Recent treatment and prognosis in 643 patients with extramammary Paget's disease.

Information about extramammary Paget's (EMPD) treatment is limited because of the rarity of the disease. The prognosis differs between in situ EMPD and invasive EMPD; therefore, therapy should be planned according to the disease stage. We collected data on 643 EMPD cases treated between 2015 and 2019 in Japan and assessed recent trends in EMPD treatment and prognosis based on the EMPD-oriented TNM staging. Among the 643 patients, 317 had stage 0 (49.3%), 185 had stage I (28.8%), 51 had stage II (7.9%), 18 had stage IIIA (2.8%), 48 had stage IIIB (7.5%) and 24 had stage IV (3.7%) disease. Each stage showed a distinct survival curve, with the exception of stages II and IIIA. Curative surgery was most common in patients with stage 0-III disease. Chemotherapy was the first-line therapy, mainly in patients with stage IIIB and IV disease, most commonly with docetaxel (DTX), followed by DTX + tegafur gimeracil oteracil potassium (TS-1) and TS-1. Patients with local disease exhibited a 4.4% recurrence rate. Univariate analysis revealed no prognostic differences according to age, sex or primary tumour site. SLNB was not related to disease-specific survival. In multivariate analysis, female sex significantly predicted local relapse in stage 0-I (HR 3.09; 95% CI, 1.13-8.43), and initial treatment with curative surgery was significantly protective in terms of disease-specific survival in stage II-IIIA (HR, 0.17; 95% CI, 0.04-0.71) and stage IIIB-IV (HR 0.16; 95% CI, 0.05-0.51). Further clinical studies are needed to improve the prognosis of patients with stage II-IV EMPD.

Systemic therapy for Asian patients with advanced BRAF V600-mutant melanoma in a real-world setting: A multi-center retrospective study in Japan (B-CHECK-RWD study).

BACKGROUND: Anti-PD-1-based immunotherapy is considered a preferred first-line treatment for advanced BRAF V600-mutant melanoma. However, a recent international multi-center study suggested that the efficacy of immunotherapy is poorer in Asian patients in the non-acral cutaneous subtype. We hypothesized that the optimal first-line treatment for Asian patients may be different. METHODS: We retrospectively collected data of Asian patients with advanced BRAF V600-mutant melanoma treated with first-line BRAF/MEK inhibitors (BRAF/MEKi), anti-PD-1 monotherapy (Anti-PD-1), and nivolumab plus ipilimumab (PD-1/CTLA-4) between 2016 and 2021 from 28 institutions in Japan. RESULTS: We identified 336 patients treated with BRAF/MEKi (n = 236), Anti-PD-1 (n = 64) and PD-1/CTLA-4 (n = 36). The median follow-up duration was 19.9 months for all patients and 28.6 months for the 184 pa tients who were alive at their last follow-up. For patients treated with BRAF/MEKi, anti-PD-1, PD-1/CTLA-4, the median ages at baseline were 62, 62, and 53 years (p = 0.03); objective response rates were 69%, 27%, and 28% (p < 0.001); median progression-free survival (PFS) was 14.7, 5.4, and 5.8 months (p = 0.003), and median overall survival (OS) was 34.6, 37.0 months, and not reached, respectively (p = 0.535). In multivariable analysis, hazard ratios (HRs) for PFS of Anti-PD-1 and PD-1/CTLA-4 compared with BRAF/MEKi were 2.30 (p < 0.001) and 1.38 (p = 0.147), and for OS, HRs were 1.37 (p = 0.111) and 0.56 (p = 0.075), respectively. In propensity-score matching, BRAF/MEKi showed a tendency for longer PFS and equivalent OS with PD-1/CTLA-4 (HRs for PD-1/CTLA-4 were 1.78 [p = 0.149]) and 1.03 [p = 0.953], respectively). For patients who received second-line treatment, BRAF/MEKi followed by PD-1/CTLA-4 showed poor survival outcomes. CONCLUSIONS: The superiority of PD-1/CTLA-4 over BRAF/MEKi appears modest in Asian patients. First-line BRAF/MEKi remains feasible, but it is difficult to salvage at progression. Ethnicity should be considered when selecting systemic therapies until personalized biomarkers are available in daily practice. Further studies are needed to establish the optimal treatment sequence for Asian patients.

