Feasibility of Organ Preservation With Short Course Radiation Therapy as Part of Total Neoadjuvant Therapy in Locally Advanced Rectal Cancer During the COVID-19 Pandemic

Abstract

\n Purpose/Objective(s)\n While long course chemoradiation therapy has been studied as part of a watch-and-wait (WW) strategy for patients with locally advanced rectal cancer, it is unclear whether short-course radiation therapy (SCRT) will be associated with similar rates of organ preservation. We hypothesized that a WW strategy to facilitate organ preservation with SCRT, as part of a total neoadjuvant therapy (TNT) approach during the COVID-19 pandemic, would be both safe and feasible.\n \n Materials/Methods\n From March to June of 2020, due to the COVID-19 pandemic, per institutional policy, all patients undergoing radiation therapy for locally advanced rectal cancer were treated with SCRT. After completion of SCRT-TNT, patients were clinically restaged by exam, endoscopy and MRI and the decision was made to manage the patient surgically or with a WW approach. The decision for WW or surgery was made by the surgeon in conjunction with patient consent. After IRB waiver was obtained, we reviewed consecutive patients treated during our SCRT mandate. The main outcome of interest was total mesorectal excision (TME)-free survival among patients eligible for WW after SCRT-TNT.\n \n Results\n Our cohort included 42 patients with a median age of 57 years (Interquartile Range [IQR] 48-67), 24 (57%) of whom were male. Median follow-up from end of SCRT-TNT was 7 months (IQR 6-8). The median tumor cranio-caudal size was 4.1 cm (IQR 3.3-5.2) with a median distance from the anal verge of 7 cm (IQR 5-9). The majority had cT3 (71%) or cN+ (74%) disease. Patients underwent a median of 14 weeks (IQR 13-15) of FOLFOX or CAPEOX chemotherapy, with 32 (76%) patients receiving chemotherapy prior to SCRT and 10 (24%) patients receiving chemotherapy after SCRT. The median time from completion of TNT to endoscopic restaging was 9 weeks (IQR 7-10). Nineteen (45%) patients were recommended to undergo surgical resection, of whom 17 went on to TME and 2 refused TME. Of the 15 patients with pathology available, 2 had a pCR (13%). Notably, one of these patients had a cCR at post-TNT endoscopy, but due to the presence of a stricture, WW was deemed unfeasible. Of the 23 patients managed by a WW strategy after SCRT-TNT completion, 19 had a clinical complete response (cCR), 3 had a near-CR, and 1 had an incomplete response. The 6-month TME-free survival was 85% for patients on WW. Four (17%) patients had a local regrowth at a median of 20 weeks (IQR 17-24), 3 of whom were salvaged with TME and 1 who declined surgery and opted for further surveillance. One of these patients had regrowth confirmed by biopsy, but had a pCR confirmed in the TME specimen. The 6-month TME- free survival of the entire cohort was 52%, and the combined pCR/6-month cCR was 52%.\n \n Conclusion\n Our data suggest WW after SCRT-TNT is feasible. Longer term follow-up is required to confirm the durability and oncologic safety of these results.\n