Prospective Comparative Study of Hypofractionated Adjuvant Radiotherapy in 2 Virsus 3 Weeks in Breast Cancer

Female breast cancer (BC) has been the leading cause of cancer morbidity and mortality among women in the majority of countries for decades. In 2020, there were an estimated 2.3 million new cases and 685,000 deaths from female BC worldwide, which accounted for one in four cancer cases and one in six cancer deaths among women. u For women with newly diagnosed, non-metastatic breast cancer, treatment consists of a multidisciplinary approach that involves input from surgery, radiation oncology, and medical oncology. The objective of adjuvant radiation therapy (RT) is to eradicate any tumor deposits remaining following surgery for patients treated by either breast-conserving surgery or mastectomy . Doing so reduces risk of locoregional recurrence and improves breast cancer-specific and overall survivals. u A historical regimen of 25-28 fractions over 6 weeks was adopted for radiotherapy (RT) following breast- conserving surgery (BCS) and total mastectomy. An early assumption that breast cancer cell lines might be more sensitive to fractional doses than acute skin reactions and other squamous carcinomas lead to development of the hypofractionated RT (HypoRT) approach, which elevated fractional dose up to 3 Gy with reduced total dose/fractions, for obtaining radiobiological equivalence to a traditional regimen of 50-50.4 Gy in 25-28 fractions. u Recently, the American Society of Radiation Oncology released a task force guideline recommending hypofractionated radiotherapy for all women of any age whether they had received chemotherapy or not ,Their evidence-based recommendations were supported by studies from Canada and the United Kingdom. u Benefits of HypoRT include both, radiobiologic advantages and reduced length of treatment courses, for improving healthcare resources and patient convenience. Consequently, HypoRT has been widely adopted worldwide based on a series of randomized clinical trials . u Recently, HypoRT over 3 weeks and with shorter courses of 5 fractions have been recommended in treatment guidelines. u Regarding clinical outcomes of a 2-week fractionation schedule , it was observed that acute and late effects were acceptable with control rates similar to those reported in other trials with hypofractionation,Based on these findings we started a trial to compare a 3-week radiotherapy schedule with a 2-week schedule .