Randomized Prospective Study Comparing Conventional Versus Hypofractionated Adjuvant Radiotherapy in Node Positive Breast Cancer

Abstract

reast cancer is the most common cancer among US women, representing 30% of all newly diagnosed cancer cases. It has been estimated that 93% of breast cancer cases are diagnosed with localized and regional stage with 31 % representing the node positive cases. In Egypt, the estimated incidence rates proportion of breast cancer among females in Lower, Middle, and Upper Egypt are 33.8%, 26.8% and 38.7% respectively. In an institutional epidemiological study done in the period between Jan 2010 to December 2014, the estimated total number of breast cancer patients was 1906 patients, 74% of them diagnosed with localized and regional disease, including 57% with node positive disease (American Cancer Society, 2018; Siegel et al., 2018; Amal et al., 2014& Gado et al., 2017). Randomized clinical trials in addition to meta-analyses have confirmed that adjuvant irradiation not only spare patients the morbidity and distress of local recurrence by improving local control, but it also improves overall survival by preventing distant metastases from remaining reservoirs of loco-regional disease (Clarke et al., 2005). Upon the historical hypothesis that breast cancer cells are less sensitive to changes in the dose per fraction than the dose limiting normal tissues; a daily fraction equal to 2 Gy for 25 fractions over total period of 5-7 weeks for total dose 50-60Gy was delivered in most of the original studies, therefore it was suggested to be the standard fractionation schedule (Fisher et al., 2002).