Prognostic factors derived from recursive partition analysis (RPA) of radiation therapy oncology group (RTOG) brain metastases trials applied to surgically resected and irradiated brain metastatic cases

Purpose: (a) To identify the prognostic factors that determine survival after surgical resection and irradiation of tumors metastatic to brain. (b) To determine if the prognostic factors used in the recursive partition analysis (RPA) of brain metastases cases from Radiation Therapy Oncology Group (RTOG) studies into three distinct survival classes is applicable to surgically resected and irradiated patients. Method: The medical records of 125 patients who had surgical resection and radiotherapy for brain metastases from 1985 to 1997 were reviewed. The patients’ disease and treatment related factors were analyzed to identify factors that independently determine survival after diagnosis of brain metastasis. The patients were also grouped into three classes using the RPA-derived prognostic parameters which are: age, performance status, state of the primary disease, and presence or absence of extracranial metastases. Class 1: patients ≤ 65 years of age, Karnofsky performance status (KPS) of ≥70, with controlled primary disease and no extracranial metastases; Class 3: patients with KPS < 70. Patients who do not qualify for Class 1 or 3 are grouped as Class 2. The survival of these patients was determined from the time of diagnosis of brain metastases to the time of death. Results: The median survival of the entire group was 9.5 months. The three classes of patients as grouped had median survivals of 14.8, 9.9, and 6.0 months respectively ( p = 0.0002). Age of < 65 years, KPS of ≥ 70, controlled primary disease, absence of extracranial metastases, complete surgical resection of the brain lesion(s) were found to be independent prognostic factors for survival; the total dose of radiation was not. Conclusion: Based on the results of this study, the patients and disease characteristics have significant impact on the survival of patients with brain metastases treated with a combination of surgical resection and radiotherapy. These parameters could be used in selecting patients who would benefit most from such treatment.