99mTc-Rituximab sentinel lymph node mapping and biopsy, the effective technique avoids axillary dissection and predicts prognosis in 533 cutaneous melanoma.

OBJECTIVE

To evaluate the efficiency of a novel lymph node radiotracer 99mTc-rituximab in sentinel lymph node (SLN) lymphoscintigraphy and SLN biopsy (SLNB), and the influence of SLNB results on the prognosis of cutaneous malignant melanoma (CMM) patients.

METHODS

A retrospective study was performed on 533 patients with CMM who underwent lymphoscintigraphy and SLNB. All patients received a preoperative peritumoral injection of 11.1-18.5 MBq of 99mTc-rituximab 0.5 to 1 h before lymphoscintigraphy and SLNB.

RESULTS

The detection rate of lymphoscintigraphy and SLNB was both 99.81% (532/533), and the average number of detected SLNs was 2.1 (range 1 to 8) and 2.7 (range 1 to 11) per patient, respectively. 12.1% SLNs and 22.2% patients were found metastatic, with an average of 1.5 (range 1 to 5) metastatic SLNs per patient. The SLN metastatic rates were different in patients with different Breslow thickness, Clark levels, ulceration, mitotic counts, and HMB45 expression (p < 0.05). Ninety patients were proceeded with the regional lymph node dissection (RLND) after SLNB, and the sensitivity, specificity and accuracy of SLNB in metastatic diagnosis is 97.4, 100 and 96.7%, respectively. And SLNs with metastases was an independent prognostic factor for OS and PFS by multivariate prognostic analyses (HR was 5.9 and 4.3, p < 0.001). For patients with metastatic SLNs, the non-SLNs with metastasis and non-SLNs without metastasis in RLND, and observation groups showed different mean PFS as 14.9, 24.8 and 25.5 months (p = 0.018), but no statistically significant difference existed in the OS.

CONCLUSION

The novel radiotracer 99mTc-rituximab could identify SLNs specifically in SLN lymphoscintigraphy and SLNB in CMM patients, and the pathology obtained from SLNB rather than from RLND better indicated the staging and long-term prognosis.