A prospective study of quality of life in breast cancer patients undergoing radiation therapy

PURPOSE: The purpose of this study was to examine the impact of radiation therapy on quality of life (QOL) of breast cancer patients during and until 1 year after radiation therapy treatment. METHODS AND MATERIALS: Thirty-nine breast cancer patients treated with breast-conserving surgery were enrolled in a prospective study before whole breast radiation therapy (50 Gy plus a 10-Gy boost). No patient received chemotherapy. Data were collected before, at week 6 of radiation therapy, and 6 weeks and 1 year after radiation therapy. The primary outcome variable was quality of life (QOL), measured by Medical Outcomes Study 36-Item Short Form Version 2 (SF-36). Risk factors potentially associated with total SF-36 scores and its physical and mental health component summary scores were also examined, including age, race, marital status, smoking history, menopausal status, endocrine treatment, cancer stage, sleep abnormalities (assessed by the Pittsburgh Sleep Quality Index), and perceived stress levels (assessed by the Perceived Stress Scale). Mixed effect modeling was used to observe QOL changes during and after radiation therapy. RESULTS: Total SF-36 scores did not change significantly during and up to 1 year after radiation therapy compared with baseline measures. Nevertheless, increased body mass index (BMI) and increased perceived stress were predictive of reduced total SF-36 scores over time (P = .0064, and P < .0001, respectively). In addition, increased BMI was predictive of reduced physical component summary scores of the SF-36 (P = .0011), whereas increased perceived stress was predictive of worse mental component summary scores (P < .0001). Other proposed potential risk factors including skin toxicity from radiation therapy were not significant. CONCLUSIONS: Radiation therapy did not worsen QOL in breast cancer patients. However, pre-radiation therapy patient characteristics including BMI and perceived stress may be used to identify women who may experience decreased physical and mental function during and up to 1 year after radiation therapy.