br Methods and Materials Patients with NR after
Methods and Materials: Patients with NR after treatment at a single cancer center during 1998 to 2013 were identified. Patients with prior distant metastases or NR without correlative imaging were excluded. All NRs were overlaid onto representative axial computed tomographic images. Multivariable analysis was performed to identify clinical and pathologic characteristics associated with NR. Kaplan-Meier curves were generated to assess the rate of relapse by nodal region according to pathologic feature or Echinomycin treatment status.
the SCV relapsed at a similar rate in the medial, but a higher rate in lateral SCV (P Z .009), compared with low-risk patients who received no nodal RT. Lym-phovascular invasion most strongly associated with IMN NR (P Z .001); grade 3 dis-ease highly associated with both IMN (P Z .001) and SCV NR (P Z .02). The presence of an IMN NR portended for significantly inferior overall survival (OS),
Reprint requests to: Carl DeSelm, MD, PhD, Washington University, Conflict of interest: none.
Department of Radiation Oncology, 1250 1st Ave, New York, NY 63110. Supplementary material for this article can be found at https://doi.org/
584 DeSelm et al. International Journal of Radiation Oncology Biology Physics
Conclusions: In this 3-dimensional image-based analysis of NR patterns in breast can-cer patients treated with contemporary therapies, the lateral and posterior SCV repre-sented a distinct site of NR that is not routinely included within current breast cancer contouring atlases. Grade 3 breast cancer and LVI were most commonly associated with the development of NR in the SCV. Modifying the CTV to encompass the lateral and posterior SCV in patients with breast cancer with these features might be justified. 2018 Elsevier Inc. All rights reserved.
Radiation therapy (RT) is an essential component in the management of breast cancer patients, enhancing both locoregional control and survival in multiple randomized trials and large meta-analyses.1 In these trials, the postmastectomy radiation portals included the internal mammary lymph nodes (IMNs), in addition to the chest wall, supraclavicular (SCV) and axillary lymph nodes. More recently, the benefits of regional nodal irradiation (RNI) after breast-conserving surgery was demonstrated by 2 large, randomized controlled trialsdNCIC MA20 and EORTC 22922din which patients who received RNI had a disease-free survival benefit compared with those who had whole breast RT alone.2,3 After the publication of these seminal trials, utilization of RNI and radiation target volumes have expanded in women with node-positive or high-risk node negative breast cancer, magnifying the need for accurate, CT-based delineation of the lymph nodes in radiation treatment planning.
Attempts to standardize target delineations in breast cancer began in 2009, when the first consensus definition of the clinical target volume (CTV) was published by the Radiation Therapy Oncology Group (RTOG).4 Subse-quently, contouring atlases were published by the European Society for Radiation therapy and Oncology (ESTRO).5-8 More recently, a Radiotherapy Comparative Effectiveness (RADCOMP) atlas was published online in 2016 to guide contouring efforts in an ongoing trial of proton versus photon therapy in breast cancer.9 Although these atlases were guided by expert opinion, large, robust data sets of locoregional patterns of nodal recurrence (NR) were not available at the time to inform the guidelines directly.
The primary goal of our study was to conduct a 3-dimensional (3D) analysis of the locations and the patterns of nodal recurrence in patients with non-metastatic breast cancer who were treated with curative intent surgery with or without adjuvant therapies. Sec-ond, we examined these patterns of failure relative to RTOG and ESTRO contouring guidelines. Finally, we explored whether certain clinical, pathologic, and treatment-related factors were associated with location-specific NRs.