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

Introduction: 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.

Materials And Methods: 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.

Results: 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.

Conclusions: 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.