RESUMEN
OBJECTIVE: The propensity of head and neck carcinomas to grow in vitro and to form a permanent cell line varies. It is not known whether the outcome of patients whose cancer gives rise to permanent in vitro growth differs from that of patients whose cancer cells fail to grow in vitro. The purpose of this study was to find out whether tumor cell capability for in vitro growth is associated with prognosis in head and neck cancer. MATERIAL AND METHODS: The study group consisted of 30 patients treated for head and neck cancer at the University Central Hospital of Turku between 1987 and 1994, and whose tumor samples had produced a permanent cell line in our laboratory. A control group was selected from patients treated during the same time period and with the same protocols in the same department. The controls were selected on the basis of similar tumor localization, TNM status, histological grade, age, gender and general condition. Tumor samples from 14 of the 30 control patients were also cultured, but did not result in a permanent cell line. The median follow-up time was 54 months in the study group and 52 months in the control group. RESULTS: The 3-year survival rate of the patients whose cancer gave rise to in vitro growth was only 19%, compared to 68% among the controls (p = 0.001). In a multivariate analysis the propensity of cancer cells to grow in vitro had independent prognostic value, the relative risk of death (RR) being 1.95 (95% CI 1.11-3.42) when compared to cancers that did not produce a cell line. Of the other factors tested, only the primary tumor size (RR 1.75; 95% CI 0.97-3.16) and the blood hemoglobin level at diagnosis (RR 0.97; 95% CI 0.95-1.01) were possibly independently associated with survival. CONCLUSIONS: The results suggest that the capability of cancer cells for in vitro growth has prognostic significance in head and neck cancer, and that cancer cells that are able to survive and grow in in vitro conditions behave aggressively in vivo. The independence of cancer cells from the paracrine signals produced by the neighboring host cells may enhance cancer cell survival and the metastatic potential in vivo.