Hormone stimulation of ovaries increases cancer risk, study shows

Nov 7, 2011, 3:06 GMT

Amsterdam - Hormone stimulation of a woman's ovaries in in-vitro fertilization (IVF) treatments can increase her risk of ovarian tumours, according to a study by the Netherlands Cancer Institute in Amsterdam.

Researchers said the treatments particularly increased the risk of what are known as borderline tumours. Their study was published in Human Reproduction, a monthly journal of the European Society of Human Reproduction and Embryology.

Borderline tumours are peculiar to ovarian cancer and not definitely classifiable as benign or malignant. Experts, however, say that they should not be underestimated.

'Borderline tumours are often on both sides and require surgery, which usually involves removing the ovary,' said Michael Ludwig, a Hamburg-based specialist on reproductive medicine. But the chances of developing a benign or malignant ovarian tumour were very low, he added.

IVF is often the last hope for couples having difficulty conceiving. Hormone injections stimulate the woman's ovaries into producing extra eggs for the treatment.

The Dutch study included 25,152 women, 19,146 of whom had ovarian stimulation for IVF between 1983-95. The 6,006 women in the control group were also sub-fertile but had not undergone ovarian stimulation. After nearly 15 years, 77 women in the study had developed ovarian tumours, of whom 61 were in the IVF treatment group and 16 in the control group.

The researchers said that larger studies were needed to corroborate the results. They also noted that having larger numbers of IVF treatments or receiving higher doses of ovarian-stimulating hormones did not increase the risk of developing a tumour.