Correlation of lymphoscintigraphy with the number of sentinel lymph nodes identified intraoperatively in patients with breast cancer

Background Numerous studies have evaluated the benefit of performing lymphoscintigraphy for the sentinel lymph node procedure in breast cancer patients. The purpose of this study is to determine if lymphoscintigraphy accurately predicts the number of radioactive sentinel lymph nodes (SLNs) identified during surgery for breast cancer patients. Methods From October 2001 to June 2004, SLN biopsy was attempted in 112 patients with breast cancer using a combination of blue dye and radioisotope. Lymphoscintigraphy was performed in 98 of the patients. A lymph node was considered an SLN when it was stained with blue dye, had a blue lymphatic afferent, had increased radioactivity, or was abnormal by palpation. Results Lymphoscintigraphy accurately predicted the number of radioactive SLN identified intraoperatively in 47 patients. In 44 of the patients who did not have concordance, there were more SLN identified intraoperatively than were seen on lymphoscintigraphy. In the other 8 patients, there were fewer SLN identified intraoperatively than seen on lymphoscintigraphy. Conclusions Lymphoscintigraphy accurately predicted the number of SLN identified intraoperatively in only 47% of the patients in this study. In a majority of the patients in whom the lymphoscintigraphy was not concordant, the number of SLN identified intraoperatively was underestimated. Thus, although lymphoscintigraphy is beneficial in showing that at least 1 radioactive SLN will be identified intraoperatively, it does not accurately predict the number.