Total neoadjuvant therapy for rectal cancer in the rural community oncology setting.

Abstract

41 Background: The treatment of localized rectal adenocarcinomas with Total Neoadjuvant Therapy (TNT) has become the national standard. Data on the efficacy of TNT in a predominantly rural community oncology setting is limited. Methods: This ongoing retrospective analysis included 94 patients with proficient MMR Stage II or III rectal adenocarcinoma treated with traditional neoadjuvant treatment of chemoradiation followed by surgical resection +/- adjuvant chemotherapy, or Consolidation (chemoradiation upfront) TNT versus Induction (chemotherapy upfront) TNT followed by surgical resection, diagnosed between 2017 and 2022 and treated at the Avera Cancer Institute in Sioux Falls, South Dakota. The primary objectives were to compare the pathologic response and treatment completion rates in patients with rectal cancer treated with TNT to patients treated with traditional neoadjuvant treatment. The secondary objective was to compare the pathologic response rate for TNT at different tumor locations. Results: Of 94 patients assessed, 54 patients received traditional neoadjuvant treatment and 40 patients received TNT. For patients treated with traditional neoadjuvant treatment, 43% (n=23) completed all recommended treatment, with 63% (n=34) achieving a partial response (PR) and 19% (n=10) a complete pathologic response (CR). For patients treated with TNT, 93% (n=37) completed all recommended treatment, and 68% (n=27) achieved a PR and 15% (n=6) achieved a CR. For patients that received Consolidation TNT (n=21), 66% (n=12) achieved a PR and 21% (n=4) achieved a CR. For patients that received Induction TNT (n=19), 68% (n=13) achieved a PR and 11% (n=2) achieved a CR. For patients with high tumor location (n=4) treated with TNT, 50% (n=2) achieved a PR and one patient achieved a CR (25%). For patients with mid tumor location (n=18) treated with TNT, 67% (n=12) achieved a PR and 22% (n=4) achieved a CR. For patients with low tumor location (n=18) treated with TNT, 72% (n=13) achieved a PR and one patient (6%) achieved a CR. Conclusions: The treatment of rectal adenocarcinoma with TNT in the rural community cancer center setting is achievable with a higher completion rate compared to traditional neoadjuvant treatment. Our results also show a trend toward a higher complete pathologic response rate in Consolidation compared to Induction approach and in high/mid rectal tumors compared to low rectal tumors. Future work will be conducted to assess for any differences in recurrence and survival.