The Role of Lymphoscintigraphy in the Detection of Lymph Node Drainage in Melanoma

Subcostal lymph nodes: An unusual sentinel lymph node basin in cutaneous melanoma

BACKGROUND AND OBJECTIVES

Lymphatic drainage from subcostal nodes, along the costal groove, have not previously been characterized as sites for melanoma drainage and metastasis. This study reports a series of patients with subcostal nodes draining primary melanomas, with characterization of the sites of primary melanomas that drain to these nodes.

METHODS

Patients who presented to our institution between 2005 and 2020 with documented cutaneous melanoma and sentinel lymph node biopsy of a subcostal node (sentinel = S), or metastases to subcostal nodes later in clinical management (recurrent = R) were included. Patient demographics, melanoma pathology, nodal features, imaging information, surgical approaches, and outcomes data were collected.

RESULTS

Six patients had subcostal sentinel nodes (SNs). Primary sites included the posterior trunk and lateral chest wall. Subcostal nodes were found under ribs 10-12. Subcostal SNs had at least one dimension measuring 3 mm or less. There were no surgical complications related to removing the subcostal SN.

CONCLUSIONS

Melanoma can metastasize to subcostal lymph nodes and be found at the time of SN biopsy or identified at recurrence. These small nodes are fed by lymphatic channels that run in the neurovascular bundle under the ribs. When lymphatic mapping identifies a subcostal SN, it should be excised.

The lymphatic system and sentinel lymph nodes: conduit for cancer metastasis

The lymphatic system is a complicated system consisting of the lymphatic vessels and lymph nodes draining the extracellular fluid containing cellular debris, excess water and toxins to the circulatory system. The lymph nodes serve as a filter, thus, when the lymph fluid returns to the heart, it is completely sterile. In addition, the lymphatic system includes the mucosa-associated lymphoid tissue, such as tonsils, adenoids, Peyers patches in the small bowel and even the appendix. Taking advantage of the drainage system of the lymphatics, cancer cells enter the lymphatic vessels and then the lymph nodes. In general, the lymph nodes may serve as a gateway in the majority of cases in early cancer. Occasionally, the cancer cells may enter the blood vessels. This review article emphasizes the structural integrity of the lymphatic system through which cancer cells may spread. Using melanoma and breast cancer sentinel lymph node model systems, the spread of early cancer through the lymphatic system is progressive in a majority of cases. The lymphatic systems of the internal organs are much more complicated and difficult to study. Knowledge from melanoma and breast cancer spread to the sentinel lymph node may establish the basic principles of cancer metastasis. The goal of this review article is to emphasize the complexity of the lymphatic system. To date, the molecular mechanisms of cancer spread from the cancer microenvironment to the sentinel lymph node and distant sites are still poorly understood and their elucidation should take major priority in cancer metastasis research.

Sentinel Lymph Node Biopsy: Indications and Technique

Sentinel lymph node biopsy is a key tool in the care of many patients with melanoma. The indications for the procedure have gradually become clearer over the 3 decades since the technique was developed. For appropriately selected patients, it carries enormous significance. Although it is a minimally invasive procedure, it does carry some risk. It is also a multidisciplinary procedure, requiring knowledge and experience from several specialties including nuclear medicine, surgery, and pathology.

Papillary thyroid carcinoma with bilateral axillary lymph node involvement: a case report outlining hypothesis for locoregional spread and therapeutic implications

Axillary lymph node involvement (ALNI) in well differentiated papillary thyroid carcinoma (WDPTC) is a rare sequela of disease presentation. We report a case of PTC with extensive cervical lymph node involvement, local extension to the skin of the neck and bilateral ALNI without evidence of distant disease. We posit that ALNI represents local extension of disease rather than distant metastasis. Therefore, in the absence of distant spread, ALNI should result in surgical intervention. This optimizes removal of all bulky disease and increases effectiveness of radioactive iodine (RAI) therapy. Future research centered on genomics should focus on ascertaining the behavior and prognosis of such cases, especially when anatomic spread is discordant with biologic behavior.

