الفهرس 
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Abstract
مستخلص اAdjuvant radiotherapy is an essential part in the management of breast cancer patients and is delivered either in conventional or hypofractionated schedules.
In this retrospective study we reviewed the medical records of 2890 female breast cancer patients and we summarized our experience in hypofractionated adjuvant breast radiotherapy over the last 10 years from Jan. 2007 to Dec. 2016 in two main radiotherapy centres in Alexandria (ACOD and AAAOC).
Our main findings with a median follow up of 45.5 months locoregional failure occurred in 11.9% in CF RT patients and in 5.8 % of the HF RT patients (P value <0.001, OR 0.46, 95% CI 0.32 - 0.66), distant relapse occurred in 23.1% in CF RT patients and 15.6% of HF RT patients (P value <0.001, OR 0.62, 95% CI 0.48 - 0.79).
There were no statistically significant difference between CFRT and HFRT in 5 year OS (90.1% vs. 88.9%), nor in 5 year DFS (73.5% vs. 76.5%) with p values of 0.276 and 0.173 respectively, with comparable reported late adverse events in both arms. However, there were a statistically significant difference in the 5 year LRFS in favour of the hypofractionated RT regimen group (P = 0.024).
We found in the multivariate analysis of prognostic factors affecting relapse that age at diagnosis >42, the use of hypofractinated RT regimen and no delay or delay shorter than 5 days (0.7 weeks) due to interruption in radiotherapy course decrease the risk of relapse, while presence of PNI and ECE increase the risk of relapse.
In addition we found that early or late locoregional failure had a significant effect on the 5 year overall survival (p < 0.001).
In the early relapsing patients we found that the use of HF RT regimen was associated with a significant better overall survival than CF RT regimen especially in the first 5 years (p =0.003), while in late relapsing patients it had a comparable effect on overall survival (p =0.56).
In a subgroup analysis, we found that HF RT regimen is equally effective or even better in terms of DFS and OS (p= 0.277 and p=0.139 respectively) than the usual CF RT regimen in node positive patients and in regional nodal irradiation.
In another subgroup analysis of postmastectomy patients we found a significant DFS benefit in favour with the use of HF RT regimen (p = 0.049) and equal OS as the usual conventional regimen used (p = 0.26).