Octreoscan in patients with bronchial carcinoid tumours

Scintigraphy with radiolabelled octreotide (octreoscan) is useful for imaging various neuroendocrine tumours, especially in patients with midgut carcinoids. We were interested in estimating the efficacy of octreoscan for detection of the primary tumour and metastases in patients with bronchial carcinoids.

Twenty-eight patients with histologically verified bronchial carcinoids underwent octreoscan and the imaging results were compared to CT regarding soft tissue metastases, and to bone scan and MRI regarding bone metastases. The primary tumour had been removed prior to the octreoscan in 12 patients. Metastatic disease was diagnosed in 22 patients.

Altogether, 20 patients (71%) had octreoscan-positive tumours, including 2/5 patients with ectopic ACTH secretion resulting in Cushing's syndrome and 8/9 patients with carcinoid syndrome. The primary tumour was octreoscan-positive in 13/16 patients and could be detected on CT in 15/16 patients. CT failed to localize the primary tumour in one octreoscan-positive patient, presenting with ectopic ACTH secretion and Cushing's syndrome. Intrathoracic recurrences/metastases were visualized by octreoscan in 7/9 patients and by CT in 8/9 patients. CT showed liver metastases in 14 patients; nine of these patients (64%) had octreoscan-positive liver metastases. Ten patients had bone metastases; octreoscan was positive in seven and bone scan in nine of these 10.

Octreoscan may be used for follow-up and detection of recurrent disease in patients with somatostatin receptor-positive bronchial carcinoids. In our limited patient material, CT however, seems to be better than octreoscan for visualization of the primary tumour as well as liver metastases.