Poosari, A., Promthet, S., Kamsa‐ard, S., Suwanrungruang, K., Longkul, J., & Wiangnon, S. (2014). Hormonal contraceptive use and breast cancer in Thai women. Journal of epidemiology, 24(3), 216-220. https://doi.org/10.2188/jea.je20130121
Poosari A, Promthet S, Kamsa‐ard S, Suwanrungruang K, Longkul J, Wiangnon S. Hormonal contraceptive use and breast cancer in Thai women. J Epidemiol. 2014;24(3):216-220. doi:10.2188/jea.je20130121
Poosari, Arisara, et al. "Hormonal contraceptive use and breast cancer in Thai women." Journal of epidemiology, vol. 24, no. 3, 2014, pp. 216-220.
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Breast cancer is the most common cancer in women worldwide. We investigated the association of hormonal contraceptive use and breast cancer in Thai women.
Methods
A cohort study was conducted in Khon Kaen, Thailand. There were 70 cases of histologically confirmed breast cancer among 11 414 women aged 30 to 69 years who were recruited as participants in the cohort study during the period from 1990 through 2001. The study population was followed-up until December 31, 2011. To identify factors associated with incidence of breast cancer, hazard ratios (HRs) and 95% confidence intervals (CIs) were estimated using a Cox proportional hazards model.
Results
The 11 414 women provided a total observation time of 157 200 person-years. Breast cancer risk among women with a history of hormonal contraceptive use was 1.31 times that of women without such a history, but the difference was not statistically significant (95% CI, 0.65-2.65). No type of hormonal contraceptive was associated with a significant increase in breast cancer risk as compared with women who had never used hormonal contraceptives (oral contraception: HR = 1.35, 95% CI, 0.65-2.78; injection contraception: HR = 1.25, 95% CI, 0.56-2.80), and there was no relationship between duration of hormonal contraceptive use and breast cancer.
Conclusions
There was no association between hormonal contraceptive use and breast cancer; however, this finding should be viewed with caution due to the small number of cases.
Little is known about whether contemporary hormonal contraception is associated with an increased risk of breast cancer. We assessed associations between the use of hormonal contraception and the risk of invasive breast cancer in a nationwide prospective cohort study involving all women in Denmark between 15 and 49 years of age who had not had cancer or venous thromboembolism and who had not received treatment for infertility. Nationwide registries provided individually updated information about the use of hormonal contraception, breast-cancer diagnoses, and potential confounders. Among 1.8 million women who were followed on average for 10.9 years (a total of 19.6 million person-years), 11,517 cases of breast cancer occurred. As compared with women who had never used hormonal contraception, the relative risk of breast cancer among all current and recent users of hormonal contraception was 1.20 (95% confidence interval [CI], 1.14 to 1.26). This risk increased from 1.09 (95% CI, 0.96 to 1.23) with less than 1 year of use to 1.38 (95% CI, 1.26 to 1.51) with more than 10 years of use (P=0.002). After discontinuation of hormonal contraception, the risk of breast cancer was still higher among the women who had used hormonal contraceptives for 5 years or more than among women who had not used hormonal contraceptives. Risk estimates associated with current or recent use of various oral combination (estrogen-progestin) contraceptives varied between 1.0 and 1.6. Women who currently or recently used the progestin-only intrauterine system also had a higher risk of breast cancer than women who had never used hormonal contraceptives (relative risk, 1.21; 95% CI, 1.11 to 1.33). The overall absolute increase in breast cancers diagnosed among current and recent users of any hormonal contraceptive was 13 (95% CI, 10 to 16) per 100,000 person-years, or approximately 1 extra breast cancer for every 7690 women using hormonal contraception for 1 year. The risk of breast cancer was higher among women who currently or recently used contemporary hormonal contraceptives than among women who had never used hormonal contraceptives, and this risk increased with longer durations of use; however, absolute increases in risk were small. (Funded by the Novo Nordisk Foundation.).
