| Objective:Currently,filtered 99mTc-sulfur colloid(99mTc-SC)is widely used for sentinel lymph node biopsy?SLNB?in breast cancer.But 99mTc-SC is a non-specific agent,which disadvantages is detecting more secondary echelon nodes,existing more residue and scattering at the injection site,resulting in excessive dissection and impeding SLN detection.99mTc-rituximab is a specific binding radiopharmaceutical that targets CD20,which is highly expressed on the surface of B lymphocytes.The principle is the antigenic antibody-specific response.If the sentinel lymph nodes are not saturated,the secondary lymph nodes won't accumulate,and suitable molecular weight means less residue at the injection site,meeting the requirements of the ideal agent.These characteristics have been verified in animal experiments,but there have been no reports of clinical trials.We conducted a clinical study in which 99mTc-Rituximab was compared with 99mTc-SC for sentinel node detection in patients with breast cancer.Methods:1.25 patients in the self-control trial were randomly divided into A and B groups.Patients in Group A received 99mTc-Rituximab at first and 99mTc-SC 2 days later.Patients in Group B first received 99mTc-SC and 99mTc-Rituximab at 2 days later.The agents were administered(1mCi/1ml99mTc-Rituximab;1.5m Ci/1.5ml 99mTc-SC)at the 6-and12-o'clock positions by using an subareolar technique,2 hours later,were performed SLN planar and fusion imaging.2.91 patients were enrolled in randomized controlled trial,and two agents were randomly injected with the same injection method,2 hours later,were performed SLN planar and fusion imaging.SLNB was performed in combination with methylene blue during the operation.3.Serial dynamic images were acquired for 2h in 31 patients.9 patients were injected with 99mTc-SC,18 patients were injected with 99mTc-Rituximab,their dynamic images of the injection site were acquired immediately after the injection and at30-minute intervals for 2 hour.The standard source was placed on the level of the contralateral clavicle in the opposite side of the breast lesions.The injection site clearance rate constant?Kc?and half-life?Tc?were calculated by using decaycorrected counts obtained from the nuclear images of the injection site.Results:1.In self controlled trials,both of them achieved higher identification rate,were96%.Both of the two tracers was failed to detect SLNs in one patients,who performed sentinel lymph node biopsy after neoadjuvant chemotherapy.All patients 99mTc-rituximab identified fewer or the same number of SLNs.While SLN is located by fault fusion imaging,all SLN identified by 99mTc-Rituximab were detected in 99mTc-SC.The total number of SLNs identified by 99mTc-rituximab and 99mTc-SC were respectively 68 vs82,?mean 2.72 vs 3.28?,the difference had statistical significance?paired sample t test,P=0.013<0.05?.The total number of SLN located in axillary was 58 vs 61,and there was no significant difference.And for internal milk and lock area was 8 vs 12,2 vs9,respectively,and the difference was statistically significant.2.In randomized controlled trials,the identification rate of SLNs imaging and SLNB was 100%for both groups.The total number of SLNs imaging and SLNB for99mTc-rituximab and 99mTc-SC were 2.61 vs 2.92,2.95vs3.14,respectively,the metastatic rate was 17.07%vs20%,and no significant difference existed.99mTc-Rituximab had lower identification rate and fewer numbers for clavicular lymph nodes than 99mTc-SC,and statistical difference exists.3.99mTc-Rituximab exhibited a significantly faster injection site clearance,compared with 99mTc-SC,0.193±0.057/hour vs 0.021±0.007/hour.Conclusion:The results of this study showed that both 99mTc-rituximab and 99mTc-SC has similar SLN identification rate.Furthermore,compared to 99mTc-SC,99mTc-rituximab detected fewer distal lymph nodes,exhibited faster injection site clearance and short half-life,which would lead to a promising application prospect. |
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