Financial Toxicity and Quality-of-Life Outcomes on a Phase 1 5-fraction Stereotactic Partial Breast Irradiation Protocol for Early-Stage Breast Cancer

Abstract

Purpose:

We report the financial toxicity and quality-of-life outcomes of our prospective phase 1 dose-escalation study of 5-fraction stereotactic partial breast irradiation (S-PBI) for early-stage breast cancer.

Materials and Methods:

Women with unifocal in situ or invasive epithelial histologies, clinical stages 0, I, or II with tumor size < 3 cm treated with lumpectomy were enrolled in our phase 1 5-fraction S-PBI dose-escalation trial. Our institutionally generated questionnaire on the “Patient Perspective Cost and Convenience of Care” and the EuroQol 5-Dimension 5-level questionnaire were administered to patients treated at follow-up.

Results:

Between 2010 and 2015, 68 of the 75 patients who enrolled and completed treatment on trial completed at least some component of either the EuroQol 5-Dimension 5-level questionnaire or the “Patient Perspective Cost and Convenience of Care” questionnaire. Nearly all patients reported very high satisfaction with their treatment overall, particularly the shortened length of treatment. Over half of the patients reported some level of financial toxicity (FT) despite a significantly shortened treatment time. Patients who reported any FT were significantly younger than patients with no financial burden of treatment (means 59.2 and 63.7, respectively, P = .03). There was no difference in those who reported any level of FT based on patient race, ethnicity, marital, or employment status. This S-PBI regimen did not significantly affect quality of life over a 4-year follow-up.

Conclusions:

These patient-reported outcomes suggest that the use of accelerated partial breast irradiation may offer low FT rates in breast cancer care, particularly for disadvantaged patient groups.

Introduction

Breast cancer is the most commonly diagnosed malignancy in women, with approximately 2 of 3 patients presenting with local disease at the time of initial diagnosis.¹ Treatment options at this stage include mastectomy or lumpectomy with whole breast irradiation (WBI), with expected 5-year overall survival outcomes bordering 99%. Given the excellent disease control, deescalation of treatment with lumpectomy and partial breast irradiation (PBI) is continuing to gain momentum, with many studies demonstrating noninferiority to whole breast radiation in terms of outcomes.² Additional focus has been given to improving quality of life (QOL), including minimizing the financial burden of treatment.

Cancer treatments can impose a significant financial burden on patients. Financial toxicity (FT) affects nearly half of all cancer patients, which can lead to poor health outcomes through limited access to health care and an inability to complete necessary treatments or supportive care.³ The combination of treatment cost burden and missed employment and/or wages can be devastating for some patients. It is imperative for physicians to recognize patients who may be at increased risk for FT and to minimize the financial burden for everyone, especially those most vulnerable. Treatment with radiation has been identified as a risk factor for developing FT. Conventional WBI can require up to 6.5 weeks of daily treatments and introduces numerous non-medical costs, including transportation and lost wages from missed employment. Reducing treatment duration is therefore one potential potent method of reducing FT.

Recently published results on the 5-fraction stereotactic body radiation therapy (RT) for PBI (S-PBI) demonstrated that tumoricidal doses of radiation can be safely delivered with acceptable control and cosmesis.^4,5 This approach offers the benefits of accelerated PBI (APBI) without the invasiveness of brachytherapy and offers improved cosmetic outcomes over traditional external radiation techniques. In addition, the short course presents an opportunity to further mitigate FT. Here we report the quality-of-life (QOL) and FT outcomes of our prospective, phase 1 dose- escalation study of 5-fraction adjuvant S-PBI.

Methods and Materials

Study design

Between 2010 and 2015, we conducted an institutional review board-approved phase 1 dose-escalation trial of 5-fraction S-PBI for early-stage breast cancer (ClinicalTrial.gov NCT01162200).⁵ Dose escalation was 30, 32.5, 35, 37.5, and 40 Gy. Eligible patients had a Zubrod performance status of 0 to 2. Patients had unifocal invasive breast histologies, with American Joint Committee on Cancer 7 stage T0, T1, or T2 (≤ 3 cm) treated with lumpectomy and axillary nodal staging with sentinel node sampling alone if negative or axillary dissection with a minimum of 6 nodes sampled. Margins of at least 2 mm were required. Patients with ductal carcinoma in situ were allowed if the disease was ≤ 3 cm and axillary staging was not required.

