A recent UK nested case-control study and meta-analysis examined the association between combined and progestagen-only hormonal contraceptives and breast cancer risk. The study, which was published on March 21, 2023, found that there is a small but significant increased risk of breast cancer associated with the use of hormonal contraceptives. The researchers found that women who were prescribed any hormonal contraception had a 25% higher risk of developing breast cancer compared to those who were not. The study’s authors emphasize the need for continued research in this area to better understand.
A recent study aimed to assess the risk of breast cancer in premenopausal women associated with the use of different types of hormonal contraceptives, particularly progestagen-only preparations. The study utilized the Clinical Practice Research Datalink (CPRD) database and conducted a nested case-control study involving 9,498 women below 50 years old with invasive breast cancer diagnosed from 1996 to 2017 and 18,171 matched controls. The study also performed a meta-analysis combining the CPRD results with those from previously published studies.
What did the researchers find?
The study found that 44% of women with breast cancer and 39% of the matched controls had a hormonal contraceptive prescription an average of 3.1 years before breast cancer diagnosis or an equivalent date for the controls. Half of the prescriptions were for progestagen-only preparations. The odds ratios for breast cancer were significantly raised for women whose last hormonal contraceptive prescription was for oral combined, oral progestagen-only, injected progestagen, or progestagen-releasing intrauterine devices (IUDs). The study also found that current or recent use of progestagen-only contraceptives, regardless of mode of delivery, was associated with a slight increase in breast cancer risk similar in magnitude to that associated with combined hormonal contraceptives.
The study provides important evidence on the association between progestagen-only contraceptives and breast cancer risk. It is important to note that the underlying risk of breast cancer increases with advancing age, and the absolute excess risk associated with the use of either type of oral contraceptive is smaller in women who use it at younger ages. The study highlights the need to balance the risks and benefits of using contraceptives during the childbearing years.
The study has limitations in that information on contraceptive use was recorded during a defined period only, with information before entry into the database generally being unavailable. Thus, the findings only provide evidence about the short-term associations between hormonal contraceptives and breast cancer risk and do not provide information regarding longer-term associations or the impact of total duration of contraceptive use on breast cancer risk.
In conclusion, the study provides important evidence on the association between progestagen-only contraceptives and breast cancer risk, highlighting the need to balance the risks and benefits of using contraceptives during the childbearing years. The findings may aid in the informed decision-making of women who are considering the use of hormonal contraceptives. Further studies are necessary to investigate the longer-term associations between hormonal contraceptives and breast cancer risk.
The researchers conducted a nested case-control study involving nearly 10,000 women under the age of 50 who had been diagnosed with breast cancer to investigate the link between hormonal contraceptive use and breast cancer risk. The study found that current or recent use of hormonal contraceptives, including combined oral, progestagen-only oral, injectable progestagen, progestagen implant, or progestagen intrauterine device, was associated with a similar increase in breast cancer risk. When the results for progestagen-only contraceptives were combined with those of previous studies, there was evidence of a broadly similar increased risk of breast cancer in current and recent users of all four types of progestagen-only preparations.
What do these findings mean?
The findings suggest that there is a relative increase of around 20% to 30% in breast cancer risk associated with current or recent use of either combined oral or progestagen-only contraceptives. When the results for oral contraceptives were combined with previous studies, the 15-year absolute excess risk of breast cancer associated with use of oral contraceptives ranged from 8 to 265 cases per 100,000 users, depending on age. However, it is important to note that these excess risks should be weighed against the established benefits of contraceptive use for women in their reproductive years. The study was unable to evaluate the long-term associations between contraceptive use and breast cancer risk due to incomplete prescription history data. Nonetheless, the findings shed light on the short-term associations between hormonal contraceptive use and breast cancer risk.