AJCC melanoma staging update: impact on dermatopathology practice and patient management

Disease-Associated Risk Variants in ANRIL Are Associated with Tumor-Infiltrating Lymphocyte Presence in Primary Melanomas in the Population-Based GEM Study

BACKGROUND

Genome-wide association studies have reported that genetic variation at ANRIL (CDKN2B-AS1) is associated with risk of several chronic diseases including coronary artery disease, coronary artery calcification, myocardial infarction, and type 2 diabetes mellitus. ANRIL is located at the CDKN2A/B locus, which encodes multiple melanoma tumor suppressors. We investigated the association of these variants with melanoma prognostic characteristics.

METHODS

The Genes, Environment, and Melanoma Study enrolled 3,285 European origin participants with incident invasive primary melanoma. For each of ten disease-associated SNPs at or near ANRIL, we used linear and logistic regression modeling to estimate, respectively, the per allele mean changes in log of Breslow thickness and ORs for presence of ulceration and tumor-infiltrating lymphocytes (TIL). We also assessed effect modification by tumor NRAS/BRAF mutational status.

RESULTS

Rs518394, rs10965215, and rs564398 passed false discovery and were each associated (P ≤ 0.005) with TILs, although only rs564398 was independently associated (P = 0.0005) with TILs. Stratified by NRAS/BRAF mutational status, rs564398*A was significantly positively associated with TILs among NRAS/BRAF mutant, but not wild-type, cases. We did not find SNP associations with Breslow thickness or ulceration.

CONCLUSIONS

ANRIL rs564398 was associated with TIL presence in primary melanomas, and this association may be limited to NRAS/BRAF-mutant cases.

IMPACT

Pathways related to ANRIL variants warrant exploration in relationship to TILs in melanoma, especially given the impact of TILs on immunotherapy and survival.

Prospective study of clinical characteristics of melanoma patients with retinopathy caused by a high-dose interferon α-2b

Retinopathy is a rare side effect of interferon α-2b treatment. The goal of this study was to prospectively investigate the clinical characteristics of Chinese patients with melanomas who developed retinopathy following high doses of interferon α-2b (HD-IFN) therapy. The study included 56 melanoma stage I-III patients that were treated with HD-IFN. Fourty-three patients developed HD-IFN-induced retinopathies. Forty-three melanoma patients (76%) developed retinopathy after being treated with HD-IFN. Among these patients, 49% had cotton-wool spots, 19% had retinal hemorrhage, and 30% had retinal hemorrhage. The median time of occurrence of retinopathy was 4 weeks after treatment, and the median time of duration was 4 weeks. No patient showed other symptoms except one who had blurred vision. A comparison of clinical characteristics (age, gender, primary site, stage, and ulceration) and laboratory examinations (white blood cell and platelet counts, hemoglobin, serum lactate dehydrogenase, alanine transaminase, aspartate aminotransferase, triiodothyronine, thyroxine, thyroid-stimulating hormone, and lipid) between the HD-IFN-induced retinopathy patients and nonretinopathy patients did not show any significant differences (P > 0.05). Although all patients that developed retinopathy had diabetes or hypertension, an equal percentage of patients were without retinopathy had diabetes or hypertension. HD-IFN therapy in patients with melanomas may induce mild retinopathy. Our results; however, do not necessarily suggest to discontinue the HD-IFN treatment because retinopathy is a reversible disorder.

Association of Melanoma-Risk Variants with Primary Melanoma Tumor Prognostic Characteristics and Melanoma-Specific Survival in the GEM Study

Genome-wide association studies (GWAS) and candidate pathway studies have identified low-penetrant genetic variants associated with cutaneous melanoma. We investigated the association of melanoma-risk variants with primary melanoma tumor prognostic characteristics and melanoma-specific survival. The Genes, Environment, and Melanoma Study enrolled 3285 European origin participants with incident invasive primary melanoma. For each of 47 melanoma-risk single nucleotide polymorphisms (SNPs), we used linear and logistic regression modeling to estimate, respectively, the per allele mean changes in log of Breslow thickness and odds ratios for presence of ulceration, mitoses, and tumor-infiltrating lymphocytes (TILs). We also used Cox proportional hazards regression modeling to estimate the per allele hazard ratios for melanoma-specific survival. Passing the false discovery threshold (p = 0.0026) were associations of IRF4 rs12203592 and CCND1 rs1485993 with log of Breslow thickness, and association of TERT rs2242652 with presence of mitoses. IRF4 rs12203592 also had nominal associations (p < 0.05) with presence of mitoses and melanoma-specific survival, as well as a borderline association (p = 0.07) with ulceration. CCND1 rs1485993 also had a borderline association with presence of mitoses (p = 0.06). MX2 rs45430 had nominal associations with log of Breslow thickness, presence of mitoses, and melanoma-specific survival. Our study indicates that further research investigating the associations of these genetic variants with underlying biologic pathways related to tumor progression is warranted.

