Local relapse after breast-conserving surgery and radiotherapy: effects on survival parameters

Optimizing the quality of breast cancer care at certified german breast centers: a benchmarking analysis for 2003-2009 with a particular focus on the interdisciplinary specialty of radiation oncology

PURPOSE

A voluntary, external, science-based benchmarking program was established in Germany in 2003 to analyze and improve the quality of breast cancer (BC) care. Based on recent data from 2009, we aim to show that such analyses can also be performed for individual interdisciplinary specialties, such as radiation oncology (RO).

METHODS

Breast centers were invited to participate in the benchmarking program. Nine guideline-based quality indicators (QIs) were initially defined, reviewed annually, and modified, expanded, or abandoned accordingly. QI changes over time were analyzed descriptively, with particular emphasis on relevance to radiation oncology.

RESULTS

During the 2003-2009 study period, there were marked increases in breast center participation and postoperatively confirmed primary BCs. Starting from 9 process QIs, 15 QIs were developed by 2009 as surrogate indicators of long-term outcome. During 2003-2009, 2/7 RO-relevant QIs (radiotherapy after breast-conserving surgery or after mastectomy) showed considerable increases (from 20 to 85% and 8 to 70%, respectively). Another three, initially high QIs practically reached the required levels.

CONCLUSION

The current data confirm proof-of-concept for the established benchmarking program, which allows participating institutions to be compared and changes in quality of BC care to be tracked over time. Overall, marked QI increases suggest that BC care in Germany improved from 2003-2009. Moreover, it has become possible for the first time to demonstrate improvements in the quality of BC care longitudinally for individual breast centers. In addition, subgroups of relevant QIs can be used to demonstrate the progress achieved, but also the need for further improvement, in specific interdisciplinary specialties.

Fibrotic changes after postmastectomy radiotherapy and reconstructive surgery in breast cancer. A retrospective analysis in 109 patients

PURPOSE

The purpose of this study was to analyze the probability and time course of fibrotic changes in breast reconstruction before or after postmastectomy radiotherapy (PMRT).

MATERIALS AND METHODS

Between 1995 and 2004, 109 patients were treated with PMRT at Tübingen University and underwent heterologous (HL) or autologous (AL) breast reconstruction prior or subsequent to radiation therapy. Fibrosis of the reconstructed breast after radiotherapy was assessed using the Baker score for HL reconstructions and the Common Terminology Criteria for Adverse Events (CTCAE) for all patients. Actuarial rates of fibrosis were calculated for the maximum degree acquired during follow- up and at the last follow-up visit documented.

RESULTS

Median time to follow-up was 34 months (3-227 months). Radiotherapy was applied with a median total dose of 50.4 Gy. A total of 44 patients (40.4%) received a boost treatment with a median dose of 10 Gy. Breast reconstruction was performed with AL, HL, or combined techniques in 20, 82, and 7 patients, respectively. The 3-year incidence of ≥ grade III maximum fibrosis was 20% and 43% for Baker and CTCAE scores, respectively. The corresponding figures for fibrosis at last follow-up visit were 18% and 2%. The 3-year rate of surgical correction of the contralateral breast was 30%. Initially unplanned surgery of the reconstructed breast was performed in 39 patients (35.8%). Boost treatment and type of cosmetic surgery (HL vs. AL) were not significantly associated with the incidence of fibrosis.

CONCLUSIONS

We found severe fibrosis to be a frequent complication after PMRT radiotherapy and breast reconstruction. However, surgical intervention can ameliorate the majority of high grade fibrotic events leading to acceptable long-term results. No treatment parameters associated with the rate of fibrosis could be identified.

Radiobiological comparison of hypofractionated accelerated partial-breast irradiation (APBI) and single-dose intraoperative radiotherapy (IORT) with 50-kV X-rays

BACKGROUND AND PURPOSE

Intraoperative radiotherapy (IORT) of the tumor bed in early breast cancer is presently performed with a single dose of 50-kV X-rays from a miniaturized X-ray machine using spherical applicators. The purpose was to model the biological effect of hypofractionated accelerated partial-breast irradiation (APBI) with ten fractions.

MATERIAL AND METHODS

The relative biologic effectiveness (RBE) was estimated from the linear-quadratic (L-Q) formalism including repair of sublethal damage or assuming a constant RBE = 1.2-1.5. The radial distribution of biological effect was assessed from clinical dose-response curves. In accordance with clinical convention, the dose for APBI was prescribed at 1 cm depth in the tumor bed, whereas for IORT it was prescribed at the applicator surface.

RESULTS

The fraction size was fitted to give the same risk of late normal-tissue reaction (fibrosis) as single-dose IORT with a maximum dose of 20 Gy. The isoeffective fraction size at 1 cm depth varied between 1.01 Gy for RBE estimated from the L-Q model and 1.64 Gy for constant RBE. The applicator size and dose prescription point influenced the radial dose distribution. The "sphere of equivalence" within which the risk for local recurrence is the same for whole-breast radiotherapy was predicted to extend to 11-15 mm distance from the applicator for alpha/beta = 10 Gy and 9-13 mm for alpha/beta = 4 Gy for hypofractionated APBI, representing an increase of the sphere of equivalence by 2.5-6 mm relative to single-dose IORT.

CONCLUSION

An increase of the therapeutic window with hypofractionated APBI relative to single-dose IORT should be feasible.