P08.13 * THE OCCURENCE OF DE NOVO IPSILATERAL DURAL METASTASES AFTER RESECTION OF A SINGLE BRAIN METASTASES

Abstract

Since the publication of the EORTC trial that investigated the value of standard WBRT after resection or radiosurgery of brain metastases, the policy of deferring WBRT or to give local stereotactic radiotherapy to the resection cavity only is increasingly applied. At our institute we also have adapted our treatment protocol following the new policy. Hence, patients with resection after brain metastases are treated with either local stereotactic radiotherapy or a wait and scan policy . As all our radiosurgery patients are routinely followed with scheduled MRI we noted in several cases the occurrence of de novo dural metastases. METHODS: From January 2010 to February 2014 a total of 268 patient with brain metastases were treated radiosurgically at our institute. Of these, 43 patients (16%) had a craniotomy with a resection followed by radiosurgery. On follow up MRI, 7 of these 43 cases showed de novo multiple dural metastases confined to the side of the brain on which the surgery had been performed. No contralateral metastases were observed. In 1 additional case the ipsilateral dural metastases appeared on the postoperative planning MRI which was performed in preparing for the radiosurgery treatment. Primary tumors were breast (4), kidney (1), NSCLC (1), sarcoma (1), colon (1). Analysis of the surgical report showed that all 8 patients (3%) were operated for a superficial metastases. This suggest that spillage of tumor cells in the subdural space during the surgical procedure may account for this phenomenon. To our knowledge this finding is not reported in the literature. CONCLUSION: We report on the presentation of de novo dural metastases after surgical resection of a single metastases that are exclusively restricted to the side of the surgical cavity. This phenomenon is to be further confirmed, but may have therapeutic consequences e.g. reinstituting WBRT after resection of metastases.