Gynaecologist-led Lynch syndrome testing may be desirable in endometrial cancer, especially when offered during routine follow-up, according to the findings of the Proportion of Endometrial Tumours Associated with Lynch Syndrome (PETALS) study, which offered testing to unselected endometrial cancer patients, irrespective of their age, family history or tumour characteristics.
In total, 305 women with suspected or known endometrial cancer undergoing treatment at a large specialist gynaecological cancer service in the North West of England were offered Lynch syndrome testing. Three patients declined because of anxiety about their cancer diagnosis and impending surgery.
All tumours underwent microsatellite instability (MSI) testing, immunohistochemistry (IHC) for mismatch repair (MMR) status and when MLH1/PMS2 IHC loss was present, targeted MLH1 methylation testing. Germline testing was only carried out if tumour triage was positive (MSI-high or MMR-deficient with normal MLH1 methylation) and/or women were aged ≤50 years or had a strong personal/family history of Lynch syndrome-associated tumours.
The average time taken to consent for testing was approximately 6 minutes 29 seconds when this was done before surgery, 3 minutes 58 seconds on the day of surgery and 10 minutes 18 seconds during follow-up.
Anxiety levels were significantly lower when women were consented during follow-up (P=.001). Anxiety levels were not affected by familial cancer history (P=.41).
Thirteen of the 300 women who underwent testing tested positive for Lynch syndrome. All were offered and received formal genetic counselling to discuss the implications of their diagnosis and opportunities to reduce their future cancer risk.
Cascade testing was offered to at-risk family members. At 12 months after the close of the study, 16 family members had tested positive, 16 tested negative and three declined testing.
The study suggests gynaecologist-led Lynch syndrome testing in women with endometrial cancer is feasible and might address the need for prior genetic counselling.