Purpose: Patients with newly diagnosed brain metastases generally benefit from whole brain radiation therapy (WBRT). However, the role of reirradiation for patients who develop progressive brain metastases has been controversial. This retrospective study examines our experience with reirradiation of patients for progressive brain metastases after an initial+ course of WBRT.
Methods and materials: From 1975-1993, 2658 patients received WBRT for brain metastases at our institution. Eighty-six patients were subsequently reirradiated for progressive brain metastases. The median age of these patients was 58 (range: 31-81). The most common primary sites were breast and lung. Fifty patients had metastatic disease at other sites. Most patients had an Eastern Cooperative Oncology Group (ECOG) performance status of 2 (40 patients) or 3 (38 patients). The median dose of the first course of irradiation was 30 Gy (range: 1.5-50.6 Gy). The median dose of the second course of irradiation was 20 Gy (range: 8.0-30.6 Gy).
Results: Twenty-three patients (27%) had resolution of neurologic symptoms, 37 patients (43%) had partial improvement of neurologic symptoms, and 25 patients (29%) had either no change or worsened after reirradiation. The median survival following reirradiation was 4 months (range: 0.25-72 months). The majority of patients had no significant toxicity secondary to reirradiation. Five patients had radiographic abnormalities of their brain consistent with radiation-related changes. One patient had symptoms of dementia that was thought to be caused by radiotherapy. Various potential prognostic factors were evaluated for possible associations with survival, including age, sex, primary site, ECOG performance status, RTOG neurologic functional class, absence of extracranial metastases, and dose of irradiation. Absence of extracranial metastasis, solitary brain metastasis, and retreatment dose > 20 Gy were associated with improved survival in univariate analysis (p=0.025, 0.033, and 0.061, respectively). The absence of extracranial disease was the only significant factor in multivariate analysis (p=0.05).
Conclusion: The majority of patients in our series had favorable symptomatic responses. Clinically significant complications were minimal. Reirradiation should be offered to patients who develop progressive brain metastases.