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Background: In metastatic renal cell carcinoma (mRCC) there has been a treatment shift towards targeted therapy, which has resulted in improved overall survival. Therefore, there is a need for better local control of the tumor and its metastases. Image-guided stereotactic body radiotherapy (SBRT) in bone metastases provides improved symptom palliation and local control. With the use of SBRT there is a need for accurate target delineation. The hypothesis is that MRI allows for better visualization of the extend of bone metastases in mRCC and will optimize the accuracy of tumor delineation for stereotactic radiotherapy purposes, compared with CT only. Methods: From 2013 to 2016, patients who underwent SBRT for RCC bone metastases were included. A planning CT and MRI were performed in radiotherapy treatment position. Gross tumor volumes (GTV) in both CT and MRI were delineated. Contouring was performed by a radiation oncologist specialized in bone metastases and verified by a radiologist, based on local consensus contouring guidelines. In both CT and MRI, the GTV volumes, conformity index (CI) and distance between the centers of mass (dCOM) were compared. Results: Nine patients with 11 RCC bone metastases were included. The GTV volume as defined on MRI was in all cases larger or at least as large as the GTV volume on CT. The median GTV volume on MRI was 33.4 mL (range 0.2–247.6 mL), compared to 18.1 mL on CT (range 0.1–195.9) (P=0.013). Conclusions: Contouring of RCC bone metastases on MRI resulted in clinically relevant and statistically significant larger lesions (mean increase 41%) compared with CT. MRI seems to represent the extend of the GTV in RCC bone metastases more accurately. Contouring based on CT-only could result in an underestimation of the actual tumor volume, which may cause underdosage of the GTV in SBRT treatment plans.

Background: The aim of this article was to systematically review the efficacy and safety of various antiemetics in prophylaxis of radiation-induced nausea and vomiting (RINV). Methods: A literature search of Ovid MEDLINE, EMBASE and Cochrane CENTRAL was performed to identify randomized controlled trials (RCTs) that evaluated the efficacy of prophylaxis for RINV in patients receiving radiotherapy to abdomen/pelvis, including total body irradiation (TBI). Primary endpoints were complete control of nausea and complete control of vomiting during acute and delayed phases. Secondary endpoints included use of rescue medication, quality of life (QoL) and incidence of adverse events. Results: Seventeen RCTs were identified. Among patients receiving radiotherapy to abdomen/pelvis, our meta-analysis showed that prophylaxis with a 5-hydroxytryptamine-3 receptor antagonist (5HT3 RA) was significantly more efficacious than placebo and dopamine receptor antagonists in both complete control of vomiting [OR 0.49; 95% confidence interval (CI): 0.33–0.72 and OR 0.17; 95% CI: 0.05–0.58 respectively] and complete control of nausea (OR 0.43; 95% CI: 0.26–0.70 and OR 0.46; 95% CI: 0.24–0.88 respectively). 5HT3 RAs were also more efficacious than rescue therapy and dopamine receptor antagonists plus dexamethasone. The addition of dexamethasone to 5HT3 RA compared to 5HT3 RA alone provides a modest improvement in prophylaxis of RINV. Among patients receiving TBI, 5HT3 RA was more effective than other agents (placebo, combination of metoclopramide, dexamethasone and lorazepam). Conclusions: 5HT3 RAs are more effective than other antiemetics for prophylaxis of RINV in patients receiving radiotherapy to abdomen/pelvis and TBI. Future RCTs should investigate the efficacy of newer agents such as substance P neurokinin 1 receptor antagonists in addition to 5HT3 RAs in prophylaxis of RINV during both acute and delayed phases.