Radiotherapy has more benefits than risks of developing a second cancer

Radiotherapy has more benefits than risks of developing a second cancer

Many patients with cancer treated with radiotherapy are afraid of developing a second tumor. Well, I had always thought that this treatment was associated with a risk of developing a second cancer, but until now was not known in what proportion. The journal 'The Lancet Oncology' has published a study of the National Cancer Institute in Rockville (USA) who reveals the mystery: eight percent. Much less than you thought.

The authors, led by Amy Berrington de González, calculated the long-term risk of secondary cancers resulting from radiation therapy to the locations of solid primary tumors of 647 672 patients over a follow up period of 30 years. During this time, nine percent of those who survived five years developed a second solid cancer.

Of these, the researchers estimated that only eight percent of these secondary cancers could be associated with radiation treatment of the first cancer. More than half of these cancers are given in survivors of breast cancer and prostate cancer. The estimated secondary cancers associated with radiation therapy proportion varied according to the location of the first cancer, four percent in the case of eye cancers by 24 percent for testicular cancer.

The risk of developing a second cancer was higher in patients treated at a younger age and in organs exposed to higher radiation dose and increased with greater time since diagnosis. For every 1,000 patients treated with radiotherapy, the researchers estimated three excess cancers associated radiation treatment in the 10 years following diagnosis of the first cancer and five excess cancers at age 15. These risks, the authors note, are small compared to the potential benefits of treatment.

Among these benefits, we could say that radiation therapy is used to reduce the size of tumors, either to make them smaller and thus facilitate surgery, either to delay its progression. This damages the tumor cells, but it can also cause some damage to healthy cells. In this way helps to reduce the possible pain associated with cancer, and to prevent relapse.