Response to Letter to the Editor: Neoadjuvant Therapy for Rectal Cancer: The Impact of Longer Interval Between Chemoradiation and Surgery

To the Editors: We thank Dr. Huerta for his kind words and thoughtful comments on our recent article. He brings forth several key issues that remain among the top challenges in treating rectal cancer. We agree that it would obviously be paramount to identify which patients would achieve a pathologic complete response (pCR), but unfortunately this is not currently possible. Indeed, our group and others are currently investigating possible genetic markers to potentially identify which patients are most likely to achieve pCR, but only the future will tell. As Dr. Huerta states, the interval of 8 weeks for analysis in this study was chosen from our previous work which identified that waiting at least 8 weeks was independently associated with a higher percentage of patients achieving pCR. This was a nonrandomized, retrospective study and the exact interval that would be most effective remains undefined. A welldesigned trial is necessary to accurately address this matter and an ongoing NIH-sponsored multicenter prospective trial is enrolling approximately 250 rectal cancer patients into one of five different treatment groups based on an increasing interval between completion of neoadjuvant therapy and surgery. The intervals being examined are 6, 12, 16, 20, and 24 weeks and the study is expected to complete enrollment within this year. Patients in the longer interval treatment arms will receive chemotherapy during the waiting period. Results of this trial will answer some of the critical issues regarding intervals between neoadjuvant chemoradiation and surgery.