Histological regression in primary melanoma: not a predictor of sentinel lymph node metastasis in a cohort of 397 patients

Invasive Cutaneous Melanoma: Evaluating the Prognostic Significance of Some Parameters Associated with Lymph Node Metastases

Background and Objectives: This study aimed to assess the clinical-pathological profile of patients with invasive cutaneous melanomas and to identify the parameters with a prognostic role in the lymph nodal spread of this malignant tumor. Materials and Methods: We performed a retrospective study on patients with invasive cutaneous melanomas who underwent surgery in the "Pius Brînzeu" County Clinical Emergency Hospital from Timișoara, Romania, and were evaluated for the status of loco-regional lymph nodes. We selected and analyzed some parameters searching for their relationship with lymph node metastases. Results: We identified 79 patients with invasive cutaneous melanomas (29 men and 50 women, mean age 59.36 years). A percentage of 58.3% of melanomas had Breslow tumor thickness >2 mm; 69.6% of melanomas showed a Clark level IV-V. Tumor ulceration was present in 59.5% of melanomas. A mitotic rate of ≥5 mitoses/mm² was observed in 48.1% of melanomas. Tumor-infiltrating lymphocytes (TILs), non-brisk, were present in 59.5% of cases and 22.8% of patients had satellite/in-transit metastasis (SINTM). Tumor regression was identified in 44.3% of cases. Lymph nodes metastases were found in 43.1% of patients. Statistical analysis showed that lymph node metastases were more frequent in melanomas with Breslow thickness >2 mm (p = 0.0002), high Clark level (p = 0.0026), mitotic rate >5 mitoses/mm² (p = 0.0044), ulceration (p = 0.0107), lymphovascular invasion (p = 0.0182), SINTM (p = 0.0302), and non-brisk TILs (p = 0.0302). Conclusions: The Breslow thickness >2 mm, high Clark level, high mitotic rate and ulceration are the most important prognostic factors for lymph nodal spread in cutaneous melanomas. However, some melanomas without these clinical-pathological features can have an unexpected, aggressive evolution, which entails the necessity of close and prolonged clinical follow-up of patients, including those with lesions considered without risk.

Operative Therapie des malignen Melanoms

Die operative Therapie ist maßgeblich im Behandlungskonzept des malignen Melanoms. Sie ist essentieller Bestandteil der Diagnosesicherung, des Stagings und der Therapie in allen Stadien der Erkrankung. Die optimale Planung und Durchführung der Primärexzision, der Sentinel-Lymphknoten-Biopsie und der Nachexzision mit Sicherheitsabstand legen den Grundstein einer erfolgreichen Behandlung, die neben oder auch in Kombination mit einer modernen Systemtherapie die Metastasen-Chirurgie miteinschließt.

Predictive Values of Pathological and Clinical Risk Factors for Positivity of Sentinel Lymph Node Biopsy in Thin Melanoma: A Systematic Review and Meta-Analysis

Background

The indications for sentinel lymph node biopsy (SLNB) for thin melanoma are still unclear. This meta-analysis aims to determine the positive rate of SLNB in thin melanoma and to summarize the predictive value of different high-risk features for positive results of SLNB.

Methods

Four databases were searched for literature on SLNB performed in patients with thin melanoma published between January 2000 and December 2020. The overall positive rate and positive rate of each high-risk feature were calculated and obtained with 95% confidence intervals (CIs). Both unadjusted odds ratios (ORs) and adjusted ORs (AORs) of high-risk features were analyzed. Pooled effects were estimated using random-effects model meta-analyses.

