3 of the 44 initial patients were discarded for IORT due to
non-compliance with the minimum safety distance (<1 cm) between the
applicator and the skin. Of the remaining patients, 32/41 patients (78%)
received a PBI, while 9/41 (22%) required adjuvant WBI due to adverse
prognostic factors identified on the definitive biopsy. The most frequent risk
factor was close resection margins (<2mm), present in 8/9 patients (88,8%).
Two patients additionally presented sentinel node involvement and in 1 case no
axillary sample was obtained. The most used IORT applicator was the 3-4 cm balloon,
with most likely filling volumes between 30cc and 40 cc. For all treatments, the mean
filling volume of the applicator was 45 cc and there were no complications
during the irradiation procedure.
Surgical bed seroma was the most common acute effect, observed in 29/41
patients (70,7%), although only 8/29 (27,5%) required drainage. We observed wound
dehiscence in 7/41 cases (17%), inflammatory complications requiring
antibiotics in 9/41 cases (19,5%), and 4/41 cases of hematoma (9,7%). Regarding
late toxicity, at the time of the analysis it was only assessable for 37
patients. We observed low rates of local grade I fibrosis (21,6%) and only 1
case of tumor bed G2 fibrosis. Hyperpigmentation G1 was observed in 8,1% of
patients and 10,8% presented occasional mild local discomfort. With median follow-up
of 17.14 months (range 4-29 months), no relapses were observed, but 1 patient
died from covid-19 pneumonia.