Ki-Hoon Song

Health Effects of Chronic Arsenic Exposure

Arsenic is a unique element with distinct physical characteristics and toxicity whose importance in public health is well recognized. The toxicity of arsenic varies across its different forms. While the carcinogenicity of arsenic has been confirmed, the mechanisms behind the diseases occurring after acute or chronic exposure to arsenic are not well understood. Inorganic arsenic has been confirmed as a human carcinogen that can induce skin, lung, and bladder cancer. There are also reports of its significant association to liver, prostate, and bladder cancer. Recent studies have also suggested a relationship with diabetes, neurological effects, cardiac disorders, and reproductive organs, but further studies are required to confirm these associations. The majority of research to date has examined cancer incidence after a high exposure to high concentrations of arsenic. However, numerous studies have reported various health effects caused by chronic exposure to low concentrations of arsenic. An assessment of the health effects to arsenic exposure has never been performed in the South Korean population; thus, objective estimates of exposure levels are needed. Data should be collected on the biological exposure level for the total arsenic concentration, and individual arsenic concentration by species. In South Korea, we believe that biological exposure assessment should be the first step, followed by regular health effect assessments.

Fractional erbium: YAG laser‐assisted photodynamic therapy for facial actinic keratoses: a randomized, comparative, prospective study

Photodynamic therapy (PDT) with methyl aminolevulinate (MAL) is effective for treating multiple actinic keratoses (AKs). Ablative fractional laser (FL) creates vertical channels that may facilitate MAL delivery and improve PDT response.

Efficacy of ablative fractional laser‐assisted photodynamic therapy with short‐incubation time for the treatment of facial and scalp actinic keratosis: 12‐month follow‐up results of a randomized, prospective, comparative trial

Photodynamic therapy (PDT) using methyl aminolevulinate (MAL) is an effective first‐line treatment for actinic keratosis (AK). Erbium:yttrium‐aluminium‐garnet (Er:YAG) ablative fractional laser‐assisted MAL‐PDT (AFL‐PDT) has shown significant benefit for the treatment of AK.

A randomized trial comparing methyl aminolaevulinate photodynamic therapy with and without Er:YAG ablative fractional laser treatment in Asian patients with lower extremity Bowen disease: results from a 12‐month follow‐up

Methyl aminolaevulinate photodynamic therapy (MAL‐PDT) is an effective treatment for Bowen disease (BD) of the lower extremities. Er:YAG (erbium:yttrium‐aluminium‐garnet) ablative fractional laser (AFL) treatment removes the stratum corneum to increase MAL uptake and may improve efficacy. However, no studies have directly compared the efficacy of MAL‐PDT with and without Er:YAG AFL therapy in treating BD of the lower extremities in Asians.

Endothelin-1 enhances the proliferation of normal human melanocytes in a paradoxical manner from the TNF-α-inhibited condition, but tacrolimus promotes exclusively the cellular migration without proliferation: a proposed action mechanism for combination therapy of phototherapy and topical tacrolimus in vitiligo treatment

Background  Vitiligo is an acquired pigmentary disorder caused by the destruction of melanocytes. Two of the major theories regarding the pathogenesis of vitiligo are the autoimmune theory and autocytotoxicity theory, but, the precise pathogenetic mechanism is still not clarified.

Efficacy of ablative fractional laser-assisted photodynamic therapy for the treatment of actinic cheilitis: 12-month follow-up results of a prospective, randomized, comparative trial.

Early identification and treatment of actinic cheilitis (AC) is recommended. Although photodynamic therapy (PDT) is an attractive therapeutic option for AC, PDT for AC does not result in the same satisfactory outcomes as in actinic keratosis (AK).

Comparative Study of Photodynamic Therapy with Topical Methyl Aminolevulinate versus 5-Aminolevulinic Acid for Facial Actinic Keratosis with Long-Term Follow-Up.

