Human papillomavirus (HPV) is thought to be the major cause of cervical cancer but other factors may also be important. Recent studies have suggested that extended use of oral contraceptives increases the risk of cervical cancer in HPV positive women.
Investigators from Cancer Research UK's Epidemiology Unit in Oxford and the International Agency for Research on Cancer in France reviewed data from 28 published studies (which included over 12,500 women with cervical cancer). The relative risk of cervical cancer increased with increasing duration of use of oral contraceptives. Compared with women who had never used hormonal contraception the relative increases in risk were: 10% for less than 5 years use; 60% for 5-9 year use; and over a doubling of cervical-cancer risk for 10 years use or more. The results were broadly similar for all types of cervical cancers, and across studies that adjusted for HPV status, number of sexual partners, cervical screening, smoking, or use of barrier contraceptives.
Amy Berrington, one of the authors, comments: "Although long duration use of hormonal contraceptives is associated with an increased risk of cervical cancer, the public-health implications of these findings depend largely on the extent to which the observed associations remain long after use of hormonal contraceptives has ceased, and this cannot be evaluated properly from published data. An international collaboration has been set up to re-analyse original data to provide more reliable estimates."
Contact: Cancer Research UK Press Office (Udani Samarasekera), 61
Lincoln's Inn Fields, London WC2A 3PX, UK;
T) 44-207-061-8311;
M)
44-705-026-4059;
E)pressoffice@cancer.org
Notes to editors
The lifetime risk of being diagnosed with cervical cancer is 1 in 80 in the UK. Cervical cancer is the second most common cancer in developing countries where the lifetime risk can be as high as 1 in 30.
Journal
The Lancet