The frequency and clinical biology of the ectopic hormone syndromes of small cell carcinoma.

Eighty-four patients with small cell carcinoma of the lung were reviewed with respect to the frequency and biologic behavior of patients with a demonstrated ectopic hormone syndrome. This subgroup of 12 patients (14%) was compared with regard to stage of disease, distribution of metastases, response rate, and survival to those patients not demonstrating a clinical syndrome. Stage, distribution, and response rates are comparable in the two groups but differences were observed with regard to sites of metastases and survival. The ectopic hormone syndrome patients had an increased likelihood of liver metastasis and CNS metastasis. The frequency of CNS metastasis in patients without the ectopic hormone syndrome was 11/72 (15%) of which four of the 11 were present at initial presentation. In contrast, 5/12 (42%) of the patients with ectopic hormone syndromes developed CNS metastasis, and all five had clinically demonstrated SIADH. Survival was consistently inferior in those patients with the ectopic hormone syndrome.