The role of human chorionic gonadotropin beta subunit elevation in small-cell lung cancer patients

Human chorionic gonadotropin (HCG)-like immunoreactivity has been found in many non-trophoblastic tumours, but the biological behaviour of HCG-producing cells has not been clarified yet. The aim of the study was to estimate the frequency of serum HCG beta subunit (s beta HCG) elevation in patients with small-cell lung cancer (SCLC) and to assess its possible prognostic role in this type of tumour. An attempt was also made to reclassify the histology in selected cases to see whether the elevated (s beta HCG) level is connected with any special subtype of small-cell lung cancer. A total of 156 SCLC patients entered the study: 93 men, 63 women, median age 58 years. s beta HCG activity was measured by immunoenzyme assay (Abbott EIA beta HCG 15-15) before treatment. s beta HCG elevation (above 5 mIU/ml) was found in 21 of 156 patients (14%). Response to treatment after chemotherapy (complete and partial response) was obtained in only 48% of those patients in whom elevated s beta HCG was found, in comparison to the 73% response rate observed in the remaining patients. Only 5% of patients with elevated s beta HCG survived 2 years, in comparison to 21% surviving for 2 years among the remaining patients. The prognostic significance of elevated s beta HCG and extent of disease were independent of each other (Cox's proportional-hazard model). Thus s beta HCG elevation in SCLC seems to be a marker of more resistant tumours and of poor prognosis. We have not found any connection between the subtype of small-cell lung cancer and elevated s beta HCG. Elevated s beta HCG was found in 2 out of 11 patients with oat-cell carcinoma, in 3 out of 10 patients with an intermediate cell type and in 5 out of 13 patients with small-cell lung cancer in which the assessment of the subtype was not possible.