It’s easy to understand why women would have this belief – it sounds quite logical ! We know that breast cancer is a hormonally dependent tumour; and that estrogen levels are high during IVF treatment. Also, a lot of hormonal injections are given during an IVF cycle , in order to help the women grow lots of eggs. If the hormonal stimulation helps them produce a lot of eggs, it’s quite reasonable to conclude that this ovarian overactivity may increase the risk of developing ovarian cancer later on as well ! Husbands are understandably scared about the impact of these drugs on their wives, and don’t want to risk her heath in their quest for a baby.
Please remember that being infertile is itself a significant risk factor for developing certain kind of gynaecological cancers. For example, women who were never pregnant have a higher risk of developing breast cancer. This is because both pregnancy and breast feeding reduces a woman’s exposure to the estrogen hormone produced by her ovaries, which stimulates the growth of the cells lining the mammary glands in the breast. Pregnancy and breast feeding also mature these breast cells into milk-producing cells , and these mature cells are refractory to the transforming effect of hormones. Women who had a full-term pregnancy also have a lower risk of ovarian and endometrial cancers – the higher the number of full-term pregnancies , the lesser is their risk of developing these kinds of gynaecological cancers. You can read more about this at http://www.cancer.gov/cancertopics/factsheet/Risk/reproductive-history.
What do the data show ? To assess whether the risk of cancer after doing IVF increases or not is an extremely complex task , because there are so many other variables which have to be taken into account . Simple examples include: an individual’s life style, family history of cancer and their exposure to carcinogens, all of which are likely to confound the results . This is why these studies are very hard to conduct. One such recent study involving 9175 Finnish women showed that the general risk of cancer or the risk of hormone-related cancer was not increased by IVF (PMID:22343550). Another study in Lancet examined the incidence of breast and ovarian cancer in 10,358 women referred for IVF between 1978 and 1992. They concluded that ovarian stimulation during IVF does not increase a woman’s risk of breast cancer. They also found that there was no significant increase in ovarian cancer after ovarian stimulation for IVF. On the other hand, they concluded that women with unexplained infertility had an increased risk of ovarian cancer ! (PMID:7475593).
This is good news. Remember that IVF hormonal injections are natural hormones, which get excreted promptly from your body, and do not linger on to cause mischief later on. Over 2 million IVF babies have been born worldwide over the last 30 years, and we have not seen an increased prevalence of breast or ovarian cancer, so this is very reassuring. Going through IVF will not increase your chance of having cancer at a later age. Infertile women should try to ensure they have a healthy lifestyle , because infertility by itself is a significant risk factor for certain forms of gynaecological cancers – but this is simple common sense advise , and you don’t need a doctor to tell you this !
This is an excerpt from our forthcoming, book, The Expert Patient's Guide to IVF. This being authored by our expert patient, Manju and me.
You can email Manju at email@example.com
Her blog is at www.myselfishgenes.blogspot.