Date Published: March 7, 2019
Publisher: Public Library of Science
Author(s): Soo Ick Cho, Jaewon Lee, Gwanghyun Jo, Sang Wha Kim, Kyung Won Minn, Ki Yong Hong, Seong Jin Jo, Kwang Hyun Cho, Byung Jun Kim, Je-Ho Mun, Aamir Ahmad.
Malignant melanoma (MM) is a lethal skin cancer in Western countries. Although the incidence is low in Asians compared to that in Caucasians, it is increasing. However, literature regarding risk factors for prognosis of MM patients who have undergone surgical excision in Asian is limited. This study aimed to investigate the predictive factors for local recurrence and metastasis in MM patients who underwent surgical treatment at a single tertiary-level hospital in Korea. Patients who underwent surgery for MM at our institution between January 1998 and December 2014 were analyzed. We retrospectively investigated risk factors for local recurrence and metastasis after surgery. In cases with distant metastasis, tumor thickness (adjusted Hazard Ratio (HR), 6.139; 95% confidence interval (CI), 2.152 to 17.509; P = 0.001) and increased mitotic number [(0-1/mm2 vs 2-6/mm2: adjusted HR, 4.483; 95% CI, 1.233 to 16.303; P = 0.023); (0-1/mm2 vs > 6/mm2: adjusted HR, 10.316; 95% CI, 2.871 to 37.063; P < 0.001)] were associated with risk in multivariate analysis. Regarding local recurrence, tumor thickness (T4 [≥4mm] vs T1) was found to be a significant risk factor (adjusted HR, 8.461; 95% CI, 2.514 to 28.474; P = 0.001). Our data revealed tumor thickness and increased mitotic count were significant risk factors for local recurrence and distant metastasis in Korean patients with MM after surgery.
Malignant melanoma (MM) is a fatal skin tumor originating from melanocytes. Although its reported age-standardized incidence is only 0.4–0.6 per 100,000 people in Korea, it is one of the leading causes of death among skin cancers.  Biological and environmental factors such as the number of common or atypical nevi, intermittent and intense sun exposure, and some phenotypic characteristics (light, fair color of skin, hair and eyes; family history of MM) increase the risk of MM.[2–4] Various epidemiologic and clinical features of MM have been studied to date.[5–7]
There have been reports comparing surgical outcomes and prognostic factors in MM to date.[15, 16] Thomas et al. reported an association between demographic and clinical factors with locoregional recurrence and death in 900 MM patients after surgery. According to the study, male sex, tumors with greater thickness, and tumors with ulceration were associated with increased local recurrence and death. Generally, acral lentiginous melanoma is considered to have worse prognosis than other subtypes because it is often diagnosed later than MM located on the trunk or limbs.[18–20] Kato et al. compared the prognosis of patients from the first half of the study period (1969–1982) with those from the second half (1983–1996) and reported an improving trend in prognosis. The authors mentioned that increased educational efforts regarding early detection of acral melanoma might have some contribution to lowering the risk of the disease. A recent report revealed that acral lentiginous melanoma had no significant prognostic difference than non-acral lentiginous melanoma. The results of our study showed similar results. MM on the acral area did not have a higher incidence of local recurrence or distant metastasis than MM located on other anatomical sites.