For patients with breast cancer who meet the newly-updated selection criteria, intraoperative radiation therapy (IORT) has similar efficacy and safety outcomes to whole breast irradiation (WBI), according to the executive summary of a recent American Society for American Oncology (ASTRO) evidence-based consensus statement.1
According to the updated recommendations, clinicians ought to counsel patients that IORT can increase one’s risk of ipsilateral breast tumor recurrence (IBTR), and that electron beam IORT should be used only for patients suitable for partial breast irradiation (PBI).
These updates were based on findings from 2 phase 3 trials—ELIOT (ClinicalTrials.gov Identifier: NCT01849133) and TARGIT (ClinicalTrials.gov Identifier: NCT00983684)—which compared the use of 2 IORT varieties with WBI: for ELIOT, electron beam was used, and for TARGIT, low-energy x-rays were used.
In ELIOT, the 5-year risk of IBTR was more than 10 times greater for patients who received IORT than for those who received WBI (4.4% vs .4%). Patients who met the suitability criteria for IORT, however, had a 5-year IBTR risk of about 1.5%, which, it should be noted, is still 3 times greater than the risk with WBI.
The 5-year risk of IBTR in TARGIT was 3.3% with IORT vs 1.3% with WBI. These estimates were, however, made after only a median of 2.4 years’ follow-up.
Other updated criteria include lowering the suitable age group to 50 years and above, including patients aged 40 to 49 years only if all other suitability criteria are met, and excluding all patients younger than 40. Patients aged 40 to 49 are considered of “cautionary” suitability. Each of these updates is given as a “weak” recommendation.
- Correa C, Harris EE, Leonardi MC, et al. Accelerated partial breast irradiation: Executive summary for the update of an ASTRO evidence-based consensus statement. Pract Radiat Oncol. 2016 Sep 17. doi: 10.1016/j.prro.2016.09.007 [Epub ahead of print]