Omission of Right Hemicolectomy May be Safe for Some Appendiceal Goblet Cell Adenocarcinomas: A Survival Analysis of the National Cancer Database.

backgroundAppendiceal goblet cell adenocarcinomas (GCC) are rare tumors with clinical behavior between classic carcinoids and adenocarcinomas. Current guidelines recommend right hemicolectomy for all GCCs. PATIENTS AND

methodsThe National Cancer Database was retrospectively queried for appendiceal GCCs undergoing appendectomy or right hemicolectomy between 2004 and 2016. Demographics, tumor characteristics, and post-operative outcomes were collected. The primary outcome was overall survival, which was examined by surgical type and tumor T stage. Multivariate logistic regression was utilized to identify predictors of survival.

resultsIn total, 1083 GCCs were included, and 81.8% underwent right hemicolectomy. Mean age was 57 years, and 89% were White. Patients undergoing hemicolectomy had higher T-stage tumors (66.6%/14.4% T3/T4 vs. 55.8%/8.1%, p < 0.001). Lymph node positivity increased with T stage (1.1%, 2.1%, 9.9%, and 29.1% for T1-T4). GCCs undergoing colectomy were more frequently moderately or poorly differentiated (16.7%/9.0% vs. 12.2%/6.6%, p = 0.011). Appendectomy surgical margins were positive in 17.3% (3.4% hemicolectomy, p < 0.001). In T3/T4 tumors, a significant survival benefit at 5 years was observed in patients undergoing colectomy as compared with appendectomy (85.4% vs. 82.0%, p = 0.028). On multivariate analysis, lymph node positivity markedly decreased survival overall for the entire cohort (HR 7.58, p < 0.001) and for T3/T4 tumors (HR 7.63, p < 0.001). In patients with T3/T4 tumors, there was a trend towards improved survival with right hemicolectomy (HR 0.42, p = 0.068).

conclusionOmitting right hemicolectomy can be considered for select T1/T2 appendiceal GCCs with negative appendectomy margins, given low rates of lymph node metastases and lack of survival benefit with right hemicolectomy.