A novel sentinel lymph node (SLN) radiotracer demonstrated nearly 100% detection/success rate in SLN and metastasis in breast cancer, a significant prognostic marker, a study published in The Journal of Nuclear Medicine has shown.1
Identifying the sentinel lymph node in patients with breast cancer, a key factor in determining prognosis and treatment, can be a challenge. SLNs retain the dyes used for identification for less than 5 minutes, and allergic reaction to the dyes is a concern. Therefore, researchers at Peking University Cancer Hospital & Institute, Beijing, China, sought to determine the safety and efficacy of 99mTc-rituximab, a new SLN radiotracer, in identifying sentinel lymph nodes.
For this study, lymphoscintigraphy was used with 99mTc-rituximab as a radiotracer in the preoperative and intraoperative setting for 2317 patients with primary breast cancer. All patients underwent both lymphoscintigraphy and SLN biopsy, 100 of whom were randomly selected for the initial study (median age 46 years; range, 27 to 73 years).
In the initial study, SLN detection via injected 99mTC-rituximab with SLN lymphoscintigraphy was 100%. SLN harvest was guided by a hand-held gamma detecting probe; biopsy of the harvested nodes was also 100% percent.
Lymphoscintigraphy and SLN biopsy detection/success rates in the remaining 2217 patients were 98.8% and 99.9%, respectively.
Although the combination of blue dye and a radiotracer has been shown effective in detecting SLNs in patients with breast cancer (89% to 97%), this study shows that the radiotracer 99mTc-rituximab alone with imaging is even more effective and avoids the potential side effects of using the blue dye, the authors commented.
Furthermore, the radiotracer may have broader applications. The researchers found 99mTC-rituximab also shows promise in lymphoscintigraphy of melanoma.
1. Li N, Wang X, Lin B, et al. Clinical evaluation of 99mTc-rituximab for sentinel lymph node mapping in breast cancer patients. J Nucl Med. 2016;57(8):1214-1220.