[Tumors of the endocrine pancreas]

Contrast enhancement pattern on multidetector CT predicts malignancy in pancreatic endocrine tumours

OBJECTIVES

Preoperative suspicion of malignancy in pancreatic neuroendocrine tumours (pNETs) is mostly based on tumour size. We retrospectively reviewed the contrast enhancement pattern (CEP) of a series of pNETs on multiphasic multidetector computed tomography (MDCT), to identify further imaging features predictive of lesion aggressiveness.

METHODS

Sixty pNETs, diagnosed in 52 patients, were classified based on CEP as: type A showing early contrast enhancement and rapid wash-out; type B presenting even (B1) or only (B2) late enhancement. All tumours were resected allowing pathologic correlations.

RESULTS

Nineteen pNETs showed type A CEP (5-20 mm), 29 type B1 CEP (5-80 mm) and 12 type B2 (15-100 mm). All tumours were classified as well differentiated tumours, 19 were benign (WDt-b), 15 with uncertain behaviour (WDt-u) and 26 carcinomas (WDC). None of A lesions were malignant (12 WDt-b; 7 WDt-u), all B2 lesions were WDC, 7 B1 lesions were WDt-b, 8 WDt-u and 14 WDC; 4/34 (12 %) lesions ≤2cm were WDC. CEP showed correlation with all histological prognostic indicators.

CONCLUSIONS

Correlating with the lesion grading and other histological prognostic predictors, CEP may preoperatively suggest the behaviour of pNETs, assisting decisions about treatment. Moreover CEP allows recognition of malignant small tumours, incorrectly classified on the basis of their dimension.

Notch 1 tumor expression is lacking in highly proliferative pancreatic neuroendocrine tumors

To date, very little is known about the development of benign organic hyperinsulinism and its metastatic potential. Typical morphologic, biochemical, or genetic differentiations for benign or malign tumor course of insulinomas do not exist. As signaling pathways may affect pancreatic cancer development and the maintenance of the neoplastic phenotype, the purpose of this study was to examine the role of Notch1 expression in organic hyperinsulinism. We examined 32 well-differentiated pancreatic endocrine tumors (wd PET); 11 wd PET of unknown behavior (wd PET ub); and 15 wd pancreatic endocrine cancer (wd PEC) for Notch1 expression by immunohistochemistry. Demographic data, clinical data, and follow-up of all patients were analyzed. Islets of the Langerhans show the strongest Notch1 staining in nearly 90 %. Positive Notch1 staining was absent in the acinar of the pancreas. In patients with a wd PET more than every second tumor (56.3 %/n = 18/32) demonstrated a negative Notch1 staining. The other 14 patients were positive for Notch1. Tumors of unknown behavior (wd PET ub) and malignant insulinomas had no signs of Notch expression in contrast to benign insulinomas. Considering the clinical and histomorphological tumor behavior, no correlation between Notch1 expression and clinical data was found. The missing Notch expression in the malignant tumor course might be used as a potential predictive marker, but further studies are needed to investigate the underlying molecular mechanism.

[Neuroendocrine tumors of the duodenum and pancreas. Surgical strategy]

The incidence of neuroendocrine tumors (NET) has increased worldwide by 3-5 times over the last decades. This is mainly based on the broad use of imaging modalities such as computed tomography (CT) and endoscopic approaches. As a consequence many duodenal and pancreatic tumors are detected in an early stage resulting in an improved prognosis of these patients. Besides the measurement of serum chromogranin A and 5-hydroxy indolic acid measured in 24 h urine collection, CT, endosonographic ultrasound (EUS) and endoscopy are important diagnostic tools. About 20% of all patients with pancreatic and duodenal NETs are diagnosed because of specific symptoms. More than 95% of diagnosed NETs are sporadic tumors. Whenever possible these patients should be treated by resection. Benign neuroendocrine duodenal tumors up to 1 cm in size can be removed endoscopically. The endoscopic resection of larger tumors should be performed surgically. The therapy of hereditary NETs of the duodenum and the pancreas should be decided after interdisciplinary discussion. However, even these patients seem to benefit from resection. In case of metastatic disease debulking surgery should be considered if more than 90% of the tumor mass can be resected. In patients with extensive liver metastases but resectable primary NET, liver transplantation is a reasonable option. There is no consensus about adjuvant or neoadjuvant treatment of duodenal or pancreatic NETs. The therapy with everolimus or sunitinib in advanced tumor stages has shown promising results. The administration of somatostatin analogues or antacids is appropriate for symptom reduction.

Neoadjuvant peptide receptor radionuclide therapy for an inoperable neuroendocrine pancreatic tumor

Pancreatic endocrine tumors are rare but are among the most common neuroendocrine neoplasms of the abdomen. At diagnosis many of them are already advanced and difficult to treat. We report on an initially inoperable malignant pancreatic endocrine tumor in a 33-year-old woman, who received neoadjuvant peptide receptor radionuclide therapy (PRRT) as first-line treatment. This resulted in a significant downstaging of the tumor and allowed its subsequent complete surgical removal. Follow-up for eighteen months revealed a complete remission. This is the first report on neoadjuvant PRRT in a neuroendocrine neoplasm with subsequent successful complete resection.

Clinical outcome and long-term survival in 118 consecutive patients with neuroendocrine tumours of the pancreas

BACKGROUND

The aim was to assess the clinical relevance of the World Health Organization and tumour node metastasis (TNM) classifications in patients with pancreatic neuroendocrine tumours (pNETs).

METHODS

Prospectively collected data from 118 consecutive patients with a pNET receiving surgical intervention were analysed.

RESULTS

Forty-one patients had well differentiated neuroendocrine tumours, 64 had well differentiated neuroendocrine carcinomas and 13 had poorly differentiated neuroendocrine carcinomas. Five-year survival rates were 95, 44 and 0 per cent respectively (P < 0.001). There was no difference in survival after R0 and R1/R2 resections in patients with neuroendocrine carcinomas (P = 0.905). In those with well differentiated neuroendocrine carcinomas, any resection and having a clinically non-functional tumour significantly increased survival (P = 0.003 and P = 0.037 respectively). The TNM stage was I in 37 patients, II in 15 patients, III in 32 patients and IV in 34 patients. There were significant differences in 5-year survival between stage I and II (88 and 85 per cent respectively) and stage III and IV (31 and 42 per cent respectively) (P = 0.010).

CONCLUSION

Both classifications accurately reflect the clinical outcome of patients with pNET. The resection status may not be critical for long-term survival in patients with pNET.