Influence of variability in assessment of Breslow thickness, mitotic rate and ulceration among US pathologists interpreting invasive melanoma, for the purpose of AJCC staging

BACKGROUND

Melanoma staging has depended on depth of invasion (Breslow thickness, BT), mitotic rate (MR) and ulceration. In anticipation of the AJCC's eighth edition, variability in pathologists' assessment of these factors and consequently in tumor staging was assessed.

METHODS

One-hundred and fifteen cases of invasive melanoma, established by a consensus panel, were assessed by 187 pathologists. Variation was studied in BT, the detection of mitotic figures, and ulceration. The sources of this variation and its effect on tumor staging are considered.

RESULTS

On average, participant assessments closely approached consensus BT. Greater variation was identified in the classification of mitogenicity, which (like ulceration) upstages a T1 melanoma from T1a to T1b in the seventh but not eighth edition. In cases with a T1a diagnosis by the consensus panel, 15.6% of participants identified one or more mitotic figures (indicative of a false positive); and in cases diagnosed asT1b by the consensus panel, 32.0% of participants failed to find mitotic figures (false negative).

CONCLUSION

Variability in the staging of T1 melanoma among pathologists when using the AJCC seventh edition criteria is closely related to the detection of mitotic figures, with BT playing a less prominent role. Decreased variability is expected after implementation of the eighth edition.

[Diagnostics of malignant melanoma of the skin : Recommendations of the current S3 guidelines on histology and molecular pathology]

The updated S3 guidelines on malignant melanoma were established in August 2016. The principles of diagnostics and classification are based on the histopathological results from the primary tumor and if necessary the sentinel lymph nodes. The most important factor for prognosis is the tumor thickness according to Breslow and the detection of sentinel node micrometastases. The surgical safety margin after excision is dependent on the tumor thickness. Furthermore, ulceration of the primary tumor and presence of mitosis in melanomas less than 1 mm in thickness are also considered in the T‑classification. The sentinel lymph nodes should be prepared according to established procedures using HE staining and immunohistochemical methods. The largest tumor diameter of a micrometastasis should be measured in tenths of a millimeter (Rotterdam classification). Molecular pathology testing for mutations in the BRAF and NRAS oncogenes should be carried out in patients with metastatic disease or surgically non-resectable tumors. In addition c-KIT mutations should be tested in acral lentiginous and mucosal melanomas. Treatment with signal transduction inhibitors is possible when mutations have been detected.

Capsular nevus versus metastatic malignant melanoma - a diagnostic dilemma

INTRODUCTION

A positive finding of metastatic melanoma in a sentinel lymph node is an ominous sign and a strong predictor of overall survival. In contrast, current data trends have shown that patients with benign nevus cells in the sentinel nodes do not require additional therapy since their prognosis has been shown to be similar to that of patients with negative lymph nodes. Distinguishing between benign capsular nevi and metastatic melanoma often proves to be diagnostically problematic.

CASE PRESENTATION

In this case report we present two cases of melanoma in which sentinel lymph node biopsies proved to be difficult in distinguishing metastatic melanocytes from capsular nevus cells. In both cases, further workup was necessary for accurate diagnoses.

DISCUSSION

A lack of standardized distinctions of benign nevus cell from melanoma pose a diagnostic pitfall. Assigning a diagnosis of malignant melanoma might seem like the safer approach to avoid a false negative, but the resultant treatment, including the possibility of additional surgical complications, may cause anxiety, discomfort, and financial instability for the patient. Current methods of distinguishing the two based solely on histology may be insufficient due to similar pathologic patterns.

