EXPLORING GENETIC COUNSELORS’ USE OF TUMOR SEQUENCING TO IDENTIFY GERMLINE VARIANTS: TIME FOR A CHANGE IN SCOPE?

Abstract

Objective: Tumor sequencing (TS) is used by most oncologists for precision treatment 1-4, and has now been found to reveal potential germline cancer predisposition variants (PGCVs) in ~12-14% of cases 5-7. Reviewing TS results to identify PGCVs requires expertise, though guidelines have not yet established different clinicians’ responsibilities in result interpretation and making necessary referrals 8-10. When PGCVs are identified, referral to cancer genetic counselors (GCs) for confirmatory germline testing and risk assessment is recommended 8-10. Cancer GCs are a good fit for both identifying PGCVs and referral for confirmatory testing, though cancer GCs current role and attitudes related to this work are unknown. This study targeted cancer GCs to describe the current state of the field and possibly inform future management. Methods: An anonymous, online, descriptive survey of closed and open-ended questions was sent to cancer GCs in North America.

Results: Of 154 responses, 135 could be used in analysis. A majority (n = 128) had training on this topic, mostly through conferences (74.2%) or self-study (67.4%). Clinical workflows were listed as a top referral facilitator for these cases by most participants (n = 101, 86.3%), though for half this was not in place at their institution (n = 68, 50.4%). Over 90% endorsed TS PGCV identification and management as part of cancer GC scope of practice (n = 123-126). This work was also seen as part of scope of practice by over 90% for pathologists (n = 126), lab GCs (n = 127), and oncologists (n = 122). Family still appeared to be an important information for GCs recommend cancer risk assessment for case vignettes. Overall, responses to the vignettes and case study varied by practice setting, role of GC involvement, and training type. A majority used variant allele frequency, founder mutation status, and tumor type as PGCV clues.

Conclusions: While most respondents agreed that evaluating TS for PGCVs falls under cancer GC scope of practice, there were variations in individual roles, views on the scope of others, and interpretation and management strategies.