Results of radiation therapy for patients with brain metastases of small-cell lung cancer

The results of cranial irradiation for brain metastases (BM) of small cell lung cancer (SCLC) were investigated. Of a total of 67 patients, aged 33 to 80, 47 patients received whole brain irradiation ranging from 30 to 57.6 Gy (mean: 44.3 Gy), and the remaining 20 with localized BM received boost irradiation up to 40-60 Gy (mean: 52.5 Gy) totally on the policy of high dose irradiation. Response to treatment was evaluated by the neurological function (NF) score proposed by Radiation Therapy Oncology Group (RTOG), as well as tumor size on computed tomography (CT) or magnetic resonance imaging (MRI), or both. The results were as follows: improvement of NF in 70%, complete response in 36%, partial response in 51%, no change in 10% and progressive disease in 1%, respectively. Overall survival rates at 1-, and 2-years from the start of cranial irradiation were 26% and 9%, respectively, resulting in a median survival time (MST) of 6.2 months. The patients who already had BM at the diagnosis of lung cancer survived much longer (p<0.01) than those who developed brain metastases after the initial treatment. Five patients with a small BM detected only by MRI had a survival of 12.9 months in MST. Multivariate analysis showed the significant prognostic factors to be a low level of serum lactate dehydrogenase, a primary lesion well-controlled at the time of cranial irradiation and age younger than 62. Our data suggest that high dose irradiation to control BM is necessary to extend survival. (author)