Additional information is available at the end of the chapter . Introduction Rectal cancer continues to affect many patients in the United States and world-wide. For instance, in , rectal cancer affected , "mericans [ ]. Patients affected with rectal cancer who have a clinical stage II T -T , NO, MO or III "ny T, N -N , M tumor are treated with pre-operative chemoradiation CRT followed by surgical intervention [total mesorectal excision TME ]. In up to % of patients treated with CRT, the tumor

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... ecomes clinically undetectable cCR [ ]. Clearly, this is a desirable outcome in oncology. "dding novel radiosanitizing agents, prolonging the period from CRT to TME, increasing the radiation dose, adding chemotherapy before CRT are few modalities that have been investigated to increase the number of patients achieving a complete response. The following chapter reviews current strategies in recent attempts at maximizing the ratio of patients who achieve a cCR. Current margins are resection following TME in the era of CRT are also reviewed. . Recent status of pre-operative biomarkers to determine a response to neoadjuvant chemoradiation Neoadjuvant chemoradiation for the management of patients with stage II and III rectal cancer results in a clinical complete response cCR , the absence of detectable rectal tumor with diagnostic modalities [i.e. endorectal ultrasound EUS , magnetic resonance imaging MRI , digital rectal exam DRE , or proctoscopy], in -% of patients [ ].