The prognostic role of the sentinel lymph node in clinically node-negative patients with cutaneous melanoma: experience of the Genoa group

Detection of cancer metastasis: past, present and future

The clinical importance of metastatic spread of cancer has been recognized for centuries, and melanoma has loomed large in historical descriptions of metastases, as well as the numerous mechanistic theories espoused. The "fatal black tumor" described by Hippocrates in 5000 BC that was later termed "melanose" by Rene Laennec in 1804 was recognized to have the propensity to metastasize by William Norris in 1820. And while the prognosis of melanoma was uniformly acknowledged to be dire, Samuel Cooper described surgical removal as having the potential to improve prognosis. Subsequent to this, in 1898 Herbert Snow was the first to recognize the potential clinical benefit of removing clinically normal lymph nodes at the time of initial cancer surgery. In describing "anticipatory gland excision," he noted that "it is essential to remove, whenever possible, those lymph glands which first receive the infective protoplasm, and bar its entrance into the blood, before they have undergone increase in bulk". This revolutionary concept marked the beginning of a debate that rages today: are regional lymph nodes the first stop for metastases ("incubator" hypothesis) or does their involvement serve as an indicator of aggressive disease with inherent metastatic potential ("marker" hypothesis). Is there a better way to improve prediction of disease outcome? This article attempts to address some of the resultant questions that were the subject of the session "Novel Frontiers in the Diagnosis of Cancer" at the 8th International Congress on Cancer Metastases, held in San Francisco, CA in October 2019. Some of these questions addressed include the significance of sentinel node metastasis in melanoma, and the optimal method for their pathologic analysis. The finding of circulating tumor cells in the blood may potentially supplant surgical techniques for detection of metastatic disease, and we are beginning to perfect techniques for their detection, understand how to apply the findings clinically, and develop clinical followup treatment algorithms based on these results. Finally, we will discuss the revolutionary field of machine learning and its applications in cancer diagnosis. Computer-based learning algorithms have the potential to improve efficiency and diagnostic accuracy of pathology, and can be used to develop novel predictors of prognosis, but significant challenges remain. This review will thus encompass latest concepts in the detection of cancer metastasis via the lymphatic system, the circulatory system, and the role of computers in enhancing our knowledge in this field.

Eight Years' Experience of Sentinel Lymph Node Biopsy in Melanoma Using Lymphoscintigraphy and Gamma Probe Detection After Radiocolloid Mapping

BACKGROUND

Isosulfan blue dye peripheral injection is used in preoperative sentinel lymph node (SLN) identification alone or, to increase sensitivity, in conjunction with radiocolloid mapping. However, isosulfan blue dye has certain drawbacks and limitations.

OBJECTIVE

This study assesses the authors' experience of SLN biopsy using only radiocolloid tracer.

MATERIALS AND METHODS

Between 2000 and 2008, 218 patients underwent SLN biopsy with radiocolloid mapping, preoperative localization by lymphoscintigraphy and intraoperative confirmation by gamma probe in primary malignant cutaneous melanoma.

RESULTS

Mean Breslow index was 2.1 mm. The SLN biopsy success rate was above 98% at all sites and 87% in head and neck locations. The 5-year overall survival rate was 90% and that of 5-year disease-free survival was 80%. False-negative rate, with a mean follow-up time of 41 months, was 5.5%.

CONCLUSION

Sentinel lymph node biopsy can be successfully performed in patients with melanoma using only radiocolloid tracer without blue dye staining. In circumstances where blue dye cannot be used such as head and neck tumors, allergic reactions and pregnancy, radiocolloid tracer mapping alone is not a loss of chance for patients with melanoma.

Frozen section analysis of SLNs in trunk and extremity melanoma has a high false negative rate but can spare some patients a second operation

OBJECTIVES

The purpose of this study was to evaluate the accuracy of frozen section (FS) analysis of sentinel lymph nodes (SLN) in melanoma.

METHODS

Five hundred seventy-one patients underwent FS analysis of SLN between 1/2000 and12/2010. Surgical and pathological characteristics, recurrence, and survival were analyzed. Comparisons were made using χ² and Fisher's exact t-test.

RESULTS

One hundred thirty-three (23%) patients were SLN positive of which 63 (47.4%) were identified on FS. 16/70 SLN metastases not identified on FS (23%) were seen only on immunohistochemistry. FS analysis detected 84% of SLN metastasis >2 mm. SLN FS false negative rate was 53%, positive predictive value 100%, negative predictive value 88%, and overall accuracy 89%. Among patients with a FS positive SLN, 17/63 (27%) had additional positive nodes on CLND, versus 1 of 70 (1.4%) with a positive SLN identified only on permanent section pathology (P < 0.0001). The nodal recurrence rate following a negative SLN biopsy was 5%.

