The study included sixty patients who underwent breast conservative surgery followed by post-operative radiotherapy. They were planned using 3D conformal technique to receive whole breast irradiation and tumor bed boost. Patients were then randomized to receive either arm (A) or arm (B) regimens; where patients in arm (A) received WBI followed by tumor bed boost i.e. sequential boost, while patients in arm (B) received WBI with a concomitant tumor bed boost immediately after WBI session. Patients were then followed up for a median period of 25 months (ranging from 14.3 to 32.9 months).Plan summation was generated twice for every patient; once for WBI plan and B-PTV photon beam plan, then again for WBI plan and B-PTV electron beam plan. Each summated plan was then reviewed, and after comparing both plan sums - regarding target coverage and dose to OAR- one was chosen for treatment (photon or electron) before randomization. Patients were then randomized to either arm (A) or arm (B). After finishing the course of irradiation, patients were kept under follow-up every 3 months for clinical examination and annual mammosonography. At the end of the study, echocardiography & PFT were repeated for each patient, and cosmetic evaluation was done