FT and QOL evaluation

Patients were administered an institutionally generated questionnaire on the “Patient Perspective Cost and Convenience of Care” at their 1-month follow-up (Supplementary 1). The following socioeconomic information was collected: marital status, educational level achieved, household income, employment status, insurance coverage, distance traveled for treatment, disruption of normal life caused by treatment, perceived FT, and overall patient satisfaction with length of treatment, etc. FT was reported as none, slight, somewhat, or significant, per the patient’s perception.

Patients also completed the EuroQol 5-Dimension 5-level (EQ-5D-5L) “self-assessed health-related QOL” questionnaire at baseline and 1, 6, 12, 24, 36, 48, and 60-month follow-ups. The questionnaire spans 5 dimensions (mobility, self-care, usual activities, pain/discomfort, and anxiety/depression) ranked on 5 levels (1, no problems, 2, slight problems, 3, moderate problems, 4, severe problems, 5, unable to perform/extreme problems), as well as an overall health score using the visual analog scale (VAS, scale, 0–100, with 100 being top health). This 5-dimension, 5-level system generates 5⁵ = 3125 unique health states using the cross-walk index, or “utility score,” normalized for a United States population as previously reported.⁶ This utility score is reported as a value between 0 and 1 (ie, 0.658), with a value of 1 representing “perfect health” and 0 representing “death.”

Study endpoints and statistics

The present study was designed with the goal to either reach a target dose of 40 Gy in 5 fractions or a maximally tolerated dose, whichever was achieved first. Secondary endpoints were to assess the cosmesis, QOL measures, and FT for S-PBI. 28586960. The global cosmesis score (was assessed using the Harvard Breast Cosmesis scale, with scores of 1, 2, 3, and 4 representing excellent, good, fair, and poor, respectively). Evaluation was completed by the physician, patient, and a panel of breast oncologists at baseline and 1, 6, 12, 24, 36, 48, and 60-month follow-ups. For this study on patient-reported outcomes, we used the patient-reported cosmesis scores.

We hereby report the FT and QOL outcomes from our 5-fraction S-PBI study. Analysis of variance or Kruskal-Wallis tests were conducted to assess for differences in continuous variables, age, race, education, income, and distance traveled between those with and without reported financial burden. If the analysis of variance or Kruskal-Wallis tests yielded significant results, 2-sample t tests or Wilcoxon rank sum tests were subsequently employed to identify pairs of groups that exhibited significant differences. Fisher’s exact test or χ² test was used to compare categorical variables. A P value ≤ .05 was considered statistically significant.

Results

Patient demographic characteristics

Of the 75 patients who enrolled and completed treatment on trial, 66 patients completed at least some component of either the EQ-5D-5L or the “Patient Perspective Cost and Convenience of Care” questionnaire. The median age of patients treated was 62 years (absolute range, 41–79). The majority of patients were White (73.3%) and 17.3% were Black. Twelve percent of patients identified as Hispanic. Patients were enrolled from both our county hospital and private hospital. Approximately half of the respondents were married (54%). With respect to their educational level, 21.9% of patients had completed high school or less, 53.1% had completed at least some college, and 25.0% had completed some postgraduate or advanced training. Thirteen percent of patients (n = 8/55) reported income of < $20K, and 45.5% (n = 25/55) reported income of > $80K. About half of the patients had private insurance for medication (49.2%), another third had government coverage (33.9%), and 7.7% of patients had no prescription insurance at all. Patients lived a median of 22 miles (range, 2–370 miles) from the treatment center; however, 10 patients reported traveling at least 50 miles 1-way for treatment, and 4 patients traveled at least 150 miles, with the maximum 1-way travel distance being 370 miles. Complete patient demographic information can be found in Table 1.

Table 1. Patient demographic characteristics.

