Dataset Information

Acral lentiginous melanoma histotype predicts outcome in clinical stage I-II melanoma patients: an International multicenter study.

ABSTRACT:

Background

In the American Joint Committee on Cancer (AJCC) classification, acral lentiginous melanoma (ALM) histotype ALM is not included as an independent prognostic factor; in small series its negative prognostic impact on disease-free survival (DFS) and overall survival (OS) has been linked to the greater Breslow thickness (BT).

Patients and methods

The study was carried out at four referral melanoma centers (three Italian and one Polish). Clinical consecutive patients with stage I-II melanoma, who were diagnosed, treated, and followed up between January 1998 and March 2018 in annotated specific databases were included.

Results

Overall, 6734 were evaluable, 4349 with superficial spreading melanoma (SSM), 2132 with nodular melanoma (NM), and 253 with ALM. At univariable analysis, a statistically significant worse DFS [hazard ratio (HR) 2.72, 95% confidence interval (CI) 2.24-3.30; P < 0.001] and OS (HR 2.67, 95% CI 2.15-3.32; P < 0.001) were found in patients with ALM compared with SSM. Similarly, the NM histotype was associated with a worse prognosis compared with the SSM histotype (DFS: HR 2.29, 95% CI 2.08-2.52; P < 0.001 and OS: HR 2.21, 95% CI 1.99-2.46; P < 0.001). At multivariable analysis, after adjusting for age, sex, BT, ulceration, and the sentinel lymph node status, a statistically significant worse DFS [adjusted HR (aHR; ALM versus SSM) 1.25, 95% CI 1.02-1.52; P = 0.028] was confirmed for patients with ALM. For patients with NM, instead, no impact of histology was found in terms of DFS [aHR (NM versus SSM) 1.04, 95% CI 0.93-1.15; P = 0.513] and OS [aHR (NM versus SSM) 0.96, 95% CI 0.86-1.08; P = 0.548].

Conclusions

ALM is associated with a worse long-term DFS. Our results could have important clinical implications for patients' stratification in future clinical trials and the incorporation of ALM histotype in the new AJCC classification as an independent prognostic factor.

SUBMITTER: Mandala M

PROVIDER: S-EPMC9271470 | biostudies-literature |

REPOSITORIES: biostudies-literature

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Project description:ImportanceAcral lentiginous melanoma (ALM) is a rare subtype of malignant melanoma typically occurring on the palmar and plantar surfaces. Although it has distinctive genetic, prognostic, and behavioral characteristics relative to cutaneous melanomas overall, owing to its rarity, treatment is largely guided by data extrapolated from more common subtypes. Although sentinel lymph node (SLN) status has been shown to be a significant prognostic factor for ALM, the independent effect of ALM-subtype disease on the likelihood of SLN positivity and the stage-specific positivity rates for ALM are not well characterized.ObjectiveTo evaluate the association of ALM with SLN status as well as to characterize the clinical stage-specific rates of SLN positivity for ALM based on the AJCC Cancer Staging Manual, 8th edition (AJCC-8).Design, setting, and participantsThe National Cancer Database (NCDB) includes all reportable cases from Commission on Cancer accredited facilities and represents approximately 50% of all newly diagnosed melanoma cases in the US. This retrospective cohort study included cases of AJCC-8 clinical stage I to II melanomas from the NCDB diagnosed from 2012 to 2015. The analysis took place between April 2021 and September 2021.ExposuresMelanoma histopathologic subtype.Main outcomes and measuresSentinel lymph node status.ResultsWe identified 60 148 patients with malignant melanomas, 959 of whom had ALM-subtype disease. Among patients in the cohort, 25 550 (42.5%) were women and the mean (SD) age was 64 (16) years. Multivariable logistic regression controlling for demographic and histopathologic characteristics revealed that ALM was independently associated with the highest risk for SLN positivity among included subtypes (vs superficial spreading melanoma: odds ratio, 1.91; 95% CI, 1.59-2.28). Subgroup analysis by AJCC clinical stage demonstrated that ALM was independently associated with the highest risk for SLN positivity for both stage IB and II disease. The rate of SLN positivity for patients with stage IB and II ALM was 18.39% (95% CI, 13.82%-24.03%) and 39.53% (34.98%-44.26%), respectively.Conclusions and relevanceIn this cohort study ALM was independently associated with SLN positivity and had relatively high positivity rates at clinical stage IB and II. This suggests that SLNB should be encouraged for all patients with clinical stage IB and II ALM, and such patients should receive appropriate counseling about the higher regional metastatic risk of their cancers. Future work with a larger cohort is required to elucidate the risk of SLN positivity for stage IA ALM.