Local control of intrathoracic disease with chemotherapy and role of prophylactic cranial irradiation in small-cell carcinoma of the lung.

Between 1978 and 1979, 39 consecutive patients at the Medical College of Wisconsin were seen with small-cell carcinoma of the lung; of these, 31 were treated with chemotherapy and prophylactic CNS irradiation (2500 rad/10 fractions) and were evaluable after 22 month median follow-up. The intrathoracic primary was not irradiated unless there was no response to chemotherapy or subsequent recurrence. Of the 31 patients, 12 had limited disease (LD) and 19 had extensive disease (ED). Twenty, including all the patients with LD, had a complete response, eight had a partial response, and three were nonresponders. Of 24 patients with complete response at the primary site, 20 subsequently displayed local failure of the intrathoracic primary tumor, most developing disseminated extrathoracic disease simultaneously with or shortly after primary failure. The median survival time (MST) of the evaluable group was ten months with an actuarial one-year survival of 39%. Patients with LD had a median remission duration of 13 months and a MST of 16 months. Three patients are still alive with no evidence of disease at 14, 20, and 27 months. Of 26 patients receiving prophylactic cranial irradiation, all are free of CNS relapse. Chemotherapy alone appears insufficient to permanently control the bulky intrathoracic tumor, leading to the use of "consolidation" irradiation of moderate dose (3750 rad/15 fractions) to follow chemotherapy. Prophylactic CNS irradiation should be used routinely.