Clinicopathological demographics of malignant melanomas of the vulva and vagina in Japan.

Malignant vulvar melanoma (VuM) and vaginal melanoma (VaM) represent a unique subgroup of rare malignant melanomas with critical biological properties that differ from other cancers. In Japan, adequate surveys have yet to be conducted. This study aimed to elucidate the clinicopathological demographics and outcomes of VuM and VaM in Japan. This retrospective observational study included women with invasive VuM or VaM identified from older medical records in Japan. We collected clinical data and used the Kaplan-Meier method to analyze progression-free survival (PFS) and overall survival (OS). Univariate and multivariate regression models were used to identify factors significantly related to survival. We identified 217 patients, 109 (50.2%) with VuM and 108 (49.8%) with VaM. The median PFS was 16.8 months in patients with VuM [95% confidence interval (CI), 23.1-87.7] and 15.6 months in those with VaM (95% CI, 8.4-12.6). The median OS was 43.9 months (95% CI, 60-138) and 31.1 months (95% CI, 24.8-45.3) in patients with VuM and VaM, respectively. Multivariate analysis showed that a disease stage higher than stage III, based on the American Joint Committee on Cancer (AJCC) guidelines, was associated with poorer PFS [hazard ratio (HR), 2.063; 95% CI, 0.995-4.278] and an unknown surgical margin was the only independent factor influencing OS (HR, 2.188; 95% CI, 1.203-3.977). The overall outcomes of invasive VuM and VaM in Japan remain poor. AJCC staging and surgical margins were significant predictors of survival.

Concordance in judgment of clinical borders of basal cell carcinomas in Japanese patients: A preliminary study of JCOG2005 (J-BASE-MARGIN).

Basal cell carcinoma is the most common type of skin cancer, and surgical excision with clear margins is the standard of care. Surgical margins are determined based on risk factors (high or low risk) for recurrence according to the National Comprehensive Cancer Network and Japanese basal cell carcinoma guidelines. The clarity of the clinical tumor border (well-defined or poorly defined) is considered a risk factor, and significant discrepancies in the judgment of clinical tumor borders among dermato-oncologists may occur. Therefore, we analyzed the dermato-oncologists' concordance in judging the clinical tumor border of basal cell carcinoma. Forty-seven dermato-oncologists (experts: 37; young trainees: 10) participated in this study. The datasets of clinical and dermoscopic photographs of 79 Japanese cases of head and neck basal cell carcinoma were used to determine the concordance in the judgment of clinical tumor border. The probability of the border that was selected more often was used to calculate the rater agreement rate for each dataset. Correct judgment was defined as a more frequently selected border, and the concordance rate of clarity of clinical tumor border for each dermato-oncologist was calculated based on the definition of the correct judgment. A median concordance rate of 85% or higher for all dermato-oncologists was predefined as an acceptable rate for clinical use. Of the 79 datasets, rater agreement rates were 80-100%, 60-79%, and 51-59% for 55, 19, and five datasets, respectively. The median concordance rate for all dermato-oncologists was 86% (interquartile range: 82-89%). There was no significant difference in the concordance rate between the experts and the trainees (median, 87% vs. 85.5%; p = 0.58). The concordance rates of dermato-oncologists for all datasets were relatively high and acceptable for clinical use.

Significance of 5-S-Cysteinyldopa as a Marker for Melanoma.

