Neoadjuvant Chemotherapy without Radiation in Colorectal Cancer

In colon cancer, primary surgery followed by postoperative chemotherapy represents the standard of care. In rectal cancer, the standard of care is preoperative radiotherapy or chemoradiation, which significantly reduces local recurrence but has no impact on subsequent metastatic disease or overall survival. The administration of neoadjuvant chemotherapy (NACT) before surgery can increase the chance of a curative resection and improves long-term outcomes in patients with liver metastases. Hence, NACT is being explored in both primary rectal and colon cancers as an alternative strategy to shrink the tumor, facilitate a curative resection, and simultaneously counter the risk of metastases. Yet, this lack of clarity regarding the precise aims of NACT (downstaging, maximizing response, or improving survival) is hindering progress. The appropriate cytotoxic agents, the optimal regimen, the number of cycles, or duration of NACT prior to surgery or in the postoperative setting remains undefined. Several potential strategies for integrating NACT are discussed with their advantages and disadvantages.