What adverse pathological features would be an indication for WBI (whole breast irradiation) after a patient receives IORT for early breast cancer?

An ASTRO APBI update readers are warned “the combination of IORT and WBI should be used only with caution and limited to women with higher risk features on final pathology.” Is there any specific recommendations in regards to what is high risk pathology aside from pathological features considered high risk on TARGIT-A (tumour-free margin smaller than 1 mm, extensive in-situ component, or unexpected invasive lobular carcinoma) ?