Acute Toxicity and Tumor Response in Locally Advanced Rectal Cancer After Preoperative Chemoradiation Therapy With Shortening of the Overall Treatment Time Using Intensity-Modulated Radiation Therapy With Simultaneous Integrated Boost: A Phase 2 Trial

Preoperative IMRT-SIB without dose escalation is well tolerated, with a low acute toxicity profile, and can achieve a high rate of pCR and downstaging.