Locally advanced breast cancer frequently involves the extra-axillary regional nodes: incidence and treatment impact.
Authors: Iyengar P , Strom EA , Zhang Y , Whitman GJ , Woodward WA , Yu T , Buchholz TA 
Published: December 2010

Abstract #4002

Background: 30% of all breast cancer patients will be diagnosed with locally advanced disease in 2008. A complete assessment of the extended regional lymphatics of these patients is critical for accurate staging and treatment. We retrospectively evaluated our institution's experience with the use of ultrasound of the extended regional lymphatics.&#x2028; Methods: We retrospectively analyzed all our patients who were treated for locally advanced breast cancer (T3/T4 or N2/N3) with radiation therapy between 1996 and 2006. Among Stage III patients treated with radiotherapy, 865/1200 had undergone ultrasound studies which included the extended regional nodal basins as part of their initial evaluation. These 865 patients are the study cohort for this analysis. Physical examination findings and mammography results were also reviewed for this subset of patients.&#x2028; Results: 37% of all patients (325/865) evaluated had additional disease beyond the breast and low axilla which was identified only by extended regional ultrasound. 90% of these patients (293/325) had pathologic evaluation of suspicious nodes during ultrasound and 91% of these abnormalities (266/293) were confirmed pathologically, usually by ultrasound guided FNA, resulting in an 82% pathologic confirmation rate. Compared to clinical examination, mammography and targeted breast ultrasound, extended regional nodal ultrasound identified previously undocumented infraclavicular disease in 32% of patients (275/865), supraclavicular disease in 16% of patients (140/865), and internal mammary chain disease in 11% of patients (98/865). While 72% of the patients with extra-axillary regional nodal involvement had T3 (94/325) or T4 (141/325) primary tumors, 28% of these patients had T1 or T2 lesions (90/325). Most commonly, regional ultrasound changed a patient's N-stage from N1 to N3 disease. In the T1-T2 cohort, there was a shift from N1 to N3 disease in 22% of patients, with an equal shift from N2 to N3 disease. For T3 patients, 13% had a change from N1 to N3 disease, and 7% converted from N2 to N3 disease. 13% of T4 patients went from N1 to N3 disease, 11% from N2 to N3 disease. When assessing stage, it was observed that all the patients found to have N3 disease (37%) in this cohort of locally advanced breast cancers would have been understaged without the use of regional ultrasound evaluation. All patients with involvement of the extra-axillary regional nodal received a radiation boost to the involved areas. Thus at least 37% of the patients with advanced breast cancer had their radiation therapy altered by information garnered from sonography.&#x2028; Conclusions: Evaluation of the extended regional lymphatics in patients with locally advanced breast cancer reveals abnormalities beyond the axilla in 37% of patients, including the infraclavicular, internal mammary and supraclavicular regions. Disease in these sites is historically under-appreciated resulting in incorrect staging and possibly in undertreatment with locoregional modalities.

Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 4002.