Patterns Of Practice Of Nodal Radiation Therapy In Breast Cancer: Results Of The Eortc "Nora" Survey

Predicting the outcome of breast cancer (BC) patients based on sentinel lymph node (SLN) status without axillary lymph node dissection (ALND) is a matter of debate, especially when it comes to the definition of nodal radiation therapy (NRT). This is even more unclear in the framework of primary systemic therapy (PST). The aim of the NORA (Nodal Radiotherapy) Survey was to examine the patterns of NRT practiced by European Radiation Oncology centers. A web questionnaire was distributed to EORTC centers, and responses were received during the period between July 2013 and January 2014. A total of 81 European and 3 non-European answers were analyzed. While 3D planning is performed in 81 (96%) of the centers for breast irradiation, nodal areas are delineated in only 51 (61%) of the centers. For breast conserving therapy (BCT), only 14 (17%) centers systematically treat the internal mammary chain (IMC), if RT to the supraclavicular area is indicated. 21 (25%) centers state that tangential fields can cover and cure residual axillary disease in patients with positive SLN without ALND. Extra-capsular extension (ECE) is the main factor impacting decision-making regarding IMC and axillary RT. Only half of the centers advocate supraclavicular RT for intermediate risk patients (1-3N+; without ECE). For macro-metastatic SLN involvement without ALND, there is a significant impact of ECE on decision-making independently from the number of positive LNs. In patients undergoing total mastectomy + ALND, supraclavicular RT is given in 5, 53 and 51 centers to patients with N0(i+), N(mi) and N1 disease, respectively. In the PST setting, NRT volumes are based on pre-PST imaging +/- biopsy in 68 (81%) centers. Only 49 (58%) centers take into account the histologic fibrotic changes of the axillary LNs in post-PST ypN- patients with unknown pre-PST status. In patients with negative axilla confirmed by either SLNB or ALND or both after PST (ypN0), 67 (80%) centers do not systematically advocate NRT. In ypN0 patients with inner and central BC, 32 (39%) centers treat the supraclavicular area, including IMC in 23 (27%) of the centers. In ypN+ patients, RT to the supraclavicular area is delivered by 30, 44, 58, 67 centers in patients with ypN(i+), ypN(mi), 1-2N+ and > 3-4N+ disease, respectively. The axilla is irradiated in 25% of the centers in patients with ypN(mi) or 1-2N+. Ninety-eight percent of the centers state that NRT is not omitted in patients > 70 y, regardless the nodal status and 90% do not consider any age limit for NRT. The NORA Survey is unique by evaluating the impact of SLN status and PST on NRT decision-making. IMC RT is not frequently coupled to supraclavicular RT. ECE is the main factor impacting decision-making for NRT. Only 58% of the centers take fibrotic changes in the LN into consideration in decision-making for NRT indications. Age is not considered as a limiting factor for a routinely use of NRT in Europe.