CONCLUSION

To avoid misdiagnosing a patient and performing unnecessary therapy, it would be beneficial to get a second opinion by additional histopathologists at a high volume center. Additionally, immunohistochemical staining should be carefully employed due to some overlap in commonly used markers. Using tissue morphology in conjunction with immunohistochemical staining may be the best way to make the most accurate diagnosis.

Revisiting determinants of prognosis in cutaneous melanoma

The American Joint Committee on Cancer staging system for cutaneous melanoma is based on primary tumor thickness and the presence of ulceration, mitoses, lymph node spread, and distant metastases as determinants of prognosis. Although this cutaneous melanoma staging system has evolved over time to more accurately reflect patient prognosis, improvements are still needed, because current understanding of the particular factors (genetic mutation, expression alteration, host response, etc) that are critical for predicting patient outcomes is incomplete. Given the clinical and biologic heterogeneity of primary melanomas, new prognostic tools are needed to more precisely identify patients who are most likely to develop advanced disease. Such tools would affect clinical surveillance strategies and aid in patient selection for adjuvant therapy. The authors reviewed the literature on prognostic molecular and immunologic markers in primary cutaneous melanoma, their associations with clinicopathologic and survival outcomes, and their potential for incorporation into current staging models. Overall, the studies considered in this review did not define prognostic markers that could be readily incorporated into the current staging system. Therefore, efforts should be continued in these and other directions to maximize the likelihood of identifying clinically useful prognostic biomarkers for cutaneous melanoma.

Early-stage non-Spitzoid cutaneous melanoma in patients younger than 22 years of age at diagnosis: long-term follow-up and survival analysis

PURPOSE

We evaluated prognostic factors among young patients with early stage melanoma, with particular attention to survival, recurrence, and development of a second primary melanoma.

METHODS

We retrospectively reviewed patients (age <22 years) with pathologically confirmed in-situ and stage 1 non-Spitzoid melanoma treated at our institution from 1980-2010, assessing demographics, clinical presentation, treatment, disease-specific survival, recurrence-free survival, and probability of developing a second primary melanoma.

RESULTS

One hundred patients with in-situ melanoma (n=16) or stage 1A (n=48) or 1B (n=36) melanoma were identified. Median age was 19.4 years (range, 11.2-21.9), and median follow-up was 7.6 years (range, 0.1-31.7). Median tumor thickness was 0.76 mm (range, 0.23-2.0). No lesions were ulcerated. All patients underwent wide local excision with negative margins, and 21 had a concomitant negative sentinel lymph node biopsy (SLNB). Sixteen patients developed recurrences, and 8 subsequently died of progressive melanoma. There were 2 non-melanoma-related deaths. Endpoints were 20-year overall survival (77.4%), melanoma-specific mortality (20.1%), recurrence rate (34.0%), and probability of developing a second primary melanoma (24.7%). Greater tumor depth and Clark level were associated with worse prognosis, but age, sex, and tumor mitotic rate were not correlated with recurrence or survival.

CONCLUSION

Among younger early-stage melanoma patients, greater lesion depth conferred higher recurrence risk and mortality. Our data did not define the role of sentinel lymph node biopsy in this group.

Association Between NRAS and BRAF Mutational Status and Melanoma-Specific Survival Among Patients With Higher-Risk Primary Melanoma

IMPORTANCE

NRAS and BRAF mutations in melanoma inform current treatment paradigms, but their role in survival from primary melanoma has not been established. Identification of patients at high risk of melanoma-related death based on their primary melanoma characteristics before evidence of recurrence could inform recommendations for patient follow-up and eligibility for adjuvant trials.

OBJECTIVE

To determine tumor characteristics and survival from primary melanoma by somatic NRAS and BRAF status.

DESIGN, SETTING, AND PARTICIPANTS

A population-based study with a median follow-up of 7.6 years (through 2007), including 912 patients from the United States and Australia in the Genes, Environment, and Melanoma (GEM) Study, with first primary cutaneous melanoma diagnosed in the year 2000 and analyzed for NRAS and BRAF mutations.

MAIN OUTCOMES AND MEASURES

Tumor characteristics and melanoma-specific survival of primary melanoma by NRAS and BRAF mutational status.

