Effect of oral contraceptives on risk of cervical cancer.

OBJECTIVE To assess the risk of oral contraceptives on the occurrence of cervical cancer. MATERIAL AND METHOD A hospital-based case-control study was conducted. Sixty women patients with histologically confirmed invasive cervical cancer and 180 healthy women as the control group who attended the King Chulalongkorn Memorial Hospital, Bangkok, Thailand were recruited. Information about the use of oral contraceptives and other cervical cancer risk factors were obtained from personal interviews. The risk factors were evaluated by using odds ratio (OR). RESULTS 60 women with invasive cervical cancer and 180 healthy controls were interviewed by the investigators. Compared with non-users, patients who had ever used or currently used oral contraceptive had an increased risk of cervical cancer (OR 1.45; 95% CI 0.79-2.64). However the risk was not statistically significant. Considering the duration of use, patients who had used oral contraceptives for 3 years or less did not have an increased risk of cervical cancer (OR 0.78; 95% CI 0.39-1.77). Nevertheless, the odds ratio of oral contraceptive pill use for more than 3 years was 2.57 (95% CI 1.22-5.49) which was statistically significant. CONCLUSION Long-term use of oral contraceptive might be a cofactor that increases the risk of cervical carcinoma. Further investigations should be conducted to confirm this risk. However, Pap smear has to be done routinely in long-term oral pill users.