Anal Adenocarcinoma Treated in the Era of Total Neoadjuvant Therapy and Nonoperative Management

Abstract

BACKGROUND: Anal adenocarcinoma bears a treatment strategy unique to other anal cancers. OBJECTIVE: To describe oncologic outcomes of total neoadjuvant therapy followed by watch and wait for anal adenocarcinoma. DESIGN: Retrospective analysis. SETTING: This study was conducted at a comprehensive cancer center. PATIENTS: Patients with anal adenocarcinoma treated between 2004 to 2019 were selected. INTERVENTIONS: Fifty-four patients received neoadjuvant therapy and were divided into two groups according to their treatment strategy: total neoadjuvant therapy versus single-neoadjuvant modality therapy. MAIN OUTCOME MEASURES: Organ preservation, tumor regrowth, local failure, distant metastasis rates, recurrence-free, and overall survival. RESULTS: The study included 70 patients with anal adenocarcinoma. Fifty-four patients (77%) received neoadjuvant therapy, of whom 30 (42%) received total neoadjuvant therapy and 24 (34%) received single neoadjuvant modality. Twenty-three (33%) patients achieved complete clinical response and were managed by watch-and-wait. The proportion of patients able to continue to watch-and-wait was higher after receiving total neoadjuvant therapy (60%) compared to single neoadjuvant modality therapy (20%) (p = 0.004). A tumor regrowth rate of 22% was observed in the total neoadjuvant therapy group. The 5-year overall survival rate was 70% (95% CI: 59%, 83%), including 61% (95% CI: 42%, 88%) for the total neoadjuvant therapy and 65% (95% CI: 48%, 88%) for single neoadjuvant modality groups. Colostomy was avoided in 50% of patients that received total neoadjuvant therapy and 83% watch and wait patients. Five-year recurrence-free survival rates of 55% (95% CI: 39%, 79%) and 30% (95% CI 15%, 58%) were observed in the total neoadjuvant therapy and single neoadjuvant modality groups, respectively. LIMITATIONS: Retrospective nature. CONCLUSIONS: This is the first report in the literature describing the safety and feasibility of non-operative management for anal adenocarcinoma. Anal adenocarcinoma treated with total neoadjuvant therapy and nonoperative management achieve comparable regrowth rates to those observed in rectal cancer, with similar oncologic outcomes to traditional treatment strategies. See Video Abstract.