Characteristics		All	No FT	Any FT	P
Age (y)
Median (range)	62 (41–79)		66 (45–75)	58 (43–79)	.03
Mean ± SD	60.7 ± 9.2		63.7 ± 7.4	59.2 ± 8.4
Race
White	78.7%	48	23	25	.87
Black	16.4%	10	5	5
Other/mixed-race	1.6%	1	0	1
Asian/Pacific Islander	1.6%	1	1	0
Native American	0.0%	0	0	0
Not specified	1.6%	1	0	1
Ethnicity
Hispanic	11.5%	7	2	5	.43
Non-Hispanic	88.5%	54	27	27
Marital status
Married	54.2%	32	18	14	.34
Single	10.2%	6	1	5
Divorced	22.0%	13	5	8
Widowed	10.2%	6	4	2
Separated	3.4%	2	1	1
People in home
Live alone	26.7%	16	8	8	.45
1	45.0%	27	16	11
2	13.3%	8	2	6
3	6.7%	4	1	3
More	8.3%	5	2	3
Education/schooling
No schooling	4.9%	3	1	2	.18
Some high school	6.6%	4	4	0
High school	11.5%	7	1	6
Some college	23.0%	14	6	8
College/university	27.9%	17	7	10
Post	26.2%	16	10	6
Annual household income
Less than 20K	10.3%	6	2	4	.56
20–50K	22.4%	13	5	8
50–80K	13.8%	8	2	6
More than 80K	43.1%	25	15	10
Do not know	10.3%	6	4	2
Prescription insurance status
Govt	32.8%	20	16	4
Private	49.2%	30	11	19	.02
Both	6.6%	4	1	3
None	8.2%	5	0	5
Do not know	3.3%	2	1	1
Cancer-related copays
None	44.8%	26	18	8	.49
Any	55.2%	32	10	22
Distance traveled (mi)
Median (range)	22 (2–370)		21 (2–200)	24 (3–370)	.03
Mean ± SD	45.8 ± 72.8		32.6 ± 41.6	62.1 ± 95.0

Abbreviation: mi = miles.

Employment and time off work

Over half of all patients worked either full-time (44.1%, n = 26) or part-time (10.2%, n = 6) (Table 2). A quarter of patients were retired (23.7%, n = 14), and the remainder reported being a homemaker (11.9%, n = 7) or unemployed (10.2%, n = 6). Of the patients who worked fulltime, 74.1% (n = 20/27) had to take time off of work for treatment. Patients reported taking a median of 5 days off (range, 0.25–10 days). The majority of patients needing to take time off were able to do so with pay (80%, n = 16/20); however, 1 patient reported her time off was unpaid, and an additional 3 patients reported using vacation time for treatment. There was also 1 patient who worked part-time and reported taking months of unpaid time off work for treatment. Furthermore, about a quarter of patients (24.2%, n = 15) reported that their family or friends took a median of 5 days (range, 1–56 days) off work to help them during their treatment.

Table 2. Employment and time off work.

		All	No FT	Any FT	P
Employment status (n = 60)
Full-time	42.6%	26	11	15	.83
Part-time	11.5%	7	4	3
Retired	26.2%	16	9	7
Homemaker	9.8%	6	3	3
Unemployed	9.8%	6	2	4
Full-time - time off (n = 26)
No	23.1%	6	4	2	.27
Yes	76.9%	20	7	13
Time off (n = 20)
With pay	80.0%	16	5	11
Without pay	15.0%	3	2	1	.79
Vacation	5.0%	1	0	1
Time off (d) (n = 20)
Median (range)		5 (0.25–10)	5 (2.5–8)	5 (0.25–10)
Mean ± SD		4.9 ± 3.0	5.2 ± 1.8	4.8 ± 3.5	.23
Time off for family (n = 58)
No	75.8%	45	25	20	.36
Yes	24.2%	13	3	10
Days off for friends/family
Median (range)		5 (1–56)	3 (1–5)	5 (2–56)
Mean ± SD		7.97 ± 13.4	3 ± 2	10.1 ± 14.9	.06

Abbreviation: FT = financial toxicity.

FT

Over half of the patients reported some degree of financial burden from 5-fraction S-PBI RT, 51.6%, n = 32, Table 1). Of those that noted any financial burden, 43.8% (n = 14) reported this burden to be slight, 37.5% (n = 12) reported somewhat, and 18.8% (n = 6) reported this burden to be significant. Given the small nature of this study, we compared patients with no reported FT with any FT (slight, somewhat, and significant). Sensitivity analyses were completed for patient demographic factors, with no clear difference between the cut-off of FT burden. Patients who reported any amount of FT were significantly younger than patients who claimed no financial burden of treatment (means 59.2 and 63.7, respectively, P = .03). There was no difference in those who reported any FT based on patient race, ethnicity, marital status, or employment. There was however a significant increase in patients with perceived FT if they had private prescription coverage only compared with patients who had some form of government prescription coverage on both univariate and multivariate analysis (ie, Medicare and Medicaid, P = .02). Unsurprisingly, patients with no coverage were more likely to have FT (P = .03). On multivariate analysis increasing distance traveled to the treatment site was also associated with FT (P = .03). Other potential predictors such as marital status, baseline health, employment status, education level, and annual household income were not found to be statistically significant on multivariate or univariate analysis (Tables E1, E2 and E3).

