Prévention du cancer du col utérin (I): apport du dépistage, récents progrès et perspectives

Abstract

Worldwide, cervical cancer is diagnosed annually in more than 500,000 women and accounts for 270,000 deaths, making it the second leading cause of cancer in women. In Europe, where many countries have set up screening program, cervical cancer ranks third among cancers in women. In France, cervical cancer is diagnosed in 3400-4500 women each year and kills 1000-1600. Since its introduction, Pap smear screening has transformed cervical cancer from a fatal disease into a rare condition. Despite the considerable success of this cytologic screening, Pap smears have not, as was first hoped, reduced incidence on a large scale. The principal reasons are related to the difficulties in ensuring optimum coverage of the population to be screened and in maximizing women's adherence: the success of screening depends on strict compliance with the calendar from 25 to 65 years of age. In 1/3 of cases, invasive cancers are found in women who undergo regular screening, because Pap smears are insufficiently sensitive. In 5% of cases, cancers are observed in women who were inappropriately managed after an abnormal Pap smear finding. The contribution of the HPV test to primary screening opens up promising perspectives of optimum protection. The test's sensitivity for high-grade lesions exceeds 95% and its negative predictive value exceeds 99%. The HPV test is the only test available for which a negative result provides instantaneous assurance that there is no risk of cervical cancer. The Pap smear alone, with its sensitivity of less than 70%, cannot provide this certainty. European and American guidelines recommend screening strategies based on a combined test using the Pap smear and HPV test after the age of 30 years. The impending availability of prophylactic HPV vaccines, which are expected to provide 70% protection against cervical cancer, will not affect the practice of screening, which must continue.