Results

Sixty-six studies reporting 38,844 patients with thin melanoma who underwent SLNB met the inclusion criteria. The pooled positive rate of SLNB was 5.1% [95% confidence interval (CI) 4.9%-5.3%]. Features significantly predicted a positive result of SLNB were thickness≥0.8 mm [AOR 1.94 (95%CI 1.28-2.95); positive rate 7.0% (95%CI 6.0-8.0%)]; ulceration [AOR 3.09 (95%CI 1.75-5.44); positive rate 4.2% (95%CI 1.8-7.2%)]; mitosis rate >0/mm2 [AOR 1.63 (95%CI 1.13-2.36); positive rate 7.7% (95%CI 6.3-9.1%)]; microsatellites [OR 3.8 (95%CI 1.38-10.47); positive rate 16.6% (95%CI 2.4-36.6%)]; and vertical growth phase [OR 2.76 (95%CI 1.72-4.43); positive rate 8.1% (95%CI 6.3-10.1%)].

Conclusions

The overall positive rate of SLNB in thin melanoma was 5.1%. The strongest predictor for SLN positivity identified was microsatellites on unadjusted analysis and ulceration on adjusted analysis. Breslow thickness ≥0.8 mm and mitosis rate >0/mm² both predict SLN positivity in adjusted analysis and increase the positive rate to 7.0% and 7.7%. We suggest patients with thin melanoma with the above high-risk features should be considered for giving an SLNB.

Coexistence of regression and tumor infiltrating lymphocytes is associated with more favorable survival in melanoma

PURPOSE

Melanoma is one of the highly immunogenic malignancies, and histological regression (HR) and tumor infiltrating lymphocytes (TILs) represent early signs of activation of the immune system against primary melanoma. In this study we aimed to investigate the potential roles of HR and TILs on survival, as combined or separately.

METHODS

A total of 916 cutaneous melanomas were analyzed retrospectively.

RESULTS

Only minority of the lesions had HR (25.1%) and they were associated with males (p = 0.002), axial localization (p = 0.0001), non-nodular histopathology (p = 0.0001), thin Breslow depth (p = 0.01) and nevus-associated melanoma (p = 0.03). Those with TILs (48.4%) were found in association with lower Clark levels (p = 0.003), thin tumor thicknesses (p = 0.001), lower mitotic rates (p = 0.02), BRAF mutation (p = 0.03), absence of neurotropism (p = 0.03), involvement of lymph node (p = 0.0001) and relapse of disease (p = 0.04). A significant relationship was found between HR and TILs (p = 0.01). TILs were independently associated with favorable RFS (p = 0.02), whereas no relationship was observed between HR and RFS (p = 0.2). A marked favorable survival advantage was noted in the group with HR (+)/TILs (+) compared to other groups with HR (-)/TILs (-) (p = 0.007), only HR (+) and only TILs (+). Both HR (p = 0.05) and TILs (p = 0.04) were correlated with favorable OS rates. Moreover, HR (+) /TILs (+) patients had more favorable OS than other groups with HR (-)/TILs (-) (p = 0.002), only HR (+) and only TILs (+).

CONCLUSION

Only HR (+) and only TILs (+) subgroups separately were found to be associated with favorable survivals in melanoma. Furthermore, coexistence of HR and TILs, HR (+)/TILs (+) subgroup, had more favorable survival rates compared to only HR (+) and only TILs (+) subgroups.

Adequacy of sentinel lymph node biopsy in malignant melanoma of the trunk and extremities: Clinical observations regarding prognosis

Background

Methods for identifying local lymph node metastasis in malignant melanoma include sentinel lymph node biopsy (SLNB) and lymph node dissection (LND). In particular, SLNB has been widely used in recent years. This study aimed to retrospectively confirm the adequacy of the current indication criteria for SLNB by applying those criteria to a mixed group of patients who previously received SLNB and LND.

Methods

This study included 77 patients with malignant melanoma of the extremities and trunk who were monitored for >24 months. The patients were classified according to whether the current indication criteria for SLNB were applicable. The sentinel lymph nodes were evaluated for each group. Patients for whom the indication criteria for SLNB and LND were applicable were analyzed according to whether SLNB or LND was performed. Finally, the outpatient records of these patients were reviewed to evaluate recurrence, metastasis, and prognosis.

