Nonoperative Management Versus Radical Surgery of Rectal Cancer after Neoadjuvant Therapy-Induced Clinical Complete Response: A Markov Decision Analysis.

BACKGROUND: Nonoperative management of rectal cancer was introduced for patients with clinical complete response after neoadjuvant chemoradiotherapy to avoid short- and long-term surgical morbidity related to radical resection. OBJECTIVE: To determine the expected life years and quality-adjusted life years for non-operative management and radical resection of locally advanced rectal cancer, following clinical complete response after neoadjuvant chemoradiotherapy. DESIGN: Markov modeling was used to simulate non-operative management and radical surgery for a base case scenario over a 10-year time horizon. Estimates for various clinical variables were obtained after extensive literature search. Outcome was expressed in both life years and quality-adjusted life years. Deterministic sensitivity analyses were completed to assess the impact of variation in key parameters. SETTING: A decision model using a Markov model was designed. PATIENTS: The base-case was a 65-year-old male with a distal rectal tumor who had achieved clinical complete response after neoadjuvant chemoradiotherapy. MAIN OUTCOME MEASURES: Life years and quality-adjusted life years. RESULTS: Quality-adjusted life years (5.79 for nonoperative management vs 5.62 for radical surgery) and life years (6.92 for nonoperative management vs 6.96 for radical surgery) were similar between non-operative management and radical surgery. The preferred treatment strategy changed with variations in the probability of local regrowth in non-operative management, the probability of salvage surgery for regrowth in non-operative management, utilities associated with non-operative management and low anterior resection and the utility of low anterior resection syndrome. The model was not sensitive to (dis)utilities associated with stoma, chemotherapy or to post-operative morbidity and mortality. LIMITATIONS: The study was limited by assumptions inherent to modeling studies. CONCLUSION: Nonoperative management and radical surgery resulted in similar (quality-adjusted) life years. Nonoperative management should therefore be considered as a reasonable treatment option. See Video Abstract at http://links.lww.com/DCR/B246.