Non-smokers found to have 1% chance of treatment leading to disease, compared with between 2% and 6% for smokers

Breast cancer patients who continue to smoke after having radiotherapy are at much higher risk of their treatment causing them lung cancer in the future, research has found.

Two in three of those diagnosed with early breast cancer in the UK are given radiotherapy. It is a long-established and highly effective treatment but does also carry potential side-effects.