Total neoadjuvant therapy approach in rectal adenocarcinoma

The treatment of locally advanced rectal cancer has improved over the years owing to advancements in surgical techniques and chemoradiation, developing into a multidisciplinary approach that has contributed to markedly reduced rates of local recurrence. Despite these advances, however, distant metastatic recurrence continues to be the main cause of rectal cancer-related death. Unfortunately, the former standard of care of neoadjuvant chemoradiation followed by surgery and adjuvant chemotherapy is still associated with significant morbidity and distant relapse rates. Many trials have studied the optimal sequence, timing, and duration of the individual components of treatment, more recently shifting both chemoradiation and systemic chemotherapy to the preoperative setting in an approach termed total neoadjuvant therapy (TNT). Some of the potential advantages of TNT include improved adherence to treatment, early treatment of micrometastases, and tumor downstaging, with the possibility of observation instead of surgery for those patients with a complete clinical response. This review provides the historical context for the shift to TNT in the treatment paradigm and discusses the critical clinical trials supporting the newer strategy. It also addresses the recent focus on the personalization of care that TNT makes possible by allowing the selective omission of radiation therapy and nonoperative management with a watch-and-wait strategy.