Comparison of Clinical Outcomes in Locally Advanced Distal Rectal Cancer Patients with Complete Clinical Response: Total Mesorectal Excision versus Nonoperative Management

Abstract

Abstract Background: Over the past few decades, nonoperative management (NOM) has become increasingly prevalent as an effort to preserve organs and improve functional outcomes compared to surgery. Objectives: This study aims to compare the clinical outcomes of patients with locally advanced distal rectal cancer (LADRC) following neoadjuvant treatment with either total mesorectal excision (TME) or NOM. Design: The study was conducted retrospectively. Patients and Methods: The study was conducted at two comprehensive cancer centers between January 1, 2014, and October 31, 2019. The study included all LADRC patients with clinical complete response (cCR) following neoadjuvant treatment, and who agreed to NOM or had a pathology report concluding that they had achieved pathologic complete response (pCR) following TME. Main Outcomes and Measurements: We evaluated patients for the presence of local regrowth or recurrence (LR), distant metastases (DM), and survival. Sample Size: A total of 462 individuals were identified from the database of the centers. Among them, 137 (31.8%) were confirmed to have achieved cCR. Results: Out of 137 patients with cCR, 67 patients were treated with NOM and 70 patients underwent TME, with 69 of them achieving pCR. In terms of baseline characteristics and tumor location, the patients in the NOM group (n = 67) did not differ from those in the pCR group (n = 69) (P > 0.05). Surveillance of the 67 patients in the NOM group revealed that 10 (15%) developed local regrowth and required salvage surgery. As a result of salvage surgery, 65 patients (97%) maintained pelvic control. Although there was no evidence of pelvic recurrence in the pCR group, three patients (4.3%) underwent metastasectomy for DM. In the NOM group, DM was observed in two (20%) out of ten patients after salvage surgery for local regrowth, whereas no DM was detected in NOM patients without local regrowth. In the NOM group, DM was significantly associated with local regrowth compared to those who did not develop pelvic regrowth (20% vs. 0%; P < 0.05). It was observed that the pCR group had improved disease-free survival rates (95.7% vs. 85.1%, P = 0.034); however, there was no difference in the overall survival rates (100% vs. 98.5%, P = 0.248). Conclusion: Compared with the traditional trimodal treatment strategy, NOM is a safe and promising treatment option for selected LADRC patients with an acceptable rate of pelvic control and overall survival. Consequently, close endoscopic and radiologic monitoring is essential to maximize the likelihood of an early detection of recurrence and a successful salvage surgery. Limitations: Due to its retrospective nature, this study has limitations primarily related to data collection from patients’ records and databases after the completion of follow-up. Conflict of Interest: The authors have no conflict of interest to declare.