214 THE JOURNAL OF COMMUNITY AND SUPPORTIVE ONCOLOGY g June 2015 www.jcso-online.com Simultaneous integrated boost using stereotactic radiosurgery for resected brain metastases: rationale, dosimetric parameters, and preliminary clinical outcomes Mark J Amsbaugh, MD, a Neal E Dunlap, MD, a Warren Boling, MD, b Akanksha Rajeurs, BS, c Timothy Y Guan, PhD, a Keith Sowards, MS, a and Shiao Woo, MD a Departments of a Radiation Oncology, b Neurosurgery, and c School of Medicine, University of Louisville, Louisville, Kentucky A n estimated 9%-26% of cancer patients develop a brain metastasis, making it one of the most common neurologic compli- cations of cancer. 1,2 Te incidence of clinically rec- ognized brain metastases will increase as modern oncologic therapies increase survival and improved imaging detects smaller brain lesions. Traditionally, whole brain radiation therapy (WBRT) is used to treat patients with brain metas- tases; however, alternative treatments are quickly evolving because of a rapid improvement in tech- niques, technology, and image guidance. A large percentage of patients present with a single brain metastasis; and in these cases, therapy may be local- ized, omitting treatment of the entire brain. 3,4 When compared with WBRT alone, surgical resection and radiosurgery are local treatments that improve local control, overall survival, and functional outcomes in patients. 5-7 In patients with limited intracranial dis- ease, evidence suggests radiosurgery may be used alone, omitting WBRT, if these patients are closely monitored and can accept higher rates of distant brain failure. 8-10 Even with high rates of local control with radio- surgery, there are many instances when surgi- cal resection is either necessary or advantageous. Surgery can provide diagnostic information, faster symptomatic relief, better local control with larger Accepted for publication April 29, 2015. Correspondence: Neal E Dunlap, MD; nedunl01@louisville.edu. Disclosures: The authors have no disclosures. JCSO 2015;13:214-218. ©2015 Frontline Medical Communications. DOI 10.12788/ jcso.0140. Background Radiosurgery has been shown to reduce the rates of local recurrence in the postoperative bed after the resection of brain metastases, but the ideal radiation dose has not been well defned. Objective To present dosimetric parameters and preliminary clinical outcomes for patients undergoing postoperative stereotactic radiosurgery (SRS) with simultaneous integrated boost (SIB) for brain metastases. Methods and materials 3 patients underwent surgery for a dominant metastatic focus and had residual or recurrent disease in the resection cavity. Our technique delivered a low dose to the resection cavity with an SIB dose to the gross tumor. Clinical target volume (CTV) was the magnetic resonance (MR)-defned resection cavity. Gross tumor volume (GTV) was the MR-defned residual disease. No additional margin was added to either the resection cavity or the residual disease area. Doses ranged from 14-15 Gy for CTV and 17-18 Gy for GTV prescribed to the 71%-78% isodose line. A traditional postoperative radiosurgery plan was constructed for each patient, and dosimetric values were compared using the paired t-test. Results 3 patients were treated at our institution using SRS with SIB. No patient experienced local recurrence. 2 patients devel- oped distant brain failure (mean, 3.5 months). No grade 3 or greater toxicities were observed. The volume of brain receiving 12 Gy was signifcantly reduced using SIB compared with traditional postoperative SRS (P = .04). There were no differences in the maximum dose delivered to the tumor (P = .15) and cavity (P = .13). The average mean cavity dose was 16.20 Gy using the SIB plan, compared with 19.71 Gy using the traditional plan (P = .05). Conclusions In patients with either recurrent or residual disease following surgical resection, SRS using SIB is technically feasible and safe. Original Report