Adverse prognostic significance of infraclavicular lymph nodes detected by ultrasonography in patients with locally advanced breast cancer

Background: Ultrasonography is increasingly used to evaluate the nodal status of breast cancer patients and specialized positioning permits assessment of the infraclavicular fossa. However, the incidence and significance of infraclavicular (level III) adenopathy detected sonographically in locally advanced breast cancer (LABC) has not been defined. Methods: The study population consisted of 146 LABC patients registered in a prospective trial of induction chemotherapy between 1991 and 1996. All patients underwent ultrasound imaging before and after chemotherapy. Median follow-up was 32 months. Results: Forty-two of 146 patients (29%) had suspicious infraclavicular adenopathy; all 42 had additional positive axillary lymph nodes by ultrasound. Disease-free and overall survival for the patients with suspicious infraclavicular adenopathy was significantly worse compared with patients without this feature; disease-free survival 50% versus 68% (P = 0.112); overall survival 58% versus 83% (P = 0.026). Conclusions: Nearly one third of LABC patients will have infraclavicular lymph node involvement by ultrasound imaging; this finding is a significant adverse prognostic feature, and we recommend that infraclavicular nodal evaluation become a routine component of the sonographic workup of breast cancer patients, particularly if lower axillary lymph nodes appear involved.