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Lymphatic metastasis in well-differentiated appendiceal cancer: Prognostic factors and associations with outcome.

406 Background: Well-differentiated appendiceal adenocarcinomas (WDAA) are rare tumors characterized by peritoneal spread. Lymph node metastasis can occur, yet the association between nodal spread and recurrence is poorly understood.


METHODS
A single institution retrospective review of patients seen between August 1993 and January 2010 with a pathologic diagnosis of WDAA who underwent colectomy was conducted. Patients with zero lymph nodes found during pathologic review were excluded. Parameters evaluated included demographics, presence of lymph node metastasis, completeness of cytoreduction and time to recurrence.


RESULTS
Of 688 patients with appendiceal neoplasms, 160 (23.3%) had WDAA. The mean age at diagnosis was 50.7 years and 81 (50.6%) were male. Median follow-up after diagnosis was 58.5 months. One hundred patients (62.5%) had regional or distant metastasis present at the time of colectomy. Seventy-eight (48.8%) colectomies were performed at outside institutions. The median number of nodes examined was 12. Twelve patients (7.5%) were found to have nodal metastasis. The rate of peritoneal metastasis did not correlate with the presence of nodal metastasis (node positive 9/12, 75% versus node negative 91/148, 61.5%; p=0.35). No difference in the ability to perform complete cytoreduction existed for those with and without nodal metastasis (66% versus 51% p=0.19). Examining patients with complete cytoreduction and ≥ 12 months of follow-up, there was an increased risk of recurrence among patients with lymphatic metastasis compared to those without (5/8, 62.5% versus 15/61, 24.6%; p=0.03). In this subset, median disease-free-survival in lymph node positive patients was 53 months compared to 109.1 months in patients without nodal metastasis (p=0.08).


CONCLUSIONS
Patients with WDAA tumors have an overall favorable prognosis; however, patients with lymph node metastasis appear to have an increased risk of recurrence and apparent shortened disease free survival. Right colectomy may be warranted in this patient population.