Estimation of the optimal brachytherapy utilisation rate in the treatment of vaginal cancer and comparison with patterns of care

Having previously modelled the optimal proportion of uterine cervix and corpus cancers that should be treated with brachytherapy (BT), we aimed to complete the assessment of the role of BT for gynaecological cancers by estimating the optimal proportion of vaginal cancer cases that should be treated with BT, the optimal BT utilisation (BTU) rate for vaginal cancer. We compared this with actual vaginal BTU and assessed quality of BT for vaginal cancer by a Patterns-of-Care Study (POCS).Evidence-based guidelines were used to construct an optimal BTU decision tree for vaginal cancer. Searches of the epidemiological literature to ascertain the proportion of patients who fulfilled the criteria for BT were conducted. The robustness of the model was tested by sensitivity analyses and by peer review. A retrospective POCS of BT in New South Wales (NSW) for 2003 was conducted, and actual BTU for vaginal cancer was determined. Differences between optimal and actual BTU were assessed. Quality of BT for vaginal cancer was compared with published benchmarks.The optimal vaginal cancer BTU rate was estimated to be 85% (range 81-87%). In NSW in 2003, actual vaginal cancer BTU was only 42% (95% confidence interval 22-62%). In NSW, only nine patients were treated, all with intra-vaginal cylinders, and two of four to lower than recommended doses.BT for vaginal cancers is underutilised in NSW compared with the proposed optimal models of care. BT quality may have been suboptimal and this may relate to the rarity of this disease.