Radiotherapy during surgery in early breast cancer – what is the risk of tumor recurrence?

This study investigated the safety and effectiveness of intraoperative radiotherapy (IORT; radiotherapy during surgery) in early breast cancer (BC). They found that tumor recurrence was low after IORT.

Early breast cancer (BC) can be treated using different approaches. Most patients undergo breast-conserving therapy (BCT). BCT involves surgery to remove the tumor only. After BCT, patients undergo whole breast irradiation therapy (WBI). The aim of WBI is to kill any cancer cells that were not removed during surgery. This lowers the risk of cancer recurrence.

Partial breast irradiation (PBI) is a new method of radiotherapy. Intraoperative radiotherapy (IORT) is a type of PBI approach. It can be used during BCT surgery. IORT is used only on the region around the tumor. It may result in fewer side effects and less damage to healthy breast tissue. It is unclear if IORT has a better impact on tumor recurrence in patients with early BC. 

129 patients with early BC underwent IORT during BCT surgery. Patients were evaluated over a 5-year period. Tumor recurrence rate (TRR) in the breast was the main outcome of interest. Cosmetic outcomes were also measured. 

The average follow-up time was 59.5 months. The TRR was 3.1% at the final follow-up. No recurrence was observed in the lymph nodes or other organs. The side effects of IORT included tissue fibrosis (scarring), necrosis (tissue death), and wound infection. These side effects were mostly mild to moderate in severity. 

Cosmetic outcomes were good-excellent in 83% of patients 3 years after IORT. This increased from 59.9% after 3 months and 78.1% after 1 year. Patients that did experience tumor recurrence underwent surgery and no further recurrence was reported. 

The authors concluded that tumor recurrence was low after IORT in patients with early BC.

This study tested IORT in low-risk patients with early BC. More investigation is needed in high-risk patients.