CONCLUSIONS

FS analysis for SLNs spared approximately half of patients a second operation. Patients with a positive SLN detected on FS were more likely to have further nodal involvement. In our experience intraoperative pathologic analysis of melanoma SLNs does not impair our ability to detect SLN metastasis or lead to a high rate of false positive results or nodal recurrences. J. Surg. Oncol. 2016;114:879-883. © 2016 2016 Wiley Periodicals, Inc.

Is complete lymph node dissection after a positive sentinel lymph node biopsy for cutaneous melanoma always necessary? A meta-analysis

BACKGROUND

The current recommendation for patients with cutaneous melanoma and a positive sentinel lymph node (SLN) biopsy is a complete lymph node dissection (CLND). However, metastatic melanoma is not present in approximately 80% of CLND specimens. A meta-analysis was performed to identify the clinicopathological variables most predictive of non-sentinel node (NSN) metastases when the sentinel node is positive in patients with melanoma.

METHODS

A systematic search was conducted using MEDLINE, PubMed, EMBASE, Current Contents Connect, Cochrane library, Google scholar, Science Direct, and Web of Science. The search identified 54 relevant articles reporting the frequency of NSN metastases in melanoma. Original data was abstracted from each study and used to calculate a pooled odds ratio (OR) and 95% confidence interval (95% CI).

FINDINGS

The pooled estimates that were found to be significantly associated with the high likelihood of NSN metastases were: ulceration (OR: 1.88, 95% CI: 1.53-2.31), satellitosis (OR: 3.25, 95% CI: 1.86-5.66), neurotropism (OR: 2.51, 95% CI: 1.39-4.53), >1 positive SLN (OR: 1.77, 95% CI: 1.2-2.62), Starz 3 (old) (OR: 1.83, 95% CI: 0.89-3.76), Angiolymphatic invasion (OR: 2.46, 95% CI: 1.34-4.54), extensive location (OR: 2.22, 95% CI: 1.74-2.81), macrometastases >2 mm (OR: 1.95, 95% CI: 1.61-2.35), extranodal extension (OR: 3.38, 95% CI: 1.79-6.40) and capsular involvement (OR: 3.16, 95% CI: 1.37-7.27). There were 3 characteristics not associated with NSN metastases: subcapsular location (OR: 0.51, 95% CI: 0.38-0.67), Rotterdam Criteria <0.1 mm (OR: 0.29, 95% CI: 0.17-0.50) and Starz I (new) (OR: 0.44, 95% CI: 0.22-0.91). Other variables including gender, Breslow thickness 2-4 mm and extremity as primary site were found to be equivocal.

INTERPRETATION

This meta-analysis provides evidence that patients with low SLN tumor burden could probably be spared the morbidity associated with CLND. We identified 9 factors predictive of non-SLN metastases that should be recorded and evaluated routinely in SLN databases. However, further studies are needed to confirm the standard criteria for not performing CLND.

Lymphatic mapping and sentinel lymph node biopsy in patients with melanoma: a meta-analysis

PURPOSE

To perform a meta-analysis of all published studies of sentinel lymph node (SLN) biopsy for staging patients with melanoma.

METHODS

Published literature in all languages between 1990 and 2009 was critically appraised. Primary outcomes evaluated included the proportion successfully mapped (PSM) and test performance including false-negative rate (FNR), post-test probability negative (PTPN), and positive predictive value in the same nodal basin recurrence.

RESULTS

A total of 71 studies including 25,240 patients met full eligibility criteria. The average PSM was 98.1% (95% CI, 97.3% to 98.6%) and increased with the year of publication, female sex, ulceration, age, and the quality score of the studies. The FNR ranged from 0.0% to 34.0%, averaging 12.5% overall (95% CI, 11% to 14.2%). FNR increased with the length of follow-up (P = .002) but decreased with greater PSM (P = .001). PTPN averaged 3.4% (95% CI, 3.0% to 3.8%), which also increased in studies with longer follow-up, younger age, female sex, deeper Breslow thickness, and with tumor ulceration while decreasing with greater PSM (P < .001). Approximately 20% of the patients with a positive SLN had additional lymph nodes in the complete lymph node dissection and 7.5% of the patients with positive SLN developed recurrence in the same nodal basin which was greater in studies that also reported higher FNR (P = .01).

CONCLUSION

The estimated risk of nodal recurrence after a negative SLN biopsy was ≤ 5% supporting the use of this technology for staging patients with melanoma.

