Intraoperative Radiotherapy as Accelerated Partial Breast Irradiation for Early Breast Cancer

Abstract

Intraoperative radiotherapy (IORT) was originally introduced in breast cancer treatment as an "anticipated boost" during the procedure of breast conserving surgery (BCS). In addition to whole breast irradiation (WBI), it has yielded excellent long-term results [31, 38]. Under the assumption that the majority of in-breast tumor recurrences (IBTR) occur in the originally affected site, accelerated partial breast irradiation (APBI) as the sole treatment modality was initiated in several studies and with different techniques, one of which was IORT first with electrons, later also with conventional x-rays [29]. The question whether and for whom the gold standard of WBI may be replaced by APBI - especially IORT - alone has recently been one of the most controversial issues of adjuvant therapy for breast cancer. Two recently published studies by Veronesi et al. [36] and Vaidya et al. [35] presenting shortterm results of single shot IORT with electrons (ELIOT) and with an orthovoltage system (TARGIT), respectively, have further invigorated this discussion as illustrated by several letters to the editor commenting on the TARGIT study. While Vaidya et al. [35] indicate their results of IORT alone as "an alternative to WBI for selected patients" and one editorial even proclaims it as standard [6], all the authors of the respective letters [10, 16, 27, 33] strongly disagree with this conclusion. The present editorial comments on the two publications and, furthermore, provides respective statements of the breast cancer expert panel of the German Society of Radiation Oncology (DEGRO).

One life saved by four prevented recurrences?

“…Mortality without recurrence was slightly higher in the irradiated group (1.09, 2p 0.14) but the excess was not significant and identiEditorial Tab. 1 The 10-year recurrence a rate and mortality [6] All patients (n =1 0,801) pN0 (n = 7,287) pN+ (n = Several new treatment modalities are currently being discussed like partial breast irradiation [10], or omitting axillary dissection (without irradiating the axilla instead!) in patients with a positive sentinel node and a clinically negative axilla [9].…”

Dose distribution changes with shielding disc misalignments and wrong orientations in breast IOERT: a Monte Carlo – GEANT4 and experimental study

“…It is mainly used as an adjuvant to surgery or as a preliminary boost to be followed later by fractionated conventional external whole‐breast radiotherapy (WBRT) (1) . The objective is to achieve a higher dose in the target volume, while dose‐limiting structures are surgically displaced (2) …”

Intraoperative Period and Breast Cancer: Review

“…Bilateral, multifocal or multicentric breast cancer patients with clinical positive lymph nodes or patients with extensive ductal carcinoma in situ are not candidate for IORT. Contraindications for standard RT such as connective tissue diseases, and pregnancy (although in the EIO preliminary study potential fetal radiation exposure was found to be negligible) are also contraindications for IORT (39,40).…”

“…An aluminum disk is placed on the pectoral muscle to protect thoracic tissues from irradiation, the skin is moved away from the applicator by as much retraction as possible. The total administered dose of 21 Gy is considered biologically equal to 60 Gy radiation applied for 5 weeks (13)(14)(15). Axxent Electronic Brachytherapy (Intracavitary systems) System (Xoft Inc., Fremont, CA) is a balloon-based brachytherapy system, and uses a 50 kilovoltage electronic radiation source.…”