New Study on IVF Treatment and Cancer Risks
For a number of years now, there has been considerable interest in the question of whether fertility drugs, fertility treatments, or infertility itself leads to a higher lifetime risk of breast or gynecologic cancers. Earlier studies suggested there may be a relationship between the use of fertility medications and cancer, especially ovarian cancer. Subsequently, several studies have not been able to find a clear association.
There was no association of breast cancer incidence within the group of patients receiving fertility treatment as compared with the infertile women receiving no treatment. Nor was there any association with breast cancer and IVF treatment, use of GnRH agonists (e.g. Lupron), or clomiphene use. Among women treated with progesterone, there was a significantly decreased risk of breast cancer. Additionally, there was no increase in endometrial cancer risk with fertility treatment.
With regards to ovarian cancer, exposure to fertility treatment was not statistically significantly related to ovarian cancer risk. As is the case with most prior studies looking at this issue, the number of cases was small (45 total), as ovarian cancer is a rare cancer. However, there was a trend towards an increased risk that was not statistically significant and the non-significant trend continued upwards with 4 or more cycles of IVF. So it is important that this issue continues to be studied, especially as the infertility patient population ages.
With cervical cancer, there was a significantly decreased risk in pre-invasive and non-significant decreased risk with invasive cervical cancers seen in treated infertility patients. The authors speculated that this may be due to fewer sexual partners and higher socio-economic status as well as more intensive monitoring with Pap smears in this population.
In summary then, this study is another study that finds that fertility drugs and fertility treatments do not seem to be associated with breast or gynecologic cancers although the issue of an association with ovarian cancer bears further follow-up and investigation. One limitation of this study was the relatively recent treatment and young population of this group of women. Whether there will be increases seen in future years bears further study. However, to quote the authors of the study itself: in this study within a large Israeli HMO, our findings regarding the relationships of fertility drugs and cancer risk were largely reassuring. Notably, we found no convincing relationships of fertility treatments to breast or endometrial cancers. For ovarian cancer, like several earlier studies, we noted some evidence of increasing risk with number of IVF cycles, but our relationship was not statistically significant, possibly owing to small numbers.
- Carolyn Givens, MD