Long-Term Quality of Life Outcomes of Proton Beam PBI Compared With Photon Whole Breast Radiation Therapy

Abstract

Purpose/Objective(s): Long-term quality of life (QoL) is a salient factor in assessing outcomes of breast conservation therapy for patients with early-stage breast cancer. This study compares patient-reported QoL outcomes among women with stage 0-II disease treated with partial mastectomy followed by partial-breast proton irradiation (PBPI) or whole-breast photon (WBI). Purpose/Objective(s): PBPI subjects were recruited from previous participation in an institutional prospective clinical trial. WBI subjects were recruited from a registry maintained at the same institution. QoL tools completed included the Harvard Cosmesis Scale (HCS), Breast Cancer Treatment Outcome Scale (BCTOS), Brief Fatigue Inventory (BFI), Medical Outcomes Study (MOS) Short Form, and Body Image Scale (BIS). Results: 180 subjects received surveys with 142 being completed and returned yielding a 79% participation rate. 13 were determined to be ineligible due to bilateral disease, disease recurrence, metastatic disease, or other serious medical co-morbidities. 129 participants completed QoL and were included for evaluation, 72 following PBPI and 57 following WBI. Median time from treatment was 7.4 years (PBPI) and 6.3 years (WBI). The two groups were well matched for age, weight, marital status, race, education, employment, recent health status, stage, tumor size, extent of surgery, and use of adjuvant systemic therapy. Significant differences favoring the proton group were seen for several domains. The HCS showed higher cosmetic mean scores for PBPI 3.4 vs WBI 2.4 (p<0.001). BCTOS results showed improved weighted BCTOS (5.5 vs 7.6, p<0.001), cosmetic BCTOS (11.6 vs 15.0, p<0.001), and BS pain (4.2 vs 5.3, p=0.005) for PBPI vs WBI respectively. BFI demonstrated reduced fatigue (2.2 vs 3.8, p=0.002) with less interference with daily general activities (1.7 vs 2.8, p=0.017) for PBPI vs WBI. MOS survey resulted in statistically significant improved perception of general health with improved emotional and social functioning for PBPI. BIS resulted in improved overall score favoring PBPI (12.1 vs 14.2, p=0.009). Conclusion: Patients' responses suggest that partial-breast proton radiotherapy is associated with higher long term overall QoL across multiple domains when compared to a comparable cohort of patients treated with whole breast radiotherapy. CN - 7.038