FT and QOL

Patients reported overall health on the VAS, per the EQ-5D-5L. These VAS values remained stable from baseline over the course of follow-up (mean, 89.5; SD, 9.7, Table 3). Likewise, cross-walk index values were calculated from the EQ-5D-5L responses. These values also remained stable from baseline through follow-up (mean, 0.91; SD, 0.11). On looking at specific domains, patients demonstrated improvement in the “usual activities” and “anxiety/depression” domains at the 6-month follow-up (mean, 1.07, SD, 1.27) and beyond, compared with baseline (mean, 1.14; SD, 1.52) and 1-month follow-up (mean, 1.50; SD, 1.35). Patients experienced an acute worsening in “pain/discomfort” at the 6-month follow-up (mean, 1.66; baseline mean, 1.47). At the 12-month time point, the scores were similar to the baseline (mean, 1.59). Graphical representations of these domains over time are illustrated in Fig. 1 and Fig. E1. Interestingly, patients who reported fair or poor breast cosmesis had significantly lower utility scores at 1 year posttreatment compared with patients who reported good or excellent cosmesis (means, 0.79 and 0.92, respectively, P = .02). There was no significant relationship between patient- reported cosmesis and utility scores at other time points (Table 3).

Table 3. Financial toxicity (FT) and related health scores, utility values, and cosmesis.

	Degree of FT		P
	No FT	Any FT
Overall health score
Baseline (n)	91.15 (27)	87.68 (31)	.15
6 mo (n)	92.03 (29)	89.10 (30)	.22
1 y (n)	91.71 (28)	88.07 (27)	.28
2 y (n)	89.81 (22)	87.74 (21)	.60
3 y (n)	89.63 (19)	91.25 (12)	.62
4 y (n)	90.20 (10)	89.20 (10)	.77
Cross-walk index/utility value
Baseline (n)	0.92 (27)	0.89 (31)	.22
6 mo (n)	0.92 (29)	0.88 (30)	.08
1 y (n)	0.95 (28)	0.87 (27)	.02
2 y (n)	0.92 (22)	0.85 (21)	.15
3 y (n)	0.93 (19)	0.88 (12)	.27
4 y (n)	0.93 (10)	0.87 (10)	.11
Patient-rated cosmesis (GCS)
Baseline (n)	1.74 (27)	1.71 (31)	.88
6 mo (n)	1.38 (29)	1.47 (30)	.53
1 y (n)	1.30 (28)	1.59 (27)	.12
2 y (n)	1.55 (22)	1.57 (21)	.90
3 y (n)	1.68 (19)	1.50 (12)	.46
4 y (n)	1.80 (10)	1.90 (10)	.77

Abbreviations: GCS = global cosmesis score.

Figure 1.

The EuroQol 5-Dimension 5-level questionnaire domains over time. Patients treated with 5-fraction stereotactic partial breast irradiation maintained their quality of life over long-term follow-up.

We investigated whether a patient’s perceived FT was related to their EQ-5D-5L derived utility score, VAS, or self-reported cosmetic outcomes (Table 3). Patients who reported any level of FT trended toward lower VAS and lower utility scores at all time points; however, this was only statistically significant for the utility score at 1 year posttreatment (mean, 0.95 - no FT vs 0.87 - FT, P = .02). There was no relationship between patient-reported cosmesis and FT.

FT and impact of treatment on daily life

The final portion of the “Patient Perspective Cost and Convenience of Care” questionnaire surveyed patients regarding treatment-related disruption to their life, including daily activities, recreation, time with friends and family, sleep, and overall enjoyment of life, rated on a scale of 0 to 10, with 0 being no disruption. This portion also surveyed patients’ satisfaction with treatment time. Overall, patients reported minimal disruption across all domains. A full breakdown of scores can be seen in Table 4. Patients who reported “significant” FT were statistically more likely to identify disruptions to their life across all domains compared with patients, with no FT (scores and respective P values compared with no FT can be seen in Table 4). Overall, patients remained very satisfied with their treatment time (mean, 8.4; SD, 3.0), and patient satisfaction with treatment time did not vary with perceived FT (8.7 ± 2.7 no FT vs 8.2 ± 3.2 any FT, P= .48).