Patterns of node mapping differ for axial and extremity primary cutaneous melanoma: A case for a more selective use of pre-operative imaging

PURPOSE

Preoperative lymphoscintigraphy for sentinel lymph node mapping in melanoma improves the ability to locate nodes. However, it still remains unclear whether this step is required for all patients.

METHODS

Patients diagnosed with cutaneous melanoma from 1996 to 2012 were identified. Exclusion criteria were in situ disease, metastatic disease, or no SLN biopsy.

RESULTS

214 patients were evaluated. Median age was 57 years, the majority were male (59.8%), white (97.2%), and stage I (60.7%). SLN revealed metastatic disease in 14.5% of patients. The most common primary site was the trunk (43.4%) followed by head and neck (21%), upper extremity (19.2%), and lower extremity (16.4%). Multiple lymphatic basins were most common for head and neck lesions (66.7%) followed by those on the trunk (28.8%), with fewer identified when lower (11.4%), and upper extremities were involved (4.2%). When comparison was restricted to extremity vs. axial, a single basin was noted in 94.5% vs. 59.9% of patients, p < 0.0001. For all extremity lesions the SLN was located in the primary basin. Additional sites included in-transit (popliteal) and second tier basins. The only melanomas with bilateral or contralateral SLN were axial melanomas.

CONCLUSIONS

Patients with axial melanomas benefit most from lymphoscintigraphy. This step may not be required for extremity melanoma.

The clinical use of PET/CT in the evaluation of melanoma

Positron emission tomography combined with computed tomography (PET/CT) has emerged in the last decade as a dominant imaging modality used for staging, monitoring response and surveillance of various cancers, including melanoma. Using 2-deoxy-2-((18)F)fluoro-D-glucose ((18)F-FDG) as the radiopharmaceutical, PET/CT has demonstrated its efficacy and its utility in the management of patients with advanced melanoma. Nonetheless, challenges remain in the early stage evaluation of melanoma and in the development of novel radiotracers to better characterize lesions found on PET/CT. This chapter focuses on the advantages and limitations of this imaging modality in melanoma. We also detail and describe the approach to perform (18)F-FDG PET/CT, the methods to accurately quantify lesions, as well as the pearls/pitfalls of image interpretation. Finally, an overview of preclinical and investigational clinical radiopharmaceuticals is presented.

Facelift and patterns of lymphatic drainage

BACKGROUND

It has commonly been assumed that deeper facelift dissection causes greater and more prolonged swelling.

OBJECTIVES

In this preliminary report, the authors compare the lymphatic reconstitution after multiple techniques of rhytidectomy by means of dynamic lymphoscintigraphy.

METHODS

Three patients were enrolled in this study. All three were female, were similar in age, and exhibited similar signs and degrees of facial aging. Each woman underwent a facelift with a different technique: (1) subcutaneous dissection with superficial musculoaponeurotic system (SMAS) plication, (2) subcutaneous dissection with SMASectomy, and (3) a "high SMAS" composite facelift. Postoperatively, (99m)Tc-sulfur colloid was injected into a standardized infraorbital location in each patient to compare patterns of lymphatic drainage using lymphoscintigraphy. Postoperative scans at two weeks, six weeks, three months, six months, and one year were compared to the preoperative scans taken seven days prior to surgery.

RESULTS

All rhytidectomy techniques appeared to temporarily create a significant and similar degree of interruption in lymphatic drainage. There was a subtotal recovery of lymphatic pathways within three months and complete return to baseline drainage pattern after six months, regardless of surgical technique.

CONCLUSIONS

Based on the results of this study, it appears that the extent of facial dissection, rather than the depth, is the most significant factor in postoperative edema.

