Association of Therapeutic Mammoplasty and Radiotherapy Side-effects.
INTRODUCTION: Patients with larger breast size and volume are at increased risk of side-effects (toxicity) from radiotherapy. Therapeutic mammoplasty (TM) extends breast-conserving surgery by combining wide local excision of the cancer with breast reduction and mastopexy techniques. The aim of this study was to determine the effect of TM using level 2 oncoplastic techniques on the incidence of early and long-term radiotherapy side-effects. PATIENTS AND METHODS: Breast cancer patients recruited prospectively into the multicenter REQUITE cohort study (www.requite.eu) at a single institution (n = 346) were included. Radiotherapy side-effects (CTCAE v4.0) were scored at baseline, following radiotherapy, and at 2-year follow-up. The association of TM and specimen resection weight were investigated in multivariable regression models. RESULTS: At 2 years, 20.1 % of patients had grade ≥ 2 atrophy, 23.2% grade ≥ 1 tumor bed induration (fibrosis), 12.6% grade ≥ 1 breast induration, and 12.1% grade ≥ 1 telangiectasia. 22.5 % of patients (n = 78) underwent TM. TM patients had larger tumors (P = .006) and specimen resection weights (P < .001). TM but not specimen resection weight was associated with reduced tumor bed induration (Odds ratio = 0.12, 95% confidence interval [CI] 0.035-0.395, P = .001), breast induration (OR 0.19, CI 0.043-0.852, P = .03) and telangiectasia (OR 0.12, CI 0.020-0.736, P = .02). Neither TM nor specimen weight had any effect on atrophy or early radiotherapy side-effects. CONCLUSION: TM but not resected specimen weight was associated with fewer long-term radiotherapy side-effects. This implies that the incidence of side-effects is affected not by reducing the overall radiotherapy target volume but by re-shaping the breast, which is likely to reduce dose inhomogeneity.