Surgical treatment of insulinomas: a single-institution experience of 48 patients
Nicolas Carrere1, Corneliu Voronca1, Delphine Vezzosi3, Marie Danjoux1, Antoine Bennet3, Charles Henri Julio1, Eric Bloom1, Janick Selves1, Rosine Guimbaud2, Philippe Otal2, Louis Buscail2, Bernard Pradére1 & Philippe Caron3
In a monocentric study on 48 patients with insulinomas treated between 1988 and 2008, we evaluate the results of the radiological and surgical procedures, and determine prognostic factors regarding the recurrence risk. Clinical, radiological, and histopathological findings were analysed along with long-term follow-up after surgery. KaplanMeier analysis studies recurrence-free survival, and uni- and multi-variable analyses determine prognostic factors related to recurrence risk. The mean age of patients was 51 years (2278). Echoendoscopy and MRI-scan had a sensitivity of 90 and 85%, respectively. The surgical procedures were duodenopancreatectomy (n=12), left-sided pancreatectomy (n=21), central pancreatectomy (n=5) and enucleation of the tumor (n=7). In three patients (6%) per-operative examination failed to localize a tumor (nesidioblastosis=2, insulinoma=1). On histopathological examination, the insulinomas were benign (n=30), of uncertain behavior (n=11) and well differentiated endocrine carcinomas (n=4). During a median follow-up of 42 months, nine patients experienced a recurrence: three patients with MEN1, four patients with well differentiated endocrine carcinomas, and two patients with a tumor classified as benign who presented liver and regional lymph nodes during follow-up. Only one patient died out of carcinoma progression. In patients with insulinoma totally removed by surgery, the recurrence-free survival rate was 72% after 5 years. A uni-variable analysis revealed that the following factors were predictive of recurrence: histopathological diagnosis of carcinoma (P<0.001), lymph node invasion (P<0.001), expression of Ki67 >1% (P=0.003), and presence of MEN1 mutation. Only endocrine carcinoma and MEN1 disease were identified as significant independent factors of recurrence. In conclusion, in this series of operated patients with insulinoma, the high recurrence rate (28% after 5 years) is mainly related to endocrine carcinomas. This underlines the importance of histopathological criteria for the prognostic evaluation, and of the long-term follow-up after surgical resection, even when the pancreatic endocrine tumor is diagnosed as benign.