Breast cancer electron intraoperative radiotherapy: assessment of preoperative selection factors from a retrospective analysis of 758 patients and review of literature

• Published in: Breast cancer research and treatment Vol. 165; no. 2; pp. 261 - 271
• Main Authors: Takanen, S., Gambirasio, A., Gritti, G., Källi, M., Andreoli, S., Fortunato, M., Feltre, L., Filippone, F. R., Iannacone, E., Maffioletti, L., Muni, R., Piccoli, F., Mauri, E. M. P., Paludetti, A., Giovanelli, M., Burgoa, L., Valerii, C., Palamara, F., Ferro, M., Fenaroli, P., Tondini, C. A., Cazzaniga, L. F.
• Format: Journal Article
• Language: English
• Published: New York Springer US 01.09.2017; Springer; Springer Nature B.V
• Subjects: Age; Breast cancer; Breast Neoplasms - diagnosis; Breast Neoplasms - mortality; Breast Neoplasms - radiotherapy; Breast Neoplasms - surgery; Cancer patients; Cancer research; Combined Modality Therapy; Diagnosis; Electrons; Female; Histology; Humans; Intraoperative Care - methods; Lumpectomy; Mastectomy; Medicine; Medicine & Public Health; Neoplasm Grading; Neoplasm Staging; Oncology; Preoperative Care; Prognosis; Radiation therapy; Radiotherapy; Radiotherapy - methods; Retrospective Studies; Review; Surgery; Treatment Outcome; Tumor Burden; Tumors; Partial breast radiotherapy; Prognostic factors; Intraoperative radiotherapy
• ISSN: 0167-6806; 1573-7217
• DOI: 10.1007/s10549-017-4321-6

Purpose To report our experience with full-dose 21 Gy IORT in early breast cancer patients after breast-conserving surgery to define most important selection factors. Methods Seven hundred and fifty eight patients, subjected to conserving surgery and IORT, were retrospectively analyzed evaluating most important clinical outcomes. Results Median follow up was 5.2 years. Results from Cox analyses defined 2 groups of patients, “suitable” (age > 50 years, non lobular histology, tumour size ≤ 2 cm, pN0 or pNmic, ki67 ≤ 20%, non triple negative receptor status and G1-G2) and “unsuitable” for IORT, with a higher rate of breast related events moving from “suitable” to “unsuitable” group. The 5 year rate of IBR is 1.8% in suitable group with significant differences versus unsuitable (1.8 vs. 11.6%, p  < 0.005). Same differences between two groups were evidenced in true local relapse (0.6 vs. 6.9%, p  < 0.005) and in new ipsilateral BC (1.1 vs. 4.7%, p  < 0.015). Conclusions In our current practice we consider the following preoperative factors to select patients suitable for IORT: age > 50 years, absence of lobular histology, tumor size ≤ 2 cm, pN0 or pNmic, according to APBI consensus statement, including also ki67 ≤ 20%, non triple negative receptor status and G1–G2.