There are some general lifestyle changes that drastically reduce the chances of developing any type of cancer. Apart from environmental factors – which few of us can fully control – we can certainly maintain a balanced diet, a normal weight and BMI and regular physical activity.
It turns out that for those cancers affecting only women, there is a very simple and obvious answer: THE PILL. Prescribed for numerous other uses, such as acne treatment or even weight loss, that magical social barriers breaker that ushered in the 60s can, in certain circumstances, substantially decrease chances of cancers of the reproductive organs.
Few people know that before being used as an oral contraceptive, the Pill was being used with Catholic church approval as early as 1958, but only as long as its contraceptive effects were “indirect” i.e., painful menses or a disease of the uterus. John Rock artificially introduced the “bleeding” which was not really necessary, in order to simulate the “natural cycle” and obtain papal blessing. But in 1968, in its encyclical “Humanae Vitae” the Catholic Church outlawed oral contraceptives and all other “artificial methods” of birth control. Writes Gladwell:
"In view of the ability of this compound to prevent menstrual bleeding as long as it is taken," Pincus acknowledged in 1958, "a cycle of any desired length could presumably be produced." But he and Rock decided to cut the hormones off after three weeks and trigger a menstrual period because they believed that women would find the continuation of their monthly bleeding reassuring. More to the point, if Rock wanted to demonstrate that the Pill was no more than a natural variant of the rhythm method, he couldn't very well do away with the monthly menses. Rhythm required "regularity," and so the Pill had to produce regularity as well.
Yet the monthly cycle is anything but natural. Beverly Strassman traveled in 1986 to Africa to live with the Dogon tribe of Mali – more precisely, the village of Sangui in the Sahel, about a hundred and twenty miles south of Timbuktu. She discovered that women in this tribe (and most likely, throughout most of human history), spent most of their lives either being pregnant or wet nursing, which in turn made ovulation and menstruation very rare events.
..she believes that the basic pattern of late menarche, many pregnancies, and long menstrual-free stretches caused by intensive breast-feeding was virtually universal up until the "demographic transition" of a hundred years ago from high to low fertility. In other words, what we think of as normal--frequent menses--is in evolutionary terms abnormal. "It's a pity that gynaecologists think that women have to menstruate every month,"Strassmann went on. "They just don't understand the real biology of menstruation." (..) It means that women's bodies are being subjected to changes and stresses that they were not necessarily designed by evolution to handle. In a brilliant and provocative book, "Is Menstruation Obsolete?," Drs. Elsimar Coutinho and Sheldon S. Segal, two of the world's most prominent contraceptive researchers, argue that this recent move to what they call "incessant ovulation" has become a serious problem for women's health. (..) for most women, Coutinho and Segal say, incessant ovulation serves no purpose except to increase the occurrence of abdominal pain, mood shifts, migraines, endometriosis, fibroids, and anaemia--the last of which, they point out, is "one of the most serious health problems in the world." Most serious of all is the greatly increased risk of some cancers. Cancer, after all, occurs because as cells divide and reproduce they sometimes make mistakes that cripple the cells' defences against runaway growth. (..) Whenever a woman ovulates, an egg literally bursts through the walls of her ovaries. To heal that puncture, the cells of the ovary wall have to divide and reproduce. (..) A woman who takes the Pill for ten years cuts her ovarian-cancer risk by around seventy per cent and her endometrial-cancer risk by around sixty per cent.
The same protective mechanism is in place for breast cancer:
When the breast is exposed to estrogen, the cells of the terminal-duct lobular unit--where most breast cancer arises--undergo a flurry of division. And during the mid-to-late stage of the menstrual cycle, when the ovaries start producing large amounts of progestin, the pace of cell division in that region doubles.
In conclusion, using the the type of Pill that prevents frequent menstruation (or being pregnant and nursing most of the time) is a significant protection from cancer. As a bonus, this particular Pill allows women to live a more relaxed, productive and pain-free life.