“However, better assessment of the women who are screened could further reduce cervical cancer rates”, says Bengt Andrae, Senior Consultant at Gävle Hospital, who lead the study together with Associate Professor Sven Törnberg and Professor Pär Sparén, Karolinska Institutet.
Cervical cancer screening programs reduce the incidence of disease, but the effectiveness of such programs varies among populations. Regular audits of such programs are valuable because they provide insight into how a program works and how it might be improved. In 2002 the Swedish National Board of Health and Welfare funded a National Cervical Cancer Screening Registry, which is coordinated by the Department of Medical Epidemiology and Biostatistics at Karolinska Institutet.
In a nationwide case–control study, published in the Journal of the National Cancer Institute, Bengt Andrae and colleagues compared the rates of cervical cancer diagnosis in women who had been screened and those who had not. Using data from the Swedish Cancer Registry and from the National Cervical Cancer Screening Registry, the researchers identified 1,230 cervical cancer cases who were diagnosed between 1999 and 2001, and 6,124 age-matched control subjects from the population register, who had not been diagnosed with cervical cancer.
Women who did not undergo a Pap smear test within the recommended 3- or 5-year interval were 2.52 times as likely to be diagnosed with cervical cancer as were women who had Pap tests regularly. These women had also a 4.82 times higher risk to be diagnosed with advanced disease than those who were screened. Novel findings were that participation in screening reduces the risk for all types of cervical cancers and also in the age group between 23 and 30. It was also possible to demonstrate a beneficial effect of screening against adenocarcinomas of the cervix.
Screening did not completely protect women from cervical cancer diagnoses, however. Abnormal smears, particularly if not assessed by a biopsy, were an important risk factor also within the Screening program. Women with abnormal Pap tests accounted for 11.5% of all of the cervical cancer cases. This increased risk was however not seen for advanced cancers.
Affiliations and funding: Bengt Andrae is Senior Consultant at the Department of Obstetrics and Gynecology, Gävle Hospital and Chairman of the Cervical Cancer Prevention Group at the the Swedish Society of Obstetrics and Gynecology. Sven Törnberg is Associate Professor at Karolinska Institutet and Senior Consultant at the Cancer Screening Unit, Oncologic Center, Karolinska University Hospital. Pär Sparén is Professor at the Department of Medical Epidemiology and Biostatistics and coordinator for the National Cervical Cancer Screening Registry Karolinska Institutet. Professor Joakim Dillén, unit for Medical Microbiology at Lund University and other scientists at the Umeå University Hospital, Sahlgrenska University Hospital, and University Hospital MAS also took part in the work with the audit. Among the funders were The Swedish Cancer Society and the Research and Development Center of Gävleborg County.
Publication: ‘Screening-Preventable Cervical Cancer Risks: Evidence From a Nationwide Audit in Sweden’, Bengt Andrae, Levent Kemetli, Pär Sparén , Lena Silfverdal, Björn Strander, Walter Ryd, Joakim Dillner, Sven Törnberg, J Natl Cancer Inst, 2008;100: 1 – 8.
For further questions, please contact:
Senior Consultant Bengt Andrae
Tel: +46 (0)70-3562486
Associate Professor Sven Törnberg
Tel: +46 (0)8-5177 3194 or +46 (0)70-484 1375
Press Officer Katarina Sternudd
Tel: +46 (0)8-524 838 95 or +46 (0)70-224 38 95