Lymphoscintigraphy in early-stage non-small cell lung cancer with technetium-99m nanocolloids and hybrid SPECT/CT: a pilot project

Feasibility of Non-Invasive Sentinel Lymph Node Identification in Early-Stage NSCLC Through Ultrasound Guided Intra-Tumoral Injection of 99mTc-Nanocolloid and Iodinated Contrast Agent During Navigation Bronchoscopy

Background: As the first sentinel lymph nodes (SLN) in lung cancer are most likely to harbor metastasis, their non-invasive identification could have a significant role in future treatments. We investigated the feasibility of adding an SLN procedure to a diagnostic navigation bronchoscopy. Methods: Thirty-one patients were included for injection of 99mTc-nanocolloid and an iodinated contrast agent intra-/peritumorally and assessment of tracer dissipation via SPECT and CBCT imaging. Injections were performed endobronchially using a multi-modal catheter (Pioneer Plus), combining radial ultrasound and an angulated retractable needle to place injections under fluoroscopy and real-time ultrasound. Results: The injection of an imaging tracer was feasible in all cases using the catheter. Ultrasound visualized 29/30 tumors, and tracer injection was performed in 100% of patients. An SLN was subsequently identified in 10 out of 31 cases (32.3%) via SPECT/CT imaging. Iodinated contrast agent injection under CBCT imaging prior to 99mTc nanocolloid injection visualized dissipation pathways and enabled needle relocation for subsequent 99mTc-nanocolloid injection. Conclusions: Performing imaging tracer injections with a multi-modal catheter provided safe and local depot placement immediately following diagnostic navigation bronchoscopy. SPECT/CT imaging using 99mTc-nanocolloid showed inconsistent results for SLN identification.

Chemical and Physical Characterisation of Human Serum Albumin Nanocolloids: Kinetics, Strength and Specificity of Bonds with 99mTc and 68Ga

Nanoparticles of Human Serum Albumin (NC) labelled with ^99mTc are widely used in Nuclear Medicine and represent the gold-standard for the intraoperative detection of the sentinel lymph node in many kinds of cancer, mainly breast cancer and melanoma. A significant amount of radionuclides can be incorporated into the HSA particle, due to the multiple binding sites, and HSA-based nanocolloid catabolism is a fast and easy process that results in innocuous degradation products. NCs labelled with different isotopes represent an interesting radiopharmaceutical for extending diagnostic accuracy and surgical outcome, but the knowledge of the chemical bond between NCs and isotopes has not been fully elucidated, including information on its strength and specificity. The aim of this study is to investigate and compare the physicochemical characteristics of the bond between NCs and ^99mTc and ⁶⁸Ga isotopes. Commercial kits of HSA-based nanocolloid particles (NanoAlbumon^®) were used. For this purpose, we have primarily studied the kinetic orders of NC radiolabelling. Langmuir isotherms and pH effect on radiolabelling were tested and the stability of the radiometal complex was verified through competition reactions carried out in presence of different ligands. The future goal of our research is the development of inexpensive and instant kits, easily labelled with a wide spectrum of diagnostic and therapeutic isotopes, thus facilitating the availability of versatile and multipurpose radiopharmaceuticals.

Sentinel lymph node biopsy for lung cancer

Sentinel lymph node biopsy is a technique to identify the first lymph node (or nodes) draining a tumor. The underlying principle is that as the first site of cancer spread, evaluation of the sentinel node will be most predictive for wider nodal involvement. The introduction of sentinel node biopsy revolutionized the surgical management of cutaneous melanoma and breast cancer, becoming a key component in the management of such patients. For over 20 years, thoracic surgeons have similarly worked to apply this technique to lung cancer but have thus far not had the same impact on lung surgery. In this review, we will summarize the ongoing discussions on the role of sentinel node biopsy in lung cancer, the methods for identifying the sentinel node, and the techniques for evaluating the sentinel node specimen. We will also highlight some of the pressing questions investigators should consider when designing a trial for sentinel node mapping. This will clarify the current status of sentinel node biopsy in lung cancer and thus highlight important future directions for research.