Follow-up testing in cervical cancer screening remains low in SG

A recent study has found an “unacceptably low” compliance of follow-up following abnormal human papillomavirus (HPV) tests among women in Singapore.

“Although many women cleared HPV spontaneously, a group of women remained HPV-positive for a long duration,” said study author Dr Sun Kuie Tay from the Department of Obstetrics and Gynecology, Singapore General Hospital, Singapore. “There was a significant absolute risk of high-grade lesions of the cervix among these women.” [Ann Acad Med Singap 2024;53:342-351]

Tay searched a prospectively managed database to identify women on surveillance by repeat HPV testing and obtained data that included women’s age, country residence status, history of colposcopy, HPV-DNA status on the first and repeat tests, dates of follow-up during the 5 years since the initial screening, and histological diagnosis of cervical lesions.

The primary outcomes measures were as follows: compliance rate for repeat HPV testing, regression and persistence rates of HPV subtypes, and detection rate of high-grade lesions (CIN2+).

A total of 680 residents (mean age 44.8 years) in the community were included in the analysis. At 12 months, the compliance rate of repeat testing was low at only 28.2 percent. Cumulatively, the rate for the entire 5-year follow-up period was 42.8 percent. Neither age (p=0.5829) nor prior colposcopy (p=0.1607) affected these rates. Five cases (1.7 percent) of CIN2+ had been detected.

Furthermore, 194 of 391 women (60.8 percent) on longitudinal follow-up cleared their HPV infection. Some of them with multiple HPV infection cleared one subtype but not the others. This resulted in a regression rate of 90.3 percent for HPV-16, 87.0 percent for HPV-18, and 65.2 percent for HPV-12-others (p=0.0001).

Similar annualized HPV regression rates were noted for HPV subtypes and for each follow-up years.

“Surveillance of HPV positivity is clinically important for detecting high-grade lesions,” Tay said. “Despite a high regression rate of HPV, surveillance hesitancy is a serious weakness in routine cervical screening.”

Poor compliance

Previous studies have shown a “highly variable” appropriate follow-up testing in cervical cancer screening, which ranged from around 50 percent in Brazil and Japan and >80 percent in European countries. [Asian Pac J Cancer Prev 2019;20:1019-1024; Int J Gynecol Cancer 2017;27:523-529; Cytopathology 2019;30:150-156; Int J Cancer 2014;135:1408-1416; J Med Screen 2014;21:30-37]

On the other hand, compliance rates in Nigeria and Hong Kong were poor (<50 percent). [Int J Gynaecol Obstet 2016;135:177-181; BMC Health Serv Res 2014;14:143]

“However, the overall follow-up rate of 42.8 percent for an extended period of 5 years found in the current study was one of the lowest rates ever reported in literature,” Tay said. “This rate was akin to the local routine primary screening rate found in several previous reports.” [Singapore Med J 2013;54:96-101; Int J Gynaecol Obstet 2015;130:230-234]

It remains unclear as to why the follow-up rate in Singapore is low. Some commonly reported reasons for the low participation rate of cervical screening include older age, poor socioeconomic status, low educational levels, and poor access to healthcare.

“These factors might not be operating for follow-up testing as the women had taken the step of initial screening,” Tay said.

“Research in compliance hesitancy and reluctance, including the evaluation of the impact of a call-recall system, is needed for formulating measures to improve the effectiveness of cervical screening,” Tay noted.