Women treated at a young age with a particular type of radiotherapy are at increased risk of getting breast cancer in later life. This research looked into other factors which may affect these women’s level of risk and found that being treated close to the time they had their first period may further increase the risk. This knowledge can be used to improve follow up and screening.

Why was this work needed?

Hodgkin lymphoma (HL) is a cancer that starts in white blood cells called lymphocytes. The number of people surviving HL has increased significantly in recent decades due to improved treatments. This means that a larger number of people are living for a longer period of time after being treated, but they are now experiencing the long term side effects of their treatment.

It is known that women treated at a young age with a particular type of radiotherapy (supradiaphragmatic) are at a substantially increased risk of getting breast cancer. However, relatively little is known about what other factors may affect these women’s level of risk.

What happened?

The researchers sent questionnaires to around 5,000 women who were under 35 when they were treated for HL with supradiaphragmatic radiotherapy between 1956 and 2003. These questionnaires asked the women detailed questions about their medical history, for example, whether they had children and when they had their first period. Beginning in 2003, they then compared information from these questionnaires with the likelihood of developing breast cancer, continuing follow up until 2012.

What were the benefits?

This research showed that if someone is given this kind of radiotherapy for HL close to when they had their first period then the risk of breast cancer is substantially increased. This knowledge can be used to guide subsequent follow up and screening for women who were treated in this way. It also suggests that it would be worth researching the potential benefits of using drugs that delay puberty for those needing this treatment.

What type of data was involved?

This research used a range of data sources, including cancer registries, to identify women eligible to participate. The study was based on a national clinical recall exercise, started in November 2003, in which women treated for HL with supradiaphragmatic radiotherapy younger than 36 were contacted for clinic visits to be counselled about their breast cancer risk and offered breast screening where appropriate.

The research also relied on the information provided by the women in the questionnaires.

Medical research ethics approval was granted by the South East Multi-centre Research Ethics Committee, and women gave signed, informed consent when they completed the questionnaire. Questionnaires were either given out at clinics or sent by post, if deemed appropriate by a patient’s consultant.

Who funded and collaborated on this work?

This work was supported by Breakthrough Breast Cancer (now Breast Cancer Now) and the European Commission.

Where can I go for more information?

Breast cancer risk following Hodgkin lymphoma radiotherapy in relation to menstrual and reproductive factors