Breast Cancer Patients Who Smoke at Higher Risk of Developing Lung Cancer from Radiation Therapy

The risk of developing the disease in non-smokers is 1%, while in smokers it is 2-6%.

Breast cancer patients who continue to smoke while receiving radiotherapy are at a much higher risk of developing lung cancer in the future as a result of the treatment, according to a new study. The Guardian reported on the 22nd (local time) based on a paper by researchers at Oxford University in the UK published in Clinical Oncology.

About two-thirds of patients diagnosed with early-stage breast cancer receive radiation therapy. Radiation therapy is a long-established and highly effective treatment, but it also has potential side effects. Radiation therapy reduces the risk of breast cancer recurring or dying from the disease after treatment, but increases the risk of developing heart disease, lung cancer, and esophageal cancer.

Breast cancer is the most common cancer in the UK, with about 56,000 new cases diagnosed each year. In Korea, more than 20,000 new cases are diagnosed each year, almost all of them women.

A new study found that breast cancer patients who don’t smoke have a less than 1 percent chance of developing lung cancer in the years after receiving radiation therapy. But for women who smoked while receiving radiation, the risk was 2 to 6 percent.

“Radiotherapy is very effective in treating cancer, and in the case of breast cancer, it reduces the possibility of the cancer coming back in the future,” said Caroline Taylor, a professor of oncology at Oxford University who led the study. “However, one of the long-term risks of radiotherapy is that it can cause a second cancer years later.” She explained, “The reason why breast radiotherapy can cause a second cancer is because when you give a dose to the breast, you can’t avoid a small amount of radiation to surrounding tissues, such as the lungs. Radiation can damage cells in the lungs.”

Radiation therapy kills cancer cells by damaging their DNA, thereby reducing the chance of cancer recurrence. However, radiation can also damage the DNA of some normal cells. This means that although it may damage the DNA of some normal cells, it is rare for this damage to normal cells to cause cancer years later.

The researchers analyzed 14 previous studies of radiotherapy for women with breast cancer in the UK. The results showed that most radiotherapy is safe for most women. Among UK women, 14% smoke. Therefore, most breast cancer patients have a risk of developing lung cancer from radiotherapy of less than 1%. However, for long-term smokers, the risk increases to 2-6%.

Deborah Arnott, chief executive of Action on Smoking and Health (ASH), a UK anti-smoking group, said: “This applies not only to breast cancer but to all cancers treated with radiotherapy. If you continue to smoke, the treatment itself will be more unpleasant, less effective and you will be at a higher risk of the cancer coming back later.” Cancer Research UK (CRUK) recently added smoking to its list of causes of breast cancer, along with diet and genes.