RESULTS

The melanomas were 13% NRAS+, 30% BRAF+, and 57% with neither NRAS nor BRAF mutation (wildtype [WT]). In a multivariable model including clinicopathologic characteristics, relative to WT melanoma (with results reported as odds ratios [95% CIs]), NRAS+ melanoma was associated with presence of mitoses (1.8 [1.0-3.3]), lower tumor-infiltrating lymphocyte (TIL) grade (nonbrisk, 0.5 [0.3-0.8]; and brisk, 0.3 [0.5-0.7] [vs absent TILs]), and anatomic site other than scalp/neck (0.1 [0.01-0.6] for scalp/neck vs trunk/pelvis), and BRAF+ melanoma was associated with younger age (ages 50-69 years, 0.7 [0.5-1.0]; and ages >70 years, 0.5 [0.3-0.8] [vs <50 years]), superficial spreading subtype (nodular, 0.5 [0.2-1.0]; lentigo maligna, 0.4 [0.2-0.7]; and unclassified/other, 0.2 [0.1-0.5] [vs superficial spreading]), and presence of mitoses (1.7 [1.1-2.6]) (P < .05 for all). There was no significant difference in melanoma-specific survival (reported as hazard ratios [95% CIs]) for melanoma harboring mutations in NRAS (1.7 [0.8-3.4]) or BRAF (1.5 [0.8-2.9]) compared with WT melanoma, as adjusted for age, sex, site, American Joint Committee on Cancer (AJCC) tumor stage, TIL grade, and study center. However, melanoma-specific survival was significantly poorer for higher-risk (T2b or higher stage) tumors with NRAS (2.9 [1.1-7.7]) or BRAF (3.1 [1.2-8.5]) mutations (P = .04) but not for lower-risk (T2a or lower) tumors with NRAS (0.9 [0.3-3.0]) or BRAF (0.6 [0.2-1.7]) (P = .65), as adjusted for age, sex, site, AJCC tumor stage, TIL grade, and study center.

CONCLUSIONS AND RELEVANCE

Lower TIL grade for NRAS+ melanoma suggests it has a more immunosuppressed microenvironment, which may affect its response to immunotherapies. The approximate 3-fold increased risk of death for higher-risk tumors harboring NRAS or BRAF mutations after adjusting for other prognostic factors compared with WT melanomas indicates that the prognostic implication of these mutations deserves further investigation, particularly in higher–AJCC stage primary melanomas.

Immunohistochemistry in dermatopathology

CONTEXT

Immunohistochemistry is not a diagnostic test but a highly valuable tool that requires interpretation within a context.

OBJECTIVE

To review the current status and limitations of immunohistochemistry in dermatopathology.

DATA SOURCES

English-language literature published between 1980 and 2014.

CONCLUSIONS

Although immunohistochemistry is rarely completely specific or sensitive, it is an important adjunctive technique in dermatopathology and can be helpful in a series of diagnostic dilemmas.

Comparison of clinicopathologic features and survival of histopathologically amelanotic and pigmented melanomas: a population-based study

IMPORTANCE Previous studies have reported that histopathologically amelanotic melanoma is associated with poorer survival than pigmented melanoma; however, small numbers of amelanotic melanomas, selected populations, lack of centralized pathologic review, or no adjustment for stage limit the interpretation or generalization of results from prior studies.OBJECTIVE To compare melanoma-specific survival between patients with histopathologically amelanotic and those with pigmented melanoma in a large international population-based study.DESIGN, SETTING, AND PARTICIPANTS Survival analysis with a median follow-up of 7.6 years.The study population comprised 2995 patients with 3486 invasive primary melanomas centrally scored for histologic pigmentation from the Genes, Environment, and Melanoma(GEM) Study, which enrolled incident cases of melanoma diagnosed in 1998 through 2003 from international population-based cancer registries.MAIN OUTCOMES AND MEASURES Clinicopathologic predictors and melanoma-specific survival of histologically amelanotic and pigmented melanoma were compared using generalized estimating equations and Cox regression models, respectively.RESULTS Of 3467 melanomas, 275 (8%) were histopathologically amelanotic. Female sex,nodular and unclassified or other histologic subtypes, increased Breslow thickness, presence of mitoses, severe solar elastosis, and lack of a coexisting nevus were independently associated with amelanotic melanoma (each P < .05). Amelanotic melanoma was generally ofa higher American Joint Committee on Cancer (AJCC) tumor stage at diagnosis (odds ratios[ORs] [95%CIs] between 2.9 [1.8-4.6] and 11.1 [5.8-21.2] for tumor stages between T1b and T3b and ORs [95%CIs] of 24.6 [13.6-44.4] for T4a and 29.1 [15.5-54.9] for T4b relative to T1a;P value for trend, <.001) than pigmented melanoma. Hazard of death from melanoma was higher for amelanotic than for pigmented melanoma (hazard ratio [HR], 2.0; 95%CI, 1.4-3.0)(P < .001), adjusted for age, sex, anatomic site, and study design variables, but survival did not differ once AJCC tumor stage was also taken into account (HR, 0.8; 95%CI, 0.5-1.2)(P = .36).CONCLUSIONS AND RELEVANCE At the population level, survival after diagnosis of amelanotic melanoma is poorer than after pigmented melanoma because of its more advanced stage at diagnosis. It is probable that amelanotic melanomas present at more advanced tumor stages because they are difficult to diagnose. The association of amelanotic melanoma with presence of mitoses independently of Breslow thickness and other clinicopathologic characteristics suggests that amelanotic melanomas might also grow faster than pigmented melanomas. New strategies for early diagnosis and investigation of the biological properties of amelanotic melanoma are warranted.

