Utility of Fallopian Tube Brush Cytology and Cell Blocks as a Screening Tool for Epithelial Ovarian Cancer in Patients Undergoing Gynaecological Surgeries for Benign and Malignant Indications: Attempt at a Classification System.

Introduction: Fallopian tube (FT) cytology is an evolving and as yet not well-established field. Through this study, we aimed to establish the utility of FT brush cytology by stratification into cytological diagnostic categories.

Methods: Cytological specimens were collected using an endobrush from the fimbrial end of the tubes at the time of gynaecological surgeries, and LBC preparation (liquid-based cytology slides prepared by SurePath technique) and cell blocks were prepared. Smears were stratified into unsatisfactory/non-diagnostic (ND), benign, atypical, suspicious of malignancy (SOM), and malignant. Correlation with histopathology was done, and the risk of malignancy (ROM) was calculated for each category. Negative predictive value (NPV) and positive predictive value (PPV) were calculated. Diagnostic accuracy was calculated.

Results: A total of 392 tubal cytology specimens of 225 patients were collected. 8.2% (n = 32) of the specimens were unsatisfactory/ND, 87% (n = 343) were benign, 2.6% (n = 10) were atypical, 0.8% (n = 3) were SOM, and 1% (n = 4) were malignant. All the cases in the SOM and malignant categories were serous carcinomas on histopathology. Of the ten atypical cases, all were non-malignant on histopathology: two were serous tubal intraepithelial lesions and negative for serous tubal intraepithelial carcinoma (STIC), four showed salpingitis, and four showed normal histology. ROM for ND, benign, and atypical categories was 0%. ROM for the malignant category, as well as the SOM category, was 100%. NPV for the benign category, as well as the benign and atypical categories, was 100%. PPV for the malignant category, as well as the malignant and SOM categories, was 100%. Cell blocks were prepared for all cases, and the grey zone categories of atypical and SOM were reduced from 13 to 8. The diagnostic accuracy was 91.3% without and 99.4% with consideration of the ND category.

Conclusion: FT brush cytology shows excellent concordance with the follow-up histopathology in all categories, barring the ND category. Excellent concordance with histopathology was seen in cases of the benign category, which comprised the majority of the samples (87.5%). Although excellent concordance was also seen in the other categories with the final histopathology, the number of samples in these categories was less for a definite conclusion. Cell block preparation, though useful, especially in the grey zone categories, did not offer statistically significant results. Another important finding was that not even a single case of incidental STIC was found. This finding raises questions on the accepted current routine practice of preventive salpingectomy for all in the correct setting.