SOMATOSTATIN RECEPTOR SCINTIGRAPHY IN PRIMARY BREAST-CANCER

Somatostatin-receptor (SS-R) scintigraphy successfully shows primary c ancers and distant metastases in most patients with carcinoids, islet cells tumours, and paragangliomas. Previous in-vitro studies indicated that somatostatin receptors are present in human breast cancers. We r eport positive scintigraphy with [In-111-DTPA-D-Phe(1)]-octreotide in 39 of 52 primary breast cancers (75%). Parallel in-vitro autoradiograp hy with [I-125-Tyr(3)]-octreotide of 30 of these showed a correspondin g somatostatin-receptor status in 28. Significantly more invasive duct al cancers could be shown than invasive lobular carcinomas (85% vs 56% ; p < 0.05). Also the number of T-1 cancers which were shown was highe r than T-1 (86% vs 61%; p < 0.05). Imaging of the axillae showed non-p alpable cancer-containing lymphnodes in 4 of 13 patients with subseque ntly histologically-proven metastases. In the follow-up after a mean o f 2.5 yr, SS-R scintigraphy in 28 of the 37 patients with an originall y SS-R-positive cancer, was positive in the 2 patients with clinically -recognised metastases, as well as in 6 of the remaining 26 patients w ho were symptom-free. Raised carcinoembryonic antigent (CEA) and CA 15 -3 values were observed in only 2 and 1, respectively, of these patien ts. Most primary breast cancers can be shown by SS-R scintigraphy, esp ecially invasive ductal cancers. This technique may be of value in sel ecting patients for clinical trials with somatostatin analogues or oth er medical treatments. Furthermore, SS-R scintigraphy is more sensitiv e than measurements of the usual serum cancer markers for detecting re currences of SS-R-positive breast cancer.