Is Adjuvant Chemotherapy Necessary for Stage 1 Appendiceal Adenocarcinoma

Keywords: appendiceal adenocarcinoma, adjuvant chemotherapy

Synopsis: Appendiceal tumor is a rare heterogenous group that exhibits varying biology. Given its rarity, management has been inconsistent. The role of adjuvant chemotherapy for stage I appendiceal adenocarcinoma is poorly studied. We conducted a large hospital-based study to evaluate whether adjuvant chemotherapy is necessary for stage I appendiceal adenocarcinoma

Methods: The National Cancer Data Base was queried to evaluate 2,954 patients diagnosed with stage I appendiceal adenocarcinoma between 2004-2016. Carcinoid, goblet cell cancer and neuroendocrine tumors were excluded. Patients were classified into (1) surgery alone (S) versus (2) surgery + chemotherapy (S+). The Kaplan-Meier method and log-rank test were used to compare unadjusted overall survival (OS). Multivariable Cox proportional hazards model with Firth’s correction was used with hazard ratios (HR) adjusted for relevant demographic and clinical variables. P-value < 0.05 was considered statistically significant.

Results: The 5-year OS for S and S+ were 92.4% and 87.4%, respectively (P>0.05). In the unadjusted model, receipt of chemotherapy was not associated with a worse OS compared to surgery alone (P=0.1004). However, on multivariable analysis, the adjusted HR for receipt of chemotherapy was 1.817 (95% CI: 1.037-3.187; p=0.0371) compared to surgery alone.

Conclusions: Adjuvant chemotherapy portends an 82% increased risk of death. Thus, surgery alone for stage I appendiceal adenocarcinoma appears to be sufficient.