Melanoma and nuclear medicine

A SPECT/NIR Fluorescence Dual-Modality Imaging Agent Composed of Drugs and Hospital Available Isotope for Preoperative Sentinel Lymph Node Mapping and Intraoperative Biopsy

Background

Sentinel lymph node (SLN) mapping-guided biopsy is crucial for cancer staging and treatment. Optical/nuclide dual-modality imaging agents for mapping SLN are ideal for preoperative planning and intraoperative biopsy, which are enabled by penetration-depth unlimited nuclide imaging and dynamic real-time optical imaging, respectively. However, commonly reported dual-modality imaging agents are composed of novel but safety-unproven materials, making their quick clinical translation challenging. Herein, we report a novel nanoparticle composed of facile hospital-available drugs and isotope for single-photon emission computed tomography (SPECT)/near-infrared (NIR) fluorescence imaging to detect SLNs.

Methods

Indocyanine green-human serum albumin (ICG-HSA) nanoparticles (NPs) were synthesized by ICG-induced HSA self-assembly and further 99mTc-labeling via a one-step, facile hospital-available method. After injecting 99mTc-ICG-HSA into the rats' forepaw pads, the rats' draining axillary lymph nodes were visualized by preoperative mapping with SPECT/CT and intraoperative biopsy with NIR fluorescence. The axillary lymph nodes of rats were identified by pathology and fluorescent staining after execution. Additionally, its toxicity testing and comparison with 99mTc-sulfur colloid imaging were also explored.

Results

The study reported a self-assembled 99mTc-ICG-HSA with a high radiochemical yield (85.6 ± 3.8%). Compared with conventional 99mTc-sulfur colloid, 99mTc-ICG-HSA NPs showed faster SLN identification, higher renal clearance, and lower hepatic retention. Furthermore, NIRF imaging allowed for the accurate visualization of the SLN and guided SLN biopsy intraoperatively. Notably, the 99mTc-ICG-HSA NPs were composed of hospital-available drugs and isotope, which are safe for acute toxicity evaluation by a certified institute.

Conclusion

The proposed 99mTc-ICG-HSA NPs are safe and capable of noninvasive SLN identification and biopsy guidance with multi-modal imaging strategies and could be a promising tool for clinically assisted SLN biopsy.

Antibody-Based Targeted Interventions for the Diagnosis and Treatment of Skin Cancers

BACKGROUND

Cutaneous malignancies most commonly arise from skin epidermal cells. These cancers may rapidly progress from benign to a metastatic phase. Surgical resection represents the gold standard therapeutic treatment of non-metastatic skin cancer while chemo- and/or radiotherapy are often used against metastatic tumors. However, these therapeutic treatments are limited by the development of resistance and toxic side effects, resulting from the passive accumulation of cytotoxic drugs within healthy cells.

OBJECTIVE

This review aims to elucidate how the use of monoclonal Antibodies (mAbs) targeting specific Tumor Associated Antigens (TAAs) is paving the way to improved treatment. These mAbs are used as therapeutic or diagnostic carriers that can specifically deliver cytotoxic molecules, fluorophores or radiolabels to cancer cells that overexpress specific target antigens.

RESULTS

mAbs raised against TAAs are widely in use for e.g. differential diagnosis, prognosis and therapy of skin cancers. Antibody-Drug Conjugates (ADCs) particularly show remarkable potential. The safest ADCs reported to date use non-toxic photo-activatable Photosensitizers (PSs), allowing targeted Photodynamic Therapy (PDT) resulting in targeted delivery of PS into cancer cells and selective killing after light activation without harming the normal cell population. The use of near-infrared-emitting PSs enables both diagnostic and therapeutic applications upon light activation at the specific wavelengths.

CONCLUSION

Antibody-based approaches are presenting an array of opportunities to complement and improve current methods employed for skin cancer diagnosis and treatment.

Contemporary update of SPECT tracers and novelties in radioguided surgery: a perspective based on urology

Recent technical advances and implementation of novel radiotracers have further increased the potential of radioguided surgery for a broad variety of malignancies. Indeed, the possibilities for future applications of novel radiotracers in diverse oncological strategies has become more promising than ever. This literature review aims to provide a contemporary update on a selected group of radiotracers and evaluates the usability of radioguided surgery and sentinel node procedures, focusing on most promising advances. For example, the impact of targeted radiotracers on prostate specific membrane antigen (PSMA), CD206 receptor-targeted agents (^99mTc-tilmanocept), and hybrid tracers adding fluorescence to radioguidance (ICG-^99mTc-nanocolloid) as well as targeting hypoxia-induced carbonic anhydrase IX (CAIX) will be covered. Furthermore, future outlooks on the implementation of gold nanoparticles (AuNP's), but also technical advances in improved radiotracer detection by hybrid gamma devices will be discussed.

