Nononcologic Resection and Survival in High-Risk Appendiceal Cancer: A National Cancer Database Study

Despite guidelines recommending oncologic colectomy (hemicolectomy with adequate lymphadenectomy) for high-risk appendiceal adenocarcinoma, some patients undergo nononcologic resection (NOR; appendectomy or ileocecectomy only). Our study examines patients with high-risk appendiceal cancer who received NOR and examines the association with survival compared to oncologic colectomy.

Patients with appendiceal adenocarcinoma who underwent surgical resection from 2010 to 2019 were identified from the National Cancer Database. Patients with any high-risk features (lymphovascular invasion, high grade, positive surgical margins, pathologic T stage 2 or greater, or American Joint Commission on Cancer stage 1, 2, or 3) were selected. The primary outcome was NOR for high-risk patients; the secondary outcome was long-term survival. Multivariable logistic regression was used to identify patient- and disease-specific variables associated with NOR. Patients were propensity score matched 1:1, and 5-y survival was compared.

We identified 4510 patients, of whom 1696 (37.6%) received NOR. NOR was associated with elderly patients, nonprivate insurance, community centers, documented stage 1-2 disease, no lymphovascular invasion, low-grade disease, positive margins, mucinous histology, and no documented chemotherapy. After multivariable regression, NOR was associated with age ≥70 y, Black race, community centers, stage 1 or stage 2 disease, positive margins, and no documented adjuvant chemotherapy. Patients who underwent oncologic colectomy had higher rates of 5-y overall survival compared to NOR before (67.7% versus 60.7%, P < 0.0001) and after (67.5% versus 60.7%, P < 0.0001) propensity score matching.

Despite established guidelines for high-risk appendiceal adenocarcinoma, some patients undergo NOR and demonstrate worse survival. Older patients and patients with early-stage disease have higher odds of NOR.