The risk for dying of cervical cancer appears higher than previously believed, especially among blacks and older women, according to new research published in Cancer.
By excluding women who have had hysterectomies, researchers from Johns Hopkins School of Medicine found that mortality rates are 77% higher than previously reported among black women and 47% higher among white women in the United States.
“This is a preventable disease and women should not be getting it, let alone dying from it,” Anne F. Rositch, PhD, MSPH, an assistant professor in the department of epidemiology at Johns Hopkins Bloomberg School of Public Health, said in a press release.
“Because the goal of a screening program is to ultimately reduce mortality from cervical cancer, then you must have accurate estimates within the population targeted by those programs — adult women with a cervix,” she added. “These findings motivate us to better understand why, despite the wide availability of screening and treatment, older and black women are still dying from cervical cancer at such high rates in the United States.”
Each year in the United States, more than 12,000 women are diagnosed with cervical cancer and more than 4,000 women die of the disease.
Rositch and colleagues used the Behavioral Risk Factor Surveillance System to collect estimates for hysterectomy prevalence, National Center for Health Statistic to calculate case accounts of death due to cervical cancer, and SEER to determine the population-at-risk denominator. They then merged these data into one database with stratification by age, race, state and year.
Hysterectomy, mortality rates
Overall, 20% (95% CI, 20-21) of women aged 20 years and older had undergone hysterectomies, and the rate was higher for black women than white women (23% vs. 21%). Previous studies indicated black women are more likely to have hysterectomies and at younger ages than white women because they are more susceptible to fibroids, benign masses in the uterus.
Researchers found that correction for hysterectomies resulted in significantly higher rates of cervical cancer mortality. Overall, mortality rates increased from 3.4 deaths per 100,000 women (95% CI, 3.3-3.4) when uncorrected to five deaths per 100,000 women (95% CI, 4.9-5.1) after correction.
Age-standardized mortality rates for black women increased from 5.7 per 100,000 women (95% CI, 5.5-6) to 10.1 per 100,000 women (95% CI, 9.6-10.6).
For white women, age-standardized mortality rates jumped from 3.2 per 100,000 women (95% CI, 3.1-3.2) to 4.7 per 100,000 women (95% CI, 4.6-4.8).
Mortality rate ratio for black women vs. white women increased from 1.8 (95% CI, 1.7-1.9) to 2.2 (95% CI, 2-2.3).
Cervical cancer mortality rates increased with age for all races but were significantly higher in older, black women. Corrected rates for black women aged 85 years and older showed a 101% increase, from 18.6 per 100,000 women (95% CI, 15.4-21.7) when uncorrected to 37.2 per 100,000 women (95% CI, 31-43.5) after correction. The highest increase occurred in black women aged 65 to 69 years, at more than 126%, whereas the percentage increase for white women of the same age was 75%.
Current screening guidelines recommend routine Pap smears to test for cervical cancer among women aged 21 to 65 years. Women who have had three healthy tests over the previous decade are not recommended for screening after the age of 65 years.
Cervical cancer also can be prevented by the HPV vaccine, which is generally offered before the age of 26 years.
“These data tell us that, as long as a woman retains her cervix, it is important that she continue to obtain recommended screening for cervical cancer [because] the risk for death from the disease remains significant well into older age,” Rositch said.
Researchers also reported that black women, especially older black women, are more likely than white women to be diagnosed with adenocarcinoma, which has a higher rate of death in comparison with squamous cell carcinoma in both early- and late-stage cervical cancer. An evaluation of Maryland Cancer Registry data found that black women had 50% lower odds of undergoing surgery and 50% higher odds of receiving radiation in comparison with white women with the same stage and insurance status.
“Black women are dying of cervical cancer at twice the rate of white women in the United States,” Rositch said, “and we need to put in place measures to reverse the trend.”
‘Glimmer of hope’
In an accompanying editorial, Heather J. Dalton, MD, who specializes in the surgical care of women with ovarian, cervical, uterine and endometrial cancers at Arizona Oncology, and John H. Farley, MD, FACOG, FACS, chief of gynecologic oncology at Cancer Treatment Centers of America, said the investigation into corrected cervical cancer mortality rates offers some “glimmer of hope” for increased and improved screening.
Dalton and Farley suggest that cultural differences, “including mistrust of the health care system,” may play a role in the disparity in cervical cancer mortality between black and white women.
“A high-risk HPV infection and a lack of adequate screening are the only factors definitely associated with the incidence of cervical cancer,” Dalton and Farley wrote. “FDA approval of the quadrivalent vaccine in 2006 began a new era in the fight against HPV infection and cervical cancer. Introduced in 2014, the nonavalent vaccine provides effective protection against five additional oncogenic HPV subtypes.”
Dalton and Farley noted that despite efficacy approaching 100%, a survey in 2014 showed that only 40% of U.S. girls aged 13 to 17 years had completed the recommended three doses of the vaccine, and that 60% had received just one dose.
“The impact of vaccination cannot be underestimated,” they wrote. “Although it will take decades to observe decreases in HPV–related cervical cancer, the prevalence of the HPV strain included in the quadrivalent vaccine has already decreased 64% among vaccinated teen girls.” – by Chuck Gormley
The study was supported in part by a grant from the Maryland Cigarette Restitution Fund. Rositch reports no relevant financial disclosures. One researcher reports reagent and travel support from Hologic for research not related to the study. Farley reports personal fees from Genentech outside the study.