Niemeyer Hultstrand J et al., 2022·Lancet Reg Health Eur·Free full text on PubMed Central
Evidence on a possible association between newer hormonal contraceptives (HC) and risk of breast cancer remains inconclusive, especially as concerns progestogen-only methods. In this nationwide prospective cohort study, all Swedish women aged 15-34 at study start on January 1(st) 2005, or who turned 15 years during the study period, were followed until December 31(st) 2017. Using information from seven National Registers, we assessed the risk ratio of developing breast cancer and breast cancer in situ in relation to different HC using Poisson regression. We adjusted the analyses for several known confounders of breast cancer. Findings: This cohort included 1.5 million women providing more than 14 million person-years. During the study period, 3842 women were diagnosed with breast cancer. Compared with never users of any HC, we found no increased risk of developing breast cancer among current users of any combined HC, IRR 1.03 (0.91-1.16), whereas current users of progestogen-only methods had an increased risk of developing breast cancer, IRR 1.32 (1.20-1.45). Across all types of HC, the risk of developing breast cancer appeared to be highest the first five years of use (combined HC IRR 1.39 (1.14-1.69); progestogen-only methods IRR 1.74 (1.44-2.10). The risk disappeared ten years after the women stopped using HC. The absolute risk of breast cancer per 100,000 women-years was 22.4 for never users, 10.9 for current users of combined HC, and 29.8 for current users of progestogen-only methods. Interpretation: Current use of progestogen-only methods is associated with a small increased risk of developing breast cancer, whereas we could only detect an increased risk among users of combined HC during the first five years of use. This may partly be explained by a selective prescription of progestogen-only methods to women with risk factors for breast cancer, like smoking or obesity. As the absolute risk of breast cancer was small, the many health benefits associated with HC must also be taken into account in contraceptive counselling. This study was funded by the Swedish Cancer Society and by the Uppsala County Council, the Faculty of Medicine at Uppsala University.
Findings on potential interactive effects of oral contraceptives (OCs) and hormone replacement therapy (HRT) on breast cancer risk have been inconsistent. We aimed to use population-based cohort data to determine whether former use of OCs affects breast cancer risk among HRT users, taking into account regimens of HRT, duration and currency of use. The cohort consisted of 16 928 Icelandic women who visited the Icelandic Cancer Detection Clinic in 1979-2006 and provided information on use of OCs and HRT when they were 48 years or older. By record linkage to the Icelandic Cancer Registry, all breast cancer diagnosed during follow-up was identified. Using Cox regression, hazard ratios (HRs) for breast cancer according to hormone use were estimated, adjusting for menstrual and reproductive risk factors. Also, interaction analyses were carried out. Breast cancer risk was significantly increased among ever users of combined estrogen and progestin (EP-HRT) preparations (HR=2.61; 95% CI 2.00-3.41) and not among users of estrogen-only regimens (E-only HRT) (HR=1.13; 95% CI 0.85-1.49). Ever users of both OCs and HRT had higher breast cancer risk than users of only one of the two (HR=2.19; 95% CI 1.67-2.87). After restricting the analysis to EP-HRT and focusing on long-term and current use, there was an indication of a negative interaction with ever OC use (p=0.06); HR=2.87; 95% CI 1.79-4.60 for never OC users and HR=2.24; 95% CI 1.51-3.34 for former OC users. After taking HRT regimen, duration and currency of use into account, the results of our population-based cohort study do not support the notion that former OC use increases breast cancer risk among HRT users, on the contrary there was an indication of a slightly lower risk in former OC users, restricted to current, long-term EP-HRT users.
To assess the risk of oral contraceptives on the occurrence of cervical cancer. Material and 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). 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. 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.
General Gynecology › Breast Health › Breast Cancer Risk · Contraception › Adverse Effects › Venous Thromboembolism
S Promthet, K Suwanrungruang, S Wiangnon, S Kamsa-ard, J Longkul, A Poosari
PMID 24614914 24614914 DOI 10.2188/jea.je20130121 10.2188/jea.je20130121 Poosari et al. 2014, Poosari 2014
Cite this article
Poosari, A., Promthet, S., Kamsa‐ard, S., Suwanrungruang, K., Longkul, J., & Wiangnon, S. (2014). Hormonal contraceptive use and breast cancer in Thai women. Journal of epidemiology, 24(3), 216-220. https://doi.org/10.2188/jea.je20130121
Poosari A, Promthet S, Kamsa‐ard S, Suwanrungruang K, Longkul J, Wiangnon S. Hormonal contraceptive use and breast cancer in Thai women. J Epidemiol. 2014;24(3):216-220. doi:10.2188/jea.je20130121
Poosari, Arisara, et al. "Hormonal contraceptive use and breast cancer in Thai women." Journal of epidemiology, vol. 24, no. 3, 2014, pp. 216-220.
