Cancers with estrogen/progesterone sensitive receptors are stimulated by the use of progesterone and estrogen in certain hormonal contraceptives.
The correlation between hormonal birth control and breast cancer came from a study which tracked 1.8 million Danish women aged 15-49 years old for more than a decade.
The Dana-Farber Cancer Institute in Boston summarizes the results of the study as follows:
Research found that it didn’t much matter whether women used contraceptive pills and IUDs: The increased risk of breast cancer was roughly the same for each method.
Breast cancer is rare among women in the age group studied, particularly those in the 20s and 30s. The paper estimated that for every 100,000 women, contraceptive use would lead to an additional 13 breast cancer cases a year, but mainly for women in their 40s.
If the 100,000 women were all under age 35, contraceptive use would yield only two additional breast cancer cases.
The reader should note that the contraceptive did not trigger the cancer itself, instead, the hormones in the contraceptive spurred cancer breakouts to grow at a rate not able to be reversed by the immune system.
Because most cancers are triggered once in one’s 40’s, there are rarely cancer cells to be accelerated in one’s 20’s and 30’s, making the hormonal contraceptive practice relatively safe.
However, once in one’s 40’s, where dense breast tissue, iodine deficiency and other age factors increase the chance of a cancer outbreak, one should switch over to a non-hormonal contraception method.
Also, when engaged with medical writing, you must understand the ways of statistics so as NOT to misinterpret conclusions. Percentages can naturally mislead you as follows:
The overall chance of developing breast cancer is 1 in 8, or approximately 12%. Studies show that hormonal contraceptives increase your risk by 7%. This 7% is not additive, which together would bring your risk to 19%. It refers to 7% of 12%, which comes to 1%. Your risk of developing breast cancer if you use hormonal contraceptives becomes 13%, but more so when in one’s 40s, and less so in one’s 20s and 30s.
The physiological changes taking place in one’s 30s, making one more susceptible to a cancer outbreak, are presented in detail within the video series master class.