Melanoma is one of the most lethal and malignant cancers and its incidence is increasing worldwide, and Japan is not an exception. Although there are numerous therapeutic options for melanoma, the prognosis is still poor once it has metastasized. The main concern after removal of a primary melanoma is whether it has metastasized, and early detection of metastatic melanoma would be effective in improving the prognosis of patients. Thus, it is very important to identify reliable methods to detect metastases as early as possible. Although many prognostic biomarkers (mainly for metastases) of melanoma have been reported, there are very few effective for an early diagnosis. Serum and urinary biomarkers for melanoma diagnosis have especially received great interest because of the relative ease of sample collection and handling. Several serum and urinary biomarkers appear to have significant potential both as prognostic indicators and as targets for future therapeutic methods, but still there are no efficient serum and urinary biomarkers for early detection, accurate diagnosis and prognosis, efficient monitoring of the disease and reliable prediction of survival and recurrence. Levels of 5-S-cysteinyldopa (5SCD) in the serum or urine as biomarkers of melanoma have been found to be significantly elevated earlier and to reflect melanoma progression better than physical examinations, laboratory tests and imaging techniques, such as scintigraphy and echography. With recent developments in the treatment of melanoma, studies reporting combinations of 5SCD levels and new applications for the treatment of melanoma are gradually increasing. This review summarizes the usefulness of 5SCD, the most widely used and well-known melanoma marker in the serum and urine, compares 5SCD and other useful markers, and finally its application to other fields.

Clinical and histopathological characteristics and survival analysis of 4594 Japanese patients with melanoma.

BACKGROUND: The incidence of melanoma among those of an Asian ethnicity is lower than in Caucasians; few large-scale Asian studies that include follow-up data have been reported. OBJECTIVES: To investigate the clinical characteristics of Japanese patients with melanoma and to evaluate the prognostic factors. METHODS: Detailed patient information was collected from the database of Japanese Melanoma Study Group of the Japanese Skin Cancer Society. The American Joint Committee on Cancer seventh Edition system was used for TNM classification. The Kaplan-Meier method and Cox proportional hazards model were used to estimate the impact of clinical and histological parameters on disease-specific survival in patients with invasive melanoma. RESULTS: In total, 4594 patients were included in this analysis. The most common clinical type was acral lentiginous melanoma (40.4%) followed by superficial spreading melanoma (20.5%), nodular melanoma (10.0%), mucosal melanoma (9.5%), and lentigo maligna melanoma (8.1%). The 5-year disease-specific survival for each stage was as follows: IA = 98.0%, IB = 93.9%, IIA = 94.8%, IIB = 82.4%, IIC = 71.8%, IIIA = 75.0%, IIIB = 61.3%, IIIC = 41.7%, and IV = 17.7%. Although multivariate analysis showed that clinical classifications were not associated with survival across all stages, acral type was an independent poor prognostic factor in stage IIIA. CONCLUSIONS: Our study revealed the characteristics of melanoma in the Japanese population. The 5-year disease-specific survival of each stage showed a similar trend to that of Caucasians. While clinical classification was not associated with survival in any stages, acral type was associated with poor survival in stage IIIA. Our result might indicate the aggressiveness of acral type in certain populations.

Classification of 3097 patients from the Japanese melanoma study database using the American joint committee on cancer eighth edition cancer staging system.

