The Clinical Value of Screening for Cervical Cancer using the High Risk Human Papilloma Virus (HR-HPV) and Liquid Based Cytology (LBC) Co-Testing Approach Compared to Screening with Individual Tests in Harare, Zimbabwe

Background: Cervical cancer is the most common malignancy in Zimbabwe. This attributed to poorly executed Pap smear based screening programs. Pap smears have poor sensitivity and high specificity while HR-HPV DNA testing has high sensitivity and poor specificity. With reference to the ASCCP guidelines, does combining these two tests have any clinical value in terms of increasing screening intervals from 3 to 5 years, predicting possible future cervical lesion and resolving the dilemma associated with managing patients with borderline ASCUS LBC results.

Aim: To assess the clinical value of LBC and HR-HPV DNA co-testing in terms of increasing screening intervals (in the NILM/HPV- group), predicting possible future cervical lesions (in the NILM/HPV+ group) and the resolution of the dilemma associated with managing patients with borderline ASCUS LBC results.

Study design: Cross sectional descriptive.

Place and duration of study: Cimas Medical Laboratories. February 2020 to November 2020.

Methodology: A Thin Prep 2000 machine was used to process the LBC samples. The slides were then stained using the Papanicolaou stain. Two independent Cytologists interpreted the LBC smears according to the 2014 Bethesda System. Discrepant results were resolved by an independent Pathologist. All interpreters were blinded of the HR-HPV test result. HR-HPV DNA testing was done using the Cepheid Xpert HPV qualitative test.

Results: A total of 542 women of ages’ ≥ 30 years were recruited into the study. The mean (SD) of the women was 39.4 (8.6) years, the median age was 37 years and the age range was 30-83 years. The mean ages’ of the HR-HPV+ and HR-HPV- were comparable (40.1 years vs. 38.9 years, respectively; p=0.412). LBC abnormalities were significantly higher in women >37years (median age) than women ≤37 years (18.2% [4/22] vs. 81.2% [18/22], respectively; p=0.002).The LBC/HR-HPV test combination results were as follows: NILM/HPV- (n=418, 77.1%), NILM/HPV+ (n=102, 18.8%), ASCUS/HPV+ (n=9, 1.7%), ASCUS/HPV- (n=5, 0.9%) and >ASCUS/HPV+ (n=8, 1.5%).

Conclusions: The co-testing approach had the clinical value of increasing screening intervals from 3 to 5 years in 77.1%, predicting possible future cervical lesion in 18.8%, instant confirmation of a precancerous lesion from ASCUS lesions in 1.7% and the instant confirmation of a non-neoplastic lesion from ASCUS lesions in 0.9% of all co-tested samples.