Cervical cancer is the most common cause of cancer death among women in Kenya. Visual inspection with acetic acid (VIA) has become the standard screening method. However, diagnostic accuracy of VIA is limited due to observer subjectivity and participation in VIA screening program is very low. We therefore compared VIA with molecular screening methods i.e. HPV testing and the p16INK4a/Ki-67 immunocytochemistry, a biomarker specific for HPV-transformed cells.
In two rural clinics belonging to the catchment area of Moi Teaching and Referral Hospital women who participated in the VIA program offered by the regional health service were invited to also participate in the molecular screening study. Consenting women had a liquid-based cytology sample taken before conducting VIA according to the manual on visual screening for cervical neoplasia published by IARC,2003. Liquid-based cytology (LBC) samples were used (i) to prepare a microscopic slide using Thinprep® 2000 processor (Hologic®) and (ii) performing HR-HPV DNA (HC2, Qiagen®) assay on the remaining sample. Slides were sent to Heidelberg, Germany, where p16INK4a /Ki-67 immunostaining using Roche® CINtec PLUS® kits was performed.
576 women have been recruited so far. The analysis is done on a preliminary dataset of 321 women. 158 (49.2%) women were 30+ years old, 37 (6.2%) were multipara, 33 (10.7%) of 308 women reported to be HIV-infected. The positivity rate of HPV DNA, VIA and p16INK4a /Ki-67 were 30.8%, 4.98%, and 2.5%. 8.1% of all HPV DNA samples were p16INK4a /Ki-67 positive. All p16INK4a /Ki-67 positive sample were also HPV DNA positive. Of all VIA positive samples 31.3% were HPVDNA positive and none p16INK4a /Ki-67 positive.
The VIA results correlated poorly with both the HPV DNA status and the biomarker p16INK4a /Ki-67. Colposcopic follow-up of all HPV positive women will be done. The use of p16INK4a /Ki-67 as a triage test for HPV DNA positive women will be studied in future.