exploring an alternative pre-operative sln mapping method using a magnetic tracer and mri for melanoma patients

Conditions: Melanoma

Summary: sentinel lymph node biopsy (slnb) is crucial in the management of malignant melanoma treatment and is currently performed by pre-operatively inject a colloid nanomaterial labeled with technetium (99mtc) as radioactive tracer. intra-operatively, patent blue (pb) will be injected to improve the visualization of the lymphatic tract. however, current pre-operative sln mapping technique is associated with disadvantages as radiation exposure for both patients and health care staff and logistic challenges, because of time constraints due to short half-live time of 99mtc. superparamagnetic iron oxide (spio) is a non-radioactive technique using a magnetic tracer (magtrace® (endomagnetics ltd.)) to identify slns. several studies showed that spio is non-inferior to dual tracing with 99mtc and pb in breast cancer patients. spio is expected to be non-inferior to dual tracing with 99mtc and pb in melanoma patients. however, further research is needed to demonstrate the use of spio in pre-operative mri scanning. the primary objective of this study is to evaluate the feasibility and diagnostic accuracy of pre-operative mri scanning using spio compared to lymphoscintigraphy (ls) and single-photon emission computed tomography/computed tomography (spect/ct) using 99mtc for identifying sln status in melanoma patients.

rationale: sentinel lymph node biopsy (slnb) is crucial in the management of malignant melanoma treatment and is currently performed by pre-operatively inject a colloid nanomaterial labeled with technetium (99mtc) as radioactive tracer. intra-operatively, patent blue (pb) will be injected to improve the visualization of the lymphatic tract. however, current pre-operative sln mapping technique is associated with disadvantages as radiation exposure for both patients and health care staff and logistic challenges, because of time constraints due to short half-live time of 99mtc. superparamagnetic iron oxide (spio) is a non-radioactive technique using a magnetic tracer (magtrace® (endomagnetics ltd.)) to identify slns. several studies showed that spio is non-inferior to dual tracing with 99mtc and pb in breast cancer patients. spio is expected to be non-inferior to dual tracing with 99mtc and pb in melanoma patients. however, further research is needed to demonstrate the use of spio in pre-operative mri scanning. objective: the primary objective of this study is to evaluate the feasibility and diagnostic accuracy of pre-operative mri scanning using spio compared to lymphoscintigraphy (ls) and single-photon emission computed tomography/computed tomography (spect/ct) using 99mtc for identifying sln status in melanoma patients. a secondary objective is to assess the feasibility and diagnostic accuracy of spio/magnetometer (sentimag®, endomagnetics ltd.) in comparison with dual trace gold standard (99mtc and pb) in sln procedures in melanoma patients. study design: a prospective single-arm feasibility study will be performed at the department of surgical oncology at zuyderland medical center sittard, the netherlands. study population: adult patients (≥18 years) with primary melanoma stage i-ii and an indication for wide local excision (1 cm) and sln procedure will be included in the study. intervention (if applicable): all patients will undergo lymphatic mapping with a spio tracer (magtrace®), 99mtc and pb. main study parameters/endpoints: the concordance in sln detection rate (sensitivity and specificity) of spio/mri and ls and spect/ct using 99mtc. the concordance in sln detection rate (sensitivity and specificity) of spio/magnetometer and the gold standard dual trace technique using 99mtc/gamma probe and pb. additionally, the number of post-injection (skin) reactions, complication and adverse events will be noted.

Eligibility criteria:
inclusion criteria: * patients ≥18 years of age at the time of consent; * histological confirmed melanoma (patient must have primary cutaneous melanoma with breslow thickness ≥ 0.8-2.0mm with or without ulceration or \<0.8mm with ulceration (pt1b - pt2b, ajcc 8th edition)); * indication for wide local excision (margin 1 cm) and sln procedure; * patients should be willing and able to provide informed consent. exclusion criteria: * intolerance/hypersensitivity to 99mtc-nanocolloid, pb, iron or dextran compounds; * iron overload disease; * pregnant or breast-feeding women; * previous surrounded lymph node surgery; * patients with head and neck melanomas; * standard mri exclusion criteria; * implantable (electrical) devices (e.g. pacemaker, cochlear implants, neurostimulator); * any other metal implants; * claustrophobia; * mr-incompatible prosthetic heart valves; * patients who are unable or refuse to provide informed consent.

Keywords: magnetic tracer sentinel lymph node melanoma mri