It may be safe to extend cervical cancer screening intervals beyond 5 years, at least for women who are not infected with human papillomavirus.
The rate of cervical cancers was the same among HPV-negative women, whether they had gone through two or three rounds of 5-year exams using both HPV testing and cervical cytology, a large Dutch study has found. This suggests a longer period between screenings wouldn’t significantly increase the risk of letting new cancers go unnoticed, Maaike G Dijkstra, MD, and associates reported (BMJ. 2016;355:i4924. doi: 10.1136/bmj.i4924).
The picture, however, is very different for women with an HPV infection, the researchers noted. These women were 12 times more likely to develop cervical cancer and up to 29 times more likely to have a cervical intraepithelial neoplasia of at least grade 3 (CIN3+), compared with women who were HPV negative.
The findings bring a measure of reassurance to the Dutch population, the researchers wrote. The Netherlands intends to lengthen its cervical cancer screening interval to 10 years for HPV-negative women aged 40 years or older.
“HPV-negative women have a very low risk of CIN3+ in the long term, indicating that extension of the current screening interval in the Netherlands to 10 years seems justifiable,” wrote Dr. Dijkstra of the VU University Medical Centre, Amsterdam, and her colleagues. “For HPV positive, triage negative women, the long term risk of CIN3+ was too high to support an extension of the screening interval beyond 5 years.”
The study assessed the 14-year risks of cervical cancer and CIN3+ in 43,339 women aged 29 years and older. As per national guidelines, all women underwent cervical cancer screening every 5 years, resulting in three rounds. They were randomized to receive HPV and cytology testing or cytology only.
Among HPV-negative women in the double-screening group, the cumulative cervical cancer incidence was 0.03% after round two and 0.09% after round three – not a statistically significant difference.
After round three, cervical cancer incidence among HPV-negative women with negative cytology (double negative) was similar to that among cytology-negative women from the control group after round two.
In the cytology-only group, the rates among negative women were 0.09% after round two of screening and 0.19% after round three.
“This indicated that a negative HPV test provides longer reassurance against cervical cancer than negative cytology,” the researchers noted.
HPV-positive women, however, faced much higher risks, regardless of the screening protocol. Even with negative cytology, they were 12 times more likely to have a cancer by round three than HPV-negative women. The risk of CIN3+ was up to 29 times higher. Even HPV-positive women with negative cytology, negative HPV 16/18 genotyping, and negative repeat cytology faced a 10-fold increased risk of CIN+3, the researchers reported.
Dr. Dijkstra reported having no financial disclosures. Several of the coauthors disclosed financial relationships with various pharmaceutical companies.
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