |
| Responses from participants who breastfed |
Survivors (N=304) N (%) |
IFPS II (N=2572) N(%) |
P value |
| Breastfeeding experience | |||
| Enough breast milk during first 2 weeks | |||
| No | 206 (67.8) | 2202 (85.7) | <0.0001 |
| Yes | 98 (32.2) | 366 (14.3) | |
| Assistance with breast feeding | |||
| Doctor helped with breastfeeding | |||
| No | 292 (96.1) | 1867 (98.5) | 0.004 |
| Yes | 12 (3.9) | 29 (1.5) | |
| Lactation consultant helped with breastfeeding | |||
| No | 166 (54.6) | 735 (38.8) | <0.0001 |
| Yes | 138 (45.4) | 1161 (61.2) | |
| Nurse helped with breastfeeding | |||
| No | 85 (28.0) | 546 (28.8) | 0.7645 |
| Yes | 219 (72.0) | 1350 (71.2) | |
| Family member helped with breastfeeding | |||
| No | 222 (73.0) | 1626 (85.8) | <0.0001 |
| Yes | 82 (27.0) | 270 (14.2) | |
| Overall breastfeeding experience | |||
| Unfavorable | 55 (18.9) | 109 (7.5) | <0.0001 |
| Favorable | 236 (81.1) | 1339 (92.5) | |
| Reasons for decision to stop breastfeeding | |||
| I didn’t have enough milk | |||
| Not important | 130 (46.1) | 768 (53.4) | 0.025 |
| Important | 152 (53.9) | 670 (46.6) | |
| Breast milk alone did not satisfy my baby | |||
| Not important | 146 (53.9) | 721 (50.1) | 0.26 |
| Important | 125 (46.1) | 717 (49.9) | |
| Had trouble getting the milk flow to start | |||
| Not important | 177 (64.6) | 1114 (77.5) | <0.0001 |
| Important | 97 (35.4) | 324 (22.5) | |
| My baby had trouble suckling or latching on | |||
| Not important | 187 (67.5) | 1117 (77.6) | 0.0003 |
| Important | 90 (32.5) | 323 (22.4) | |
| My nipples were sore, cracked, or bleeding | |||
| Not important | 190 (70.4) | 1187 (82.5) | <0.0001 |
| Important | 80 (29.6) | 251 (17.5) | |
| Thought baby was not gaining enough weight | |||
| Not important | 206 (76.0) | 1215 (84.5) | 0.0006 |
| Important | 65 (24.0) | 223 (15.5) | |
| Breastfeeding was too painful | |||
| Not important | 210 (77.5) | 1253 (87.1) | <0.0001 |
| Important | 61 (22.5) | 185 (12.8) | |
| My breasts were overfull or engorged | |||
| Not important | 216 (80.3) | 1293 (89.9) | <0.0001 |
| Important | 53 (19.7) | 145 (10.1) | |
| My baby lost interest or weaned him or herself | |||
| Not important | 223 (83.2) | 1012 (70.4) | <0.0001 |
| Important | 45 (16.8) | 426 (29.6) | |
| Breastfeeding was too inconvenient | |||
| Not important | 232 (86.2) | 1200 (83.4) | 0.25 |
| Important | 37 (13.8) | 238 (16.6) | |
| Future breastfeeding intentions | |||
| Less likely | 52 (17.8) | 90 (6.2) | <0.0001 |
| Likely | 240 (82.2) | 1353 (93.8) | |
| Perception and Preferences of participants who did not breastfeed |
Survivors (N=154) N (%) |
IFPS II (N=461) N (%) |
P value |
| Formula is as good/better than breastfeeding | |||
| Not important | 58 (44.6) | 145 (35.1) | 0.0507 |
| Important | 72 (55.4) | 268 (64.9) | |
| Breastfeeding would be too inconvenient | |||
| Not important | 96 (74.4) | 193 (47.0) | <0.0001 |
| Important | 33 (25.6) | 218 (53.0) | |
| Want/need someone to feed baby other than me | |||
| Not important | 102 (80.3) | 225 (54.1) | <0.0001 |
| Important | 25 (19.7) | 191 (45.9) | |
| Someone else wants to feed my baby | |||
| Not important | 113 (89.7) | 248 (60.5) | <0.0001 |
| Important | 13 (10.7) | 162 (39.5) | |
| I thought I would not have enough milk | |||
| Not important | 90 (70.3) | 313 (76.0) | 0.1988 |
| Important | 38 (29.7) | 99 (24.0) | |
Variable numbers for comparison are due to missing responses to survey items
A higher prevalence of early, undesired weaning was reported in survivors compared to the general population, 57.5% (95% CI 51–64) vs 45.2% (95% CI 44–47, P=.016). Among survivors that reported early, undesired weaning, the median duration of breastfeeding was shorter, 1.38 months (IQR 0.5–3.5 months) compared to a median duration of 2.7 months (IQR 0.9–5.4 months) in the IFPS II group. The most frequently endorsed reasons for stopping breastfeeding in both the survivor group and the IFPS II population were “I didn’t have enough milk” and “Breastmilk alone did not satisfy my baby.” More women in the general population stopped breastfeeding when they thought their baby lost interest or began to wean him or herself (P<.0001) compared to survivors.
