Surveillance Intensity Comparison by Risk for T1NX Locally Excised Rectal Adenocarcinoma: a Cost-Effective Analysis

Controversy exists regarding the optimal surveillance strategy following local excision of T1NX rectal adenocarcinoma. This study aims to determine the cost-effectiveness of surveillance strategies for locally excised T1NX rectal adenocarcinoma based on histopathologic and local staging risk factors.

A Markov model with 10-year follow-up was developed for cost-effectiveness analysis of high-, medium-, and low-intensity surveillance strategies after local excision of T1NX rectal adenocarcinoma. Literature review and expert consensus were utilized to populate state/transition probabilities and rewards. Based on this data, 87% of T1NX patients undergoing local excision were low risk. Healthcare utilization costs were based on Centers for Medicare and Medicaid Services data. The primary outcomes were costs in 2018 US dollars and effectiveness in life-years presented as net monetary benefit and incremental cost-effectiveness ratios. One-way sensitivity and probabilistic sensitivity analyses were performed.

Net monetary benefit for low-, medium-, and high-intensity surveillance strategies ($393,117.00, $397,978.80, and $397,290.00) shows medium-intensity surveillance to be optimal. One-way sensitivity analysis shows medium-intensity surveillance to be optimal when the cohort is 73-94% low risk. High-intensity surveillance is preferred when less than 73% of the cohort is low risk. Low-intensity surveillance is preferred when greater than 94% is low risk. Probabilistic sensitivity analysis of the base-case shows medium-intensity surveillance is the optimal strategy for 51.5% of the iterations performed.

Medium-intensity surveillance is the most cost-effective surveillance strategy for locally excised T1NX rectal adenocarcinoma in a clinically representative population model.