1145 - Improved Acute and Long-Term Patient-Reported Outcomes (PRO) after Accelerated Partial Breast Irradiation (APBI) vs. Whole Breast Irradiation (WBI) Post-Lumpectomy for Early-Stage Breast Cancer as Measured by Breast-Q TM
Presenter(s)
N. W. Johnson1, S. S. Varghese2, Y. Cao2, R. C. Chen2, M. G. Boersma3, J. P. Einck2, D. Keleti2, A. Morris2, K. Rhodes-Stark4, C. K. Savioz2, S. R. Stecklein2, A. Tejwani2, and J. R. White5; 1University of Missouri, Kansas City, MO, 2Department of Radiation Oncology, University of Kansas Medical Center, Kansas City, KS, 3Department of Radiation Oncology, University of Kansas Medical Center, Kansas City, KS, 4Deaprtment of Radiation Oncology, University of Kansas Medical Center, Kansas City, KS, 5University of Kansas Comprehensive Cancer Center, Kansas City, KS
Purpose/Objective(s): Despite evidence from multiple trials, APBI has had limited adoption into clinical practice, in part due to uncertainty regarding toxicity and cosmetic outcomes. Our institution has prospectively collected disease-specific PROs on all patients receiving radiation therapy (RT) since 2022. We compared PROs related to skin toxicity and breast well-being for APBI versus (vs) WBI.
Materials/Methods: We included patients treated with WBI or APBI from 1-2022 to 12-2024 who completed PRO surveys at baseline and at least 1 follow-up. Skin toxicity and physical well-being were measured using the Breast-QTM Breast Cancer Core Checklist (“adverse effects of radiation”, and "Physical Well-Being: Chest” forms) Version 2.0, administered at baseline, then 1-, 6-, 12-, and 24-months post RT. For Skin Toxicity, patient bother is scored on 6 items (1-none, 2-a little, 3-a lot), yielding a total score of 6 to 18 (lower score = less bother) and analyzed as raw scores. Per the BREAST-QTM protocol, physical well-being of the breast scores the frequency of experiencing 10 breast symptoms in the last week (1-none, 2-sometimes, 3-always) that are totaled and undergo Rasch transformation, ranging from 0-100 (higher score = better well-being). Mean, standard deviation (SD), median, interquartile range, and confidence intervals were calculated at baseline and at each time point. Between-group comparisons were performed using two-sample t-tests and Mann–Whitney U tests. Minimal important difference (MID) was calculated to be =3 for Rasch-transformed scores based on 0.2 times the SD of the entire group’s mean Rasch score at baseline and at each time point.
Results: A total of 402 patients are included: 188 in the WBI group and 214 in the APBI group. APBI was delivered over 5 fractions daily or every other day, and WBI was delivered mostly over 15-16 fractions, with or without a boost. The mean age was 66 years, 67.2% had pT1 tumors, 100% cN0, 82.3% pN0, 16.8% pNx, and 95.3% were ER+. APBI was associated with significantly lower skin toxicity scores than WBI at 1, 6, and 12 months (all p < 0.05). Mean Rasch-transformed physical well-being scores were significantly higher in the APBI cohort at 1, 6, 12, and 24 months compared to the WBI cohort (all p < 0.05), with between-group differences meeting the threshold for clinical significance (MID = 3). Clinically meaningful improvement from baseline was observed earlier in the APBI cohort (12 months) compared to the WBI cohort (24 months).
Conclusion: The APBI group reported significantly lower skin toxicity and superior physical well-being compared to the WBI group at all evaluated time points. The APBI group demonstrated clinically meaningful improvements in physical well-being at all post-treatment time points and achieved clinically significant recovery from baseline earlier (12 months) than the WBI cohort (24 months). This analysis can help inform shared decision-making for patients considering APBI vs WBI.