Disrupted lactation among survivors
The analysis compared outcomes of women who reported expected (N=63) or early desired weaning (N=36) to those who endorsed disrupted lactation (n=124) (Table 5). Of those who endorsed disrupted lactation, median duration of breastfeeding was 1.4 months (SD 0.5–3.0) compared to 8.0 months (SD 0.5–3.0) in the expected/early desired weaning group (P<.0001). The rate of self-reported postpartum depression was higher in participants with disrupted lactation but not statistically different from those in the expected/early desired weaning group (29% vs 20%, P=.11). Multivariable analysis showed that overweight/obesity was associated with disrupted lactation (RR 1.4, 95% CI, 1.1–1.8, P=.003) (Table 6).
Table 5.
Comparison of clinical characteristics of childhood cancer survivors with expected/desired weaning and disrupted lactation
| Expected weaning/early desired (N = 102) |
Disrupted lactation (N = 124) |
||
|---|---|---|---|
| Variable | n (%) | n (%) | P value |
| Race | |||
| Non-Hispanic White | 88 (86.3) | 114 (91.9) | 0.1693 |
| Other | 14 (13.7) | 10 (8.1) | |
| Age at study | |||
| Mean ± SD | 37.5 ± 7.5 | 38.1 ± 8.0 | 0.6108a |
| Age at time of birth of first child after treatment | |||
| Mean ± SD | 26.2 ± 4.9 | 25.0 ± 4.5 | 0.0450a |
| Time since diagnosis to when first child after treatment was born | |||
| Mean ± SD | 16.5 ± 7.0 | 15.9 ± 7.4 | 0.5417a |
| Time since diagnosis to study | |||
| Mean ± SD | 27.8 ± 8.2 | 29.0 ± 8.8 | 0.2920a |
| Duration of breastfeeding | |||
| Median (IQR) | 8.0 (4.0–12.0) | 1.4 (0.5–3.0) | <0.0001b |
| Marital status | |||
| Married | 85 (83.3) | 104 (83.9) | 0.9134 |
| Not married | 17 (16.7) | 20 (16.1) | |
| Educational level | |||
| High school, some college or less | 43 (42.2) | 66 (53.2) | 0.0975 |
| College or postgraduate | 59 (57.8) | 58 (46.8) | |
| Household income | |||
| Under $40,000 | 40 (41.2) | 66 (54.5) | 0.0507 |
| $40,000 or more | 57 (58.8) | 55 (45.5) | |
| Employment status | |||
| Employed | 65 (65.0) | 86 (70.5) | 0.3827 |
| Unemployed | 35 (35.0) | 36 (29.5) | |
| Diagnosis | |||
| Hodgkin/Non-Hodgkin Lymphoma | 26 (25.5) | 26 (21.0) | 0.8262 |
| Leukemia | 32 (31.4) | 45 (36.3) | |
| CNS | 5 (4.9) | 6 (4.8) | |
| Solid Tumor | 39 (38.2) | 47 (37.9) | |
| Childhood cancer treatment | |||
| Brain radiation | |||
| No | 88 (86.3) | 98 (79.0) | 0.1557 |
| Yes | 14 (13.7) | 26 (21.0) | |
| Neck radiation | |||
| No | 72 (70.6) | 80 (64.5) | 0.3331 |
| Yes | 30 (29.4) | 44 (35.5) | |
| Chest radiation | |||
| No | 73 (71.6) | 91 (73.4) | 0.7604 |
| Yes | 29 (28.4) | 33 (26.6) | |
| Abdomen radiation | |||
| No | 80 (78.4) | 100 (80.6) | 0.6808 |
| Yes | 22 (21.6) | 24 (19.4) | |
| Neurosurgery | |||
| No | 94 (92.2) | 115 (92.7) | 0.8682 |
| Yes | 8 (7.8) | 9 (7.3) | |
| Thyroidectomy | |||
| No | 100 (98.0) | 123 (99.2) | 0.5903c |
| Yes | 2 (2.0) | 1 (0.8) | |
| Breast surgery | |||
| No | 96 (94.1) | 114 (91.9) | 0.5245 |
| Yes | 6 (5.9) | 10 (8.1) | |
| Chronic health conditions | |||
| Growth hormone deficiency | |||
| No | 100 (98.0) | 123 (99.2) | 0.5903c |
| Yes | 2 (2.0) | 1 (0.8) | |
| Hypothyroidism | |||
| No | 90 (88.2) | 110 (88.7) | 0.9114 |
| Yes | 12 (11.8) | 14 (11.3) | |
| Diabetes | |||
| No | 100 (98.0) | 123 (99.2) | 0.5903c |
| Yes | 2 (2.0) | 1 (0.8) | |
| BMI | |||
| Normal/underweight | 75 (75.8) | 72 (60.0) | 0.0135 |
