Locally Advanced Rectal Cancer: Time for Precision Therapeutics

Abstract

The year 2015 marks the 30th anniversary of the publication of NSABP-R01, a landmark trial demonstrating the benefit of adding pelvic radiation to the treatment regimen for locally advanced rectal cancer with a resultant decrease in local recurrence from 25% to 16%. These results ushered in the era of multimodal therapy for rectal cancer, heralding modern treatment and changing the standard of care in the United States. We have seen many advances over the past 3 decades, including optimization of the administration and timing of radiation, widespread adoption of total mesorectal excision (TME), and the implementation of more effective systemic chemotherapy. The current standard is neoadjuvant chemoradiation with 5-fluorouracil (5-FU) and a radiosensitizer, TME, and adjuvant chemotherapy including 5-FU and oxaliplatin. The results of this regimen have been impressive, with a reported local recurrence rate of less than 10%. However, the rates of distant relapse remain 30% to 40%, indicating room for improvement. In addition, trimodality therapy is arduous and many patients are unable to complete the full course of treatment. In this article we discuss the current standard of care and alternative strategies that have evolved in an attempt to individualize therapy according to risk of recurrence.