Results

Of the 77 patients, SLNB was indicated according to the current criteria in 60 cases. Among the 60 patients for whom SLNB was indicated, 35 survived the follow-up period disease-free, 21 died during the follow-up period, and four experienced metastasis. The 17 patients for whom SLNB was not indicated had no recurrence or metastasis.

Conclusions

Patients for whom SLNB was not indicated had no recurrence or metastasis. In cases where SLNB is indicated, the possibility of metastasis and recurrence may be high even if SLNB is negative or LND is performed, so more aggressive treatment and careful follow-up are crucial.

Phenotypic characterisation of immune cells associated with histological regression in cutaneous melanoma

Histological regression and tumour infiltrating lymphocytes represent an early sign of activation of the immune system against primary melanoma. The first phenomenon has been especially discussed in the literature because of its prognostic role, but no clear agreement on its evaluation has been reached. Immunotherapy of advanced stage melanoma has recently shown promising results; an improved understanding of the initial interplay between melanoma cells and the immune system would potentially help tailor treatment for patients. Seventy consecutive melanomas with regression were analysed to identify a prognostic cut-off value of regression extension. Then, we compared the immune infiltrate between regressed and not regressed areas of these regressed melanomas, assessing CD3, CD4, CD8, CD20, CD123, PD1 and FOXP3/CD25 expression. The immune infiltrate of these cases was further compared with 28 control melanomas without regression. A regression extension of 10% represented a reliable cut-off to distinguish two different risk categories in regressed melanomas. Regressed areas were less infiltrated by CD4/CD25, FOXP3/CD4 or PD1/CD4 compared to not regressed areas of each sample. These lymphocyte subsets are associated with anergy and hamper the immune CD8+ response towards the cancer cells. Moreover, the relevance of these findings was further supported by the observation that not regressed controls were significantly more infiltrated by these anergic immune cell subsets compared to the regressed cases. These results help understand the real meaning of regression in melanoma. Moreover, the association here identified between specific immunomodulatory immune cell subsets and regression could help in developing new therapeutic strategies.

Vertical Growth Phase as a Prognostic Factor for Sentinel Lymph Node Positivity in Thin Melanomas: A Systematic Review and Meta-Analysis

BACKGROUND

The 2010 American Joint Committee on Cancer guidelines recommended consideration of sentinel lymph node biopsy for thin melanoma (Breslow thickness <1.0 mm) with aggressive pathologic features such as ulceration and/or high mitotic rate. The therapeutic benefit of biopsy-based treatment remains controversial. The authors conducted a meta-analysis to estimate the risk and outcomes of sentinel lymph node positivity in thin melanoma, and examined established and potential novel predictors of positivity.

METHODS

Three databases were searched by two independent reviewers for sentinel lymph node positivity in patients with thin melanoma. Study heterogeneity, publication bias, and quality were assessed. Data collected included age, sex, Breslow thickness, mitotic rate, ulceration, regression, Clark level, tumor-infiltrating lymphocytes, and vertical growth phase. Positivity was estimated using a random effects model. Association of positivity and clinicopathologic features was investigated using meta-regression.

RESULTS

Ninety-three studies were identified representing 35,276 patients with thin melanoma who underwent sentinel lymph node biopsy. Of these patients, 952 had a positive sentinel lymph node biopsy, for an event rate of 5.1 percent (95 percent CI, 4.1 to 6.3 percent). Significant associations were identified between positivity and Breslow thickness greater than 0.75 mm but less than 1.0 mm, mitotic rate, ulceration, and Clark level greater than IV. Seven studies reported on vertical growth phase, which was strongly associated with positivity (OR, 4.3; 95 percent CI, 2.5 to 7.7).

CONCLUSIONS

To date, this is the largest meta-analysis to examine predictors of sentinel lymph node biopsy positivity in patients with thin melanoma. Vertical growth phase had a strong association with biopsy positivity, providing support for its inclusion in standardized pathologic reporting.