| Overweight/obese | 24 (24.2) | 48 (40.0) | |
| Postpartum depression | |||
| Yes | 20 (20.0) | 35 (29.4) | 0.1096 |
| No | 80 (80.0) | 84 (70.6) | |
| Doctor helped with breastfeeding | |||
| No | 97 (95.1) | 121 (97.6) | 0.4727c |
| Yes | 5 (4.9) | 3 (2.4) | |
| Lactation consultant helped with breastfeeding | |||
| No | 49 (48.0) | 70 (56.5) | 0.2075 |
| Yes | 53 (52.0) | 54 (43.5) | |
| Nurse helped with breastfeeding | |||
| No | 30 (29.4) | 29 (23.4) | 0.3048 |
| Yes | 72 (70.6) | 95 (76.6) | |
| Family member helped with breastfeeding | |||
| No | 75 (73.5) | 92 (74.2) | 0.9099 |
| Yes | 27 (26.5) | 32 (25.8) | |
T test
Wilcoxon rank-sum test
Fisher exact test
SD, standard deviation
Table 6.
Multivariable analysis of predictors of disrupted lactation in childhood cancer survivors
| Variable | Relative risk | 95% CI | P value |
|---|---|---|---|
| Age at birth of first child after treatment | |||
| Per year | 0.98 | 0.95–1.00 | 0.0655 |
| Educational level | |||
| College or postgraduate | 1.00 | ||
| Under college | 1.02 | 0.76–1.37 | 0.8814 |
| Household income | |||
| $40,000 or more | 1.00 | ||
| Under $40,000 | 1.08 | 0.81–1.43 | 0.6059 |
| BMI | |||
| NormalNormal/underweight | 1.00 | ||
| Overweight/obese | 1.41 | 1.12–1.78 | 0.0031 |
Discussion
This study examined cancer treatment and endocrine-related late effects on lactation outcomes among a large, clinically diverse cohort of childhood cancer survivors. Findings indicate that survivors, compared to the general population, have lower intention to breastfeed, shorter duration of breastfeeding, and higher prevalence of negative breastfeeding experiences. This growing population of childhood cancer survivors has an increased risk for treatment-related late effects, including second malignancies, cardiovascular disease, and endocrine disorders [22, 23], problems for which breastfeeding has been shown to mitigate in healthy women [24]. These data underscore the importance of educating survivors contemplating pregnancy about the physiologic benefits breastfeeding provides and providing lactation support after delivery.
There is a dearth of studies evaluating lactation outcomes among women treated with chest and cranial irradiation. One case series observed lactation failure in 10 of 12 women treated with 24 Gy cranial irradiation, hypothesized to result from GH deficiency [6]. In another study of 83 survivors of Hodgkin lymphoma treated with chest irradiation, 57 of 94 (61%) reported successful breastfeeding attempts [5]. We hypothesized that cancer-/treatment-related endocrinopathy adversely impacts breastfeeding, however lactation difficulties were not endorsed more frequently among survivors with GH deficiency, hypothyroidism or diabetes mellitus. Obesity was the only health-related variable that significantly affected breastfeeding. Previous studies in healthy populations have reported associations between maternal obesity and decreased intention, initiation, and duration of breastfeeding, less adequate milk supply, and delayed onset of stage II lactogenesis [25–27]. Collectively, these data underscore the importance of educating survivors that treatment-related endocrinopathies are unlikely to adversely affect their ability to breastfeed and encouraging attainment/maintenance of a healthy weight when planning pregnancy.
