(P024) Predictors of Radiation-Induced Skin Toxicity: Data From a Prospective Cohort Receiving Breast Radiation

April 30, 2015

In this prospectively followed cohort of breast cancer patients receiving RT to the intact breast, novel predictors for more severe skin toxicity were identified, including PR-negative status, invasive ductal histology, and receipt of chemotherapy, as well as known risk factors, including BMI and fractionation scheme.

Jean Wright, MD, Cristiane Takita, MD, Isildinha M. Reis, Wei Zhao, MD, BS, Eunkyung Lee, MS, Jennifer Hu, PhD; Johns Hopkins University; University of Miami

PURPOSE/OBJECTIVES: Breast radiation (RT) is generally well tolerated, but acute skin toxicity is a common side effect that can impact receipt of treatment and quality of life. We sought to identify predictors of radiation-induced skin toxicity in a racially and ethnically diverse cohort of women receiving RT to the intact breast.

MATERIALS AND METHODS: We evaluated the first 392 patients in an ongoing prospective study assessing radiation-induced skin toxicity in patients receiving breast RT. We recorded patient demographics, body mass index (BMI), and disease and treatment characteristics. Skin toxicity grade using Common Terminology Criteria for Adverse Events (CTCAE) and a modified scale capturing moist desquamation were captured at Week 3 and at RT completion. Logistic regression analyses were conducted to evaluate the effect of potential predictors on the risk of skin toxicity.

RESULTS: A total of 20.2% self-identified as African American, 15% self-identified as non-Hispanic white, 61.5% self-identified as Hispanic white, and 3.3% self-identified as other. Mean age was 56.2 years, and 74.2% had a body mass index (BMI) ≥ 25. Disease was stage 0 in 20.2% (in situ), I in 49.2%, and II or III in 30.6%. Further, 17.2% of patients were treated with hypofractionated regimens to the breast +/− regional nodes with a whole-breast dose of < 45 Gy, and 82.8% of patients were treated with conventionally fractionated regimens with a dose of ≥ 45 Gy. On multivariate analysis, both scales identified higher BMI, higher disease stage, invasive ductal histology, progesterone receptor (PR)-negative status, and conventionally fractionated regimens with total radiation dose ≥ 45 Gy as predictors for higher skin toxicity grade. The modified scale also identified larger breast volume as a predictor for moist desquamation, and the CTCAE scale identified chemotherapy use as a predictor for grade 2/3 skin toxicity.

CONCLUSION: In this prospectively followed cohort of breast cancer patients receiving RT to the intact breast, novel predictors for more severe skin toxicity were identified, including PR-negative status, invasive ductal histology, and receipt of chemotherapy, as well as known risk factors, including BMI and fractionation scheme.

Proceedings of the 97th Annual Meeting of the American Radium Society - americanradiumsociety.org