Assessment of tumor mitotic rate in primary cutaneous malignant melanomas 1 mm or less in thickness

BACKGROUND

Tumor mitotic rate in thin melanomas is recognized as a powerful, independent prognostic factor predicting survival. In nonulcerated cases, the presence of any dermal mitotic activity upstages the disease to pT1b. The extent to which tissue should be histologically examined to assess mitogenicity, however, has not been studied.

OBJECTIVE

We sought to determine whether in staging thin melanomas, there is a significant benefit in examining numerous tissue sections containing invasive disease.

METHOD

In all, 71 cases of thin cutaneous melanomas diagnosed between January 2012 and June 2013 were identified after a search performed on the Pathlab database. The slides were retrieved and reviewed retrospectively, comparing the identification of the first dermal tumor mitotic figure, if present, at 4 check-points: the first, third, fifth, or tenth tissue section examined.

RESULTS

A statistically significant difference in identification of the first dermal mitotic figure was found in examining 1 versus 3 tissue sections (P = .0411). No significant difference was found in examining numerous tissue sections.

LIMITATIONS

This was a retrospective study from a single institution with a limited number of participants.

CONCLUSION

In staging thin melanomas without ulceration, the optimal number of sections to assess is 3. No additional benefit is gained by examining numerous tissue sections.

Identification of metastasis-suppressive microRNAs in primary melanoma

BACKGROUND

Surgical management of primary melanoma is curative for most patients with clinically localized disease at diagnosis; however, a substantial number of patients recur and progress to advanced disease. Understanding molecular alterations that influence differential tumor progression of histopathologically similar lesions may lead to improved prognosis and therapies to slow or prevent metastasis.

METHODS

We examined microRNA dysregulation by expression profiling of primary melanoma tumors from 92 patients. We screened candidate microRNAs selected by differential expression between recurrent and nonrecurrent tumors or associated with primary tumor thickness (Student's t test, Benjamini-Hochberg False Discovery Rate [FDR] < 0.05), in in vitro invasion assays. We performed in vivo metastasis assays, matrix remodeling experiments, and molecular studies to identify metastasis-regulating microRNAs and their cellular and molecular mechanisms. All statistical tests were two-sided.

RESULTS

We identified two microRNAs (hsa-miR-382, hsa-miR-516b) whose expression was lower in aggressive vs nonaggressive primary tumors, which suppressed invasion in vitro and metastasis in vivo (mean metastatic foci: control: 37.9, 95% confidence interval [CI] = 25.6 to 50.2; miR-382: 19.5, 95% CI = 12.2 to 26.9, P = .009; miR-516b: 12.5, 95% CI = 7.7 to 17.4, P < .001, Student's t test). Mechanistically, miR-382 overexpression inhibits extracellular matrix degradation by melanoma cells. Moreover, we identified actin regulators CTTN, RAC1, and ARPC2 as direct targets of miR-382. Depletion of CTTN partially recapitulates miR-382 effects on matrix remodeling, invasion, and metastasis. Inhibition of miR-382 in a weakly tumorigenic melanoma cell line increased tumor progression and metastasis in vivo.

