Cervical cancer brachytherapy in Canada: A focus on interstitial brachytherapy utilization

Brachytherapy (BT) techniques for cervical cancer in Canada have changed over the last decade, with evolution to high-dose-rate and image-guided BT. However, there are currently no national data on the use of interstitial BT (IBT). The purpose of this study was to document IBT utilization in Canadian centers, as well as update details of cervical cancer BT practices.

All Canadian centers with gynecologic BT services (n = 33) were identified, and one gynecology radiation oncologist per center was sent a 33-item e-mail questionnaire regarding their center's practice for cervical cancer BT in 2015. Responses were reported and compared with practice patterns identified in a 2012 Canadian survey.

The response rate was 85% (28/33 centers). The majority (93%) of respondents used high-dose-rate BT, similar to the 2012 survey; 96% of centers had transitioned to three-dimensional (MRI/CT)-based planning in 2015 vs. 75% in 2012 (p = 0.03); 57% centers incorporated MRI for treatment planning in 2015 compared to 38% in 2012 (p = 0.15); the majority (13/16) using a combination of MRI and CT; 50% (14/28 centers) had the capacity to perform IBT, whereas 71% of those that did not referred patients to other centers. Of centers performing IBT, the majority (11/14) used template-based techniques with a median of 6 (range 2-20) needles/catheters and an average of 4 (range 1-5) fractions. Catheters were placed using: strategy based on pre-op imaging (21%), intra-op ultrasound (50%), intra-op MRI (7%), and intra-op CT (21%). The most common dose/fractionation schedules were 6 Gy × 5 fractions (40%), 8 Gy × 3 fractions (19%), and 7 Gy × 4 fractions (15%).

In Canada, treatment of cervical cancer continues to evolve. IBT has been adopted by half of the responding centers. As more centers move to MRI-based image-guided treatment planning, IBT will become an even more integral part of cervical cancer treatment.