BACKGROUND: The American Joint Committee on Cancer (AJCC) 8th Edition Cancer Staging System was implemented in 2018; however, it has not been validated in an Asian melanoma population. OBJECTIVE: The purpose of this study was to validate the new system using a cohort of Japanese melanoma patients. METHODS: The AJCC 7th and 8th Editions were used for TNM classification of patients in a database established by the Japanese Melanoma Study Group. Patient data with sufficient information to be applicable to the AJCC 8th staging were selected. The Kaplan-Meier method was used to estimate disease-specific survival and relapse-free survival. RESULTS: In total, data for 3097 patients were analyzed. The 5-year disease-specific survival according to the 7th and 8th Edition staging system were as follows: IA = 98.5%/97.9%; IB = 95.4%/96.2%; IIA = 94.2%/94.1%; IIB = 84.6%/84.4%; IIC = 72.2%/72.2%; IIIA = 76.2%/87.5%; IIIB = 60.7%/72.6%; IIIC = 42.0%/55.3% and IIID = none/26.0%. The 5-year relapse-free survival according to the 7th and 8th Edition staging was as follows: IA = 94.5%/92.7%; IB = 85.4%/85.3%; IIA = 80.1%/79.4%; IIB = 71.4%/70.6%; IIC = 56.8%/55.7%; IIIA = 56.8%/69.4%; IIIB = 42.6%/56.8%; IIIC = 20.0%/33.3% and IIID = none/6.5%. CONCLUSION: The results show that new staging system could efficiently classify our Japanese melanoma cohort. Although there was no difference in Stage I and II disease between the 7th and 8th Edition systems, we should be careful in managing Stage III disease since the survival curves of the 8th Edition staging were completely different from the 7th Edition. Moreover, our results indicate that adjuvant therapies for Stage IIB and IIC should be developed, since the relapse-free survival for these stages were equivalent to Stage IIIA and IIIB, respectively.

Prognostic Factors of Extramammary Paget's Disease.

OPINION STATEMENT: Most patients with extramammary Paget's disease (EMPD) show a good prognosis; however, some patients develop fatal metastases. Early detection is important for improving prognosis, due to the difficulties associated with the treatment of distant EMPD metastases. Several studies have emphasized the importance of the invasion level of the primary lesion for predicting the presence of metastasis, and deeper invasion or increased thickness is correlated with poorer prognosis. Vascular tumor invasion of the primary lesion can also predict the risk of metastasis. Lymph node metastasis is a strong indicator for poor prognosis, and the number of lymph node metastases affects patient outcome, in that there is a significant difference in survival between patients with zero or one lymph node metastasis and those with more than two lymph node metastases. Serum markers may be able to predict the presence of systemic metastases, and carcinoembryonic antigen and cytokeratin 19 fragment 21-1 reflect disease progression and may be clinically valuable. Although several genetic alterations have been determined for EMPD, factors determining prognosis should be further explored.

The first nationwide surveillance of antibacterial susceptibility patterns of pathogens isolated from skin and soft-tissue infections in dermatology departments in Japan.

To investigate the trends of antimicrobial resistance in pathogens isolated from skin and soft-tissue infections (SSTI) at dermatology departments in Japan, a Japanese surveillance committee conducted the first nationwide survey in 2013. Three main organisms were collected from SSTI at 30 dermatology departments in medical centers and 10 dermatology clinics. A total of 860 strains - 579 of Staphylococcus aureus, 240 of coagulase-negative Staphylococci, and 41 of Streptococcus pyogenes - were collected and shipped to a central laboratory for antimicrobial susceptibility testing. The patient profiles were also studied. Among all 579 strains of S. aureus, 141 (24.4%) were methicillin-resistant (MRSA). Among 97 Staphylococcus epidermidis strains, 54 (55.7%) were methicillin-resistant (MRSE). MRSA and MRSE were more frequently isolated from inpatients than from outpatients. Furthermore, these methicillin-resistant strains were also isolated more frequently from patients with histories of taking antibiotics within 4 weeks and hospitalization within 1 year compared to those without. However, there were no significant differences in MIC values and susceptibility patterns of the MRSA strains between patients with a history of hospitalization within 1 year and those without. Therefore, most of the isolated MRSA cases at dermatology departments are not healthcare-acquired, but community-acquired MRSA. S. pyogenes strains were susceptible to most antibiotics except macrolides. The information in this study is not only important in terms of local public health but will also contribute to an understanding of epidemic clones of pathogens from SSTI.

A proposal for a TNM staging system for extramammary Paget disease: Retrospective analysis of 301 patients with invasive primary tumors.