CONCLUSIONS

Aberrant expression of specific microRNAs that can functionally impact progression of primary melanoma occurs as an early event of melanomagenesis.

5-Hydroxymethylcytosine expression in metastatic melanoma versus nodal nevus in sentinel lymph node biopsies

Sentinel lymph node biopsies are conducted to stage patients with newly diagnosed melanomas that have histopathological attributes conferring defined levels of metastatic potential. Because benign nevic cells may also form 'deposits' in lymph nodes (nodal nevus), the pathological evaluation for metastatic melanoma within sentinel lymph nodes can be challenging. Twenty-eight sentinel lymph node biopsy cases containing either metastatic melanoma (N=18) or nodal nevi (N=10) were retrieved from the archives of the Brigham and Women's Hospital, Department of Pathology (2011-2014). In addition, two sentinel lymph node cases that were favored to represent metastatic disease but whose histopathological features were viewed as equivocal, with melanoma favored, were also included. Dual labeling for the melanocyte lineage marker, MART-1, and the epigenetic marker, 5-hydroxymethylcytosine, a functionally significant indicator that has been shown to distinguish benign nevi from melanoma, was performed on all cases using immunohistochemistry and/or direct immunofluorescence. All (18 of 18) metastatic melanoma cases showed complete loss of 5-hydroxymethylcytosine nuclear staining in MART-1-positive cells, and all (10 of 10) nodal nevus cases demonstrated 5-hydroxymethylcytosine nuclear staining in MART-1-positive cells. In addition, 5-hydroxymethylcytosine staining confirmed the favored diagnoses of metastatic melanoma in the two 'equivocal' cases. Thus, 5-hydroxymethylcytosine may be a useful adjunctive marker to distinguish between benign nodal nevi and metastatic melanoma during the evaluation of sentinel lymph node biopsies for metastatic melanoma.

Overexpression of HMGB1 in melanoma predicts patient survival and suppression of HMGB1 induces cell cycle arrest and senescence in association with p21 (Waf1/Cip1) up-regulation via a p53-independent, Sp1-dependent pathway

Although laboratory studies have implicated the high mobility group box 1 (HMGB1) in melanoma, its clinical relevance remains unclear. We analyzed nearly 100 cases of human melanoma and found that HMGB1 was highly overexpressed in melanoma samples relative to normal skin and nevi tissues. Significantly, higher levels of HMGB1 correlated with more advanced disease stages and with poorer survival in melanoma patients. Unlike the well-documented pro-inflammatory role of the extracellular HMGB1, we found that its intracellular activity is necessary for melanoma cell proliferation. An absolute dependency of melanoma cell proliferation on HMGB1 was underscored by the marked response of cell cycle arrest and senescence to HMGB1 knockdown. We demonstrated that HMGB1 deficiency-induced inhibition of cell proliferation was mediated by p21, which was induced via a Sp1-dependent mechanism. Taken together, our data demonstrate a novel oncogenic role of HMGB1 in promoting human melanoma cell proliferation and have important implications in melanoma patient care.

A probabilistic analysis of mitotic counts in melanoma

OBJECTIVES

Mitotic counts in melanoma are important and have now become part of the staging of this tumor. Yet, this change was largely based on studies that evaluated the mitotic counts in a limited fashion. Because counts of things with a microscope are often distributed as a Poisson random variable, the major goal of this study was to uncover the probabilistic nature of mitotic counts in melanoma.

METHODS

Specifically, a general double Poisson model was applied to mitotic counts in 53 cutaneous melanomas representing both thin and thick tumors.

RESULTS

The general double Poisson probability model fit the data well. A single Poisson function was sufficient for 46 of the 53 study cases, and two Poisson functions were required for seven cases because of tissue heterogeneity. Furthermore, the success of the model implied that there is a high probability for false-negative mitotic counts, especially in thin melanomas, and that the "hot" spot methodology introduces bias.

CONCLUSIONS

Mitotic counts in melanomas are a probabilistic phenomenon closely related to the Poisson probability distribution, and this factor needs to be considered when using mitotic counts for staging and prognosis in melanoma.

