Having chemotherapy alongside radiation therapy for Hodgkin's disease reduces the radiation-associated risk of later breast cancer.

It has already been observed that women who are treated with radiation for Hodgkin's disease have an increased risk of later developing breast cancer. Now researchers at the Netherlands Cancer Institute report that adding chemotherapy to the radiation seems to reduce this risk.

They looked at the treatment undergone by women who had developed Hodgkin's disease before age 41, comparing those who did and did not go on to develop breast cancer. Among those who had radiation alone, the risk of breast cancer went up with increasing radiation dose. But this dose-dependent increase was not seen in women who also had chemotherapy.

The researchers believe that the protective effect of chemotherapy might come from inducing an early menopause. Radiation may trigger changes that result in breast cancer while sex hormones act to promote the disease after the trigger. In the absence of sex hormones - at menopause - the changes induced by radiation are less likely to cause disease.

However, this study is based on earlier and more toxic forms of chemotherapy; newer drugs don't tend to lead to earlier menopause and might not be protective. It is also not necessary to use radiation to cure Hodgkin's disease - except in patients who did not respond to chemotherapy or who have advanced disease.

Source

Journal of the National Cancer Institute 2nd July 2003