Acquired disorders with depigmentation: A systematic approach to vitiliginoid conditions

Acquired disorders with depigmentation are commonly encountered by dermatologists and present with a wide differential diagnosis. Vitiligo, the most common disorder of acquired depigmentation, is characterized by well-defined depigmented macules and patches. Other conditions, such as chemical leukoderma, can present with similar findings, and are often easily mistaken for vitiligo. Key clinical features can help differentiate between acquired disorders of depigmentation. The first article in this continuing medical education series focuses on conditions with a vitiligo-like phenotype. Early recognition and adequate treatment of these conditions is critical in providing appropriate prognostication and treatment.

Complete lymphadenectomy following positive sentinel lymph node biopsy in cutaneous melanoma: a critical review

Cutaneous melanoma is the solid neoplasia with the highest growing incidence among all tumors. It spreads predictably to the lymphatic vessels and sentinel lymph node, and when the latter is affected the prognosis worsens dramatically. Sentinel lymph node biopsy is considered when thickness of the primary tumor exceeds 1mm and/or when there are adverse features in thinner melanomas. When there is nodal metastasis, current evidence in the literature recommends complete lymphadenectomy, although this procedure has its intrinsic risks (i.e., lymphedema and cellulitis), and there are no published clinical trials proving additional overall survival benefits. The current in-depth literature review thus aims to identify patients that will benefit most from the procedure, including those with the highest likelihood of presenting additional affected lymph nodes in the same nodal basin. The authors also discuss techniques for identification of the sentinel lymph node, false-negative rates, and predictive models for lymph node involvement. In conclusion, complete elective lymphadenectomy should always be discussed on a case-by-case basis when metastases are detected in the sentinel lymph node.

Regression and Sentinel Lymph Node Status in Melanoma Progression

BACKGROUND The purpose of this study was to assess the role of regression and other clinical and histological features for the prognosis and the progression of cutaneous melanoma. MATERIAL AND METHODS Between 2005 and 2016, 403 patients with melanoma were treated and followed at our Department of Dermatology. Of the 403 patients, 173 patients had cutaneous melanoma and underwent sentinel lymph node (SLN) biopsy and thus were included in this study. RESULTS Histological regression was found in 37 cases of melanoma (21.3%). It was significantly associated with marked and moderate tumor-infiltrating lymphocyte (TIL) and with negative SLN. Progression of the disease occurred in 42 patients (24.2%). On multivariate analysis, we found that a positive lymph node and a Breslow index higher than 2 mm were independent variables associated with disease free survival (DFS). These variables together with a mild TIL were significantly correlated with overall survival (OS). The presence of regression was not associated with DFS or OS. CONCLUSIONS We could not demonstrate an association between regression and the outcome of patients with cutaneous melanoma. Tumor thickness greater than 2 mm and a positive SLN were associated with recurrence. Survival was influenced by a Breslow thickness >2 mm, the presence of a mild TIL and a positive SLN status.

Regression in primary cutaneous melanoma: etiopathogenesis and clinical significance

Though not required currently for staging, regression is a histopathologic parameter typically reported upon diagnosis of an invasive primary cutaneous melanoma. The studies examining the prognostic significance of regression in patient outcome have yielded controversial findings; likely because the definition and assessment of regression have not been consistent, in addition to subjectivity of pathologists' interpretation. Regression is histologically characterized by variable decrease in the number of melanoma cells accompanied by the presence of a host response consisting of dermal fibrosis, inflammatory infiltrate, melanophages, ectatic blood vessels, epidermal attenuation, and/or apoptosis of keratinocytes or melanocytes; the relative extent of these features depends on the stage of the regression. However, the magnitudes to which these individual changes must be present to meet the threshold of histologic regression have not been well defined or agreed upon, and thus, the definition and classification of histologic regression in melanoma varies considerably among institutions and even among individual pathologists. In order to determine the clinical significance of histologic analysis of regression, there is a compelling need for a universal scheme to objectively define and assess histologic regression in primary cutaneous melanoma, so that the biologic and prognostic significance of this process may be completely understood.Laboratory Investigation advance online publication, 27 February 2017; doi:10.1038/labinvest.2017.8.

