According to one study, screening for HPV DNA testing in women aged 55 may have little benefit

However, for the most commonly used and cheapest cytology screening (also known as a Pap test or Smear test), regular screening up to age 75 can still prevent some cancers, although benefits decrease with age. The results come from a new modeling study, published in Lancet Oncology newspaper.

"Cervical cancers are caused by oncogenic HPV infections, and we have a long history of using cytology to detect precancerous lesions caused by HPV, which can be treated even before they develop into cancer." cervical screening has reduced the number of women cervical cancer, it is far from perfect because it does not always detect the precancerous lesions that develop into cancer.We have known for some time that the screening The type of HPV that causes cervical cancer is as good as, if not better than, cytology screening in women under the age of 60. It was not known whether an HIV-negative elderly woman could stop the cancer as well. screening of an elderly woman with a negative cytology test, "said Dr. Talia Malagon of McGill University, Canada.

"Our study does not necessarily suggest that all screening should stop at age 55, as the value of ongoing screening depends on the type of screening used." For countries that still use cytological screening, screening at a later age should further reduce the risk of cervical cancer.However, our results suggest that for countries that use the HPV test as part of their screening, it might be possible to stop the screening earlier than we currently do, provided that women undergo a negative HPV test, the analysis, which will be a useful next step in informing policy decisions before any policy changes are considered ", adds she.

The HPV vaccine has the potential to reduce the incidence of cervical cancer in the long term and vaccination programs have been introduced in many countries. However, older women who have not benefited from vaccination will still be dependent on regular screening for cervical cancer prevention.

Cervical cancer incidence and mortality remain high in older women – for example, American women aged 70 and older are at higher risk of cervical cancer death (between 5.3 years and older). and 6.5 per 100,000 women), compared to women aged 40 to 44 (3.2 per 100,000). Previous studies have shown that women screened beyond age 65 have a lower risk of cervical cancer than women who are not screened, but it is difficult to determine if the residual effect of screening is lower.

Most guidelines recommend stopping uterine cervix screening (with cytology or HPV testing) after the age of 65 to 69, but high quality evidence for this recommendation are insufficient. In addition, few studies take into account the rate of hysterectomy in older women in their risk estimates.

There are two types of cervical cancer screening tests. Cytology remains the most widely used test in the world and is less expensive than the HPV test. Cytology can detect approximately 55% of CIN2 + cases (precancerous high grade lesions). Many countries are implementing HPV testing to detect approximately 96% of CIN2 +. The increasing availability of HPV testing means that it may replace cytology in many countries, but because of the higher cost of HPV testing, high-income countries may be more likely to switch.

The research team used a mathematical model to estimate the risk of cervical cancer during lifetime in unvaccinated older women. They developed, calibrated and validated their model using Canadian health data, including Statistics Canada cervical cancer incidence rates and the HPV prevalence of the BC screening program (more data). 200,000 women). According to Canadian data, they hypothesized that 42% of women who live up to the age of 100 will undergo a total hysterectomy.

Cancer progression was divided into seven stages: uninfected infection, transient infection, persistent infection, CIN1, CIN2, CIN3 and cervical cancer. The researchers predicted the risk of cervical cancer over the lifetime, both assuming that women fully adhere to screening guidelines (screening every 3 years) and assuming a more typical adherence to cancer screening. cervix (closer to the actual frequency of screening in real life, which may be longer for many women than every 3 years).

The model predicts that without screening or vaccination, one in every 45 women would be diagnosed with cervical cancer during her lifetime. Perfect adherence to cytologic screening every 3 years between 25 and 69 years has reduced the risk of cervical cancer in the lifetime of 1 in 532 women.

For unvaccinated women with typical adhesion to cytologic screening, stopping screening at age 55 was associated with a lifetime risk of cervical cancer for 1 year. out of 138, against 1 out of 160 when screening was stopped at age 70. Although the increase in the age at which women stopped cytologic screening from 55 to 75 years of age resulted in a further decrease in cancer risk later in life, the findings suggest that some Significant risk reduction is due to screening before the age of 55.

However, the residual lifetime risk (after-age risk estimate of final screening) after stopping screening depends on the type of screening used. Unvaccinated women who stop screening at age 55 with a negative HPV test should be at risk of cervical cancer for the entire life of 1 in 1940 (

Similarly, the lifetime risk at age 70 was 1 in 1206 for women with a negative cytology test, but even lower (1 in 6525) for a negative HPV test. A co-test for cytology and negative HPV screening at age 70 was associated with a lifetime risk of 1 in 9550.

The authors point out that their results may not be applicable to future cohorts with high vaccination coverage or who have been screened for HPV for most of their lives. However, since it will take many decades before the vaccinated adolescent cohorts reach the age of 50 to 70, they note that the results will likely be applicable to cohorts of older women in the years to come.

The authors also note that although the HPV DNA test is more sensitive than cytology for detecting high-risk HPV types, used alone, it may miss lesions caused by other types of oncogenic HPV. However, estimates suggest that lesions not detected by the HPV DNA test at age 55 have a low probability of progressing to cervical cancer over the course of life remaining.

Explore further:
ACOG: New recommendations for cervical cancer screening

More information:
Lancet Oncology (2018). www.thelancet.com/journals/lan… (18) 30536-9 / full text