Over the recent years , breast cancer remains the most common cancer in women in the world . With nearly 107 Million new Cases diagnosed in 2012 (second most common cancer over all) . this represent about 12 % of all new cancer cases and 25 % of all cancers in women . By contrast the mortality rate has declined dramatically since the introduction of adjuvant systemic therapy \& radiation therapy, which are now used extensively for their established benefit in local (radiotherapy ) ,survival without metastasis (chemotherapy) and overall survival of both of them . However , the optimal sequence of chemotherapy \& radiotherapy remain controversial three sequence were investigated:
1. Delivering all radiotherapy first .
2. A " Sandwich " approach .
3. Delivering all chemotherapy first . Observational studies have suggested that delaying initiation of chemotherapy increase the incidence of distant metastasis \& delaying the initiation therapy more than 6 months after breast cancer diagnosis might increase risk of local regional recurrence . Concurrent chemoradiation therapy has an advantage of shortening the duration of therapy , allowing radiotherapy \& chemotherapy to start temporally and potentially improving local control via radiation sensitizing effect of chemotherapy.The feasibility of concurrent radiotherapy with taxane, which constitute a standard treatment used as adjuvant therapy has been evaluated in stage II,III breast cancer. Taxane Promote stabilization of microtubules causing cell cycle arrest in G2/M junction and serve as radio sensitizing agents.In a prospective study using Paclitaxel \& radiotherapy concurrently Paclitaxel given every 3 weeks for 4 cycles the authors concluded that Concurrent chemoradiation therapy improve local control with acceptable toxicity.
