Is IORT ready for roll-out?

Area of Science:

• Oncology
• Radiotherapy
• Surgical Oncology

Background:

• Two large randomized controlled trials (TARGIT-A and ELIOT) evaluated intraoperative radiotherapy (IORT) in breast-conserving surgery.
• Published 14 years after initiation, trial results have not altered current clinical practice regarding IORT use.

Purpose of the Study:

• To assess the efficacy and safety of IORT compared to external beam radiation therapy (EBRT) in breast cancer patients undergoing breast-conserving surgery.
• To evaluate local recurrence rates (LRR) and compare them against pre-specified non-inferiority margins.

Main Methods:

• Analysis of data from the TARGIT-A and ELIOT randomized controlled trials.
• Comparison of in-breast local recurrence rates (LRR) between IORT and EBRT arms.
• Assessment of actual LRR against initially estimated rates for EBRT.

Main Results:

• IORT met pre-specified non-inferiority margins for LRR (3.3% in TARGIT-A, 4.4% in ELIOT).
• Actual LRR in EBRT arms were significantly lower than estimated (1.3% in TARGIT-A, 0.4% in ELIOT vs. estimated 6% and 3% respectively).
• Median follow-up ranged from 2.4 to 5.8 years, with longer-term data emerging.

Conclusions:

• IORT can be considered for select breast cancer patients, particularly those at low risk of local recurrence or suitable for partial breast irradiation, under strict protocols.
• Further follow-up is needed to increase confidence in the data, but clinical implementation should not be unduly delayed.
• Development of specific guidelines for IORT would aid clinicians in patient selection and treatment protocols.