BRAF and Epithelial-Mesenchymal Transition: Lessons From Papillary Thyroid Carcinoma and Primary Cutaneous Melanoma

The increased prevalence of BRAF mutations in thyroid carcinoma and primary cutaneous melanoma (PCM) hint that dysregulation of BRAF might contribute to the noted association between PCM and thyroid carcinoma. A recent study evaluating the rate of BRAFV600E mutations among patients who had been diagnosed with primary papillary thyroid carcinoma (PTC) and PCM showed that patients with either PCM or PTC were at an increased risk of developing the other as a second primary malignant neoplasm. Furthermore, the authors noted that samples from patients suffering from both malignancies exhibited a higher rate of incidence of the BRAFV600E mutation, compared with patients not suffering from both malignancies. These studies support the hypothesis that the pathogenesis of these 2 malignancies might share a conserved molecular pattern associated with dysregulation of the BRAF protein. One mechanism through which BRAF might contribute to PCM and thyroid carcinoma progression is through induction of epithelial-mesenchymal transition (EMT). Specifically, the Snail/E-cadherin axis has been demonstrated as a pathway dysregulated by BRAF, leading to EMT in both malignancies. Our analysis focuses on the results of these recent investigations, and through a review of select molecules relevant to EMT, looks to provide a context by which to better understand the relevance and role of stromal-parenchymal signaling and the BRAF mutation in the pathogenesis of PTC and PCM.

Variations in the expression of TIMP1, TIMP2 and TIMP3 in cutaneous melanoma with regression and their possible function as prognostic predictors

Regression in melanoma is a frequent biological event of uncertain prognostic value as the lesion exhibits heterogeneous phenotypical features, both at the morphological and immunohistochemical level. In the present study, we examined the expression of tissue inhibitors of metalloproteinases (TIMP1, TIMP2 and TIMP3) in melanoma with regression. We specifically examined the expression levels of these TIMPs in regressed components (RC) and non-regressed components (NRC) of the tumor and compared their expression levels with those in non-regressed melanomas. We found that TIMP1 was overexpressed in the NRC of melanomas with partial regression (PR) compared with the NRC in melanomas with segmental regression (SR) (P=0.011). TIMP2 was overexpressed in the NRC of melanomas with PR compared with the NRC in melanomas with SR (PR/SR, P=0.009); or compared with the NRC in melanomas with simultaneous SR-PR (P=0.002); or compared with melanomas without regression (absence of regression) (P=0.037). Moreover, TIMP3 was overexpressed in the NRC of all melanomas with SR as compared to the RC component (P=0.007). Our findings on the differential expression of TIMP1, TIMP2 and TIMP3 in melanomas with regression support the hypothesis that the morphological differences identified in the melanoma regression spectrum may have a correlation with prognosis. This may explain the controversial findings within the literature concerning the biological and prognostic role of regression in melanoma.

Sentinel Lymph Node Biopsy in Thin Cutaneous Melanoma: A Systematic Review and Meta-Analysis

BACKGROUND

Most patients with melanoma have a thin (≤1.00 mm) lesion. There is uncertainty as to which patients with thin melanoma should undergo sentinel lymph node (SN) biopsy. We sought to quantify the proportion of SN metastases in patients with thin melanoma and to determine the pooled effect of high-risk features of the primary lesion on SN positivity.

METHODS

Published literature between 1980 and 2015 was searched and critically appraised. Primary outcome was the proportion of SN metastases in patients with thin cutaneous melanoma. Secondary outcomes included the effect of high-risk pathological features of the primary lesion on the proportion of SN metastases. Summary measures were estimated by Mantel-Haenszel method using random effects meta-analyses.

