Abstract P4-16-01: Accelerated hypofractionated whole breast radiotherapy for localized breast cancer: the effect of a boost on patient reported long-term cosmetic outcome

Abstract

Abstract PURPOSE: Equivalent long-term local control and cosmetic outcomes between conventional and accelerated, hypofractionated whole breast radiotherapy (AWBRT) for early-stage breast cancer have been demonstrated. However, there is uncertainty about the long-term cosmetic outcome of a boost to the tumor bed following AWBRT (AWBRT+B). The primary outcome of this study was to evaluate the cosmetic effect of a boost using a patient reported questionnaire. The cosmetic subscale in the questionnaire was used to compare the appearance of the treated versus non treated breast between the boost and non-boost groups. MATERIALS AND METHODS: Between 2000 and 2005, 4392 women 75 years and under with unilateral early-stage breast cancer received AWBRT alone or AWBRT+B. Random samples of 800 women treated with AWBRT alone and 800 women treated with AWBRT+B were identified from the 3960 women still alive at least 5 years after treatment without contralateral disease. The women were contacted by mail to complete a questionnaire based on the Breast Cancer Treatment Outcomes Scale (22 questions regarding cosmetic, pain and functional outcomes). Cochrane-Armitage (CA) trend test and Wilcoxon Rank-sum (WR) were used to compare baseline patient and treatment variables to long-term cosmetic outcomes between the two treatment groups. RESULTS: 312 women (154 received AWBRT alone and 158 received AWBRT+B) completed the questionnaire. The median (range) age of respondents was 57 (40–75) years in the AWBRT alone group and 52 (32–75) years in the AWBRT+B group (p < 0.001). The median (range) follow-up time after radiotherapy treatment was 8.7 (5.5–11.5) years in the AWBRT alone group and 7.8 (5.5–11.5) years in the AWBRT+B group (p < 0.001). Boost doses ranged between 7.5 Gy in 3 fractions to 16 Gy in 8 fractions. The most commonly used boost regimen was 10 Gy in 4 fractions (70% of respondents). Women treated with AWBRT+B also had higher T stage, higher grade, were more likely to have had chemotherapy and trended towards having an increased number of positive nodes compared to the AWBRT alone group. Current weight, ER status, and use of hormonal therapy were similar between both groups. When comparing the overall appearance of the treated to untreated breast, there was no significant difference between the women who received AWBRT alone and those who received AWBRT+B (42% stating no or slight difference vs. 41%) (p = 0.87 CA). Focusing on the cosmetic subscale in the questionnaire, the average summed score for the AWBRT alone group was slightly worse to the score for the AWBRT+B group (2.3 vs. 2.1, p = 0.02 WR). On the functional subscale, the average summed score for the AWBRT alone group was worse than the AWBRT+B group (1.8 versus 1.5, p < 0.001 WR). On the pain subscale, the average summed score for the AWBRT alone group was better than the AWBRT+B group (1.6 versus 2.0, p < 0.0001 WR). However, when the pain subscale was only applied to the area around the scar, the two groups were similar (2.0 for AWBRT alone and 2.0 for AWBRT+B, p = 0.71). CONCLUSION: Similar to conventionally fractionated WBRT, patients who receive a boost after AWBRT self-report long-term slightly worse cosmetic and pain outcomes compared AWBRT alone. Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P4-16-01.