Sentinel Node Biopsy for Head and Neck Cutaneous Melanoma

Sentinel lymph node biopsy is the most precise and accurate staging technique for malignant melanoma. This resulted from international collaborations and technical innovations across subspecialties and systematic and methodical study of real-time clinical problems. This article describes sentinel node biopsy from conception to current techniques. Indications for the procedure and evidence of its prognostic value are discussed. Controversies surrounding results of Multicenter Selective Lymphadenectomy Trial I and II and German Dermatologic Cooperative Oncology Group Selective Lymphadenectomy trial are reviewed. Head and neck melanoma is presented as a unique subsite for performing sentinel node biopsy and when considering completion cervical lymphadenectomy.

[Case study of vulvar malignant melanoma conducted at the Cinquantenaire General Hospital in Lubumbashi]

Le mélanome malin primitif de l'appareil génital féminin est une tumeur extrêmement rare. Il est néanmoins plus observé à la vulve qu’au col utérin et au vagin. La localisation vulvaire représente environ 1% (toutes localisations confondues) des mélanomes, puis par ordre de fréquence la localisation vaginale, utérine puis ovarienne; et moins de 200 cas de cancers de la vulve ont été décrits à travers le monde. Nous présentons ici un cas clinique de mélanome malin vulvaire chez une femme ménopausée de 72 ans. Une hemivulvectomie partielle et une lymphadénomectomie superficielle inguinale bilatérale ont été réalisées. Les suites postopératoires étaient globalement favorables et la patiente a quitté le service au 15^e jour post opératoire.

Practice Patterns and Prognostic Value of Sentinel Lymph Node Biopsy for Thick Melanoma: A National Cancer Database Study

BACKGROUND

Sentinel lymph node biopsy (SLNB) has been somewhat controversial for patients with a diagnosis of thick (> 4 mm) melanoma. This study aimed to characterize the national practice pattern in performing SLNB for this patient population and to determine the predictors and prognostic value of nodal positivity using population-level data.

METHODS

Patients with a diagnosis of clinically node-negative, thick melanoma (2010-2015) were identified using the National Cancer Database. Factors associated with performing regional nodal evaluation were characterized. Predictors of nodal positivity were determined using multivariable logistic regression. Overall survival (OS) was estimated using standard statistical methods.

RESULTS

Of 9847 study patients, 7513 (76.3%) underwent SLNB. The patients who underwent nodal evaluation were younger (median age, 66 vs 81 years; P < 0.001), less likely to have comorbid conditions (19.6% vs 26.0%; P < 0.001), more often privately insured (40.4% vs 16.4%; P < 0.001), and more frequently treated at an academic center (49.5% vs 43.9%; P < 0.001). Among those who underwent nodal evaluation, 25.5% had metastatic nodes. Multivariable regression identified age, Charlson-Deyo score, primary location, ulceration, mitoses, vertical growth phase, and lymphovascular invasion as independent predictors of nodal positivity, but with only moderate predictive accuracy (optimism-adjusted area under the curve, 0.684). Furthermore, compared with node negativity, node positivity was significantly associated with decreased OS (hazard ratio, 2.05; P < 0.001).

CONCLUSION

Although nodal status provides important prognostic information, at a national level, nearly one fourth of patients with clinically node-negative, thick melanoma do not undergo SLNB. Appropriate pathologic staging would allow these high-risk patients to be candidates for effective adjuvant therapy.

Melanoma & nuclear medicine: new insights & advances

The contribution of nuclear medicine to management of melanoma patients is increasing. In intermediate-thickness N0 melanomas, lymphoscintigraphy provides a roadmap for sentinel node biopsy. With the introduction of single-photon emission computed tomography images with integrated computed tomography (SPECT/CT), 3D anatomic environments for accurate surgical planning are now possible. Sentinel node identification in intricate anatomical areas (pelvic cavity, head/neck) has been improved using hybrid radioactive/fluorescent tracers, preoperative lymphoscintigraphy and SPECT/CT together with modern intraoperative portable imaging technologies for surgical navigation (free-hand SPECT, portable gamma cameras). Furthermore, PET/CT today provides 3D roadmaps to resect 18F-fluorodeoxyglucose-avid melanoma lesions. Simultaneously, in advanced-stage melanoma and recurrences, 18F-fluorodeoxyglucose-PET/CT is useful in clinical staging and treatment decision as well as in the evaluation of therapy response. In this article, we review new insights and recent nuclear medicine advances in the management of melanoma patients.