Simulation-based graduate medical education in MR-guided brachytherapy for cervical cancer.

PURPOSE: Brachytherapy is critical for the curative treatment of locally advanced cervical cancer. Although brachytherapy use is declining in the United States (U.S.), novel interstitial or intracavitary applicators and advances in image guidance for applicator placement and treatment planning have allowed for tumor dose escalation while reducing normal tissue toxicity. Recent survey data have suggested insufficient brachytherapy training for radiation oncology trainees in the United States. This study aimed to address these gaps by developing and piloting a simulation-based education (SBE) workshop for MR-guided cervical cancer brachytherapy. METHODS AND MATERIALS: An SBE workshop was developed for graduate medical education (GME) trainees focusing on MR-guided brachytherapy for cervical cancer. Four hands-on stations, simulating aspects of the procedure, were led by a team of gynecological brachytherapy experts. The learners were radiation oncology residents and fellows in a U.S. GME training program. The primary outcome was feasibility, assessed by completion of the workshop within the time constraints of the curriculum. Learners completed preworkshop and postworkshop surveys to provide information on efficacy. RESULTS: The workshop was successfully completed in a 1-h block of GME didactic time. Ten trainees completed all four stations, and all completed preworkshop and postworkshop surveys, which showed improvements in knowledge and technical proficiency. Feedback was positive, and trainees requested additional learning opportunities. CONCLUSIONS: This study showed that GME-focused SBE in MR-guided cervical cancer brachytherapy was feasible. SBE provided a nonclinical environment in which to practice aspects of MR-guided brachytherapy. Ongoing work includes collaboration with other U.S. institutions. Future studies should focus on international adaptation.

Vaginal recurrence of endometrial cancer: MRI characteristics and correlation with patient outcome after salvage radiation therapy.

PURPOSE: To evaluate MRI characteristics in vaginal recurrence of endometrial cancer (EC) including tumor volume shrinkage during salvage radiotherapy, and to identify imaging features associated with survival. METHODS: Patients with vaginal recurrence of EC treated with external beam radiotherapy (EBRT) followed by brachytherapy (BT), and with available pelvic MRI at two time points: baseline and/or before BT were retrospectively identified from 2004 to 2017. MRI features including recurrence location and tissue characteristics on T2- and T1-weighted images were evaluated at baseline only. Tumor volumes were measured both at baseline and pre-BT. Survival rates and associations were evaluated by Cox regression and Fisher's exact test, respectively. RESULTS: Sixty-two patients with 36 baseline and 50 pre-BT pelvic MRIs were included (24/62 with both MRIs). Vaginal recurrence of EC was most commonly located in the vaginal apex (27/36, 75%). Tumors with a post-contrast enhancing peripheral rim or low T2 signal rim at baseline showed longer recurrence-free survival (RFS) (HR 0.2, 95% CI 0.1-0.9, P < 0.05 adjusted for histology; HR 0.2, 95% CI 0.1-0.8, P < 0.05, respectively). The median tumor shrinkage at pre-BT was 69% (range 1-99%). Neither absolute tumor volumes nor volume regression at pre-BT were associated with RFS. Lymphovascular space invasion (LVSI) at hysterectomy and adjuvant RT were associated with recurrence involving the distal vagina (both P < 0.05). CONCLUSION: Vaginal recurrences with rim enhancement at baseline MRI predicted improved RFS, while tumor volume shrinkage at pre-BT did not. Distal vaginal recurrence was more common in patients with LVSI and adjuvant RT at EC diagnosis.

Do radiation oncology outreach clinics affect the use of radiotherapy?

BACKGROUND AND PURPOSE: The scope and effect of radiation oncology (RO) outreach activities within centralized radiotherapy (RT) systems is poorly defined. The purpose of this study was to describe the outreach activities of Ontario's regional cancer centres, and to explore the relationship between radiation oncology (RO) outreach clinics and rates of radiotherapy (RT) utilization at hospitals without RT on site (HWOS-RT). MATERIALS AND METHODS: Ontario RO centres' outreach activities were identified by semi-structured interview. A multivariate analysis determined the association between on-site RT facilities, or presence of RO clinic at HWOS-RT, and RT utilization within one year of diagnosis (RT1Y), for all patients diagnosed with cancer in Ontario in 2011-2012. RESULTS: RO outreach varied widely by region. Of the largest 58 diagnosing hospitals, 14 had RT on-site, 19 had no RT but RO outreach clinic(s) and 25 had no RT or RO clinic. RT was used more frequently for patients diagnosed at hospitals with on-site RT compared to those at HWOS-RT (RT1Y = 35% vs. 29%, RR = 1.32 [95% CI 1.27-1.38]). For HWOS-RT, RT was used more frequently if there was an RO clinic (RT1Y = 31% vs. 29%, RR = 1.06 [95% CI 1.02-1.10]). CONCLUSIONS: RO outreach clinics were associated with a small but significant increase in RT utilization. There is opportunity to improve access to RT by optimizing the effectiveness of RO outreach.

