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High-grade neuroendocrine carcinomas (HGNECs) of the colon and rectum: A single-institution retrospective analysis.

e14040 Background: HGNECs of the colon and rectum are uncommon with no standard treatment guidelines.


METHODS
We undertook a single institution IRB approved retrospective evaluation of patients (pts) with HGNECs of the colon and rectum from 1991-2010. 95 pts with histologically confirmed HGNEC with adequate follow up information for survival analysis were identified.


RESULTS
Median age of pts was 55 (range 34 to 89) and the median follow up was 12.5 months. 53% were male. Majority of the HGNECs had poorly differentiated and/or small cell histology (92.6%) while the remaining had large cell histology. Immunohistochemistry demonstrated positivity with chromogranin, synaptophysin and neuron specific enolase in 59%. 92.6% and 86.7% cases, respectively. Rectosigmoid was the most common primary site (55%) followed by the cecum (17%). Metastatic disease was present at diagnosis in 63% pts. Liver was the most common site of metastasis (92%) and was an isolated site of metastatic disease in 51% of pts. Pts with right sided tumors presented more often with metastatic disease at initial diagnosis (79%) compared to patients with left sided tumors (38%) and rectosigmoid tumors (58%), (p=0.046). Among pts with localized disease, 80% underwent resection of primary tumor. Distribution among stages I, II and III were 13%, 8% and 79%, respectively based on histopathologic and operative staging. Among the 28 pts who underwent surgery 6 underwent neo-adjuvant therapy, 17 underwent adjuvant therapy and 5 received both. Among pts with metastatic disease at presentation, 90% underwent first line palliative chemotherapy and 49% received second line palliative chemotherapy. Pts with localized disease had a median survival of 20.4 months and 5-year survival of 28%, while pts with metastatic disease had a median survival of 8.6 months.


CONCLUSIONS
This single-institution retrospective analysis suggests that HGNEC arising in the right colon may have a more aggressive biology compared to other sites in the colon and rectum, however even localized disease has a very low 5-year survival. Further evaluation of treatment patterns in this cohort may provide guidance on optimized treatment approaches in a poor prognosis group of pts.