Clinical Evaluation of ^99mTc-Rituximab for Sentinel Lymph Node Mapping in Breast Cancer Patients

Abstract

The metastatic status of sentinel lymph nodes (SLNs) might be the most important prognostic factor in breast cancer. In this paper, we report to our knowledge the first study of 99m Tc-rituximab as a radiotracer for imaging of SLNs using lymphoscintigraphy in both preoperative and intraoperative breast cancer patients. Methods: 99m Tcrituximab was designed as an SLN tracer targeting the CD20 antigen, which expresses extensively in LNs. A retrospective study was performed on 2,317 patients with primary breast cancer who underwent lymphoscintigraphy and sentinel lymph node biopsy (SLNB). Before imaging, all patients were administered a preoperative peritumoral injection of 37 MBq of 99m Tc-rituximab. Results: 99m Tc-rituximab was synthesized in both high radiolabeling yield and high radiochemical purity (.95%), with molecular integrity and immune activity well maintained. The initial study of 100 breast cancer patients showed that the success rate of SLN lymphoscintigraphy by injection of 99m Tc-rituximab, as compared with SLNB, was 100%, and the sensitivity, specificity, accuracy, and false negative rate were 97.4%, 100%, 98.0%, and 2.60%, respectively. Of the following 2,217 patients studied, the success rate of lymphoscintigraphy and SLNB was 98.8% and 99.9%, and the average number of SLN was 1.78 (range, 1-10) and 2.85 (range, 1-15). Age was an independent predictor of the number of SLNs identified by lymphoscintigraphy and intraoperative handheld γ-probe (P , 0.05), and other factors-such as sex, imaging time, primary tumor site, histopathologic subtype, clinical T stage, and immunochemistry-were not (P . 0.05). However, the SLN metastatic rates were different in patients with different histopathologic subtype, clinical T stage, and immunochemistry (P , 0.05). Conclusion: Here we report the first study of the new radiotracer 99m Tc-rituximab for breast cancer lymphoscintigraphy. This tracer showed great feasibility, safety, and effectiveness for SLN mapping in breast cancer patients.

New techniques for sentinel node biopsy in breast cancer

“…The advantage is its uniform molecular weight and molecular size so it will not escape easily from SLNs to the second-echelon LNs achieving a clear SLN imaging in patients and high success rate of lymphoscintigraphy. The sensitivity, specificity, and accuracy of SLNB was 97.40%, 100% and 98%, respectively; the FN rate was 2.60%, which is better than that of other studies (FN rate ranging from 6% to 10%); moreover, its feasibility, safety, and effectiveness have been confirmed by clinical SLNB application with large samples (34). Recently İlem-Özdemir et al prepared a new RI for SLN mapping which chemically combined a RI and a BD, the 99m Tc-isosulfan blue, to be injected as a single dose.…”

^99mTc-labeled sodium phytate and stannous chloride injection accurately detects sentinel lymph node in axillary of early stage breast cancer: a randomized, controlled study

“… 12 , 13 Location of SLN is normally assessed by injecting blue dye or radioisotope technetium-labeled nano colloid, which could also be other isotopic carriers such as rituximab and dextran. 14 – 16 Despite that sulfur colloid (SC) or albumin colloid is the most common radiotracer, the detection rate, true-positive rate, and false-negative rate varied among studies and were not satisfactory, thus, no standard or optimal carriers were identified in SLN location. 17 , 18 Sodium phytate and stannous chloride (PHY) has been used in lymphoscintigraphies for liver, spleen, and bone marrow, and it has been reported that PHY could be used as radiotracer in SLNB for patients with papillary thyroid carcinoma.…”

Comparative research on 99mTc-Rituximab and 99mTc-sulfur colloid in sentinel lymph node imaging of breast cancer

“…99m Tc-Rituximab was synthesized and radiolabeled according to the 2-mercaptoethanol (2-ME) method, described by Li Nan [9], at the Peking University Cancer Hospital. Radiochemical purity was > 92%.…”