Basis for treatment of functioning neuroendocrine tumours

Multiple Effects of Somatostatin Analogs Verified in Three Cases of Metastasized Neuroendocrine Tumors of the Gastroenteropancreatic System

Aims and Background

In neuroendocrine tumors of the gastroenteropancreatic (GEP) system, radiolabeled analogs of somatostatin (SST) are useful to the surgeon in different phases of treatment: preoperatively, to identify the lesion with somatostatin receptor scintigraphy (SRS), intraoperatively for localization using a hand-held gamma probe, and postoperatively acting directly to eliminate any residual tumor cells. Additional features of these analogs that are of value in treating such GEP tumors include their antiproliferative potential, which is in the process of being verified, and, above all, their antisecretory action, so effective in symptom control. In this study the authors, based on their own experience, evaluate the effectiveness of SST analogs in treating GEP endocrine tumors.

Methods

Three patients with malignant GEP apudomas were studied. In case 1, an insulinoma, the patient underwent four surgical procedures for ablation of the pancreatic tumor and of hepatic and lymph node metastases in addition to local radiofrequency treatment and radiometabolic therapy. Case 2 was a carcinoid tumor of the small intestine with hepatic metastases, managed by ileal resection, local radiofrequency treatment and receptor-mediated radionuclide therapy. In case 3, a non-functioning pancreatic carcinoma with liver and lymph node metastases, the patient underwent four surgical procedures, hepatic chemoembolization, antiproliferative treatment using octreotide (OCT) and metabolic radionuclide therapy.

Results

In all three cases SRS proved highly sensitive in the early detection of even the smallest recurrences. There was uncertainty, however, regarding the effectiveness of therapy with radiolabeled SST analogs. Hepatic metastases from the carcinoid were completely unresponsive, but in the case of the insulinoma, the hepatic metastases showed necrosis following treatment, while lymph node metastases were unaffected. In the case of the non-functioning carcinoma, there was a correlation between treatment and a marked improvement in the patient's clinical condition, although the appearance of the lesions themselves remained unchanged. The antiproliferative effect of OCT in this case was nil.

Conclusions

SRS proved highly accurate in detecting recurrences during follow-up. The merits of radiometabolic therapy, on the other hand, were unclear, a finding reported elsewhere in the literature, and in the only case treated by prolonged OCT treatment, no antiproliferative action was observed. The diagnostic usefulness of SRS was thus confirmed and it appears likely that radiolabeled analogs used intraoperatively for tumor localization will prove equally of value. The effectiveness of receptor-mediated radionuclide therapy is still in the process of being verified. Based on the expectation of analogs with an universal affinity for SST receptors (sst), it is reasonable to look forward to a significant increase in the efficacy of this type of therapy.

Primary tumour resection in metastatic nonfunctioning pancreatic endocrine carcinomas

BACKGROUND

The role of debulking surgery in metastatic nonfunctioning pancreatic endocrine carcinomas (M-NF-PECs) with resectable primary tumour and unresectable liver metastases is debated.

AIM

Aim of the study is to evaluate whether the resection of the primary tumour in metastatic nonfunctioning pancreatic endocrine carcinoma improves survival.

PATIENTS AND METHODS

Fifty-one metastatic nonfunctioning pancreatic endocrine carcinoma patients with unresectable liver metastases were enrolled from 1990 to 2004 at the time of diagnosis. Nineteen patients underwent complete resection of the primary tumour whilst 32 were judged unresectable. All cases were classified according to the WHO 2000 classification. All clinico-pathological parameters, including grade of differentiation and the Ki-67 proliferation index were considered in univariate and multivariate models.

RESULTS

Of the 19 resected patients, 14 (73.7%) underwent left-pancreatectomy and 5 (26.3%) pancreaticoduodenectomy. In the unresected group of 32 patients, 9 (28.1%) underwent surgical biliary and/or gastric by-pass. There was no postoperative mortality and the median survival was 54.3 months (95% CI: 25.7-82.9). No difference in survival was observed between the two groups [resected: median 54.3 months (95% CI: 25-83.6), unresected: median 39.5 months (95% CI: 5.4-73.6); p=0.74]. Upon multivariate analysis poor differentiation (HR 3.01; 95% CI 1.08-8.4; p=0.035) and a Ki-67 index > or = 10% (HR 4.4; 95% CI 1.2-16.1; p=0.023) were significant predictors of survival.

CONCLUSIONS

Resection of the primary pancreatic tumour in metastatic nonfunctioning pancreatic endocrine carcinoma patients with unresectable liver metastases does not significantly improve survival. Resection can be considered as symptomatic palliative therapy in patients with well-differentiated endocrine carcinomas and a proliferative index lower than 10%.