RESULTS

Sixty studies (10,928 patients) met the criteria for inclusion. Pooled SN positivity was 4.5 % [95 % confidence interval (CI) 3.8-5.2 %]. Predictors of a positive SN were: thickness ≥0.75 mm [adjusted odds ratio (AOR) 1.90 (95 % CI 1.08-3.34); with a likelihood of SN metastases of 8.8 % (95 % CI 6.4-11.2 %)]; Clark level IV/V [AOR 2.24 (95 % CI 1.23-4.08); with a likelihood of 7.3 % (95 % CI 6.2-8.4 %)]; ≥1 mitoses/mm² [AOR 6.64 (95 % CI 2.77-15.88); pooled likelihood 8.8 % (95 % CI 6.2-11.4 %)]; and the presence of microsatellites [unadjusted OR 6.94 (95 % CI 2.13-22.60); likelihood 26.6 % (95 % CI 4.3-48.9 %)].

CONCLUSIONS

The pooled proportion of SN metastases in thin melanoma is 4.5 %. Thickness ≥0.75 mm, Clark level IV/V, mitoses, and microsatellites significantly increased the odds of SN positivity and should prompt strong consideration of SN biopsy.

Breslow thickness, clark index and ulceration are associated with sentinel lymph node metastasis in melanoma patients: a cohort analysis of 612 patients

BACKGROUND

Sentinel lymph node biopsy (SLNB) is the most sensitive procedure for assessing nodal status in patients with primary melanoma.

OBJECTIVE

To evaluate the predictive ability of usual primary melanoma prognosis factors of detecting sentinel lymph node (SLN) metastasis in patients with melanoma.

PATIENTS AND METHODS

A cohort of 612 consecutive patients presenting with primary skin melanoma who underwent a SLNB was evaluated. Assessment of the determinants of SLN metastasis was based on general linear model analysis. The model performance was studied using the concordance statistic and the net reclassification index. The calibration was estimated using the Hosmer-Lemeshow test.

RESULTS

The discrimination ability did not differ significantly between Breslow thickness (0.57), Clark index (0.61), ulceration (0.57) and histological subtype (0.55). Clark index, ulceration and Breslow thickness were all significant and independent determinants of SLN metastasis. The predictive ability of the final model was 0.657.

CONCLUSION

Breslow thickness, Clark index and ulceration are independent predictors of a SLN metastasis.

Long-term survival analysis and clinical follow-up in acral lentiginous malignant melanoma undergoing sentinel lymph node biopsy in korean patients

BACKGROUND

In cutaneous malignant melanoma (MM) with clinically uninvolved regional lymph nodes, sentinel lymph node (SLN) status is the most powerful indicator of both overall survival (OS) and disease-free survival (DFS). However, no studies on the long-term survival and clinical follow-up of Korean patients with acral lentiginous MM (ALM) undergoing SLN biopsy (SLNB) have been published.

OBJECTIVE

The purpose of this study was to investigate the clinical prognosis and long-term survival of Korean patients with ALM according to SLN status.

METHODS

Thirty-four ALM patients undergoing SLNB were included in this study. We evaluated clinical and histopathological follow-up data such as the stage of disease, treatment, recurrence, and metastasis, and analyzed OS and DFS according to SLN status.

RESULTS

The median follow-up time was 60.5 months (range 3~127 months). Positive SLNs were noted in 14 patients (41.2%). Patients with negative SLNs had better OS and DFS than those with positive SLNs (p<0.05). Increased Breslow thickness was associated with short OS and DFS (p<0.05), and female patients showed better DFS than male patients (p<0.05).

CONCLUSION

To our knowledge, this is the first study on the long-term survival and clinical follow-up of patients undergoing SLNB for ALM in Korea. Our findings show that SLN status is an important prognostic factor for predicting OS and DFS.

Sentinel node biopsy improves prognostic stratification in patients with thin (pT1) melanomas and an additional risk factor

BACKGROUND

Sentinel lymph node (SLN) biopsy (SLNB) for pT1 melanomas is not generally recognized as a clinical standard. We studied the value of SLNB for pT1 melanoma patients having at least one additional risk factor.

PATIENTS

Among 931 patients with SLNB, 210 had pT1 melanomas. All of the latter showed at least one of the following risk factors: ulceration (4 %) Clark level IV (44 %), nodular growth pattern (11 %), mitoses (59 %), regression (38 %) or age ≤ 40 years (27 %).

