Study Calls into Question Appropriate Age to Stop Cervical Cancer Screening

Jan 31, 2014

New evidence reveals that there may be a benefit to continuing cervical cancer screening beyond age 65 years.

Adult women are recommended to undergo regular screening for cervical cancer until the age of 65 years. At 65, current recommendations call for the cessation of cervical cancer screening in women who have adequate negative prior screening and who are not at increased risk for the disease. Results of a recent study may call this recommendation into question.

The 2012 recommendations calling for cessation of screening at age 65 years were issued by two groups, the US Preventive Services Task Force (USPSTF) and a multidisciplinary partnership among the American Cancer Society, the American Society for Colposcopy and Cervical Pathology, and the American Society for Clinical Pathology.1,2 The USPSTF recommendation was graded as a “D” recommendations, meaning that the group found “no net benefit or that the harms outweigh the benefit” of the screening procedure.

However, in a study published in PLoS Medicine, Peter Sasieni, and colleagues from Queen Mary University of London, United Kingdom, found that there may in fact be benefits for continuing to screen women for cervical cancer past age 65 as the protective effect of screening weakens with time.3

According to an accompanying editorial by Anne F. Rositch, PhD, of the University of Maryland School of Medicine, and colleagues, the data from Sasieni et al calls increased attention to the fact that “estimates of risk of invasive cervical cancer following negative screening tests in older women” are insufficient to adequately inform the current recommendations.4Decreasing Protective Effect

Sasieni and colleagues3 conducted a case control study looking at the link between women screened for cervical cancer from age 50 to 64 years and a cervical cancer diagnosis between ages 65 to 83 years. The data were drawn from population registers that included all women aged 65 to 83 years in England and Wales with a diagnosis of cervical cancer between 2007 and 2012 (n=1,341). These women were then age-matched to control women.

The results showed that those women who had adequate negative screening at age 65 years-at least 3 tests between ages 50 and 64 years with the last negative screening occurring after age 60-were 6 times less likely to have a diagnosis of cervical cancer compared with those women not screened at age 50 to 64 years. Screened women had a 20-year risk of 8 cancers per 10,000 women, compared with 49 cancers per 10,000 women in those not screened.

In addition, there was a 75% reduced risk of cervical cancer between the ages of 65 and 79 years for women who underwent screening at least every 5.5 years from age 50 to 64 years. Without cervical cancer screening, the researchers estimated that cervical cancer rates in women aged 65 years or older would have been 2.4 times greater.

However, the odds ratio for a cervical cancer diagnosis in women who had adequate negative screening increased with increasing age. The odds ratio for cervical cancer was 0.07 for ages 65 to 69 years, was 0.28 for ages 75 to 79 years, and was 0.37 for ages 80 to 83 years.

“Screening up to age 65 years greatly reduces the risk of cervical cancer in the following decade, but the protection weakens with time and is substantially less 15 years after the last screen,” the researchers wrote. “In the light of increasing life expectancy, it would seem inappropriate for countries that currently stop screening between the ages of 60 and 69 years to consider reducing the age at which screening ceases,” Sasieni and colleagues wrote.3

Women Living Longer

Maurie Markman, MD, vice president of patient oncology services and national director for medical oncology at Cancer Treatment Centers of America, said that the new study and commentary both provide a strong argument that a rigid cut off of cervical cancer screening at age 65 is not supported by the data.

Cervical cancer is a unique cancer in that screening can have a large effect on survival, he said.

“The purpose of screening is to find either a precancerous condition or evidence of cancer,” Markman said. “One can either prevent the cancer by finding a precancerous lesion, or even if you do find cancer in its early stages, the therapy would be highly successful.”

According to data from the SEER Cancer Statistics Review, the current 5-year survival rate of cervical cancer is about 68%. When caught in its earliest stages, the 5-year survival rate can be greater than 90%.

Given these high rates of survival, cutting off screening at age 65 may not make sense, Markman said, especially as the population of aging patients continues to have a long life.

“We have people in general, but especially women, who can live excellent quality of lives into their late 80s and 90s,” Markman said. “The idea that screening for cervical cancer after the age of 65 does not matter is slightly wrong.”

When to Stop

What is the appropriate age to stop screening? In their study, Sasieni and colleagues provided an example of the effect of screening until age 55, 65, or 75 years.3 They used the cumulative incidence of cervical cancer in 1975, 892 per 100,000 women, as a baseline value. Using the odds ratios found in this study and adjusting them for unobserved confounding, screening until age 65 would reduce the number from 892 to 250 per 100,000. In contrast, stopping screening at age 55 years would have resulted in an additional 182 cancers; whereas, continuing screening until age 75 years would have resulted in 103 fewer cases.

“Among those with adequate negative screening, ceasing screening at age 50 years is unlikely to provide lifelong protection, but continuing screening till age 80 years is not necessary,” the researchers wrote. “As life expectancy increases (at age 65 years it is about 20 additional years for women in many industrialized countries), consideration should be given to increasing the upper age of screening, possibly by extending the final screening interval from 5 to 10 years.”

The decision to extend screening to woman older than 65 years must carefully consider the risks and benefits. Unfortunately, according to Rositch and colleagues, there is a lack of evidence examining this topic.

“The reproductive harms associated with screening are no longer relevant in older women, and it is unclear whether the discomfort and false-positive test results are significantly different in women 55-65 compared to 65-75 years and whether these risks outweigh the perceived benefit,” Rositch and colleagues wrote.4

Given the results recently published by Sasieni and colleagues3 and other case control studies, the issue of whether women aged 65 years or older should continue cervical cancer screening may be far from settled.

References:

References


1. Screening for Cervical Cancer. Available at: http://www.uspreventiveservicestaskforce.org/uspstf/uspscerv.htm. Accessed on January 13, 2013.
2. Saslow D, Solomon D, Lawson HW, et al. American Cancer Society, American Society for Colposcopy and Cervical Pathology, and American Society for Clinical Pathology screening guidelines for the prevention and early detection of cervical cancer.

CA Cancer J Clin.

2012;62:147-172.
3. Castañón A, Landy R, Cuzick J, Sasieni P. Cervical screening at age 50-64 years and the risk of cervical cancer at age 65 years and older: population-based case control study.

PLoS Med.

2014;11:e1001585. doi:10.1371/journal.pmed.1001585.
4. Rositch AF, Silver MI, Gravitt. Cervical cancer screening in older women: new evidence and knowledge gaps.

PLoS Med.

2014;11: e1001586. doi:10.1371/journal.pmed.1001586.