Prenatally, survivors expressed doubts about having sufficient milk supply and concerns about passing cancer through breastmilk. Past experiences with diminished health may contribute to worries of potentially negative infant feeding experiences. Oncology and obstetrical providers should counsel survivors that there is no data to support transmission of cancer through breastfeeding. Among survivors who successfully initiated breastfeeding, a substantial proportion experienced early weaning due to disrupted lactation. This group had significantly shorter breastfeeding durations than those with undisrupted lactation and did not meet their breastfeeding goals. It is important to recognize that shorter breastfeeding duration among survivors may lead to feelings of failure and depressive symptoms in the postnatal period. In the general population, failed lactation and perinatal depression frequently occur together [28] and our data indicated a high occurrence of both clinical problems in survivors. Obstetric providers should be aware of these common comorbid conditions and assess women with breastfeeding problems for depression, as well as refer women with depressive symptoms for breastfeeding support [28].
Strengths of our study include our large and well-characterized population of childhood cancer survivors with detailed information on lactation outcomes. Aligning our assessment of lactation outcomes with those used by IFPS II allowed for comparisons to population norms. However, our results should be considered in the context of its limitations. There is potential for bias considering the 66% participation rate, yet previous analyses have indicated that SJLIFE participants are generally representative of all potential eligible survivors [14]. A methodological challenge in our study was the use of self-report to determine prevalence of lactation dysfunction. Perception of insufficient milk supply is common among most new mothers [29], and the potential for misreporting should be considered. Another issue is the potential for misclassification from recall errors. In addition, the small number of endocrine late effects in this population of survivors who were able to achieve a pregnancy limited the statistical power of analyses when evaluating their relationship to lactation outcomes. Finally, while not a lactation outcome, the finding of higher rates of unplanned or emergency cesarean deliveries in survivors compared to the IFPS II cohort is of interest. A previous study found no elevated risk of emergency cesarean among childhood cancer survivors [30] however, our finding of higher rates compared to the general population warrants further investigation.
Our results have considerable clinical implications and highlight the importance of professional lactation support for this growing population. Knowledge deficits among healthcare professionals about late effects following cancer therapies can be an obstacle to providing good care [31]. Healthcare providers, especially obstetricians, are in a unique position to encourage breastfeeding, which is known to have beneficial physiological effects [32] that may mitigate the severity or impact late effects of pediatric cancer/therapy, while also evaluating and treating breastfeeding complications. Survivors in our study were more likely to report receiving help from family members as opposed to lactation specialists. Previous studies show that mothers are less likely to discontinue breastfeeding if they receive encouragement from their clinician [33]. The Surgeon General’s Call to Action to Support Breastfeeding asserts that most problems can be alleviated by supportive care, especially by professionals with certifications in lactation management [34]. Risk factors that lead to weaning are critical issues to address during obstetrical visits, especially with overweight/obese survivors. Pre-and postnatal counseling should be tailored to the survivor’s understanding and concerns.
Acknowledgments
Funding: This study was supported by NCI U01CA195547 (MMH/LLR) and the American Lebanese Syrian Associated Charities (ALSAC).
Footnotes
Conflict of Interest: The authors declare that they have no conflict of interest
Compliance with ethical standards
Ethical Approval: This study has been approved by the St. Jude Children’s Research Hospital Institutional Review Board and has been performed in accordance with the ethical standards as laid down in the in the 1964 Declaration of Helsinki and its later amendments or comparable ethical standards. Completion and return of the survey implied consent to participate in the study, thereby granting a waiver for signed consent.
Clinical Trial Registration: www.clinicaltrials.gov/show/NCT02399956
Publisher's Disclaimer: This Author Accepted Manuscript is a PDF file of an unedited peer-reviewed manuscript that has been accepted for publication but has not been copyedited or corrected. The official version of record that is published in the journal is kept up to date and so may therefore differ from this version.
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