Cervical cancer screening

No proven benefit of detection of human papillomavirus alone compared with the conventional Pap smear

Under the aegis of the French Society of Clinical Cytology, physicians at the Institut Curie have evaluated the relevance of the papillomavirus detection test, Hybrid Capture‚ II, in screening for cervical cancer, the second most common cancer in women worldwide. They have shown that this test cannot replace cytological analysis of the cervical smear.
For the first time a learned society, the French Society of Clinical Cytology, has organized a multicenter, national study in general practice. Cervical cancer screening is one of 70 priority measures in France’s Cancer Plan, and an important goal is to establish a test that combines reliability, feasibility and affordability. This work was published in the October 2003 issue of the American Journal of Clinical Pathology.

Cervical cancer is the second most common cancer in women, with 465 000 new cases and 200 000 deaths worldwide every year. In France, 3 387 new cases and 1 000 deaths were recorded in 2000. Cervical cancer affects women in all age ranges, from 25 years upwards.

Cervical cancer screening: a national priority

Early detection of cervical cancer through intensified screening is one of the 70 measures of the Cancer Plan launched in France by the President of the Republic. Screening is based on the cervical smear test. In this simple and painless test, cells are collected from the surface of the cervix and are examined under the microscope for any anomaly suggestive of lesions that are precancerous or cancerous. It should be performed every three years.

The Cancer Plan is intended to broaden availability of the smear test (family planning, occupational medicine…) to women who do not have a gynecologist, so as to intensify information actions and facilitate testing for papillomavirus infection.
In France, generalization of the smear test has already led to a reduction in the incidence of cervical cancer: the number of cases decreased from 5 992 in 1975 to 3 387 in 2000, i.e. a 46 % decrease in 25 years.

This incidence though is still high, possibly due to the fact that the female population is not fully covered and also because some women develop cervical cancer despite regular smear tests, which clearly have shortcomings (false-negatives, absence of abnormal cells in the area of the smear…). Screening should be improved by the implementation of more sensitive tests.

Comparison of detection of HPV and cytologic analysis

Close to 90% of cervical cancers develop from pre-invasive lesions due to a human papillomavirus (HPV). The efficiency of screening could be improved by the inclusion of testing for HPV.

Under the aegis of the French Society of Clinical Cytology, physicians of the Institut Curie, coordinated by Dr Béatrix Cochand-Priollet (1) have evaluated the efficiency and relevance of the Hybrid Capture‚ II papillomavirus DNA test (HC-II) (2). This test performed on the cervical smear detects papillomavirus DNA and distinguishes high-risk from low-risk HPVs.

By comparing cytologic analyses and the HC-II test in 1 785 patients, the Institut Curie physicians have shown that the HC-II test performed alone is less sensitive than cytologic analysis of a cervical smear.

In conclusion, comparative analysis of the sensitivity and specificity of the HC-II technique and of the conventional Pap smear reveals no advantage of HPV detection alone in the framework of cervical cancer screening.

It is therefore unlikely that the HC-II test will replace cytologic analysis, but it could in certain cases be complementary. Further studies are needed to define the role of the HC-II test in cervical cancer screening and follow-up.

Note

(1) Dr Béatrix Cochand-Priollet works in the Pathological Anatomy and Cytology Department of the Hôpital Lariboisière.
(2) This test is manufactured by Digene“ (Gaithersburg, USA).