medwireNews: Two articles present information to support upcoming and potential changes to cervical cancer screening guidelines.
The first study, published in The BMJ, used long-term data from the POBASCAM trial to assess the viability of extending screening intervals beyond 5 years for a Dutch human papillomavirus (HPV)-based programme.
In the POBASCAM trial, 44,938 women aged 29–61 years were randomly assigned to undergo cytology testing either with or without concomitant HPV analysis (intervention and control arms, respectively) for a maximum of three screening assessments, each conducted once in 5 years. The current analysis included 43,339 participants with negative findings on the HPV and/or cytology test.
Among HPV-negative women in the intervention group, the cumulative incidence of cervical cancer and cervical intraepithelial neoplasia (CIN) of grade 3 or worse after three rounds of screening was 0.09% and 0.56%, respectively. These were comparable to the rates after two rounds in women with negative cytology results in the control arm, at 0.09% and 0.69%, respectively.
Researcher Johannes Berkhof (VU University Medical Centre, Amsterdam, the Netherlands) and co-workers note that their results support the upcoming change in the Netherlands screening programme by which the screening interval will be extended from 5 to 10 years for HPV-negative women aged 40 years and above. “[T]he risks after three screening rounds after a negative HPV test are similar to the risks after two rounds after negative cytology”, they write.
But the investigators point out that “an increase in the cancer risk cannot be ruled out completely”, and they stress that “it remains important to closely monitor the number of interval cancers observed under the new HPV based screening programme.”
In the second study, Cosette Wheeler (University of New Mexico Health Sciences Center, Albuquerque, USA) and team evaluated the effect of HPV vaccination on CIN incidence after adjusting for cervical cancer screening, with a view to understanding the implications for screening programmes.
Using the New Mexico HPV Pap Registry, they found that among female participants aged 15–19 years, the incidence of all examined grades of CIN decreased significantly from 2007, when HPV vaccination was introduced, to 2014. The incidence of grade 1 CIN reduced from 3468.3 to 1590.6 per 100, 000 women screened, while that of grade 2 and 3 CIN dropped from 896.4 to 414.9 and from 240.2 to 0, respectively.
For women in the 20–24 years age bracket, only the reduction in grade 2 CIN was significant, decreasing from 1027.7 to 627.1 per 100, 000 women screened.
By contrast, the incidence of grade 1 and 3 CIN increased significantly for women aged 25–29 years, from 2092.4 to 2342.9 and from 437.9 to 879.8, respectively, the study authors report in JAMA Oncology.
Nonetheless, they observe that “[b]ased on vaccination coverage, reductions were greater than anticipated, supporting vaccine cross-protection, efficacy of less than 3 vaccine doses, and herd immunity contributions.”
Our results indicate “a rapidly approaching need to revisit guidelines for cervical cancer screening in the United States, including increasing the age to begin screening”, comment Wheeler et al.
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