Impact of the 2009 (7th edition) AJCC melanoma staging system in the classification of thin cutaneous melanomas

CONTEXT

The 7th (2009) edition of the AJCC melanoma staging system incorporates tumor (Breslow) thickness, MR, and ulceration in stratifying T1 primary melanomas. Compared to the prior 6th (2001) edition, MR has replaced CL for thin melanomas.

OBJECTIVE

We sought to identify and report differences of the classification of thin melanomas as well as outcome of SLNB in patients according to the 6th and 7th editions at our institution.

RESULTS

106 patients were identified with thin melanomas verified by wide excision. 31 of 106 thin melanomas were reclassified according to the 7th edition of the AJCC. Of those 31, 15 CL II/III patients (6th edition T1a) were reclassified as T1b based on the presence of mitoses while 16 CL IV patients (6th edition T1b) were categorized as T1a based on the absence of mitoses. 26/31 reclassified patients underwent SLNB, and all were negative. Patients with thin melanoma and a +SLNB (N = 3) were all classified as T1b according to both staging systems.

CONCLUSIONS

In our experience, 29% of thin melanomas were reclassified according to the 7th edition with similar proportions of patients re-distributed as T1a (14%) and T1b (15%). Cases with +SLN corresponded with T1b lesions in both 6th and 7th editions.

Tumor-infiltrating lymphocyte grade in primary melanomas is independently associated with melanoma-specific survival in the population-based genes, environment and melanoma study

PURPOSE

Although most hospital-based studies suggest more favorable survival with tumor-infiltrating lymphocytes (TILs) present in primary melanomas, it is uncertain whether TILs provide prognostic information beyond existing melanoma staging definitions. We addressed the issue in an international population-based study of patients with single and multiple primary melanomas.

PATIENTS AND METHODS

On the basis of the Genes, Environment and Melanoma (GEM) study, we conducted follow-up of 2,845 patients diagnosed from 1998 to 2003 with 3,330 invasive primary melanomas centrally reviewed for TIL grade (absent, nonbrisk, or brisk). The odds of TIL grades associated with clinicopathologic features and survival by TIL grade were examined.

RESULTS

Independent predictors (P < .05) for nonbrisk TIL grade were site, histologic subtype, and Breslow thickness, and for brisk TIL grade, they were age, site, Breslow thickness, and radial growth phase. Nonbrisk and brisk TIL grades were each associated with lower American Joint Committee on Cancer (AJCC) tumor stage compared with TIL absence (P(trend) < .001). Death as a result of melanoma was 30% less with nonbrisk TIL grade (hazard ratio [HR], 0.7; 95% CI, 0.5 to 1.0) and 50% less with brisk TIL grade (HR, 0.5; 95% CI, 0.3 to 0.9) relative to TIL absence, adjusted for age, sex, site, and AJCC tumor stage.

CONCLUSION

At the population level, higher TIL grade of primary melanoma is associated with a lower risk of death as a result of melanoma independently of tumor characteristics currently used for AJCC tumor stage. We conclude that TIL grade deserves further prospective investigation to determine whether it should be included in future AJCC staging revisions.

Proliferation indices of phosphohistone H3 and Ki67: strong prognostic markers in a consecutive cohort with stage I/II melanoma

Cellular proliferation is correlated with the progression of melanoma. Accordingly, the proliferation index of H&E-stained thin melanomas was recently included in the staging system of the American Joint Committee on Cancer. Yet, the immunohistochemical markers of proliferation phosphohistone H3 and Ki67 may improve such indices. To accurately quantify these markers, they should be combined with a melanocytic marker, for example, MART1 in an immunohistochemical double stain; also enabling automated quantification by image analysis. The aim of the study was to compare the prognostic impact of phosphohistone H3/MART1, Ki67/MART1, and H&E stains in primary cutaneous melanoma, and to determine the difference between indices established in hot spots and the global tumor areas. The study included 153 consecutive stage I/II melanoma-patients. The follow-up time was 8-14 years for event-free melanoma. Recurrent disease occurred in 43 patients; 37 died of melanoma. Both events occurred in only three thin melanomas. Their paraffin-embedded tissue was stained for phosphohistone H3/MART1, Ki67/MART1, and with H&E. And proliferation indices were established in 1-mm(2) hot spots and in the global tumor areas. In multivariate Cox analyses, only hot spot indices of phosphohistone H3/MART1 and Ki67/MART1 were independent prognostic markers. Phosphohistone H3/MART1 tended to be better than Ki67/MART1 with adjusted hazard ratios of 3.66 (95% CI, 1.40-9.55; P=0.008) for progression-free survival and 3.42 (95% CI, 1.29-9.04; P=0.013) for melanoma-specific death. In all stains, prognostic performance was substantially improved by using hot spots instead of the global tumor areas. In conclusion, phosphohistone H3/MART1 and Ki67/MART1 were superior to H&E stains, and hot spots superior to the global tumor areas. Given the potential for automated analysis, these double stains seem to be robust alternatives to conventional mitotic detection by H&E in stage I/II melanomas in general. This was particularly true for thick melanomas whereas no specific analyses for thin melanomas only could be performed.

