Non-Functioning Endocrine Pancreatic Tumors: Factors Predicting Recurrence and Outcome

Capitanio V¹, Albarello L², Zerbi A¹, Balzano G¹, Rocchetti S¹, Beneduce AA¹, Varale R¹, Di Carlo V¹

¹Pancreas Unit and ²Department of Pathology, San Raffaele H. Milan, Italy

Background Only few data exist on long-term outcome and prognostic factors of pancreatic neuroendocrine tumors because of their low incidence, heterogeneous behaviour and different treatment modalities.

Aim to evaluate risk factors for recurrence and prognostic factors for long-term outcome in non-functioning endocrine pancreatic tumors.

Methods Eighty-five patients with non-functioning endocrine pancreatic tumors were observed at our Institute in the period 1987-2004. In 67 of them (29 female and 38 male; mean age 54 years) complete data were available to perform an univariate analysis, correlating recurrence and survival with clinical and histopathological factors. The following parameters were studied: age, clinical presentation (with or without symptoms), size of the primary tumor, presence of angioinvasion, adjacent organs involvement, synchronous or metachronous metastases, ki-67-index, surgical resection, medical therapy. Mean follow-up was 58 months (range 3-267 months).

Results Tumors were classified according to WHO 2000 system: 14 resulted benign neoplasm, 17 tumors with uncertain behaviour, 29 well differentiated carcinoma, 7 poorly differentiated carcinoma. 62 patients underwent surgical resection, whereas 5 did not. Eighteen patients showed a local or distant recurrence of disease (mean interval from diagnosis: 31.5 months; range 3-158 months): 4 tumors with uncertain behaviour, 10 well differentiated and 4 poorly differentiated carcinoma. Tumor size greater than 2 cm (odds ratio: 9.5; 95% CI: 1.172-78.55) and angioinvasion (odds ratio: 6; 95% CI: 1.5-24.01) were the strongest predictors of recurrence; mean time of recurrence was: 30 months in neoplasms greater than 2 cm in size, 54 months in neoplasms less than 2 cm, 30 months in patients with angioinvasion, and 47 months in patients without angioinvasion. Univariate analysis showed that lymph node status, proliferation fraction (ki-67-index) and surgical treatment displayed a significant correlation with overall survival. The results of analysis are showed in the Table.

Conclusions Tumor size greater than 2 cm and vascular invasion were risk factors for recurrence; metastases to lymph nodes and ki-67-index greater than 5% were prognostic factors of an unfavorable outcome; surgical resection was related to a favorable prognosis.

Congress Proceedings in PDF format