Quality of Life After Partial or Whole Breast Irradiation After Breast-Conserving Surgery for Low-Risk Breast Cancer: 1-Year Results of a Phase 2 Randomized Controlled Trial

Abstract

We conducted a phase 2 randomized trial comparing partial breast irradiation (PBI) with whole breast irradiation (WBI) after breast-conserving surgery (BCS) in patients with low-risk breast cancer. Here, we report the quality of life (QoL) at 1 year.Women aged≥45 years with low-risk breast cancer after BCS were randomly assigned (1:1) to receive either PBI (40 Gy in 10 fractions over 2 weeks), or WBI (43.5 Gy in 15 fractions over 3 weeks) using tangential-field based IMRT technique. The primary endpoint, the incidence of ³ grade 2 acute and late toxicities, will be reported when participants have completed 5 years of follow-up. QoL was assessed at baseline (T0), end of radiotherapy (T1), and at 6 (T2), 12 (T3) months after radiotherapy (RT), using EORTC QLQ-C30 and QLQ-BR23 questionnaires. We calculated scores for all QOL domains, and focused on the difference in mean scale. Manne-Whitney U test was used to compare the difference between the two groups. Wilcoxon-signed rank test was used to examine the difference between T1, T2, T3 and T0 respectively in each group. The longitudinal analysis of QoL changes over time and between groups were assessed with generalized estimating equations (GEE) with log link function for mean scores. An interaction term between time and treatment group was used to assess if mean scale score change over time was statistically different between the two arms. Longitudinal analyses were mainly focused on selected subscales of the QLQ-C30 (global health status, physical functioning, role functioning, emotional functioning, social functioning, fatigue, pain, dyspnea, financial difficulties), and of the QLQ-BR23 (body image, future perspective, breast symptoms, and arm symptoms). The patients who completed the questionnaires at T0 and at least one other timepoint were eligible for analysis. All analysis was done according to treatment received (per protocol population). Two-sided P value<0.01 was considered statistically significant.Between June 2017 and January 2019, 140 women were randomly assigned to receive PBI (n = 70) or WBI (n = 70). Fifty- nine patients treated with PBI and 56 patients treated with PBI were eligible for QoL analysis. There were no significant differences in all subscales between the PBI and WBI groups at T0, T1, T2 or T3. Compared with T0, most QoL subscales that was influenced by RT recovered to the similar or better level within 1 year after RT, except for dyspnea. Longitudinal analysis showed that treatment, and the interaction term between treatment and time had no significant impact on the selected subscales. Time since RT showed significant impact on role functioning, social functioning, fatigue, pain, dyspnea, financial difficulties, body image, breast symptom and arm symptom.PBI using IMRT technique provides comparable QoL with WBI. Most QoL subscales that was influenced by RT recover to the similar or better level as compared to baseline within 1 year after RT.