Sentinel node biopsy in melanoma: technical considerations of the procedure as performed at the John Wayne Cancer Institute

Since its first description in 1990, sentinel node (SN) biopsy has become the standard for accurate staging of a melanoma-draining regional lymphatic basin. This minimally invasive, multidisciplinary technique can detect occult metastases by selective sampling and focused pathologic analysis of the first nodes on the afferent lymphatic pathway from a primary cutaneous melanoma. An understanding of preoperative lymphoscintigraphy, intraoperative lymphatic mapping, and the definition of SN are critical for surgical expertise with SN biopsy.

Sentinel lymph node biopsy in melanoma patients

Appropriate surgical management of regional lymph nodes is critical in patients with cutaneous melanoma. The use of intraoperative lymphatic mapping and sentinel lymph node biopsy (SLNB) has increased significantly in the past decade. SLNB is performed as minimally invasive procedure that provides accurate staging of melanoma patients with no clinically detectable nodal disease. In many melanoma units across the world, it became the standard for detection of occult regional node metastasis in patients with intermediate-thickness primary melanoma. Use of SLNB in patients with thin melanomas is still under evaluation. Although SLNB has been established as staging procedure in melanoma patients, its therapeutic role is still not clear. Large-scale ongoing randomized trials should elucidate whether SLNB with complete lymphadenectomy has a survival benefit in melanoma patients with early lymph node metastases compared to 'watch-and-wait' policy (observation).

EANM-EORTC general recommendations for sentinel node diagnostics in melanoma

The accurate diagnosis of a sentinel node in melanoma includes a sequence of procedures from different medical specialities (nuclear medicine, surgery, oncology, and pathology). The items covered are presented in 11 sections and a reference list: (1) definition of a sentinel node, (2) clinical indications, (3) radiopharmaceuticals and activity injected, (4) dosimetry, (5) injection technique, (6) image acquisition and interpretation, (7) report and display, (8) use of dye, (9) gamma probe detection, (10) surgical techniques in sentinel node biopsy, and (11) pathological evaluation of melanoma-draining sentinel lymph nodes. If specific recommendations given cannot be based on evidence from original, scientific studies, referral is given to "general consensus" and similar expressions. The recommendations are designed to assist in the practice of referral to, performance, interpretation and reporting of all steps of the sentinel node procedure in the hope of setting state-of-the-art standards for good-quality evaluation of possible spread to the lymphatic system in intermediate-to-high risk melanoma without clinical signs of dissemination.

Surgery and sentinel lymph node biopsy

In patients with melanoma, surgery is pivotal not only for the primary tumor but also for regional and often distant metastases. The minimally invasive technique of sentinel node (SN) biopsy has become standard for detection of occult regional node metastasis in patients with intermediate-thickness primary melanoma; in these patients it has a central role in determining prognosis and a significant impact on survival when biopsy results are positive. Its role in thin melanoma remains under evaluation. The regional tumor-draining SN also is a useful model for studies of melanoma-induced immunosuppression. Although completion lymphadenectomy remains the standard of care for patients with SN metastasis, results of ongoing phase III trials will indicate whether SN biopsy without further lymph node surgery is adequate therapy for certain patients with minimal regional node disease.

Confirmation of sentinel lymph node identity by analysis of fine-needle biopsy samples using inductively coupled plasma-mass spectrometry

Background

The sentinel lymph node (SLN) biopsy technique is a reliable means of determining the tumor-harboring status of regional lymph nodes in melanoma patients. When technetium 99 m-labeled antimony trisulfide colloid (^99 mTc-Sb₂S₃) particles are used to perform preoperative lymphoscintigraphy for SLN identification, they are retained in the SLN but are absent or present in only tiny amounts in non-SLNs. The present study investigated the potential for a novel means of assessing the accuracy of surgical identification of SLNs. This involved the use of inductively coupled plasma–mass spectrometry (ICP-MS) to analyze antimony concentrations in fine-needle biopsy (FNB) samples from surgically procured lymph nodes.