Predictive role of preoperative lymphoscintigraphy on the status of the sentinel lymph node in clinically node-negative patients with cutaneous melanoma

We reviewed our experience to assess the predictive role of preoperative lymphoscintigraphy with regard to the pathological status of sentinel lymph node (sN) in patients with cutaneous melanoma, to optimize the surgical treatment planning with regard to the use of intraoperative frozen section examination of sN. Eighty-eight patients with clinically node-negative cutaneous melanoma pT1b-T4 stage underwent preoperative lymphoscintigraphy for the lymphatic mapping of sN. A lymphoscintigraphic 'score' (from L1 to L5) was developed based on the ratio of radiotracer concentration within sN nodes as compared with the injection site. Our score allowed us to foresee that sN of patients with thick melanomas (T3 and T4) and a low preoperative score (L1-L2-L3) had a 90% expected likelihood (P<0.001) of harboring metastasis, whereas sN in patients with thin melanomas (T1b-T2) and high preoperative score (from L4 to L5) showed a 100% likelihood of being metastasis free. In conclusion, the sN is a reliable predictor of regional lymph node status in patients with cutaneous malignant melanoma. Moreover, we suggest that a low score (L1-L2-L3) associated with a thick melanoma is a good predictive factor of the positive sN involvement. This information could be useful in scheduling the intraoperative frozen-section examination with an expected benefit of a positive test in almost 90% of patients. Such patients might be selected for a 'one-stage' procedure with a more effective cost/benefit ratio and decreased hospitalization costs.

Imaging in cutaneous melanoma

Cutaneous melanoma (CM) is a common malignancy and imaging, particularly lymphoscintigraphy (LS), positron-emission tomography with 2-fluoro-2-deoxyglucose (FDG-PET), ultrasound, radiography computed tomography (CT) and magnetic resonance imaging have important roles in staging and restaging, surgical guidance, surveillance and assessment of recurrent disease. This review aims to summarize the available data regarding these and other imaging modalities in CM and provide the basis for subsequent formulation of guidelines regarding the use of imaging in CM. PubMed and Medline searches were performed and reference lists from publications were also searched. The published data were reviewed and tabulated. There is level I evidence supporting the use of LS and sentinel lymph node biopsy in nodal staging for CM. There is level III evidence demonstrating the superiority of ultrasound to palpation in the assessment of lymph nodes in CM. There is level IV evidence supporting FDG-PET in American Joint Committee on Cancer stage III/IV and recurrent CM and that FDG-PET/CT may be superior to FDG-PET. Level IV evidence also supports the use of CT in the same group of patients and the role of CT appears to be complementary to FDG-PET. Various imaging modalities, especially LS/sentinel lymph node biopsy and FDG-PET/CT, add incremental information in the management of CM and the various modalities have complementary roles depending on the clinical situation.

Utility of frozen-section analysis of sentinel lymph node biopsy specimens for melanoma in surgical decision making

BACKGROUND

Debate exists whether frozen-section analysis of sentinel lymph nodes (SLNs) for melanoma is an accurate method to detect disease that has metastasized to the lymph nodes. The purpose of this study was to evaluate the utility of intraoperative frozen section for SLNs in melanoma.

METHODS

We reviewed 133 patients (271 nodes) who underwent SLN biopsy with frozen section for melanoma between April 2003 and September 2007. Frozen-section diagnosis was compared with final diagnosis to determine concordance between intraoperative and postsurgical diagnosis.

RESULTS

A total of 11 nodes (8% of patients) were found to have metastatic disease. All patients underwent lymph node dissections at the time of SLN biopsy. No false-positive SLNs were found on frozen section. The false-negative rate for SLN biopsy frozen section was 8% (1 of 133 patients).

CONCLUSIONS

Intraoperative frozen section can be an accurate and reliable tool in the right setting for analysis of sentinel nodes in cutaneous melanoma and deserves further study.

Interference with serum indices measurement, but not chemical analysis, on the Roche Modular by Patent Blue V

BACKGROUND

Patent Blue V is an inert dye increasingly being used during cancer surgery to identify the sentinel lymph node. We recently discovered three cases with falsely elevated lipaemic indices on the Roche Modular, following intramammary injection of Patent Blue. This, and other potential interferences by Patent Blue, is examined in this study.

METHODS

Serum samples which visually appeared normal, haemolysed or icteric were spiked with Patent Blue to a concentration of 7.3 mg/L and the effect on the lipaemic, haemolysis and icteric indices and routine chemical analyses (sodium, potassium, urea, creatinine, bilirubin, alanine aminotransferase, gamma-glutamyltransferase, aspartate aminotransferase, magnesium, creatine kinase, lactate dehydrogenase, amylase, albumin, calcium and phosphate) undertaken. Dose-response curves in the range of 4.9 mg/L to 22.7 mg/L of Patent Blue were established for normal, icteric and haemolysed pooled serum samples.

RESULTS

Significant positive interference by 7.3 mg/L of Patent Blue was observed in the lipaemic index, with an increase of 149 +/- 6.3 (mean +/- standard deviation [SD]; P < 0.001). Significant negative interference was observed in both the haemolysis and icteric indices, with decreases of 71 +/- 9.7 (P < 0.001) and 46 +/- 8.9 (P < 0.001), respectively. Patent Blue had a linear dose-response effect on the serum indices. No significant differences were observed in the chemical analyses assessed.

CONCLUSIONS

The effects observed on the Roche Modular serum index measurements with Patent Blue raises the novel concept of interference in methods routinely used to detect interference. Despite Patent Blue having no direct effect on chemical analysis, failure to reliably detect potential interference, particularly haemolysis, may lead to misleading results being issued.