Right hemicolectomy for mucinous adenocarcinoma of the appendix: just right or too much?

The surgical management of mucinous adenocarcinoma of the appendix (MA) is controversial, given its infrequent nodal metastases and its propensity for peritoneal dissemination compared to nonmucinous adenocarcinoma. We sought to identify the appropriateness of a right hemicolectomy (RH) for MA in staging and treatment of these tumors.

We queried all patients with MA captured in the Surveillance, Epidemiology, and End Results (SEER) database from 1973 to 2007. Demographics, and tumor and therapy characteristics were extracted. Overall and disease-specific survival was compared by Cox regression analyses.

Of 2,101 patients with MA, the median age was 59 (range 49-72) years; 55 % were women (n = 1,151). Tumor, node, metastasis staging revealed that tumors were frequently T3 (33 %) or T4 (46 %), N0 (80 %), and M1 (46 %). Fifty-one percent (n = 666) of patients underwent an appendectomy. In patients with complete staging information who underwent RH, nodal metastases were less frequent than the nonmucinous adenocarcinoma group (odds ratio 0.63, p = 0.003). Well-differentiated tumors had a low likelihood of nodal metastases (6 % T1, 0 % T2, 7 % T3, 22 % T4). Adjusted survival for patients undergoing appendectomy was similar to those undergoing a RH (hazard ratio 0.93, p = 0.52). Median survival for both groups was similar with positive nodes (28 [appendectomy] vs. 26 months [RH], p = 0.26) or metastatic disease (52 [appendectomy] vs. 43 months [RH], p = 0.28).

There does not appear to be a therapeutic benefit to a RH in the setting of known node-positive or metastatic disease. Benefits of a staging operation can be individualized on the basis of the probability of nodal metastases, which is lower than nonmucinous tumors.