Abstract P1-15-19: Effects of statin use on skin toxicity during breast radiation therapy

Abstract

Abstract Background: Recent San Antonio Breast Cancer Symposium abstracts have suggested that statin use confers a significant benefit in breast cancer risk reduction and specifically in the subset of inflammatory breast cancer. Additional studies evaluating the combination of statin use with various breast cancer treatments are currently on-going. The primary objective of this study was to determine the effects of statin use on acute skin toxicity during breast radiation therapy (RT). Methods: We performed a retrospective chart review of 325 patients diagnosed with breast cancer who underwent RT between 2004 and 2012. Of these, 227 patients were considered evaluable. Patients were excluded if the course of RT was fewer than 16 treatments. Patients were also excluded if follow-up at the end of RT was not obtainable. Of the evaluable patients, 46 were on statins at time of RT, while 181 were not. Patients were evaluated at two time points - midway through RT and at completion of RT. Skin reactions were measured using the RTOG grading system for acute radiation morbidity. Grade 1 reactions were erythema and slight skin atrophy. Grade 2 indicated follicular, faint or dull erythema/ epilation/dry desquamation/ decreased sweating. Grade 3 was tender or bright erythema, patchy moist desquamation/moderate edema. Lastly, Grade 4 was ulceration, hemorrhage, necrosis. Results: Our results showed a statistically significant increase in acute radiation skin toxicity in patients on statins at the time of radiation therapy. By the midway point of RT, 67% of the statin group had developed Grade 1-3 skin toxicity vs. only 42% of the control group. Odds ratio midway through RT was 2.75. By the completion of RT, 94% of the statin group compared with 67% of the control group had Grade 1-3 skin toxicity (p=0.005). Odds Ratio at completion of RT was 7.29. The statin group also progressed to more advanced stages of toxicity more rapidly than our control group. Grade 1 skin reactions were seen in 62% of our statin group vs. 41% of our control group midway through treatment (p=0.044). Grade 2-3 reactions were seen in almost 5% of patients in the statin group vs. 1% in the non-statin group midway through treatment. At the end of treatment, 48% of patients on statins had developed Grade 2-3 reactions when compared with 29% in the non-statin group (p=0.0199). These results still remained significant when controlled for chemotherapy use. Conclusion: Our study revealed that patients on statins developed acute skin toxicity at higher rates than our control group. These results were statistically significant at both the midway point as well as at the completion of RT. Study limitations include the small sample size and the retrospective nature of the study. Our data also raises the question of what effect statins may have on local recurrence rates as well as the potential effects of radiosensitization in various breast cancer cell lines. These results are hypothesis-generating and require larger retrospective analyses or prospective trials to verify this effect. Citation Format: Scott M Lieberman, Elizabeth Stone, Christopher Chen, Marlow Hernandez, Leah Roberts. Effects of statin use on skin toxicity during breast radiation therapy [abstract]. In: Proceedings of the Thirty-Seventh Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2014 Dec 9-13; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2015;75(9 Suppl):Abstract nr P1-15-19.