Methods

A total of 47 FNB samples from surgically excised lymph nodes (32 SLNs and 15 non-SLNs) were collected. The SLNs were localized by preoperative lymphoscintigraphy that used ^99 mTc-Sb₂S_3, blue dye, and gamma probe techniques. The concentrations of antimony were measured in the FNB samples by ICP-MS.

Results

The mean and median antimony concentrations (in parts per billion) were .898 and .451 in the SLNs, and .015 and .068 in the non-SLNs, the differences being highly statistically significant (P < .00005).

Conclusions

Our results show that ICP-MS analysis of antimony concentrations in FNB specimens from lymph nodes can accurately confirm the identity of SLNs. Used in conjunction with techniques such as proton magnetic resonance spectroscopy for the nonsurgical evaluation of SLNs, ICP-MS analysis of antimony concentrations in FNB samples could potentially serve as a minimally invasive alternative to surgery and histopathologic evaluation to objectively classify a given node as sentinel or nonsentinel and determine its tumor-harboring status.

Magnetic lymphatic targeting drug delivery system using carbon nanotubes

By controlling size, nanoparticles can be effectively taken up into lymphatics. On this basis, various nanoparticles have been investigated for transporters of chemotherapeutic pharmaceuticals, but only a few were retained in the draining lymph node. Here, we present a technology using a magnetic carbon nanotubes (MNTs) delivery system, and it may be possible to facilitate the targeted delivery of drugs in the lymphatic tissue more effectively. Chemotherapeutic agents were incorporated into the pores of functionalized MNTs synthesized with a layer of magnetite nanoparticles on the inner surface of the nanotubes. To improve drug delivery to cancer cells in the lymph nodes, individualized MNTs were noncovalently functionalized by folic acid (FA). By using an externally placed magnet to guide the drug matrix to the regional targeted lymph nodes, the MNTs can be retained in the draining targeted lymph nodes for several days and continuously release chemotherapeutic drugs. Selective killing of tumor cells overexpressing the folate receptors (FRs) in the lymph nodes can be achieved, as FR is overexpressed across a broad spectrum of human tumors.

The evolution of the management of regional lymph nodes in melanoma

The last two decades have seen sweeping changes in the surgical approach to melanoma. Traditionally, patients without evidence of nodal metastases were considered for elective lymph node dissection. This approach placed many patients at risk of morbidity while many derived no benefit. As investigators gained a deeper understanding of melanoma and lymphatic biology, newer methods of managing regional lymph nodes were sought. The advent of sentinel node biopsy has radically changed the approach to melanoma.

Using GIS for spatial analysis of rectal lesions in the human body

BACKGROUND

Geographic Information Systems (GIS) have been used in a wide variety of applications to integrate data and explore the spatial relationship of geographic features. Traditionally this has referred to features on the surface of the earth. However, it is possible to apply GIS in medicine, at the scale of the human body, to visualize and analyze anatomic and clinical features. In the present study we used GIS to examine the findings of transanal endoscopic microsurgery (TEM), a minimally-invasive procedure to locate and remove both benign and cancerous lesions of the rectum. Our purpose was to determine whether anatomic features of the human rectum and clinical findings at the time of surgery could be rendered in a GIS and spatially analyzed for their relationship to clinical outcomes.

RESULTS

Maps of rectal topology were developed in two and three dimensions. These maps highlight anatomic features of the rectum and the location of lesions found on TEM. Spatial analysis demonstrated a significant relationship between anatomic location of the lesion and procedural failure.

CONCLUSION

This study demonstrates the feasibility of rendering anatomical locations and clinical events in a GIS and its value in clinical research. This allows the visualization and spatial analysis of clinical and pathologic features, increasing our awareness of the relationship between anatomic features and clinical outcomes as well as enhancing our understanding and management of this disease process.