Evaluation Of Two Boost Radiation Schedules In Post Lumpectomy Early Stage Carcinoma Breast.

Introduction Breast-conserving surgery (BCS) followed by radiation therapy to the intact breast is an established standard of care for the majority of women with early stage invasive breast cancer. Recommended whole breast irradiation (WBI) schedule is 45 to 50 Gy and it is followed by a boost of 10 to 16 Gy to the tumour bed. In this study we compared boost schedule of 10Gy/5#/1 week with 16Gy/8#/1.5 weeks in post lumpectomy patients of early stage breast cancer. Materials and methods From October 2012 to December 2016, the study included 87 early stage breast cancer patients post BCS. All patients were treated by WBI of 40Gy/16#/3weeks. WBI was followed by tumor bed boost of 10Gy/5#/1 week in 44 patients or 16Gy/8#/1.5 weeks in 43 patients with either electron beam therapy or 3 dimensional conformal radiotherapy (3D CRT). The primary end point of the study was the assessment of acute and late radiation toxicities, cosmetic score analysis and local control between two schedules. Assessment of acute and late skin toxicity was done as per RTOG scores and LENT SOMA scale. Cosmetic assessment was done with Harvard/NSABP/RTOG Breast Cosmesis Grading Scale. Results Acute skin grade 2 toxicity was more in patients with 16Gy boost 33% as compared to 23% in 10Gy boost arm. Late skin toxicities were also high in patients with 16Gy boost. Grade 2 induration was seen in 4.5% and 12% patients with 10Gy and 16Gy boost respectively. None of the patients with 10Gy had grade 3 induration as compared to 2% with 16Gy. Similarly none of the patients with 10Gy had grade 2 oedema as compared to 5% with 16Gy. Pigmentation was observed in 9% and 23% patients with 10Gy and 16Gy boost respectively. Grade 1 fibrosis was 2% versus 12% in patients with 10Gy and 16Gy boost respectively. Median follow up was 39 months. Cosmetic score was good/excellent in 91% and 84% patients with 10Gy and 16Gy boost respectively. It was fair/poor in 9% and 17% with 10Gy and 16Gy boost respectively. Local recurence occurred in one patient in 16Gy arm. Conclusion Acute and late skin toxicity was higher with 16Gy boost dose. Cosmetic score was better with 10Gy boost. [ABSTRACT FROM AUTHOR]