[Prophylactic axillary radiotherapy for breast cancer]

Should the management of radiation therapy for breast cancer be standardized? Results of a survey on current French practices in breast radiotherapy

Background

Breast cancer is the most frequent cancer in women in France. Its management has evolved considerably in recent years with a focus on reducing iatrogenic toxicity. The radiotherapy indications are validated in multidisciplinary consultation meetings; however, questions remain outstanding, particularly regarding hypofractionated radiotherapy, partial breast irradiation, and irradiation of the internal mammary chain and axillary lymph node area.

Materials and methods

An online survey was sent to 47 heads of radiotherapy departments in France. The survey consisted of 22 questions concerning indications for irradiation of the supraclavicular, internal mammary and axillary lymph node areas; irradiation techniques and modalities; prescribed doses; and fractionation.

Results

Twenty-four out of 47 centers responded (response rate of 51%). This survey demonstrated a wide variation in the prescribed dose regimen, monoisocentric radiotherapy, and indications of irradiation of the lymph node areas.

Conclusion

This survey provides insight into the current radiotherapy practice for breast cancer in France. It shows the need to standardize practices.

[Prophylactic nodal radiotherapy for breast cancer]

Adjuvant radiotherapy is a key treatment in early-stage breast cancer. The meta-analysis by the Early Breast Cancer Trialist's Collaborative Group (EBCTCG) has demonstrated a decreased risk of locoregional relapse and death after whole-breast radiotherapy. Prophylactic lymph nodes irradiation in breast cancer has also proven to be beneficial in several therapeutic trials. At a time when three-dimensional conformal radiotherapy has become the standard procedure and with the development of intensity-modulated radiation therapy, defining nodal volumes is essential and practices should be harmonized to assess and compare the efficiency and toxicity of radiotherapy. Furthermore, the indication of lymph nodes irradiation has to take into account the risk/benefit balance as expanding the irradiated volume can increase radio-induced toxicity. Selection of patients receiving this treatment is essential. The aim of this update is to define nodal volumes, to precise the indications of their irradiation and to present the expected benefits as well as the potential side effects.

Management of the Axilla in the Era of Breast Cancer Heterogeneity

Systemic cancer therapies take into account breast cancer (BC) heterogeneity by targeting pathways specifically involved in some BC subtypes. On the other hand, BC intrinsic radiosensitivity is poorly understood and studied. Hence, radiotherapy personalization in BC is still “work in progress”. In this review, we will summarize the existing data on the management of axillary lymph nodes in BC, the impact of BC radiotherapy on axillary management, the indications for axillary radiotherapy, and biomarkers to predict patients’ outcome (tumor control and late toxicities) after axillary irradiation.

[Establishing margins from CTV to PTV in breast cancer treatment]

The benefit of postoperative radiotherapy for breast cancer both in terms of local control and overall survival is widely acknowledged. Today, technological advances in simulation imaging and positioning control enable the definition of new margins from CTV to PTV. Improvements in mathematical modeling of random and systematic errors impact the treatment plans. However, there is no universal absolute value to consistently determine the margins from CTV to PTV. It is down to each centre to assess and correct as much as possible uncertainties due to positioning and internal movements depending on techniques and methods used for the implementation of treatment and monitoring. IMRT and respiratory gating techniques for breast radiotherapy will be considered more systematically in the years to come.

[Not Available]

REFLEXIONS ABOUT NEW STRATEGIES OF RADIOTHERAPY FOR EARLY BREAST CANCER: Radiotherapy (RT) remains a major treatment element in early breast cancer, with a major impact on local control and survival. For ductal carcinoma in situ (DCIS), RT reduces local recurrence (LR) rates by 50 to 60 % after conservative surgery (both in situ and invasive). This was confirmed by four randomized trials and one meta-analysis. For infiltrating breast cancers (IBC), RT also reduces LR rates by 65 to 75 % after conservative surgery. Boost allows an additional reduction of LR. RT is efficient in all age categories, but hypofractionated schemes are particularly adapted to elderly women. Partial breast irrradiation techniques are very much heterogeneous and lack follow-up. They should be used in LR low-risk patients only and in the frame of controlled studies. Locoregional RT for high-risk patients (especially in pN+) remains essential to reduce the locoregional recurrence rate and to increase survival, as confirmed in several meta-analyses. Four studies showed a survival benefit (2-3 %), thanks to internal mammary chain irradiation in LR high-risk patients. Moreover, axillary RT seems to be a likely valuable alternative to axillary dissection in case of sentinel node invasion. Finally, with the modern techniques and dosimetric optimization, RT toxicity was reduced, or even cancelled, arousing hope for a better increased benefit for the patients in the future.