New treatment strategies for non-metastatic rectal cancer.

The most widely practiced (standard) treatment of non-metastatic rectal cancer is based on proctectomy with mesorectal excision (partial or total according to the location of the tumor and commonly called TME). Surgery is preceded by CAP50-type chemoradiotherapy (capecitabineand 50 Grays radiation) and performed 6-8 weeks after the end of chemoradiotherapy. The development of new endoscopic, surgical, radiation-based and chemotherapeutic modalities leads surgeons to envisage customized treatment to find the best compromise between functional and oncologic results according to the locoregional extension of the tumor. Superficial lesions are amenable to transanal excision. T2-3 tumors<4cm are amenable to rectal preservation when neoadjuvant treatment obtains a complete response, allowing local excision or close surveillance. Intensification endocavitary radiotherapy and induction and consolidation chemotherapy regimens to avoid recourse to salvage abdomino-perineal resection (APR) are under investigation. For locally advanced rectal cancers (T3-4 and all N+ irrespective of T), the following scenarios can be envisaged: for initially resectable tumors (T3N0, T1-T3N+, circumferential resection margin>2mm), neoadjuvant chemotherapy alone aims to minimize the risk of local recurrence while avoiding the sequelae of radiotherapy. In case of initially non-resectable tumors (T4, circumferential resection margin<1mm), induction chemotherapy before chemoradiotherapy and consolidation chemotherapy after short course radiotherapy provide better results than standard treatment in terms of complete response and recurrence-free survival, and should be routinely proposed in this indication.