Defining the role of stereotactic radiosurgery versus microsurgery in the treatment of single brain metastases

Stereotactic radiosurgery (RS) and surgery have proved to be effective trea tment modalities for brain metastasis. We followed 133 patients whose treat ment for intracranial disease was either RS or a single surgical resection at the University of Vienna from August 1992 through October 1996. All pati ents who received additional Whole Brain Radiotherapy were included. This w as a retrospective, case-control study comparing these treatment modalities . Sixty-seven patients were treated by RS and 66 patients were treated by mic rosurgery. The median size of the treated lesions for RS patients was 7800 mm(3), and 12500 mm(3) for microsurgery patients, respectively. The median dose delivered to the tumour margin for RS patients was 17 gray. The median survival for patients after RS was 12 months, and 9 months for patients after microsurgery. This difference was not statistically signific ant (p = 0.19). Comparison of local tumour control, defined as absence of r egrowth of a treated lesion, showed that tumours following RS had a preferr ed local control rate (p < 0.05). Univariate and multivariate analysis show ed that this fact was due to a greater response rate of "radioresistant" me tastasis to RS (p < 0.005). Postradiosurgical complications included the on set of peritumoural oedema (n = 5) and radiation necrosis (n = 1). Two pati ents after microsurgery experienced local wound infection. One postoperativ e death occurred due to pulmonary embolism in this group. On the basis of our data we conclude that RS and microsurgery combined with Whole Brain Radiotherapy are comparable modalities in treating single brai n metastasis. Concerning morbidity and local tumour control, in particular in cases of "radioresistant" primary tumours, RS is superior. Therefore we advocate RS except for cases of large tumours (>3 cm in maximum diameter) a nd for those with mass effect.