Adherence to referral guidelines: Genetic testing in an Australian triple negative breast cancer (TNBC) cohort

A significant subset of patients (12 per cent) with triple negative breast cancer (TNBC) is BRCA mutation carriers, which can be identified through genetic testing. The purpose of this paper is to evaluate the referral practice for TNBC patients with reference to New South Wales (NSW) referral guidelines at the time of diagnosis and to assess the effectiveness of such guidelines in identifying BRCA mutations. Robust health governance requires monitoring of adherence to evidence-based guidelines such as those that underpin referral for cancer genetic testing in this clinical scenario.

The authors conducted a retrospective clinical audit of identified TNBC patients at St Vincent’s Hospital (SVH) between 2006 and 2016 in NSW, comparing referral practice to guidelines extant at the time of diagnosis. Family history was considered for age guideline-inappropriate referrals to SVH while the results of BRCA gene testing were assessed for all referred.

Overall, of the 17 patients eligible for referral based on the age criterion, 10 (58.5 per cent) were referred appropriately; however, there were substantial improvements from 2012 with 100 per cent referred. Of note, 12 (33.4 per cent) of 36 patients referred to SVH were referred outside of guidelines, pointing to other reasons for referral, such as patient age (OR 0.945; 95% CI 0.914–0.978) and calendar year (OR: 1.332; 95% CI: 1.127–1.575) at TNBC diagnosis. Referral guidelines captured 66.67 per cent of identified deleterious BRCA mutations in those tested.

Substantial under-referral of guideline-eligible patients was identified, with evidence-based guidelines effective in identifying high-risk individuals for BRCA mutation testing. There was, however, a substantial proportion of guideline-inappropriate referrals.