Cervix cancer prevention and detection update.

Abstract

I NVASIVE cervical cancer is the second most common malignancy in women throughout the world. 1 Over 500,000 women were diagnosed with this cancer in 1992, and approximately 50% of those women died of their disease. 2 However, invasive cervical cancer in developed countries is less common than in underdeveloped countries. 3'4 In the United States, the incidence rate has dropped 70% over the last 30 years. According to the American Cancer Society, invasive cervical cancer ranked ninth in incidence (13,500 new cases) and last as a cause of cancer death (4,400 deaths) among women in 1993. 5 The average age of diagnosis is 50 years, but one fifth of cervical cancers are diagnosed in women under the age of 35 years, and one fourth occur in women over the age of 65 years. 2'3'6 The incidence of cervical cancer varies among ethnic and racial groups in the United States. Native American women have the highest incidence, 2'3 more than double that for whites. 7 The incidence rates for blacks and Hispanics are nearly twice as high as those for whites. 7,s The 5-year survival rates are higher for whites (68%) than for blacks (57%) 5 and Hispanics (63%). 7 Black, Native American, and Hispanic women are diagnosed at a more advanced stage than whites, 7'8 and Native Americans and Hispanics are less likely to receive treatment than whites. 7 Based on comparisons of mortality rates from 1973 to 1974 and 1985 to 1986, deaths in women over 50 years of age declined only 17% compared with 43% in women under 50 years of age. Almost 50% of the cervical cancer deaths are in women over 65 years of age.9 Although the incidence of cervical cancer has markedly decreased, the incidence of cervical intraepithelial neoplasia (CIN), the preinvasive lesion, has dramatically increased. 3 An estimated 600,000 cases of CIN are diagnosed each year. 2 CIN includes the continuum of CIN I (mild dysplasia), CIN II (moderate dysplasia), and CIN III (severe dysplasia/carcinoma in situ). 2'3'1~ CIN can progress, persist, or regress. However, it is currently not possible to predict which lesions will progress, which will regress, and the transit time of progression, lo The average age for women diagnosed with CIN HI is 28 years, a decrease from the average age of 42 years in the 1940s and 1950s. Ninety percent of all cervical cancer is squamous, and 10% is adenocarcinoma. Adenocarcinoma rates, however, are increasing. 2 Most squamous cancer emerges from the epithelium of the squamocolumnar junction, and adenocarcinoma originates in the columnar epithelium of the endocervix.