Partial Breast Radiation as Effective as Entire Breast Radiotherapy in Low-Risk Cancers, UK Study Reports

Radiotherapy after breast cancer surgery that’s limited to former tumor sites is just as effective in treating early cancers as whole breast radiation and has fewer long-term side effects, according to results of a clinical study presented at the recent 10th European Breast Cancer Conference.

The trial, called IMPORT LOW and supported by Cancer Research UK, looked at ways to improve radiotherapy treatment for low-risk early stage breast cancer, since research has shown that radiotherapy after breast conserving surgery lowers the risk of recurrence.

Thirty radiotherapy centers, led by The Institute of Cancer Research, in London, studied about 2,000 women (ages 50 and older) with early breast cancer who had already undergone breast conserving surgery. In the study, women were randomly assigned to three distinct groups: group 1 patients were treated with full-dose radiotherapy (the current standard) to the whole breast;  group 2 received full-dose radiotherapy to the affected area and a lower dose to the rest of the breast; group 3 patients were treated with full-dose radiotherapy only to the area of the breast where the tumor(s) had existed.

All three groups of women received 15 treatments, over a three-week period, of intensity modulated radiotherapy (IMRT), a technique that uses linear accelerators to safely and painlessly deliver radiation doses to a tumor while minimizing the dose to surrounding normal tissue. Five years post-treatment, results showed that 1 percent or fewer women in each group had breast cancer recurrence, and those women who received partial breast radiotherapy reported greater satisfaction with the appearance of their breast.

Researchers are hopeful these findings might contribute to changes in medical practice. The team also expects that, after 10 years, side effects will continue to be lower for women in the partial breast radiotherapy group compared to those who received a similar dose but to the entire breast.

“We’re really pleased we have demonstrated a very effective radiotherapy approach that also reduces the side effects of treatment,” Dr. Charlotte Coles, the trial leader and a consultant clinical oncologist at Cambridge University Hospital NHS Foundation Trust, said in a press release. “Minimising these long term side effects is essential, as not only do they impact on physical health, but they can also cause psychological distress.”

Professor Judith Bliss, a study co-leader, and director of clinical trials and statistics unit at Cancer Research institute, added: “We hope that these important results will contribute to a change in practice in the very near future. The simple radiotherapy techniques used in this trial can be carried out on standard radiotherapy machines across the UK, so widespread implementation would be relatively straightforward.”