Breast cancer: can radiotherapy sometimes be avoided?

In order to reduce the impact of treatments (we speak of “therapeutic de-escalation”), researchers wanted to assess the relevance of radiotherapy after breast cancer surgery in women over the age of 65 with early form of hormone-dependent breast cancer.

Radiotherapy for early hormone-dependent cancers: useful or not?

The indications for these women are generally conservative surgery, followed by radiotherapy and long-term hormone therapy. But radiotherapy can have different side effects: fatigue, breast pain, heart or lung complications…

Researchers have therefore studied the fact of not treating certain patients affected by this early form of breast cancer with radiation, provided that they receive five years of hormone therapy.

“Almost identical” overall survival

In this study, 1,326 women with breast cancer over the age of 65 (with hormone-dependent early breast cancer) were operated on for their disease. Of these volunteers, 658 of the women were randomly assigned to receive radiation therapy to their entire breast and 668 of them received no radiation therapy.

The trial was conducted at 76 centers in the UK, Greece, Australia and Serbia. Results: The 10-year overall survival was almost identical: 80.8% in the group without radiotherapy and 80.7% with, according to the researchers’ conclusions. There were a total of 16 deaths in the no radiotherapy group and 15 deaths in the radiotherapy group, caused by breast cancer.

Higher recurrence without radiotherapy

On the other hand, there is a difference between the two groups, relating to the recurrence of the disease. In the group that did not receive radiation, the cumulative incidence of local recurrences was 9.5% and only 0.9% in the group of women who had been irradiated.

“The incidence of local recurrences up to 10 years in patients who received radiotherapy remained low, whereas that in patients who did not receive radiotherapy continued to increase with no apparent plateau. However, the absolute difference in the incidence of local recurrences at 10 years was modest” write the researchers from the University of Edinburgh and the Western General Hospital in Scotland.

“Omitting radiation therapy was associated with an increased incidence of local recurrence, but had no detrimental effect on distant recurrence (in an organ other than the affected breast) as the first event or on overall survival in women 65 years or older with low-risk, hormone receptor-positive early breast cancer“they conclude.

Different techniques to enable therapeutic de-escalation

The ability to omit radiation therapy is one of many options from a long list that also includes the use of abbreviated radiation therapy regimens (hypofractionated regimens with fewer sessions and higher doses), and higher target volumes small (with partial breast irradiation or intraoperative radiotherapy, conducted at the same time as the surgery, as described in the video below).