HPV Testing Screening Finds Invasive Cervical Cancers Early
Human papillomavirus (HPV) testing is known to be more sensitive than cytology for detecting cervical intraepithelial neoplasia (CIN). HPV testing not as specific as cytology and can result in more false positives than conventional Pap smears.
Dr. Guglielmo Ronco and colleagues have found that human papillomavirus (HPV) DNA tests prevented more invasive cervical cancer than pap smears due to detection of CIN at earlier stages. The results of the New Technologies for Cervical Cancer (NTCC) screening study was published online yesterday in the journal The Lancet Oncology.
The NTCC study consisted of two separate recruitment phases between March, 2004, and December, 2004. Nearly 100,000 women aged 25-60 years were randomly assigned to conventional cytology or to HPV testing in combination with liquid-based cytology (first phase) or alone (second phase).
During phase one, women who were HPV-positive and aged 35-60 years were referred to colposcopy. The younger women (25-34 years) were referred to colposcopy only if cytology was also abnormal or HPV testing was persistently positive.
During phase two, women in the HPV group were referred for colposcopy if the HPV test was positive. Two rounds of screening occurred in each phase. The second screening was cytology testing for all women. The primary endpoint was the detection of grade 2 and 3 CIN, and of invasive cervical cancers during the first and second screening rounds. Analysis was done by intention to screen.
Of the 47,001 women randomly assigned to the cytology group, 33,851 had a second round of screening. Of the 47,369 randomly assigned to HPV testing group, 32,998 had a second round of screening.
The detection of invasive cervical cancers was similar for the two groups in the first round of screening (9 in the cytology group vs 7 in the HPV group). No invasive cervical cancer were detected in the round two screening of the HPV group, but 9 were in the cytology group.
Among women aged 35—60 years, HPV testing detected twice as many cervical cancer than cytology [HPV vs cytology was 2·00 for CIN2, 2·08 for CIN3, and 2·03 for CIN2 and 3 together]. At round two the relative detection was 0·54 for CIN2, 0·48 for CIN3, and 0·51 for CIN2 and 3 together.
Among women aged 25—34 years, the relative detection of CIN3 at round one was 0·93 in phase one and 3·91 in phase two. At round two the relative detection was 1·34 in phase one and 0·20 in phase two.
The researchers feel that HPV-based screening is more effective than cytology in preventing invasive cervical cancer by detecting persistent high-grade lesions earlier and providing a longer low-risk period. However, the researchers note in younger women, HPV screening leads to over-diagnosis of regressive CIN2.
Cervical cancer forms in tissues of the cervix (the organ connecting the uterus and vagina). It is usually a slow-growing cancer that may not have symptoms but can be found with regular Pap tests (a procedure in which cells are scraped from the cervix and looked at under a microscope). Cervical cancer is almost always caused by human papillomavirus (HPV) infection.
In the United States, there were an estimated 11,270 new cases and 4,070 deaths from cervical (uterine cervix) cancer in the United States in 2009.