In the United States, rates of invasive cervical cancer declined between 1998 and 2002, although significant racial, ethnic and geographic differences persisted, according to pre-vaccine surveillance data covering 87 percent the population of women.

Altogether, 59,848 cases of cervical cancer cases were identified during the five-year study period. The annual number of cases fell from 12,720 in 1998 to 11,071 in 2002.

The incidence rate declined from 10.2 per 100,000 women in 1998 to 8.5 per 100,000 in 2002, report Dr. Mona Saraiya from the Centers for Disease Control and Prevention, Atlanta, and colleagues in the latest issue of Obstetrics and Gynecology.

Highest risk for Hispanics
For the period as a whole, the average annual incidence rate was highest among Hispanic women (14.8 per 100,000), followed by black women (13.5 per 100,000). Rates among Asian or Pacific Islander women and white women were similar (8.9 per 100,000).

"We confirmed that in the United States there is a 50 percent higher incidence of cervical cancer among African-American (compared with white) and 66 percent higher incidence among Hispanic women (compared with non-Hispanic)," note the authors.

Cervical cancer rates rose with age for all groups. Among Hispanic women 40 years or older, rates were 26.5 or more per 100,000; among black women older than 50 years, rates were 23.5 or more per 100,000 women.

"Our findings confirm the need to continue screening older women as recommended by guidelines and to find better strategies for access to screening of women of color," Saraiya and colleagues note.

There is evidence that suggests that the difference in cervical cancer incidence among black, Hispanic and white women may be due "in substantial measure, to differences, by race, in the follow-up of abnormal Pap tests."

There were also geographic differences in cervical cancer rates, with higher rates of squamous cell carcinoma - the most common type of cervical cancer - seen in the South than in other regions.

"Clearly, our approach to preventing cervical cancer in the United States should include more focused attention on pockets of high risk," the team notes.

Measuring vaccine's effect
Introduction in 2006 of the vaccine for human papillomaviruses (HPV), which cause most cases of cervical cancer, gives doctors "an additional tool" to reduce illness and death from cervical cancer. When administered appropriately, the HPV vaccine can prevent about 70 percent of all cervical cancers in this country and worldwide, they point out.

The surveillance system in place in the U.S., Saraiya's team adds, will provide a consistent means of measuring trends in the incidence of invasive cervical cancer in the post-cervical cancer vaccine era, although the effect of the vaccine may not be seen for two decades.