Clinical Results - Boost IORT with Electrons (IOERT)
References:
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4167210/, Int J Breast Cancer. 2014; 2014: 472516., Published online 2014 Sep 2. doi: 10.1155/2014/472516, PMCID: PMC4167210, Boost IORT in Breast Cancer: Body of Evidence, Felix Sedlmayer, 1 , 2 ,* Roland Reitsamer, 3 Christoph Fussl, 1 Ingrid Ziegler, 1 Franz Zehentmayr, 1 , 2 Heinz Deutschmann, 1 , 2 Peter Kopp, 1 and Gerd Fastner 1
Despite its retrospective character, the International Society of Intraoperative Radiotherapy (ISIORT) Europe pooled analysis on IOERT provides the best available evidence so far :
25. Sedlmayer F, Fastner G, Merz F, et al. IORT with electrons as boost strategy during breast conserving therapy in limited stage breast cancer: results of an ISIORT pooled analysis. Strahlentherapie und Onkologie. 2007;183(2):32–34. [PubMed]
26. Fastner G, Sedlmayer F, Merz F, et al. IORT with electrons as boost strategy during breast conserving therapy in limited stage breast cancer: long term results of an ISIORT pooled analysis. Radiotherapy and Oncology. 2013;108:279–286. [PubMed]
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4167210/, Int J Breast Cancer. 2014; 2014: 472516., Published online 2014 Sep 2. doi: 10.1155/2014/472516, PMCID: PMC4167210, Boost IORT in Breast Cancer: Body of Evidence, Felix Sedlmayer, 1 , 2 ,* Roland Reitsamer, 3 Christoph Fussl, 1 Ingrid Ziegler, 1 Franz Zehentmayr, 1 , 2 Heinz Deutschmann, 1 , 2 Peter Kopp, 1 and Gerd Fastner 1
Despite its retrospective character, the International Society of Intraoperative Radiotherapy (ISIORT) Europe pooled analysis on IOERT provides the best available evidence so far :
25. Sedlmayer F, Fastner G, Merz F, et al. IORT with electrons as boost strategy during breast conserving therapy in limited stage breast cancer: results of an ISIORT pooled analysis. Strahlentherapie und Onkologie. 2007;183(2):32–34. [PubMed]
26. Fastner G, Sedlmayer F, Merz F, et al. IORT with electrons as boost strategy during breast conserving therapy in limited stage breast cancer: long term results of an ISIORT pooled analysis. Radiotherapy and Oncology. 2013;108:279–286. [PubMed]
5.1.1. The ISIORT Europe Pooled Analysis (BIO-Boost) [26]
The joint investigation evaluated the long-term outcome of the IOERT strategy aimed at reducing local recurrence in breast cancer and was carried out in a joint effort by seven institutions from Austria, Germany, Italy, and France—all members of ISIORT's European Group (ISIORT Europe). Until October 2005, 1109 unselected patients of any risk group have been identified among seven centers using identical methods, sequencing, and dosage for intra- and postoperative radiotherapy. A median IOERT dose of 10 Gy was applied (90% reference isodose), preceding WBI with 50–54 Gy (single doses 1.7–2 Gy). 60% of all patients (n = 655) presented with at least one of the following adverse prognostic factors for local recurrence: tumour size > 2 cm, high grade, age < 45 years, and positive lymph nodes. In the most recent long-term analysis, at a median follow-up of 72.4 months (0.8–239), only 16 in-breast recurrences were observed, half of them accounting for true local recurrences; this yields an in-breast tumour control rate of 99.2% at 73.3 months. Relapses occurred 12.5–151 months after primary treatment. In a multivariate analysis, grade 3 tumour was found to be predictive of recurrence (P = 0.024). A significant univariate trend was found for in-breast relapse in case of negative hormonal status and young age (below 40 years). Annual in-breast recurrence rates amounted to 0.64%, 0.34%, 0.21%, and 0.16% in patients <40 y; 40–49 y; 50–59 y, and ≥60 y, respectively. In all risk subgroups, a 10 Gy IOERT boost prior to WBI provided local control rates which compare favourably to the reported figures in all trials with similar length of follow-up, irrespective of the used boost methods [5,27–29].
Furthermore, in a retrospective matched-pair analysis, 188 patients with external e-boost (6 × 2 Gy Dmax (1.8 Gy ref D)) were compared to the pooled analysis' first 190 patients from Salzburg IOERT (10 Gy Dmax (9 Gy ref D)) [30]. At 10-year follow-up, the in-breast recurrence rate in the external e-boost group was 7.2% and 1.6% in the IOERT group, respectively. This significant difference was almost entirely due to a reduction in true local recurrence.
CONCLUSION [26]:
In all risk subgroups, a 10 Gy IOERT boost prior to WBI provided outstanding local control rates, comparing favourably to all trials with similar length of follow up.
Furthermore, in a retrospective matched-pair analysis, 188 patients with external e-boost (6 × 2 Gy Dmax (1.8 Gy ref D)) were compared to the pooled analysis' first 190 patients from Salzburg IOERT (10 Gy Dmax (9 Gy ref D)) [30]. At 10-year follow-up, the in-breast recurrence rate in the external e-boost group was 7.2% and 1.6% in the IOERT group, respectively. This significant difference was almost entirely due to a reduction in true local recurrence.
CONCLUSION [26]:
In all risk subgroups, a 10 Gy IOERT boost prior to WBI provided outstanding local control rates, comparing favourably to all trials with similar length of follow up.