Acral lentiginous melanoma versus other melanoma: A single‐center analysis in Japan

Abstract

We summarize herein our 14-year experience of conventional treatment outcomes before the era of moleculartargeted therapy and immunotherapy. Specifically, we conducted a retrospective review of our 252 patients with primary cutaneous melanoma (acral lentiginous melanoma [ALM], n = 121; non-acral lentiginous melanoma [non-ALM], n = 131), and compared the prognostic factors between ALM and non-ALM. Melanoma-specific survival and disease-free survival were estimated using the Kaplan-Meier method. Regarding the results, all patients were Japanese (106 male and 146 female), with a mean age of 60.1 years. Among ALM patients, age was elder and primary tumor size was larger than non-ALM. As for tumor thickness, in situ lesions were more frequently observed in ALM. There was no significant difference in the distribution of tumor thickness between the two groups when excluding the in situ lesions. For treatment of the primary melanoma, 248 patients (98.4%) had undergone curative surgical excision and 120 patients with more than 1 mm or ulcerated melanoma had undergone sentinel lymph node biopsy. Patients with systemic metastasis primarily underwent dacarbazine-based chemotherapy. The Kaplan-Meier survival curves revealed no significant difference in melanoma-specific survival and disease-free survival between those with ALM and non-ALM. The results also showed that both ALM and non-ALM, when they initially metastasize, first affect the regional lymph nodes. Incisional biopsy was not an adverse prognostic factor. These results suggest that ALM does not differ in its biological behavior from non-ALM, so we can consider ALM as being equivalent to non-ALM. The initial treatment for ALM and non-ALM can involve the same strategy.

Efficacy and clinical significance of omitting blue dye injection during sentinel lymph node biopsy before Mohs micrographic surgery for malignant melanoma of the lower extremities

“…The cohort of the present study can be considered representative of patients undergoing SLNB for melanoma in Asia, as the demographic distributions, tumour depths, Breslow thicknesses and tumour locations were consistent with data from previous studies in Korea and other Asian countries . Our data show that performing SLNB while omitting blue dye injection can still yield a high biopsy success rate (98%) that is similar to the 95–100% detection rate achieved in previous studies that used a combination of LSG and blue dye injection, and is higher than rates reported when using blue dye injection alone (52–95%) …”

Is the survival rate for acral melanoma actually worse than other cutaneous melanomas?

“…In Korea, according to a previous study, 58.3% of melanomas arose on the feet (40.9%) and hands (17.4%) . Likewise, the incidence of AM is high in other Asian groups, reported to be 58% in Taiwanese and 40% in Japanese cutaneous melanoma patients . This number drops dramatically in Western countries, especially in non‐Hispanic whites, to only 1% .…”

“…Malignant melanoma is one of the most dangerous malignant neoplasms and is associated with a high risk of death . Acral melanoma (AM) is defined as melanoma arising in the palm, sole and subungual areas .…”

“…Some studies hypothesized that the reduced survival of AM patients may be due to delayed diagnosis or the biological aggressiveness of AM compared with other melanomas . In contrast, a study conducted in a Japanese institution in 2017 reported that there was no statistically significant difference in survival between AM patients and patients with other cutaneous melanomas . Because of these controversies, it is still not clear whether the survival of patients with AM is better or worse than that of patients with cutaneous melanomas developed at other sites.…”

“…Malignant melanoma is one of the most dangerous malignant neoplasms and is associated with a high risk of death. [1][2][3] Acral melanoma (AM) is defined as melanoma arising in the palm, sole and subungual areas. 2 AM is rare among all melanomas but it is the most common type of melanoma in darker-skinned people, including Asians and Africans.…”