RESULTS

In this selected pT1 population, we observed a surprisingly high SLN positivity rate of 18 %. The melanoma-specific overall survival significantly depended on SLN status. Compared with Clark IV, a lower invasion level (Clark II/III) was associated with a higher proportion of positive SLNs (25 vs. 10 %; p < 0.01). There was a trend towards a higher SLN positivity rate in younger patients (p = 0.06). Breslow, ulceration, mitoses, nodular growth pattern, and sex did not reach significance. Regression was significantly more frequently found in very thin melanomas (≤ 0.75 mm) and tended to be significant in this subgroup (p = 0.075).

CONCLUSIONS

SLNB improves prognostic stratification in patients with thin melanomas having an additional risk factor. Clark level IV most likely does not belong to these risk factors. The impact of regression deserves further consideration. Our data suggest that SLNB should be offered to patients with thin melanomas, if ulceration, nodular growth pattern, mitoses, or regression are present, or if the patient is younger than 40 years of age.

Prognosis of patients with transected melanomas

BACKGROUND

The management of melanoma is directly related to Breslow's depth. Biopsying melanomas in a fashion that transects the deep margin precludes an accurate measurement of the true depth.

OBJECTIVE

To examine the prognosis of melanomas transected along the deep margins, as well as cases where no residual melanoma was seen on re-excision after transection.

METHODS

Records from a cohort of patients at one institution were examined from 1996 through 2007. Patients were considered to have "transected" melanomas if tumor cells were present on the deep margin of the biopsy. Overall survival was determined.

RESULTS

Seven hundred fourteen patients were examined. 171 (24%) of all melanomas were transected. 101(59%) of those lacked tumor cells on re-excision. Patients with transected melanomas were older (OR = 1.03, p < .001), and had higher Breslow's depths (OR = 1.21, p < .001) than those without transected tumors. Those with no residual melanoma after transection were younger (OR = 0.98, p = .010) and more likely to have no lymph node involvement (OR = 2.23, p = .037). Neither transection (p = .760), nor lack of residual melanoma on re-excision after transection (p = .793) influenced survival.

CONCLUSION

A high number of melanomas are transected at diagnosis, many of which lack visible tumor. The original Breslow's depth of transected melanomas without residual tumor on re-excision accurately predicts survival and prognosis.

Outcome of sentinel lymph node biopsy and prognostic implications of regression in thin malignant melanoma

Thin melanomas with partial or complete regression may provide clues about antitumor immunity, but their management remains controversial. We have characterized the management and clinical outcomes of regressed thin (<1 mm) T1a melanomas and hypothesized that regression increases the risk of regional metastases when compared with nonregressed thin melanomas. A prospectively collected clinical database was reviewed, and T1a melanomas with regression were identified. Histology, surgical approach, outcome, and survival were evaluated. The primary outcome measures were sentinel node positivity, subsequent lymph node metastasis, and survival. A total of 75 patients with T1a or in-situ melanomas were grouped into three subsets. Group 1: 35 underwent a sentinel node biopsy (SNBx), none of which were positive. No patients developed nodal recurrence. The 5-year survival of this group was 93%, with a median follow-up of 52 months. Group 2: 31 were followed up without SNBx; two developed regional nodal disease (6.5%), neither of whom died of subsequent distant disease. The 5-year survival was 89%, with a median follow-up of 38 months. There was no significant difference in the survival between groups 1 and 2. Group 3: nine patients presented with metastatic disease concurrent with a regressed thin melanoma. These patients had a median survival of 2.3 years and a 4-year survival estimate of 22%. Regression should not be used as an indication for SNBx in T1a melanomas; we recommend that such patients be managed with wide local excision and a long-term clinical follow-up. The poor prognosis of thin regressed primary melanoma with simultaneous metastatic disease may indicate the existence of immune escape phenotypes supporting melanoma progression.