Surgical treatment of extra-appendiceal colorectal neuroendocrine tumors.

BACKGROUND: Extra-appendiceal colorectal neuroendocrine tumors are rare neoplasms with a variable biological behavior. MATERIALS AND METHODS: The study group consisted of 15 patients with an extra-appendiceal colorectal neuroendocrine tumor who underwent surgical resection (M/F=3:12, mean age=62.9 years). Lower-grade neuroendocrine tumors and neuroendocrine carcinomas were recognized in 5 and 10 patients, respectively. Data were evaluated retrospectively with regard to clinical and pathologic characteristics and outcomes. RESULTS: The median age of the patients with lower-grade NETs was significantly lower than that in patients with NECs (53 yr vs. 68 yr, p=0.03). NETs G1-G2 were significantly smaller than neuroendocrine carcinomas (4.0 cm vs. 6.4 cm, p=0.02). There were no differences between lower-grade NETs and NECs with regard to tumor location, rate of nodal involvement and distant metastases. All the patients underwent open segmental resection of the colon or rectum. Complete resection was achieved in 3 of 5 patients from the lower-grade NET group, and in 5 of 10 patients in the NEC group. Overall survival was significantly better for lower-grade NETs tumors (p=0.005). The median survival was 4.8 months in the NEC group. The median survival in the lower-grade NET group was not achieved after a median follow-up of 69 months. Three-year overall survival was 100% for lower-grade NETs, and only 27% for NECs. CONCLUSION: Lower-grade neuroendocrine tumors seem to exhibit comparable potential for dissemination as neuroendocrine carcinomas, but prognostic implications of metastases are distinct.

Radioguided surgery in patient with pancreatic neuroendocrine tumour followed by PET/CT scan as a new approach of complete resection evaluation--case report.

Radioguided surgery using 68-gallium labelled somatostatin analogues is a promising method for detection of small, intra-abdominal, neuroendocrine neoplasm (NEN). However, due to high background activity (physiological uptake in e.g. spleen, adrenal glands and kidneys) tumours of the tail and body of pancreas might be impossible to detect with hand-held gamma probe. Therefore a new concept of intraoperative PET/CT scan of the resected tissue can be helpful in determining whether the tumour has been excised within the margins of healthy tissue. A 71-year-old woman with primary, non-metastatic NEN of the tail of pancreas is described. The tumour was diagnosed using MRI and PET/CT scan. Before operation patient was administered intravenously 80 MBq of 68Ga-DOTATATE. The surgery procedure was performed 60-180 minutes post injection. During the procedure pancreas was visualized, but the tumour could not be localized neither with palpation nor gamma probe. The tail of the pancreas was resected en bloc with spleen and adjacent lymph nodes. PET/CT scan of the tissue specimen was performed immediately followed by pathological examination. PET/CT scan of the resected tissue showed moderate activity in the tail of pancreas, and a small focus of high activity in the tail. Area of high SSTR expression in the tail corresponded with preoperative findings in MRI and whole-body PET/CT. Histopathological examination of the specimen confirmed the presence of neuroendocrine tumour grade 1. Immediate PET/CT scan of the surgical specimen can bring new quality to intraoperative assessment of completeness of resection of neuroendocrine tumours.