Table 4. Impact of treatment on patient life.

	Daily activities		Recreational		Family and friends		Sleep		Enjoyment		Disrupt people		Satisfied with/time
All patients
Median (range)	3	(0–8)	2	(0–10)	1	(0–9)	1	(0–8)	1	(0–9)	1	(0–10)	10	(0–10)
Mean	2.9		2.6		2.2		2.4		2.0		2.4		8.3
No FT
Median (range)	1	(0–7)	1	(0–7)	1	(0–8)	1	(0–8)	1	(0–7)	0	(0–8)	10	(0–10)
Mean	1.7		1.9		1.7		2.0		1.3		1.4		8.7
Slight
Median (range)	3.5	(0–8)	1.5	(0–10)	1	(0–7)	1.5	(0–8)	1	(0–6)	1	(0–7)		(0–10)
Mean	3.4		2.6		2.2		2.5		1.6		2.1		7.4
P value	< .05		.43		.48		.57		.55		.38		.19
Somewhat
Median (range)	5	(0–7)	3	(0–5)	2	(0–7)	2	(0–7)	3	(0–8)	3.5	(0–10)	10	(8–10)
Mean	3.5		2.9		2.5		2.3		2.8		3.9		9.5
P value	< .05		.20		.34		.71		< .05		.34		< .05
Significant
Median (range)	6	(0–8)	4.5	(0–9)	4	(0–9)	6	(0–8)	5.5	(0–9)	6.5	(0–8)	10	(2–10)
Mean	5.2		4.8		4.3		5.2		5.5		5.2		7.5
P value	< .05		< .05		< .05		< .05		< .05		< .05		.36
Any FT
Median (range)	4.5	(0–8)	3	(0–9)	2	(0–9)	2	(0–8)	2	(0–9)	2.5	(0–10)	10	(0–10)
Mean	3.8		3.1		2.7		2.9		2.8		3.3		8.2
P value	< .05		.07		.11		.18		< .05		< .05		.48

Abbreviations: FT = financial toxicity

Discussion

This study presents FT and QOL results from our phase 1 5-fraction adjuvant S-PBI dose-escalation trial. This S-PBI regimen did not significantly affect QOL, and nearly all patients reported very high satisfaction with their treatment overall, particularly the shortened length of treatment. Importantly, many patients still report a financial burden of treatment, despite a significantly shortened treatment time. Our study demonstrates an encouraging outcome: vulnerable patient populations, such as low-income, uninsured, and unemployed patients who are often at higher risk of experiencing FT, did not exhibit an elevated risk in this study using APBI. This finding suggests that this shortened treatment strategy may offer a way to mitigate FT in cancer care, particularly for disadvantaged patient groups.

The association between FT of breast cancer treatment with patient demographic characteristics and disease characteristics has been previously established. Factors such as advanced stage of disease, unemployment at the time of diagnosis, lower household income, marital status, and increased out-of-pocket spending have been linked with worsening FT.⁷ A recent prospective study investigating the FT of stage 0 to III breast cancer patients undergoing RT concluded that the duration of RT was not associated with FT.⁸ In this study, 51% of patients were treated with long-course RT (≥ 25 fractions), 39% were treated with intermediate-course RT (6–24 fractions), and only 10% of patients received short-course RT (≤ 5 fractions). The authors compared the long-course radiation cohort with the combined short- and intermediate-course RT patient cohort. Therefore, FT outcomes in the short/intermediate cohort are primarily driven by patients in the intermediate group, which overwhelmingly (81%) received at least 20 fractions.

Our study is unique in that all patients had a similar stage of disease and were treated with a similar extent of surgery and duration of RT. This removes many of the variables previously impacting studies in breast cancer FT outcomes and also identifies specific features of patients who are more likely to be at risk for FT. Given the single-arm nature of the study, we are unable to compare the outcomes of patients who received 5 treatments to a conventional course of 25 treatments, which arguably carries more financial burden in both medical and nonmedical related costs, such as lost wages, transportation, and childcare. Furthermore, our study looked at patients’ perceived financial burden, which, while relevant to patient perception of overall care, is very subjective and patients are unable to serve as their own control in a study comparing treatment length (eg, 5 vs 25 fractions).

