Prophylactic cranial irradiation in adenocarcinoma of the lung. A possible role.

Seventy-eight patients with modified Stage II or Stage IIIM0 adenocarcinoma of the lung were evaluated retrospectively with regard to the impact of prophylactic cranial irradiation (PCI) (30 Gy in 15 fractions) in preventing central nervous system (CNS) metastases. Twenty patients received PCI and 58 did not. There were no significant differences between these groups with respect to age, sex, stage, or median survival (17.4 months with PCI versus 16.9 months without PCI; P = 0.6). One (5%) of 20 patients receiving PCI developed CNS metastases, compared with 14 (24%) of 58 patients not receiving PCI (P = 0.06). The time from diagnosis to development of CNS metastases and survival after CNS involvement was 51 weeks and 14 weeks, respectively, for the patient who received PCI; and a median time of 50 weeks and 26 weeks, respectively, for the patients not receiving PCI. In nine (64%) of the 14 non-PCI patients the CNS was the first and only site of relapse. A Cox regression analysis demonstrated that nodal involvement was significantly associated with an increased risk of CNS metastases. These data suggest that PCI may decrease the incidence of CNS metastases, and that it may be beneficial in the management of patients with N1 or N2 disease.