BACKGROUND: Although extramammary Paget disease (EMPD) usually appears as carcinoma in situ, it sometimes becomes invasive (iEMPD) and fatal. However, a TNM staging system for iEMPD has yet to be established. OBJECTIVE: The aim of this study was to establish a TNM staging system for iEMPD. METHODS: We retrospectively collected iEMPD patients treated at 12 institutes in Japan. Factors reported to be associated with survival such as distant metastasis, lymph node (LN) metastasis, and primary tumor status were evaluated using the log-rank test. RESULTS: We enrolled 301 iEMPD patients, of whom 114 had remote metastases (49 had both distant and LN metastasis; 2, distant metastasis only; and 63, LN metastasis only) and the remaining 187 patients had no remote metastasis. Distant metastasis (M1) showed worse survival (P<0.00001). In the analysis of the 250 patients without distant metastasis, LN metastasis also showed worse survival (P<0.00001). Among the patients with LN metastasis, 2 or more LN metastases (N2) showed worse survival than did single LN metastasis (N1, P=0.02). Lastly, in the analysis of the 187 patients without metastasis, tumor thickness of over 4mm or lymphovascular invasion showed worse survival (T2, P<0.05 and P<0.001, respectively). Patients with neither of these features were defined as T1. From these results, we propose this TNM staging system: stage I, T1N0M0; stage II, T2N0M0; stage IIIa, anyTN1M0; stage IIIb, anyTN2M0; stage IV, anyTanyNM1. Other than stages II and IIIa, each stage had a statistically distinct survival curve. CONCLUSION: We propose a TNM staging system for EMPD using simple factors for classification that could provide important prognostic information in managing EMPD. However, accumulation of more patient data and further revision of the system are required.

Frequency of level II and III axillary nodes metastases in patients with positive sentinel lymph nodes in melanoma: a multi-institutional study in Japan.

BACKGROUND: Axillary lymph node dissection (ALND) has been recommended to include levels I-III for melanoma patients who have evidence of metastasis in the axillary sentinel lymph node (SLN). The extent of the subsequent axillary dissection is in debate. The objective of this study was to determine the frequency of metastasis of level III nodes in addition to that of level II nodes in this setting. METHODS: A multi-institutional retrospective study was undertaken in 14 melanoma treatment centers in Japan. RESULTS: Between 2007 and 2012, 69 patients with involved axillary SLNs underwent a subsequent ALND and 55 underwent level I and II dissections. Level III metastatic nodes, which is our primary endpoint, were seen in only 1 patient (1.5 %). The level II metastatic rate was 4.4 %. CONCLUSIONS: Our study sample size was small, but melanoma patients with positive SLN rarely had level III disease, suggesting that level III dissection may be unnecessary. We also found that level II metastasis was not so frequent. More evidence is needed to standardize the extent of ALND and to identify the patients who would have the most benefit with undergoing level II dissection for positive axillary SLNs.

Peripheral blood Th9 cells are a possible pharmacodynamic biomarker of nivolumab treatment efficacy in metastatic melanoma patients.

Although nivolumab is associated with a significant improvement in overall survival and progression-free survival, only 20 to 40% of patients experience long-term benefit. It is therefore of great interest to identify a predictive marker of clinical benefit for nivolumab. To address this issue, the frequencies of CD4+ T cell subsets (Treg, Th1, Th2, Th9, Th17 and Th22), CD8+ T cells, and serum cytokine levels (IFNγ, IL-4, IL-9, IL-10, TGF-ß) were assessed in 46 patients with melanoma. Eighteen patients responded to nivolumab, and the other 28 patients did not. An early increase in Th9 cell counts during the treatment with nivolumab was associated with an improved clinical response. Before the first nivolumab infusion, the responders displayed elevated serum concentrations of TGF-ß compared to non-responders. Th9 induction by IL-4 and TGF-ß was enhanced by PD-1/PD-L1 blockade in vitro. The role of IL-9 in disease progression was further assessed using a murine melanoma model. In vivo IL-9 blockade promoted melanoma progression in mice using an autochthonous mouse melanoma model, and the cytotoxic ability of murine melanoma-specific CD8+ T cells was enhanced in the presence of IL-9 in vitro. These findings suggest that Th9 cells, which produce IL-9, play an important role in the successful treatment of melanoma patients with nivolumab. Th9 cells therefore represent a valid biomarker to be further developed in the setting of anti-PD-1 therapy.

