Cervical cancer and duration of using hormonal contraceptives

Aim: To address the association between the duration of using oral contraceptives and cervical cancer, excluding HPV-DNA positive women. Methods: The sample consisted of 300 women over 30 years of age with newly diagnosed invasive cervical cancer who were admitted to the seven general hospitals in Tehran between 1 January 2005 and 31 December 2006. The control group consisted of 319 women in the same age group admitted to the same hospitals with conditions judged to be unrelated to any of the known or suspected risk factors for cervical cancer. The main outcome measures were the duration of using oral contraceptives and risk of cervical cancer. Results: Forty-five patients versus 48 controls had ever used oral contraceptives, and the corresponding unadjusted odds ratio (OR) was 0.9 (0.6-1.2). The OR of cervical cancer increased with the duration of using oral contraceptives, being 3.4 (1.2-11) for more than 20 years of use and 2.3 (1.2-5) for a use of 15-20 years, compared with less than a use of oral contraceptives for 10 years. The adjusted OR for parity and less than 8 years since they had last used oral contraceptives were 1.2 (1.08-1.4) and 1.4 (1.01-2.1) respectively. Conclusion: Our findings suggest that parity and a duration of less than 8 years since the women last used oral contraceptives increase their risk of cervical cancer.