Fallopian tube cytology combined with p53 and PAX-8 immunocytochemistry in diagnosing ovarian carcinoma: a prospective study

Ovarian cancer has a high mortality rate, primarily due to delayed diagnosis caused by the lack of effective diagnostic tools. Based on the tubal origin of extra-uterine high grade serous carcinomas, we aimed to evaluate the diagnostic accuracy of cytological examination of ex vivo fallopian tube brushings, alone and in combination with p53 and PAX-8 immunocytochemistry, for the identification of ovarian carcinoma, with a particular focus on high-grade serous carcinoma (HGSC). Our study included patients who underwent pelvic surgery for any adnexal pathology. Ex vivo, fallopian tube smears were collected using a soft brush and placed on both microscopic slides and in Thin Prep solution. The cytological samples were classified as benign, atypical or malignant, followed by immunocytochemical evaluation for p53 protein and PAX-8. The SEE-Fim protocol was used for tubal histopathological assessment. Out of 103 evaluable cases, pathology identified 12 borderline tumors, 44 benign cases and 47 malignant ones, including 28 high-grade serous carcinoma cases. Cytology alone demonstrated an overall accuracy of 71.88%, while p53 showed an accuracy of 73.79% and PAX-8 an accuracy of 69.90%. After combining all three methods through logistic regression analysis, specificity increased to 83.93%, positive predictive value to 78.05%, and overall accuracy to 76.60%. Following a sub-analysis focusing on high-grade serous carcinoma, cytology reached a sensitivity of 92.86%, while p53 and PAX-8 reached 82.14% and 78.57% respectively. The combination of cytology with PAX-8 further increased sensitivity to 100%. The combination of tubal cytology and immunocytochemistry could be used as a reliable diagnostic tool for extrauterine high-grade serous carcinoma. Further evaluation of a larger sample size is warranted.