Background
The optimal time sequences for chemotherapy and radiation therapy after breast surgery for patients with breast cancer remains unknown. Most of published studies were done for early breast cancer patients. However, in Egypt advanced stages were the common presentation. This retrospective analysis aimed to assess the optimum sequence for our population.

Methods
267 eligible patients planned to receive adjuvant chemotherapy [FAC] and radiotherapy. Majority of patients (87.6%) underwent modified radical mastectomy while, 12.4% had conservative surgery.

We divided the patients into 3 groups according to the sequence of chemotherapy and radiotherapy. Sixty-seven patients (25.1%) received postoperative radiotherapy before chemotherapy [group A]. One hundred and fifty patients (56.2%) were treated in a sandwich scheme (group B), which means that 3 chemotherapy cycles were given prior to radiotherapy followed by 3 further chemotherapy cycles. A group of 50 patients (18.7%) was treated sequentially (group C), which means that radiotherapy was supplied after finishing the last chemotherapy cycle. Patients' characteristics are balanced between different groups.

Results
Disease free survival was estimated at 2.5 years, and it was 83.5%, 82.3% and 80% for patient receiving radiation before chemotherapy [group A], sandwich [group B] and after finishing chemotherapy [group C] respectively (p > 0.5). Grade 2 pneumonitis, which necessitates treatment with steroid, was detected in 3.4% of our patients, while grade 2 radiation dermatitis was 17.6%. There are no clinical significant differences between different groups regarded pulmonary or skin toxicities.

Conclusion
Regarding disease free survival and treatment toxicities, in our study, we did not find any significant difference between the different radiotherapy and chemotherapy sequences.