Clinical characteristics and prognosis of acral lentiginous melanoma: a single-center series of 211 cases in China

Research hotspots and frontiers in acral melanoma: A bibliometric analysis from 1999 to 2023

Background

Acral melanoma (AM), an aggressive subtype of melanoma with poor prognosis, has been increasingly studied. The present study aims to discuss the current status, hotspots and future directions of AM studies through visualized analysis with bibliometrics and knowledge graph.

Method

Publications related to acral melanoma from January 1999 to May 2023 were searched and retrieved from the Web of Science. Data extraction and visualization of the top 10 publications by year of publication, journal, country and core author were performed using R Studio (Version 4.3.0) and Scimago Graphica (Version 1.0.34). Co-reference graphs regarding country/region, organization, author, and keywords, as well as reference collaborative network, co-occurrence network, and references were plotted using VOSviewer (Version 1.6.19) and CiteSpace (Version 6.2.R3).

Results

A total of 1387 articles related to AM published in English from 1999 to 2023 were included in the present study. A total of 7499 authors were from 2092 organizations in 50 countries. The articles were published in 356 journals, involving 4131 keywords and 28,200 references. The 1387 articles related to AM had been cited a total of 10,014 times by the time of this study. The result showed that Journal of the American Academy of Dermatology had the largest number of citations and citation rate, with a total of 60 publications having been cited 2191 times. Having the top three productivity institutions in the world, the US is the most productive country in this field, with a total of 361 publications. The authors with the highest number of publications were Guo Jun (n = 43) and Si Lu (n = 38) from Peking University. The keyword burstiness test found that "ipilimumab", "open label", "efficacy" and "nivolumab" appeared most frequently in recent years. The co-cited reference timeline graph showed that the clustering of "advanced melanoma" and "melanocytic lesion" has been a hotspot since 2016.

Conclusions

The number of AM-related studies has been increasing. The clinical characteristics and immunotherapy of AM are still key research directions, with the US playing a leading role in this field. This bibliometric analysis found up to 1387 publications, which not only comprehensively and quantitatively reflected the research trends and hotspots, but also provided a theoretical basis for future studies of AM. Researchers can benefit from choosing the right journals and finding potential collaborators or partner institutions.

A nomogram incorporating Ki67 to predict survival of acral melanoma

BACKGROUND

The proliferation marker Ki67 is associated with the progression and prognosis of melanoma. However, its prognostic impact on acral melanoma (AM) remains unclear.

METHODS

A total of 314 AM patients were enrolled from a cohort of 5758 patients with melanoma at Peking University Cancer Hospital between 2006 and 2018. The patients were divided into Ki67 high- and low-expressing groups using a cut-off value of 30%. The associations between Ki67 and clinicopathologic characteristics as well as survival were analyzed. Cox proportional regression analysis was used to establish a nomogram to predict the survival probabilities of AM.

RESULTS

Among 314 patients, the Ki67-high group (Ki67 ≥ 30%) included 49.4% of patients at diagnosis. Patients in the Ki67-high group had lower median melanoma-specific survival (MSS) than those in the Ki67-low group (60.7 months vs. not reached, p < 0.001). In multivariate analyses, Ki67, lymph node metastasis and primary site were independent prognostic factors for MSS. The nomogram showed that Ki67 had the fourth greatest impact on survival, following Breslow thickness, lymph node metastasis and primary site. The C-index of the nomogram was 0.765 and 0.758 in the training and validation cohort, respectively. Area under the curve values were both near 0.8 in the training and validation cohorts. Net reclassification improvement and integrated discrimination improvement demonstrated that the predictive nomogram performed better than the traditional AJCC staging system.

CONCLUSION

Ki67 expression is an independent prognostic factor for MSS in AM. A predictive model incorporating Ki67 and clinical factors was constructed to predict the prognosis of AM.

Impact of clinical and histopathological characteristics on the disease-free survival of stage I-II acral melanoma patients

BACKGROUND

Acral melanoma is rare and associated with a worse prognosis compared to cutaneous melanoma in other locations. Despite this, few studies have focused on the prognosis of acral melanoma, particularly in patients with initial clinical stage. The aim of this study was to assess the impact of clinical and histopathological characteristics on the disease-free survival (DFS) of stage I-II patients.

METHODS

We analyzed 154 stage I-II acral melanoma cases, all of whom underwent a review of the histopathological and clinical parameters. Patients were divided into groups based on the presence or absence of disease recurrence within 5 years. We used Cox proportional regression to analyze independent risk factors and computed DFS curves using the Kaplan-Meier method.

RESULTS

Within 5 years, 27.9% of patients experienced disease recurrence, with 90.4% occurring during the first 3 years. Univariate and multivariate analyses did not identify any clinical parameters with a significant influence on DFS. The DFS rate at 5 years was 72.7%. The median duration of disease recurrence after the initial diagnosis was 21 months. However, Breslow thickness, presence of ulceration, >3 mitosis/mm2 , presence of tumor-infiltrating lymphocytes (TIL), and perineural invasion were significantly associated with a decrease in time to first recurrence.

CONCLUSIONS

Despite the favorable prognosis of stage I-II acral melanoma compared with advance stage, clinical and histopathological characteristics can impact prognosis. In addition to Breslow thickness and ulceration, attention should be paid to mitotic rate, presence of TIL, and perineural invasion to optimize follow-up of acral melanoma patients diagnosed in the initial clinical stage.

Clinical features, molecular pathology, and immune microenvironmental characteristics of acral melanoma

Acral melanoma (AM) has unique biology as an aggressive subtype of melanoma. It is a common subtype of melanoma in races with darker skin tones usually diagnosed at a later stage, thereby presenting a worse prognosis compared to cutaneous melanoma. The pathogenesis of acral melanoma differs from cutaneous melanoma, and trauma promotes its development. Compared to cutaneous melanomas, acral melanomas have a significantly lighter mutational burden with more copy number variants. Most acral melanomas are classified as triple wild-type. In contrast to cutaneous melanomas, acral melanomas have a suppressive immune microenvironment. Herein, we reviewed the clinical features, genetic variants, and immune microenvironmental characteristics of limbic melanomas to summarise their unique features.