Predictors of SNL Positivity in Cutaneous Melanoma
Background Histological features such as Breslow thickness, ulceration and mitosis are the main criteria to guide sentinel lymph node biopsy (SLNB) in melanoma. Dermoscopy may add complementary information to these criteria.
Objectives To evaluate the correlation between dermoscopy structures and SLNB positivity.
Methods Retrospective analysis of 123 consecutive melanomas with Breslow thickness > 0·75 mm, SLNB performed during follow-up and dermoscopic images.
Results Men were more likely to have a positive SLNB. The presence of ulceration and blotch and the absence of a pigmented network in dermoscopy correlated with positive SLNB. Histological ulceration also correlated with positive SLNB. A dermoscopy SCORE predicted SLN status with a sensitivity of 96·3% and a specificity of 30·2%. When sex and Breslow thickness were added (SCOREBRESEX), the sensitivity remained at 96·3% but the specificity increased to 52·1%. This study is limited by the number of patients and was performed in only one institution.
Conclusions Dermoscopy allowed a more precise prediction of SLN status. If a combined SCOREBRESEX was used to select patients for SLNB, 41·5% of procedures might be avoided.
Dermoscopy is a useful and noninvasive technique that uses a magnifying device for early melanoma detection. Dermoscopy may represent an alternative tool for the preoperative assessment of melanoma thickness. A good correlation between dermoscopic criteria based on pattern analysis and the histopathological thickness of melanoma has already been identified.
The total dermoscopic score (TDS) calculated by the ABCD rule of dermatoscopy (asymmetry, borders, colour, diameter) provides useful information for the preoperative assessment of melanomas thicker than 0·75 mm. A TDS > 6·8 correlates with Breslow thickness > 0·75 mm.
A statistically significant association was also found between the presence of an irregular pigmented network and melanomas with a Breslow thickness ≤ 0·75 mm; on the contrary, some criteria such as grey-blue areas, radial streaming and atypical vascular pattern are associated with thicker melanomas (Breslow > 0·75 mm).
Combination of palpability, diameter > 15 mm and dermoscopic criteria allow the correct prediction of melanoma thickness. The presence of a flat lesion predicts a thin melanoma (Breslow < 0·75 mm) in 100% of cases, and a diameter > 15 mm and ulceration correlate with Breslow thickness > 0·75 mm.
The invasive technique of sentinel lymph node biopsy (SLNB) has become the standard procedure to detect occult regional node metastasis, and has a high value for staging and prognosis in clinically localized intermediate-thickness primary melanomas (1·2–3·5 mm in thickness). SLNB with consecutive lymphadenectomy improves disease-free survival and diminishes recurrence among patients with tumour-positive sentinel lymph nodes (SLNs). SLN status is the most important prognostic indicator for disease-specific survival in patients with primary cutaneous melanoma, but the impact of SLNB on overall survival remains unclear. In the recent paper by Morton et al., analysing 2001 patients with melanoma randomized to SLNB or observation, there was no significant treatment-related difference in the 10-year melanoma-specific survival rates. However, the subanalysis of positive SLNs of intermediate-thickness melanoma showed a better melanoma-specific overall survival compared with nodal recurrence in the intermediate-thickness melanoma observational group.
According to international consensus and the latest American Joint Committee on Cancer (AJCC) classification, SLNB is generally indicated as the staging procedure in melanomas with Breslow thickness > 1 mm, and/or with ulceration, and/or with at least one dermal mitosis per mm. However, it is well known that at least 80% of SLNBs performed are negative. A better preoperative estimation of the positivity of the SLNB with a lower number needed to treat (NNT) is therefore of major interest.
The purpose of our study was to evaluate the correlation between dermoscopic structures and the positivity of SLN. Additionally, in combination with histological criteria we aimed to develop an algorithm for the better selection of patients to be subjected to SLNB with lower NNT.
Abstract and Introduction
Abstract
Background Histological features such as Breslow thickness, ulceration and mitosis are the main criteria to guide sentinel lymph node biopsy (SLNB) in melanoma. Dermoscopy may add complementary information to these criteria.
Objectives To evaluate the correlation between dermoscopy structures and SLNB positivity.
Methods Retrospective analysis of 123 consecutive melanomas with Breslow thickness > 0·75 mm, SLNB performed during follow-up and dermoscopic images.
Results Men were more likely to have a positive SLNB. The presence of ulceration and blotch and the absence of a pigmented network in dermoscopy correlated with positive SLNB. Histological ulceration also correlated with positive SLNB. A dermoscopy SCORE predicted SLN status with a sensitivity of 96·3% and a specificity of 30·2%. When sex and Breslow thickness were added (SCOREBRESEX), the sensitivity remained at 96·3% but the specificity increased to 52·1%. This study is limited by the number of patients and was performed in only one institution.
Conclusions Dermoscopy allowed a more precise prediction of SLN status. If a combined SCOREBRESEX was used to select patients for SLNB, 41·5% of procedures might be avoided.
Introduction
Dermoscopy is a useful and noninvasive technique that uses a magnifying device for early melanoma detection. Dermoscopy may represent an alternative tool for the preoperative assessment of melanoma thickness. A good correlation between dermoscopic criteria based on pattern analysis and the histopathological thickness of melanoma has already been identified.
The total dermoscopic score (TDS) calculated by the ABCD rule of dermatoscopy (asymmetry, borders, colour, diameter) provides useful information for the preoperative assessment of melanomas thicker than 0·75 mm. A TDS > 6·8 correlates with Breslow thickness > 0·75 mm.
A statistically significant association was also found between the presence of an irregular pigmented network and melanomas with a Breslow thickness ≤ 0·75 mm; on the contrary, some criteria such as grey-blue areas, radial streaming and atypical vascular pattern are associated with thicker melanomas (Breslow > 0·75 mm).
Combination of palpability, diameter > 15 mm and dermoscopic criteria allow the correct prediction of melanoma thickness. The presence of a flat lesion predicts a thin melanoma (Breslow < 0·75 mm) in 100% of cases, and a diameter > 15 mm and ulceration correlate with Breslow thickness > 0·75 mm.
The invasive technique of sentinel lymph node biopsy (SLNB) has become the standard procedure to detect occult regional node metastasis, and has a high value for staging and prognosis in clinically localized intermediate-thickness primary melanomas (1·2–3·5 mm in thickness). SLNB with consecutive lymphadenectomy improves disease-free survival and diminishes recurrence among patients with tumour-positive sentinel lymph nodes (SLNs). SLN status is the most important prognostic indicator for disease-specific survival in patients with primary cutaneous melanoma, but the impact of SLNB on overall survival remains unclear. In the recent paper by Morton et al., analysing 2001 patients with melanoma randomized to SLNB or observation, there was no significant treatment-related difference in the 10-year melanoma-specific survival rates. However, the subanalysis of positive SLNs of intermediate-thickness melanoma showed a better melanoma-specific overall survival compared with nodal recurrence in the intermediate-thickness melanoma observational group.
According to international consensus and the latest American Joint Committee on Cancer (AJCC) classification, SLNB is generally indicated as the staging procedure in melanomas with Breslow thickness > 1 mm, and/or with ulceration, and/or with at least one dermal mitosis per mm. However, it is well known that at least 80% of SLNBs performed are negative. A better preoperative estimation of the positivity of the SLNB with a lower number needed to treat (NNT) is therefore of major interest.
The purpose of our study was to evaluate the correlation between dermoscopic structures and the positivity of SLN. Additionally, in combination with histological criteria we aimed to develop an algorithm for the better selection of patients to be subjected to SLNB with lower NNT.
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