Melanoma staging: where are we now?

The seventh version of the American Joint Committee on Cancer (AJCC) Melanoma Staging guidelines, published in 2009, has significant revisions compared with the previous version. The current schema was based on the largest melanoma patient cohort analyzed to date and is the result of a multivariate analysis of 30,946 patients with stages I, II, and III melanoma and 7972 patients with stage IV melanoma. This article summarizes the findings and the new definitions included in the 2009 AJCC Melanoma Staging and Classification. The TNM categories and the stage groupings are defined. Changes in the melanoma staging system are summarized.

The pathology of melanoma

Although melanoma represents only 10% of all skin cancer diagnoses, it accounts for at least 65% of all skin cancer-related deaths. The number of new cutaneous melanoma cases projected during 2010 was 68,000-a 23% increase from the 2004 prediction of 55,100 cases. In 2015, the lifetime risk of developing melanoma is estimated to increase to 1 in 50. As the incidence of melanoma continues to rise, now more than ever, clinicians and histopathologists must have familiarity with the various clinical and pathologic features of cutaneous melanoma.

Single versus multiple primary melanomas: old questions and new answers

BACKGROUND

In patients with multiple primary melanomas (MPM), mean tumor thickness tends to decrease from the first melanoma to the second melanoma, and prognosis may be improved compared with the prognosis for patients who have a single primary melanoma (SPM). In this study, the authors compared the clinicopathologic features of patients with MPM and SPM to better characterize the differences between these 2 groups and to determine whether or not there is an inherent difference in tumor aggression.

METHODS

In total, 788 patients with melanoma who were enrolled prospectively in the Interdisciplinary Melanoma Cooperative Group database from 2002 to 2008 were studied. Patients with SPM and with MPM were compared with regard to clinical and primary melanoma characteristics.

RESULTS

Of 788 patients with melanoma, 61 patients (7.7%) had 2 or more primary melanomas. The incidence of developing a second primary melanoma 1 year and 5 years after initial melanoma diagnosis was 4.1% and 8.7%, respectively, and most of the risk accumulated within the first year. The incidence of MPM was greater in patients aged ≥60 years than in those aged ≤60 years. The absence or presence of mitosis and other tumor characteristics did not differ significantly between patients with SPM and patients with MPM (P = .61).

CONCLUSIONS

No difference was observed in the presence or absence of mitoses, a marker of tumor proliferation, in SPM and MPM. Because it has been demonstrated that the presence of mitosis is a powerful prognostic marker, the current findings suggested that the tumors behave similarly in patients with SPM and patients with MPM. The authors concluded that differences in tumor thickness and prognosis between SPM and MPM more likely are caused by factors other than tumor biology, such as increased surveillance.

5th Canadian Melanoma Conference: research frontiers

The prospects for the treatment of metastatic melanoma are improving. Whereas previous scientific meetings dedicated to the treatment of metastatic melanoma patients were overshadowed by our inability to improve overall survival or lengthen the time to progression, the results presented at the most recent meetings are hopeful. The 5th Canadian Melanoma Conference held on 24-27 February in Banff (AB, Canada) was nothing short of optimistic. This year's meeting was divided into three themes: basic science and pathology, dermatology and surgery, and immunology and systemic treatment. In addition, dermoscopy case studies were presented, and Hoffmann la Roche sponsored a symposium on the evaluation of treatment for advanced melanoma. It underscored the importance of early detection and patient stratification, based upon the molecular profile of the tumor, in order to optimize the response to targeted therapy.