ESTRO 36 Abstract Book

S749 ESTRO 36 _______________________________________________________________________________________________

who received five-fraction stereotactic body radiation therapy (SBRT) at our institution. Material and Methods Patients presenting with biopsy-proven, solitary, small (<5 cm) extracranial metastasis from a gynecologic primary cancer, treated with robotic SBRT, were retrospectively reviewed. Vaginal cuff recurrences or multiple sites of disease were considered exclusion criteria for this analysis. Patients were stratified by the presence or absence of sarcomatous histology. The Kaplan-Meier method was used to estimate local control and overall survival. Durable local control was defined as lasting ≥12 months. Toxicity was scored per the CTC-AE v4.0. Results Twenty patients were treated over a five year period from July 2007 to July 2012 for solitary extracranial metastases from gynecologic malignancies. Sixteen patients were noted to have non-sarcomatous histology (six uterine and ten ovarian primary tumors), while four tumors were identified as sarcoma (all uterine primaries). No patients with solitary cervical cancer metastases were identified. Metastases involved the liver, lung, abdomen, spine, pelvis, and extremity. Thirteen patients had fiducials placed for tumor tracking; abdominal and spine metastases were tracked with a fiducial-less spinal tracking system. The median gross tumor volume (GTV) was 42.5 cc (range: 5 - 273 cc). The median dose delivered to the GTV was 35 Gy (range: 30 - 50 Gy) over 5 to 9 days (median: 6 days). At a median follow-up of 56 months (range: 6 - 108 months), the 5-year local control and overall survival rates were 71.2% and 47.5% respectively. However, when stratified by histology, the local control at 5 years was 93.7% in patients with classical histology versus 25.0% in patients with metastatic gynecologic sarcoma (p < 0.01) and only 50.0% of the sarcoma patients experienced durable local control. No grade 3 or higher toxicity was observed during or following treatment. Conclusion Five-fraction SBRT is a versatile, well-tolerated, and highly effective treatment option for small extracranial gynecologic metastases with an excellent 5-year local control of 93.7% in patients with classical ovarian and uterine primary tumors. However, patients with metastatic uterine sarcoma may require a more aggressive or alternative treatment approach. EP-1402 Impact of SBRT on pain and local control for bone metastases: a systematic review and meta-analysis J.M. Van der Velden 1 , A.S. Gerlich 1 , E. Wong 2 , E. Chow 2 , M. Intven 1 , N. Kasperts 1 , W.S.C. Eppinga 1 , E. Seravalli 1 , M. Van Vulpen 1 , H.M. Verkooijen 1 1 UMC Utrecht, Department of Radiation Oncology, Utrecht, The Netherlands 2 Sunnybrook Odette Cancer Center, Radiation Oncology, Toronto, Canada Purpose or Objective Pain due to bone metastases is the most common cancer- related pain syndrome. Besides analgesics, conventional radiotherapy has been the cornerstone in the management of bone metastases. However, control of pain after conventional radiotherapy is modest, approximately 60%. Advances in radiotherapy technique enable the delivery of potentially ablative radiation doses, while respecting healthy tissue constraints under the heading of stereotactic body radiotherapy (SBRT). We conducted a systematic review and meta-analysis to quantify pain response and local control after SBRT for bone metastases. Material and Methods Following the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guideline, Embase, PubMed and Cochrane Libraries were searched with the (synonym) terms ‘bone metastases’ and ‘stereotactic body

radiotherapy’. Studies delivering SBRT in 1 – 6 fractions to patients with or without previous radiotherapy or surgery were included. Information from studies reported in more than one publication was collated, and the most complete or recent article was cited. Study variables, including pain response and local control rates, were extracted from the selected articles. Pain response was defined as a complete or partial (i.e., at least 2 points decrease in pain score) response. To qualify for inclusion in the meta-analysis, outcomes had to be reported on an individual patient or lesion level, follow up had to be recorded at least 45% of the study population, and the size of the study population had to be 10 or more. Pooled estimates using random- effects models were calculated for pain response and local control rates. Results After screening of 2619 unique articles, 54 articles (3359 patients) were included in the systematic review. Twenty- six articles (1627 patients/lesions) were included in the meta-analysis for pain response, and 36 articles (2875 lesions) in the meta-analysis for local control. After SBRT, pain response rate ranged from 62% to 98% (see forest plot), and local control rate ranged between 25% and 97% (see forest plot). Excluding the study with the lowest local control rate, which included patients with spinal lesions from hepatocellular carcinoma, the local control rates varied between 74% and 97%. Pooled pain response rate was 80% (95% confidence interval [CI] 72% – 87%) with high heterogeneity (I 2 = 77%). Pooled local control rate was 87% (95% CI 84% – 90%) with high heterogeneity (I 2 = 76%).

Conclusion SBRT for bone metastases results in high pain control and high local control rates. This observation needs to be further confirmed within large randomized controlled trials.