Cytology material is equivalent to tumor tissue in determining mutations of BRCA 1/2 genes in patients with tubo-ovarian high grade serous carcinoma.

Background: High-grade serous ovarian cancer is a detrimental disease. Treatment options in patients with a recurrent disease are dependent on BRCA1/2 mutation status since only patients with known BRCA mutation are eligible for treatment with poly(ADP-ribose) polymerase inhibitors (PARPi). The aim of this study was to compare concordance of BRCA mutation analyses from cytological samples (CS) with BRCA mutation analyses from histological formalin fixed paraffin embedded (FFPE) samples.

Methods: Mutation analysis of BRCA1 and BRCA2 genes was performed in 44 women diagnosed with primary or recurrent high-grade ovarian cancer from three different samples: blood, cytological sample (ascites, pleural effusion and enlarged lymph nodes) and tumor tissue. Results from all three samples were compared.

Results: Among 44 patients, there were 15 germline mutations and two somatic mutations. A 100% concordance was found between cytological and histologic samples.

Conclusion: There is a 100% concordance in BRCA mutation testing between cytological and histologic samples. BRCA mutation testing from CS could replace testing from FFPE tissue in clinical decision making in ovarian cancer patients.

Trial Registration: The study was retrospectively registered at ISRCTN registry on 24/11/2015 - ISRCTN42408038 .