The natural history of surgically treated primary adenocarcinoma of the appendix.

OBJECTIVE: The aim of this investigation was to determine the prognostic variables and optimal surgical procedure for patients with adenocarcinoma of the appendix. SUMMARY BACKGROUND DATA: Primary adenocarcinoma of the appendix is a rare malignancy that constitutes less than 0.5% of all gastrointestinal neoplasms. However, the prognostic factors and the preferred surgical procedure and outcome are poorly understood.
METHODS: The authors reviewed their institutional experience from 1976 to 1992 in treating 94 consecutive patients with primary adenocarcinoma of the appendix. Patients with carcinoid tumors or those in whom the diagnosis of primary cecal cancer could not be ruled out were excluded from the study.
RESULTS: Fifty-two (55%) patients had the mucinous variety, of which 22 had pseudomyxoma peritonei; the other 45% had the colonic and adenocarcinoid types of tumor. The most common presentation was that of acute appendicitis. Interestingly, in no patients was the correct diagnosis made before surgery, and it was entertained intraoperatively in only 30 patients (32%). The cure 5-year survival rate was 55%, but it varied with stage (A, 100%; B, 67%; C, 50%; and D, 6%; p < 0.01) and with grade (I, 68%, and III, 7%; p < 0.01). Patients with the mucinous type had a better prognosis than those with the colonic type (p < 0.01). The survival rate was superior after right hemicolectomy versus appendectomy alone (68% vs. 20%, p < 0.001). Right hemicolectomy performed as a secondary procedure resulted in the upstaging of 38% of the patients' tumors. A second primary malignancy occurred in 33 patients (35%), of which 17 were located in the gastrointestinal tract.
CONCLUSIONS: Primary adenocarcinoma of the appendix should be treated by right hemicolectomy, even if it is a secondary procedure. Surveillance for synchronous or metachronous tumors, especially in the gastrointestinal tract, is warranted.