A limitation of our study is the lack of validation of our institutionally derived survey of FT. While the exact level of financial hardship our patients experienced remains to be validated, we did directly assess patient-perceived FT. Additionally, because of the small size of this study, we grouped patients who reported any level of FT from slight to severe. Given the hypofractionation in our trial, patients were treated over 2 weeks (5 fractions) versus 4 to 6 weeks for conventional WBI, and those patients who were employed during treatment likely missed far less work as a result of therapy. Accordingly, employment status and time off work were also not found to be a factor in patient-perceived FT. About a quarter of patients also reported friends and/or family took time off work to help get them to appointments, which was similarly minimized in this patient population and not found to be a significant risk factor for FT. Despite typically being associated with FT, our results also show that when S-PBI is used, neither annual income nor educational status was associated with perceived worsening FT. While patients with significant FT traveled significantly further for treatment, it is highly likely that the financial burden would have been exacerbated if required to travel for 4 to 6 weeks of daily treatment. Overall, we show that patient factors typically associated with FT of breast cancer treatment, such as employment status and annual income, are no longer significant when APBI is used. Importantly, the positive implications we show on FT are likely broadly applicable to other APBI regimens, such as the FAST-Forward regimen.⁹

Since our study was initiated, new methods for quantifying FT have been developed and validated, with the most widely used being the comprehensive score for FT (COST).¹⁰ Similar to our survey, this is also a patient- reported outcome. While the COST survey features 11 questions specific to FT, which may be more comprehensive, it is specifically limited to the past 7 days preceding the survey as opposed to our institutional survey, which spans the course of treatment.

Furthermore, our study demonstrated outstanding utility analysis as assessed using the widely validated EQ- 5D-5L tool. While our study did not have a conventional treatment arm comparison, patients treated with our regimen experienced no long-term detriment across any of the 5 domains evaluated. Overall health scores and the cross-walk indices remained stable from baseline through long-term follow-up. Other APBI studies reported positively on QOL outcomes using different validated tools as summarized below, although it is difficult to make direct comparisons with different studies that use different QOL outcome tools for assessment. The European GEC-ESTRO APBI Trial reported QOL outcomes for APBI with interstitial multicatheter brachytherapy in 7 to 8 fractions, were not worse than standard of care WBI per the European Organization for Research and Treatment of Cancer QLQ-C30 and the breast cancer module, QLQ-BR23 assessments.¹¹ More promisingly, the University of Florence APBI trial reported significantly improved health- related QOL across physical, emotional, and social functioning with their 5-fraction APBI regimen compared with the conventional WBI arm.¹² Likewise, patients in the TARGIT-A study arm treated with single-fraction intraoperative RT reported more positive breast-related QOL outcomes than those in the conventional external beam RT arm.¹³ Similar to the GEC-ESTRO study, both the Florence and TARGIT-A studies assessed QOL through the QOL questionnaire (QLQ) core30 (QLQ-C30) and QLQ for breast cancer specific-questionnaire (QLQ-BR23) questionnaires. Likewise, we anticipate the QOL results of the FAST-Forward study, which also used the QLQ-BR23, and suspect similarly positive outcomes.⁹ Both the QLQ-C30, and QLQ-BR23 questionnaires, and the EQ-5D-5L questionnaire that we used in our study assess global health; however, the EQ-5D-5L assesses 5 health domains (mobility, self-care, usual activities, pain/discomfort, and anxiety/depression) more generally. While the QLQ-C30 can be more specific, it is longer and more cumbersome for patients, and the QLQ-BR23 is more specific to breast QOL.

Even with administration of only 5 fractions, many patients in our study were still affected by the financial burden of breast cancer RT; however, we found that low-income, unemployed, and uninsured patient populations are not at increased risk of FT compared with all patients when treated with accelerated breast irradiation. Patients impressively maintained an excellent QOL and were uniformly satisfied with the shortened treatment time. Reduction of FT in breast cancer patients has direct implications on not just patients but also their loved ones and society at large, affecting hours at work, job productivity, health care spending, and nonmedical out-of-pocket spending. Reducing the number of radiation fractions for early-stage breast cancer appears to be extremely promising in minimizing this financial burden.

Supplementary Material

Supplementary material associated with this article can be found in the online version at doi:10.1016/j.prro.2024.08.012.