Prognostic factors for patients with microsurgically resected brain metastases

With the advent of new therapies for metastatic carcinoma to the brain, patterns of intracranial disease and factors influencing survival become important considerations when examining treatment options. This study was conducted at a single institution to determine prognostic factors for tumor response and patient survival after microsurgical resection of brain metastases.

187 consecutive patients who underwent microsurgical resection of brain metastases between July 1989 and September 1996 were retrospectively reviewed and statistically analyzed. The primary cancers included lung cancer (85), gastrointestinal cancer (20), renal cell cancer (19), breast cancer (17), malignant melanoma (8) and 38 cases of various other carcinomas or of unknown primary site. 111 patients received whole-brain radiation therapy (WBRT) with a mean dose of 32 Gy after tumor resection. The influence of number, size, and localization of brain metastases as well as histology of the primary tumor, preoperative performance status, presence of extracranial systemic disease, time course and adjuvant radiation therapy were statistically evaluated (uni- and multivariate) as prognostic factors for survival.

Early postoperative Karnofsky score was improved in 59%, unchanged in 32% and worse in 9% of patients. Median survival time (MST) was 9.8 months (range 1 day-5.3 years). The most important parameter showing a significant influence on survival time was the histology of the primary tumor, with prediction of a bad outcome especially for patients with metastases from renal-cell cancer and malignant melanomas. Patients with breast cancer showed longer survival than patients with other primary cancers. Furthermore, survival varied significantly depending on location of brain metastases, performance status at time of craniotomy and duration of symptoms. None of the other studied variables gained prognostic significance.

Microsurgical resection of one or more brain metastases followed by WBRT still is a useful and efficient treatment in a carefully selected patient group to prolong median survival and improve or stabilize the performance status. Among the factors determining the survival times in this patient group, histology of the primary tumor is most important, together with preoperative Karnofsky score, location of metastasis and preoperative duration of symptoms.