Standardization of Nodal Radiation Therapy through Changes to a Breast Cancer Clinical Pathway throughout a Large, Integrated Cancer Center Network

Publication date: Available online 20 July 2017
Source:Practical Radiation Oncology
Author(s): Brian J. Gebhardt, Joel Thomas, Zachary D. Horne, Colin E. Champ, Gretchen M. Ahrendt, Emilia Diego, Dwight E. Heron, Sushil Beriwal
BackgroundStudies demonstrate safety of omitting axillary nodal dissection (ALND) for early-stage breast cancer with positive sentinel lymph node (+SLN) biopsy, though trial designs differed in radiotherapy (RT) fields. Regional nodal irradiation (RNI) was separately shown to improve outcomes in high-risk patients. This led to lack of consensus in RT volumes. Clinical pathways (CP) standardize care where practice varies unnecessarily. We evaluated the impact of changes to a CP guiding post-operative RT in women with +SLNs on practice patterns throughout a network.Methods/MaterialsWe implemented a CP for management of breast cancer with post-operative RT designed to promote uniform nodal treatment. The CP recommended modified tangents (MT) including level I/II nodes for women with micrometastases (pN1mi). For women with macrometastases (pN1a), CP recommended including level I/II LN in MT and a third supraclavicular (SCN) LN +/− internal mammary nodes for women with adverse factors present.ResultsRT fields of 233 women undergoing breast conserving surgery with +SLN but not ALND were retrospectively reviewed: 25% had pN1mi disease, and 75% pN1a. Of 127 women treated before CP changes, 35% with pN1mi and 22% with pN1a were treated with whole-breast irradiation (WBI) alone. Following CP changes, 106 women were treated: 5% with WBI alone, 58% with MT, and 38% with MT+SCN field. Utilization of MT was associated with CP changes. Utilization of a 3rd SCN field was associated with CP changes, pN-Stage, extracapsular extension, and total number of adverse factors.ConclusionCP's translate published data and institutional experience into management plans that promote evidence-based care and eliminate unnecessary practice variations. Recognizing that post-operative RT treatment volumes were heterogeneous, we modified the CP based upon the latest evidence for RNI, after which we found increased compliance and consistency with quality guidelines, which will also aid in tracking outcomes in future investigations.



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