Polymorphism and Radiation-Induced Fibrosis in Patients With Early-Stage Breast Cancer
Posted: Tuesday, September 25, 2018
Patients with early-stage breast cancer who expressed the C-509T variant allele of the TGFB1 gene seemed to be at higher risk for developing radiation-induced fibrosis, according to a randomized clinical trial by Aaron J. Grossberg, MD, PhD, of The University of Texas MD Anderson Cancer Center, Houston, and colleagues, published in JAMA Oncology. The researchers advised that the C-509T allele may be used prospectively as a genetic marker to identify patients at elevated risk for fibrosis following radiotherapy.
From 2011 through 2014, 287 women (aged 40 or older) with stage 0 to IIA breast cancer treated with breast-conserving surgery were enrolled in this trial, which compared hypofractionated whole-breast irradiation and conventionally fractionated whole-breast irradiation. TGFB1 genotype and 3-year radiotherapy-induced toxicity data were available for 174 patients. Of this group overall, 51% had at least one copy of C-509T, further delineated as 48% of the conventional group and 54% of the hypofractionated group. Patients were observed for at least 3 years.
The overall rate of grade 2 or higher fibrosis was significantly higher for patients with the C-509T allele, occurring in 13.8% of patients, compared with 3.8% of patients without the allele. This finding was independent of radiotherapy fractionation regimen or postsurgical, preradiotherapy cosmesis. On multivariate analysis, the C-509T genotype and baseline postsurgical, preradiotherapy panel physician-assessed cosmesis were both significantly associated with fibrosis risk.
“Assessing TGFB1 genotype may facilitate a more personalized approach to locoregional treatment decisions in breast cancer,” the authors concluded.
