Appendiceal Cancer Survival Not Improved With Adjuvant Chemotherapy

Adjuvant chemotherapy was not associated with improved recurrence-free survival (RFS) or overall survival (OS) after resection of localized appendiceal adenocarcinoma, according to a retrospective cohort study published in JAMA Surgery. Investigators reported that relapse was uncommon overall but varied by histologic subtype and molecular features.

Analysis included 439 patients with stage I to III localized appendiceal adenocarcinoma managed at MD Anderson Cancer Center from January 2000 through February 2024. Of these, 202 underwent surgery at MD Anderson, and the study also included a validation cohort of 128 patients with stage II disease from Memorial Sloan Kettering Cancer Center. Median follow-up was 62.6 months. Outcomes included recurrence rate, RFS, and OS.

Among the 202 surgical patients at MD Anderson, 19 (9.4%) relapsed. Relapse occurred in 9 patients with stage II disease (6%) and 8 with stage III disease (19.5%). Five-year OS was 95.7% among patients without relapse and 77.2% among those with relapse (hazard ratio [HR], 5.50; 95% CI, 3.07-9.83; P < .001).

Compared with goblet cell tumors, mucinous histology (HR, 5.60; 95% CI, 2.1-15) and enteric-type histology (HR, 6.60; 95% CI, 2.9-15) were independently associated with relapse. Pathologic T4 status was also associated with relapse (HR, 3.30; 95% CI, 1.9-5.7). Poor differentiation, perforation, lymphovascular invasion, and perineural invasion were not significantly associated with relapse. TP53 mutation in goblet cell tumors and GNAS mutation in nongoblet tumors were associated with greater relapse risk.

In multivariable models, adjuvant chemotherapy was not associated with improved RFS (HR, 0.98; 95% CI, 0.43-2.28; P = .90) or OS (HR, 0.71; 95% CI, 0.24-2.1; P = .53). The investigators concluded that histopathologic subtype and molecular profiling may refine relapse risk after resection, while adjuvant chemotherapy was not associated with benefit.

Source: El Khoury S, Fanaeian MM, Yousef M, et al. Risk of relapse and efficacy of adjuvant chemotherapy in localized appendiceal adenocarcinoma. JAMA Surg. Published online September 9, 2026. doi:10.1001/jamasurg.2026.4000