Usefulness of docetaxel as first-line chemotherapy for metastatic extramammary Paget's disease.

In invasive extramammary Paget's disease (EMPD), distant metastases may develop and the condition may become fatal; however, no standardized treatment has been established. Although based on only a few cases, several chemotherapy regimens were reported to be promising. We conducted a multicenter, retrospective study to evaluate the efficacy of docetaxel for metastatic EMPD. We retrospectively collected data on 18 metastatic EMPD patients treated using docetaxel from 1998 to 2012 in 12 institutes in Japan. The following clinical data were collected: tumor response, time to progression, overall survival and adverse effects. Of those, three patients treated combined with S-1, one patient treated with weekly schedule and one patient treated combined with radiotherapy were excluded from the further analysis. All 13 patients received monthly docetaxel as the first-line treatment. The average number of treatment cycles was 9.1. Among the 12 patients with a confirmed response, seven (58%) showed a partial response, three (25%) stable disease and two (17%) progressive disease. The disease control rate (partial response + stable disease) was as high as 83%. The time to progression and median overall survival were 7.1 and 16.6 months, respectively. The 1-year overall survival rate determined by the Kaplan-Meier method was 75.0%. All adverse effects were manageable and no treatment-related deaths were observed. The high disease control rate and overall survival shown by this study suggest that first-line use of docetaxel may be a promising treatment for metastatic EMPD. A prospective clinical trial is required to confirm our results.

Clinical characteristics associated with BRAF, NRAS and KIT mutations in Japanese melanoma patients.

BACKGROUND: The importance of the genetic background of melanoma cells to the individual susceptibility to treatment has become apparent. In Caucasians, BRAF mutations are frequently detected in lesions on the skin of younger patients compared to NRAS and KIT mutations. However, clinical and pathological characteristics associated with BRAF, NRAS and KIT mutations have not been fully evaluated in East Asians. OBJECTIVE: To clarify clinical and pathological characteristics associated with BRAF, NRAS and KIT mutations in Japanese melanoma patients. METHODS: Clinical data were retrospectively collected from 11 hospitals in Japan. BRAF, NRAS and KIT mutations were evaluated with polymerase chain reaction and Sanger sequencing. The relationships between these gene mutations and pathological and clinical findings were analyzed. RESULTS: The number of cases examined was 171 (primary: 135, metastases: 11, paired: 25), and all were Japanese patients. The detection rates of BRAF, NRAS and KIT mutations were 30.4%, 12.3% and 12.9%, respectively. Compared with the wild type, the presence of BRAF mutations was significantly associated with younger age (median, 50.0 years vs. 70.0 years, p<0.001). BRAF mutation was frequently detected in the lesions of the scalp (80%; 4/5), trunk (72.0%; 18/25), extremities (56.7%; 17/30) and neck (44.4%; 4/9), and the least prevalent were the face (22.2%; 2/9), nail (12.5%; 3/24), palm or sole (8.9%; 4/45) and mucosa (0%). NRAS mutations were prevalent in the face (33.3%) and palm or sole (20.0%), and the median age of these patients was 70.5 years. A KIT mutation was observed in the nail apparatus (25%), palm or sole (15.6%) and mucosa (18.2%). The median age of the patients with a KIT mutation was 63.0 years. Heterogeneity of mutations between primary and metastatic lesions was detected in six of 25 cases (24%). Solar elastosis was identified in 12 of 71 cases (15.3%), among which four cases harbored BRAF(V600E) (2 cases), BRAF(V600K), NRAS(Q61K) or NRAS(Q61L), respectively. CONCLUSION: Some clinical characteristics associated with BRAF, NRAS and KIT mutations were observed in Japanese patients, and we observed both similarities to and differences from those of Caucasians. Our findings could provide useful information in efforts to clarify the tumor genesis of malignant melanomas.

