Prophylactic cranial irradiation in limited‐stage small cell lung cancer

Background. The role of prophylactic cranial irradiation (PCI) for patients with limited‐stage small cell lung cancer (LSSCLC) remains a controversial issue. This study evaluated PCI in patients with LSSCLC who achieved a complete response to initial chemotherapy. Methods. A retrospective case study of all nonprotocol patients with LSSCLC examined at our institution from 1982 to 1990 was performed. Of the 67 nonprotocol patients who were treated with combination chemotherapy (cyclophosphamide‐based) and thoracic radiotherapy during those years, 43 achieved a complete response. Twenty‐four patients prophylactic cranial irradiation (PCI+) (25‐36 Gy in 10‐16 fractions), and 19 did not (PCI‐) at the physician's or patient's discretion. Results. The distribution of prognostic factors between the PCI+ and PCI‐ groups was well balanced. Of the PCI+ patients, the 2‐year actuarial freedom from relapse in the central nervous system was 93% versus 47% for the PCI‐ patients (log rank analysis, P = 0.001). An initial central nervous system relapse developed in 2 of the 24 PCI+ patients as the only site of failure versus 7 of 19 PCI‐ patients (P = 0.003). The 2‐year actuarial overall survival was 50% for the PCI+ patients versus 21% for the PCI‐ patients [P = 0.01). The addition of prophylactic cranial irradiation was the only significant factor contributing to an improvement in time to central nervous system relapse and survival for the PCI+ patients. There were five patients alive at the time of this report, and all prophylactic cranial irradiation. None had cognitive or neurologic impairment. Conclusions. Prophylactic cranial irradiation may contribute to improved survival in patients with LSSCLC who achieve a complete response after chemotherapy and thoracic radiation therapy. Cancer 1995;75:1302‐9.