Injection of rectal spacer is feasible in the post-LDR brachytherapy setting and reduces dose to the rectum with minimal toxicity. Prostate and urethral dosimetries do not appear to be affected by the placement of a spacer. Further studies with long-term followup are warranted to assess the impact on reduction of late rectal toxicity.

Irinotecan is stably entrapped in the active lactone conformation within preformed copper-containing liposomes as a result of metal-drug complexation.

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PURPOSE To present the clinical commissioning of a novel 103Pd directional brachytherapy device (CivaSheet™) for intraoperative radiation therapy. METHODS AND MATERIALS Clinical commissioning for the CivaSheet™ consisted of establishing: (i) source strength calibration capabilities, (ii) experimental verification of TG-43 dosimetry parameters, (iii) treatment planning system validation, and (iv) departmental practice for dose specification and source ordering. Experimental verification was performed in water with radiochromic film calibrated with a 37kVp x-ray beam. Percentage difference ([measurements – calculation] / calculation) and distance to agreement (difference between film-to-source distance and distance that minimized the percentage difference) were calculated. Nomogram values (in U/100 Gy) for all configuration (up to 20 × 20 sheets) were calculated for seed ordering. Clinical commissioning was used on patients enrolled in an ongoing IRB-approved protocol. Results A source calibration procedure was established and the treatment planning system was commissioned within standard clinical uncertainties. Percentage dose differences (distances to agreement) between measured and calculated doses were 8.6% (−0.12mm), 0.6% (−0.01mm), −6.4% (0.22mm), and −15.8% (0.72mm) at depths of 2.3mm, 5.1mm, 8.0mm, and 11.1mm respectively. All differences were within the experimental uncertainties. Nomogram values depended on sheet size and spatial extent. A value of 2.4U/100 Gy per CivaDot™ was found to satisfy most cases, ranging from 2.3 to 3.3U/100 Gy. Nomogram results depended on elongation of the treatment area with a higher variation observed for smaller treatment areas. Post-implantation dose evaluation was feasible. CONCLUSIONS Commissioning and clinical deployment of CivaSheet™ was feasible using BrachyVision™ for post-operative dose evaluation. Experimental verification confirmed that the available TG-43 dosimetry parameters are accurate for clinical use.

Aims: Recurrent gynaecological tumours can cause significant morbidity with limited salvage options. This study investigates the strategy of salvage singlemodality interstitial brachytherapy (SM-ISBT) for recurrent gynaecological pelvic cancer at two specialised ISBT centres. Materials and methods: Patients who had received salvage SM-ISBT for pelvic recurrence of gynaecological cancers from September 2008 to January 2017 were included. None had distant metastasis at the time of recurrence. Local control, progression-free and overall survival and long-term toxicities were evaluated. Results: Twenty-six patients with a median follow-up of 24 months (range 2.5e106.3 months) after SM-ISBT were included. Primary cancer sites were endometrium (20), cervix (4), vulva (1) and vagina (1). All patients had prior whole-pelvic external beam irradiation and 16 had prior brachytherapy. The median disease-free survival prior to SM-ISBT was 20.3 months (interquartile range 9.9e30.5). SM-ISBT was delivered with high dose rate technique over three to six fractions. The median high-risk clinical target volume was 34.6 cm 3 , with a median D90 of 29.1 Gy (range 16.1e64.6). The median bladder, rectum and sigmoid D2cm 3 were 15.5, 18.7 and 3.7 Gy, respectively. After SM-ISBT, complete and partial responses were achieved in 17 (64%) and 5 (19%) patients, respectively. Two (7.4%) patients had grade 3 toxicities (both vaginal stenosis), with no grade 4 complications. Eighteen patients (69%) recurred, including local, regional and metastatic in 14 (54%), 8 (30%) and 5 (19%) patients, respectively. Two-year local control, progression-free survival and overall survival were 50, 38 and 78%, respectively. In follow-up, 12 patients (46%) remained in local control. Conclusions: Salvage SM-ISBT re-irradiation for pelvic recurrence of gynaecological malignancies was feasible and safe. With limited salvage options, the local control obtained in more than a quarter of patients seems reasonable. Further efforts are needed to establish a consensus about the optimal patient selection, dose fractionation, implant technique and combination with systemic therapies.

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Introduction: Liver metastases are common in patients with neuroendocrine neoplasms. The role of stereotactic ablative radiotherapy (SABR) is not well understood in this population. Objective: To evaluate the safety and efficacy of SABR in treating well-differentiated neuroendocrine liver metastases (WD-NELM). Methods: A retrospective review of patients with WD-NELM treated with SABR between January 2015-July 2019. Demographic, treatment and clinical/radiographic follow-up data were abstracted. RECIST 1.1 criteria were applied to each individual target to evaluate the response to treatment. Local control (LC) and progression free survival (PFS) were determined using Kaplan-Meier methodology. Toxicity was reported according to CTCAE v5.0. Results: Twenty-five patients with a total of 53 liver metastases treated with SABR were identified. Most patients (68%) had midgut tumors, were Grade II (80%) and had high volume intrahepatic and/or extrahepatic disease (76%). Median number of liver metastases treated was 2 with a median size of 2.5 cm. Median radiation dose delivered was 50Gy/5 fractions. Median follow-up was 14 months; 24 of the 25 patients were alive at time of analysis. The objective response rate (ORR) was 32%, with improvement or stability in 96% of lesions treated. The median time to best response was 9 months. The 1-year LC and PFS were 92% and 44% respectively. No Grade III/IV acute or late toxicity was identified. Conclusions: Liver SABR is a safe and promising means of providing local control for WD-NELM. This treatment modality should be evaluated in select patients in concert with strategies to manage systemic disease.