A comparison of evidence-based estimates and empirical benchmarks of the appropriate rate of use of radiation therapy in ontario.

PURPOSE: Estimates of the appropriate rate of use of radiation therapy (RT) are required for planning and monitoring access to RT. Our objective was to compare estimates of the appropriate rate of use of RT derived from mathematical models, with the rate observed in a population of patients with optimal access to RT. METHODS AND MATERIALS: The rate of use of RT within 1 year of diagnosis (RT1Y) was measured in the 134,541 cases diagnosed in Ontario between November 2009 and October 2011. The lifetime rate of use of RT (RTLIFETIME) was estimated by the multicohort utilization table method. Poisson regression was used to evaluate potential barriers to access to RT and to identify a benchmark subpopulation with unimpeded access to RT. Rates of use of RT were measured in the benchmark subpopulation and compared with published evidence-based estimates of the appropriate rates. RESULTS: The benchmark rate for RT1Y, observed under conditions of optimal access, was 33.6% (95% confidence interval [CI], 33.0%-34.1%), and the benchmark for RTLIFETIME was 41.5% (95% CI, 41.2%-42.0%). Benchmarks for RTLIFETIME for 4 of 5 selected sites and for all cancers combined were significantly lower than the corresponding evidence-based estimates. Australian and Canadian evidence-based estimates of RTLIFETIME for 5 selected sites differed widely. RTLIFETIME in the overall population of Ontario was just 7.9% short of the benchmark but 20.9% short of the Australian evidence-based estimate of the appropriate rate. CONCLUSIONS: Evidence-based estimates of the appropriate lifetime rate of use of RT may overestimate the need for RT in Ontario.

Surface mold brachytherapy for nonmelanoma skin cancer: Canadian patterns of practice.

PURPOSE: We sought to describe the use of surface mold brachytherapy (SMBT) for nonmelanoma skin cancer in Canada. METHODS AND MATERIALS: A list of Canadian Association of Radiation Oncologists membership and provincial registries were used for a preliminary survey to identify radiation oncologists and physicists involved in the practice of SMBT. A detailed survey was sent electronically to individuals involved in treating with SMBT. RESULTS: Of 41 centers in Canada, 39 responded, with 7 centers indicating use of SMBT. Seven radiation oncologists and 5 physicists from 6 of 7 treating centers responded to the detailed survey, with an overall 75% individual response rate (12/16). General agreement was found regarding indications for SMBT which included irregular or curved surfaces, avoidance of deep structures, and requirement for small fields. There was consensus regarding some contraindications for SMBT such as tumor depth and size. Hypofractionated schedules were used in 5 of 6 centers and doses ranged from 50 Gy in 5 fractions once per week to 30 Gy in 10 fractions twice a day over 5 days. The most common dosimetric parameters for plan evaluation included D90, D95, D100, and maximum skin dose. CONCLUSIONS: A minority of Canadian centers practice SMBT. In centers practicing SMBT, general agreement exists on general indications for its use. Given the wide variation in dose and fractionation used and the rarity of the indication a phase 2 Canadian protocol would be invaluable.

Brachytherapy practice across Canada: A survey of workforce and barriers.

PURPOSE: To determine the current use of brachytherapy, characteristics of the brachytherapy workforce, and barriers to development and maintenance of brachytherapy programs across Canada. METHODS AND MATERIALS: A survey was designed to inquire about the use of brachytherapy and was sent to all Canadian radiation oncologists. RESULTS: Of the 116 respondents, we identified 80 radiation oncologists from 33 of 41 responding centers who currently or in the past have practiced brachytherapy. Responses were received from 30% overall and 80% of provinces. Approximately 58% of the respondents treat in one site with brachytherapy, whereas 12% treat in three or more sites. Gynecologic (GYN) and genitourinary are the most commonly treated sites (49% of respondents). For all sites, there was a large range in the number of patients treated with brachytherapy by each radiation oncologist per year (i.e., cervix: 1-50). Approximately 49% of the respondents have discontinued practicing brachytherapy for a certain site, most commonly head and neck (28%), GYN (25%), and bronchus (24%). The most common reasons include reassignment or lack of a local program. The most common reasons why brachytherapy is not used for sites other than GYN and prostate include lack of infrastructure and insufficient training of radiation oncologists rather than insufficient patient numbers or lack of evidence for a benefit of brachytherapy. CONCLUSIONS: Within its limitations, our study suggests a mismatch between demand and availability of brachytherapy programs across Canada. In light of finite resources, a rational approach to investment in brachytherapy is needed and this must be based on a formal audit of brachytherapy demand and use.