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Pelvic arteriovenous malformation is a rare vascular abnormality, espescially in male patients, and is difficult to treat because of its nature supplied by multiple arterial feeders. We report a 70-year-old male patient admitted due to symptoms of benign prostatic hyperplasia. Ultrasound was performed initially, and no other abnormalities were found other than an enlarged prostate. CT scan later demonstrated a pelvic arteriovenous malformation adjacent to the prostate, with multiple arterial feeders from the right internal iliac artery. Angiography confirmed the diagnosis, and transaterial embolization was successfully done. The symptoms disappeared several days later, and the patient remained asymptompmatic during follow-up.

Mauro Loi,1 Joost J Nuyttens,2 Isacco Desideri,1 Daniela Greto,1 Lorenzo Livi1 1Radiotherapy Department, University of Florence, Florence, Italy; 2Radiotherapy Department, Erasmus MC Cancer Center, Rotterdam, The NetherlandsCorrespondence: Mauro LoiRadiotherapy Department, University of Florence, L.go Brambilla 3, Florence 50100, ItalyEmail mauro.loi@unifi.itAbstract: Bone metastases are a frequent and important source of morbidity in cancer patients. Stereotactic body radiation therapy (SBRT) is an established treatment option for local control and pain relief of bone metastases, and it is increasingly used as upfront treatment, postoperative consolidation or salvage treatment after prior RT. However, heterogeneity of dose schedules described in literature represents a severe limitation in the definition of the role of SBRT as a standard of care. No consensus is available on the use of single versus multiple fraction SBRT for bone metastases. Advantages of single-fraction SBRT include shorter overall duration of treatment, absence of inter-fraction uncertainty, improved compliance, theoretical increased efficacy, and lower costs. However, caution has been advised due to reports of severe late toxicities, in particular, vertebral collapse fracture (VCF). The aim of this paper is to review dose fractionation and indications for the management of bone metastases using SBRT.Keywords: SBRT, stereotactic radiotherapy, radiosurgery, bone metastases, spine, non-spine

A phase II trial was conducted to assess the feasibility, safety, and activity of a single 21 Gy preoperative robotic radiosurgery (prRS) in early breast cancer patients, 50+ years old, hormonal receptors positive/human epidermal growth factor receptor 2 negative (HR+/HER2-), sized up to 25 mm. Breast surgery was performed 2 to 4 weeks after radiosurgery. A translational study was carried out to explore the modulation of tumor-immune microenvironment before and after irradiation and the transcriptome on tumor samples before irradiation. Among the 70 patients recruited, 22 patients were successfully treated with prRS. Fresh pre-treatment tumor biopsies and fresh post-radiosurgery and post-operative tumor samples were retrieved. For immunohistochemistry analysis, pre-radiosurgery biopsies and post-operative tumors were stained with specific antibodies to evaluate the expression of different immune-related biomarkers. For the transcriptome analysis, total RNA was extracted from frozen pre-treatment samples and RNA sequencing was performed by using a total of 10 ng/uL. The statistical analyses aiming at detecting differences in gene expression according to tumor downstaging were conducted by fitting age-adjusted linear regression models, and applying the false discovery rate (FDR) method for correcting for multiple tests. As clinical output, we considered tumor downstaging according to pTNM and patients were classified as Radio-Responders (R-R = 8) and non-Radio-Responders (nR-R = 13) after prRS. IHC was performed on available 19 pairs of pre- and post-irradiation tissues for evaluation of CD68, CD163, CD4, CD8, CD56 and CD16: preliminary analysis showed a marked increase in CD68, CD163 and CD4 staining after tumor prRS. RNAseq results showed 170 differentially expressed genes between R-R and nR-R. Statistical analysis identify CCDC97 and MDIFC as genes that were significantly up- and down-regulated respectively in R-R patients. CCD97 is an orphan gene previously described as part of a nuclear interactome with functional role in DNA damage repair, while MDFIC is reported to be associated with pro- or anti-tumoral functions as chemoresistance induction or cell proliferation inhibition. The phase II trial enrolled 22 patients; this little number limits the statistical power of results obtained in the translational analysis. Based on the preliminary results, IHC analysis showed that prRS modulates the immune microenvironment composition in early breast cancer patients. Furthermore, we hypothesized that the differential expression of CCDC97 and MDFIC may play a role in prRS response. The role of orphan genes CCDC97 and MDFIC in response to radiation and to hypofractionation makes worthy further pre- and clinical investigations. [ABSTRACT FROM AUTHOR]

Prescription of ablative doses in pancreas SBRT requires steep dose fall-off to fulfill OARs dose limits. Both geometric errors and organ deformation may lead to OARs doses violation. We aimed at evaluating effects of intra-fraction errors and inter-fraction deformation on OARs doses, investigating their predictability in terms of target-to -OAR proximity Twenty patients, treated for pancreatic cancer in 5 fraction prescribing 40Gy/50Gy to PTV/GTV, were considered. Plan optimization required for duodenum, stomach and bowel V35Gy< 0.5 cc. Target-to-OAR proximity was quantified for each patient computing the expansion-intersection volume (EIV) on the planning CT (pCT), as the intersection between the PTV expanded by 5 mm and duodenum, stomach and bowel. All patients were treated at a frameless robotic radiosurgery system using fiducial real time respiratory tracking modality. Residual tracking errors were extracted for 100 fractions using the system log-files. Standard uncertainties (mean values + 2 standard deviations) along the three directions (SI, LR; AP) were used as descriptive statistics. To simulate the effects of tracking errors on OARs doses, a perturbed plan was created modifying each CK beam coordinates by the corresponding errors and a perturbed dose distribution was calculated. Inter-fraction OARs deformation was evaluated acquiring pre-fraction CT scans with a maximum of 2 repeated scans per patient. Deformed OARs were contoured by the same physician who contoured the pCT. Planned doses were re-calculated on the deformed anatomy using the fiducials alignment center, to rigidly register the pCT to each pre-fraction scan. OARs constraints of perturbed plan and deformed anatomy were considered met at V35 Gy < 1 cc. EIV values ranged from 0.5 to 28 cc (median 9.6 cc). Tracking errors standard uncertainties ranged from 0.6 mm to 7.2 mm, with respective median values 3.5 mm (SI), 2.4 mm (LR), 2.0 mm (AP). For plans perturbed by tracking errors, OARs constraints were violated only in 2 / 20 patients (V35Gy respectively 1.4 cc and 1.2 cc). For these two patients, EIV values were above 25 cc, and errors uncertainties were above 5 mm along at least one direction. The recalculated doses on deformed OARs, contoured on repeated CT scans, showed constraints violation in 13/20 cases with V35Gy values up to 5 cc (median 2.1 cc). The 7 patients for whom constraints were still met on the deformed anatomy (V35Gy<1cc) showed EIV values below 1.5 cc. CK tracking errors have small effects on OAR doses, but attention must be paid to minimize these errors for patients with large EIV values. Although OARs deformation has larger effects, constraints were still met in 33% of patients. EIV is a promising parameter to predict who is at risk of exceeding OARs constraints during pancreas SBRT, needing plan adaptation. [ABSTRACT FROM AUTHOR]