Comparative research on Tc-Rituximab and Tc-sulfur colloid in sentinel lymph node imaging of breast cancer.

BACKGROUND

Tc-Rituximab is a new specific radiopharmaceutical that binds to the CD20 receptor which is highly expressed on the surface of B cells. We conducted a study in which Tc-Rituximab was compared with filtered Tc-sulfur colloid (fTcSC) for sentinel lymph node (SLN) detection in patients with breast cancer.

METHOD

The study is divided into three parts. 1. Initially, 25 patients were selected for an internal controlled trial to received both Tc-Rituximab and fTcSC, the interval time is separated by ≥2 days. 2. Then, 91 patients were selected for a randomized controlled trial (41 and 50 patients in the Tc-Rituximab and fTcSC groups, respectively). All patients were administered either agent at the 6- and 12-o' clock positions by subareolar injection technique. SLN mapping was then performed 2 h after injection. 3. Serial dynamic images were further acquired for 2 h in 31 patients (22 and 9 patients from Tc-Rituximab and fTcSC cohorts, respectively).

RESULTS

The identification rate of lymphoscintigraphy and SLNB in all and axilla regions for Tc-Rituximab and Tc-SC were 98.5% vs 98.7, 100% vs 98.4%, respectively. The mean number of SLNs identified by Tc-Rituximab and fTcSC was respectively 2.72 and 3.28, with a significant difference of P = 0.013 (paired sample t-test). The difference exists in the internal mammary and clavicular area, not in the axillary. The mean number of axillary sentinel lymph node biopsy (SLNB) for Tc-Rituximab and fTcSC was 2.95 vs 3.14, respectively, and no significant difference existed. Tc-Rituximab also exhibited a significantly faster injection site clearance rate when compared with fTcSC (0.193 ± 0.057 h vs 0.021 ± 0.007 h, respectively).

CONCLUSION

No significant difference was observed in identification rate and number of axillary SLN imaging and SLNB, between the two tracers. Compared to fTcSC, Tc-Rituximab based imaging demonstrated a fewer number of secondary lymph nodes and had faster injection site clearance rate.

TRIAL REGISTRATION

www.chictr.org.cn, ChiCTR1900024990 (retrospectively registered August 6, 2019).