The Impact of Metachronous Colorectal Neoplasia Requiring Surgery After Cessation of Colonoscopic Surveillance at Age 75.

Background: To assess the clinical and financial impact of metachronous colorectal neoplasia (MCRN) requiring surgery after cessation of colonoscopic surveillance at age 75.

Methods: The Otago Clinical Audit database was interrogated to identify all colorectal neoplasia (CRN) resections between January 2020 and November 2022 and additional patients undergoing surgery for MCRN aged ≥ 75 (MCRN ≥ 75) between 2010 and 2020. The morbidity, hospital stay, and costs of surgery for MCRN ≥ 75 cases were compared to first colorectal neoplasia (FCRN) cases ≥ 75 and to all other colorectal resections, with and without propensity matching.

Results: MCRN was identified in 3.1% of patients < 75 and 13.1% of patients ≥ 75. Identifying a further 41 patients with surgery for MCRN ≥ 75 after 2010 resulted in 55 patients with MCRN aged ≥ 75, 93 with FCRN aged ≥ 75, and 130 with CRN aged < 75. The median(IQR) age for MCRN ≥ 75 was 81 (78-86). Surgery for MCRN ≥ 75 compared to FCRN ≥ 75 resulted in complication rates of 70.9% and 50.5% (p = 0.024), hospital stay nine versus seven days (p = 0.012), readmissions 20% versus 6.5% (p = 0.026) and cost of NZD 31 021 versus 24 157 (p = 0.028). When compared to all other resections, and adjusting for different approaches to rectal cancer in elderly patients, these differences all increased. The estimated annual hospital cost for MCRN ≥ 75 surgery was NZD 317 777.

Conclusion: MCRN accounted for 13.1% of operations in patients aged ≥ 75. This resulted in more morbidity and cost than surgery for FCRN ≥ 75. Stopping surveillance of those with previous surgery for CRN at 75 years of age results in significant institutional cost and patient morbidity.