Can intraoperative radiotherapy be used to treat early-stage breast cancer?

This article looked at 5-year outcomes of intraoperative radiation therapy (IORT) for breast cancer (BC). The authors found that IORT may have a higher rate of cancer return compared to whole-breast radiation therapy (WBRT).

BC is one of the most common forms of cancer found in women. Standard care for BC is usually a combination of RT, surgery to remove tumors, and chemotherapy. Tumors that are hormone-sensitive usually grow in response to a hormone such as estrogen. Hormonal therapy (HT) is given to patients with these types of tumors to prevent their growth.

IORT is the use of radiotherapy (RT) given in the operating room during surgery. Previous studies have found IORT to be effective in the management of early-stage cancer. Traditional use of RT has disadvantages. One such disadvantage is the time interval between surgery and RT. This can sometimes cause cancer cells to repopulate an area. Until now, 5-year outcomes have not been reported from the use of IORT in early-stage BC treatment.

There were 667 patients with early-stage BC in this study. All patients were treated with a lumpectomy (removal of the tumor, while conserving the breast). Primary IORT (RT at the time of surgical tumor removal) was performed for 72% of these patients. IORT after tumor removal was performed for 3% of patients (delayed IORT). Boost therapy (a higher amount of RT given to reduce the risk of recurrence) was used in 8% of patients (intended boost group). Primary IORT followed by whole-breast RT was performed in 17% of patients (unintended boost group). Patients were also given HT. The average follow-up was 5.1 years.

6.6% of all patients had a recurrence. 8.1% of the primary IORT group had cancer return. In the unintended boost group, there was cancer return in 1.7% of patients. There was no cancer return identified in the delayed IORT group or the intended boost group. 

Patients who take their HT as prescribed had a 3.9% rate of recurrence at 5 years compared to 14.1% for those who did not take the prescribed HT. The 5-year overall survival for patients who received primary IORT was 99%.

The authors concluded that IORT may have a higher recurrence rate than RT to the whole breast. However, they suggested that IORT could be an option for patients who cannot receive WBRT.

This study was based on medical records. Information might have been incomplete. Also, there was no direct comparison between IORT and WBRT. Further long-term studies are needed in order to provide more information about the use of IORT in the treatment of early-stage BC.