A retrospective survival analysis of whole brain radiotherapy (WBRT) for brain metastases at Mount Vernon Cancer Centre (MVCC)

2068 Background: The primary purpose of this retrospective study was to determine the survival of patients with brain metastases following WBRT with regards to the influence of tumor type, age < 65 versus ≥ 65 (RPA RTOG prognostic factor) and recency of treatment date. Methods: From treatment records we identified 1,926 patients with brain metastases from solid tumors who were treated with WBRT at MVCC between February 1992 and March 2008. Dates of death were sourced from records at MVCC, the Cancer Registry and GP practices. Results: We obtained dates of death for patients with lung (n=804), breast (n=457), colorectal (n=129), skin (n=119), kidney (n=82), and unknown primary (n=124) cancers. 42 patients were excluded from analysis as their tumor types were unspecified. A heterogeneous group of 169 patients with a variety of other primary tumor types were also excluded from our primary analyses. 22% of the patients died within the first month following WBRT and only 2.4% remained alive at 2 years. Log-rank analysis of age < 65 versus ≥ 65 demonstrated improved survival for the former for the colorectal, lung, and skin tumor types (p = 0.0048, 0.0001, and 0.0456 respectively). This relationship did not reach significance for the breast, unknown primary, and renal cancer groups (p = 0.14, 0.13, and 0.06 respectively). With the exception of colorectal cancer, the analysis of the effect of treatment date on survival did not reveal recent improvements in survival for patients with brain metastases. An improvement in survival was experienced by the colorectal subgroup treated after March 2006 (HR= 0.51 95% CI 0.27- 0.96). Conclusions: Our data validate age as an important prognostic factor for many tumor types with notable exceptions for as yet undetermined reasons. Metastasis to the brain is a late stage feature of colorectal malignancy. The survival of the majority of patients undergoing WBRT for brain metastases is poor and with the possible exception of colorectal cancer, has not improved over the last decade. [Table: see text] [Table: see text]