Family with MSH2 mutation presenting with keratoacanthoma and precancerous skin lesions.

Muir-Torre syndrome (MTS) is a familial cancer syndrome characterized by a predisposition to keratoacanthoma (KA) and sebaceous tumors. Although MTS and hereditary non-polyposis colorectal cancer (HNPCC) share the same genetic alterations in mismatch repair (MMR) genes, the other skin lesions in MTS or HNPCC have been only rarely reported. We report a family with an MSH2 mutation c.1126_1127delTT (p.Leu376Thrfs*12). A 46-year-old male proband developed KA with sebaceous differentiation, colon cancer and gastric cancer, and fulfilled the diagnostic criteria for MTS. His 80-year-old mother, diagnosed with HNPCC, presented with multiple gastrointestinal tract cancers, Bowen's disease and actinic keratosis. Immunostaining revealed attenuated MSH2 protein expression in KA, as well as in Bowen's disease and actinic keratosis lesions. These findings suggest that MMR gene abnormality is also critical in the development of benign or malignant cutaneous tumors such as actinic keratosis and Bowen's disease in MTS/HNPCC patients.

The role of sentinel lymph node biopsy in the management of invasive extramammary Paget's disease: Multi-center, retrospective study of 151 patients.

BACKGROUND: Although extramammary Paget's disease (EMPD) mostly presents as intraepithelial carcinoma, we sometimes encounter patients with invasive EMPD (iEMPD) who have lymph node metastasis and may develop distant metastasis. Although sentinel lymph node biopsy (SLNB) is widely accepted for various cancers, there is no large study that has assessed its role in iEMPD. OBJECTIVE: The main objective of this study is to assess the role of SLNB in patients with iEMPD. MATERIALS AND METHODS: We retrospectively collected data on 151 iEMPD patients treated from 1998 to 2012 in 11 institutes in Japan. All 151 patients received curative surgery for their primary tumor and none of them had distant metastasis. SLNB was performed on the 107 patients without lymphadenopathy to determine their LN status. The 44 other patients with lymphadenopathy underwent one of the following procedures to determine their LN status: SLNB in 22 cases, immediate LN dissection in 21, and LN biopsy in 1. RESULTS: Compared to those without lymphadenopathy, patients with lymphadenopathy had advanced primary tumors (nodule in the primary tumor, thicker tumor, deeper invasion level, and lymphovascular invasion). The rate of LN metastasis in patients with lymphadenopathy was 80%, compared to 15% in patients without lymphadenopathy who underwent SLNB. Compared to those with negative SLN, patients with positive SLN had advanced primary tumors (nodule in the primary tumor, deeper invasion level, and lymphovascular invasion). Multivariate analysis revealed that dermal invasion (odds ratio 5.8, p=0.04) and lymphovascular invasion (odds ratio 18.0, p=0.0023) were independent factors associated with SLN positivity. Notably, there was no difference in survival between patients with or without SLN metastasis (p=0.71). On the other hand, patients with lymphadenopathy showed worse survival than those with positive SLN (p=0.045). CONCLUSION: Clinical lymphadenopathy was strongly correlated with pathological LN metastasis and also associated with worse survival than absence of lymphadenopathy. The rate of occult LN metastasis detected by SLNB was 15%. Survival was not affected by SLN status even when an advanced primary tumor was present in patients with positive SLN. Our results raise the possibility that SLNB and subsequent LN dissection improved the survival of patients with early stage lymphatic spread. Our study indicates that SLNB should be considered for iEMPD if lymphadenopathy is not apparent.