Background Few studies have compared the efficacy, cosmetic outcomes, and adverse events between 5-aminolevulinic acid photodynamic therapy (ALA-PDT) and methyl aminolevulinate-PDT (MAL-PDT) for actinic keratoses (AKs) in Asian ethnic populations with dark-skin. Objective We retrospectively compared the long-term efficacy, recurrence rates, cosmetic outcomes, and safety of ALA-PDT versus MAL-PDT for facial AKs in Koreans. Methods A total of 222 facial AKs in 58 patients were included in this study. A total of 153 lesions (29 patients) were treated with 5-ALA, and 69 lesions (29 patients) with MAL. ALA and MAL creams were applied for 6 hours and 3 hours, respectively; the lesions were then illuminated with a halogen lamp at 150 J/cm2 for ALA-PDT and a diode lamp at 37 J/cm2 for MAL-PDT. Results The complete response rates of ALA-PDT and MAL-PDT were 56.9% and 50.7%, respectively, with no significant difference at 12 months after treatment. No significant difference in recurrence rates was observed between the 2 PDT modalities at either 6 or 12 months after treatment. There was no significant difference in the cosmetic outcomes between the 2 treatment modalities at 12 months after PDT. However, ALA-PDT caused significantly more painful than MAL-PDT (p=0.005). The adverse events were mild to moderate, transient, and self-limiting for both modalities. Conclusion MAL-PDT was similar to ALA-PDT in terms of long-term efficacy, recurrence rates, cosmetic outcomes, and adverse events; however, it was a significantly less painful procedure than ALA-PDT in our study.

Er:YAG ablative fractional laser-primed photodynamic therapy with methyl aminolevulinate as an alternative treatment option for patients with thin nodular basal cell carcinoma: 12-month follow-up results of a randomized, prospective, comparative trial.

Surgical excision is conventionally regarded as the treatment of choice for nodular basal cell carcinoma (nBCC), and methyl aminolevulinate photodynamic therapy (MAL‐PDT) has relatively low efficacy for nBCC. However, Er:YAG ablative fractional laser (AFL)‐primed MAL‐PDT (Er:YAG AFL‐PDT) may offer enhanced efficacy for nBCC, especially thin nBCC (thickness ≤2 mm).

Effect of Methyl Aminolevulinate Photodynamic Therapy With and Without Ablative Fractional Laser Treatment in Patients With Microinvasive Squamous Cell Carcinoma: A Randomized Clinical Trial

Importance Surgical excision is the standard treatment for cutaneous squamous cell carcinoma (SCC). However, microinvasive SCC (Clark level II) is limited to the papillary dermis, and it should be differentiated from invasive SCC. Ablative fractional laser-primed photodynamic therapy (AFL-PDT) may have enhanced efficacy. Objective To compare 1 session of AFL-PDT with 2 sessions of conventional methyl aminolevulinate-PDT (MAL-PDT) for the treatment of microinvasive SCC. Design, Setting, and Participants A 2-armed, randomized, single-blind, comparative trial of 45 patients with histologically proven microinvasive SCC. Twenty-one patients were randomized to treatment with a single AFL-PDT session, and 24 patients were randomized to 2 MAL-PDT sessions with a 1-week interval between sessions using a computer-generated program. Standard pretreatment such as curettage was not performed prior to PDT owing to a tendency to bleed. The efficacy, recurrence rate, cosmetic outcomes, and safety were assessed 1 week, 3, 12, and 24 months after the last treatment. Interventions AFL was performed with an ablation depth of 550 µm to 600 µm, coagulation level of 1, treatment density of 22%, and a single pulse. Then, MAL cream was applied under occlusion for 3 hours and illuminated by using a red light-emitting diode light at 37 J/cm2. A second session of MAL-PDT was administered after 7 days. Main Outcomes and Measures The primary outcome measures were the lesion response at 3 and 12 months, and the recurrence rate 12 months after the last treatment. Results Twenty-one patients (6 men, 15 women) with a mean (SD) age of 76 (6) years were randomized to treatment with a single AFL-PDT session, and 24 patients (11 men, 13 women) with a mean (SD) age of 75 (6) years were randomized to 2 MAL-PDT sessions. The overall complete response rates 3 months after treatment were 84.2% with AFL-PDT and 52.4% with MAL-PDT (P = .03). These differences in efficacy remained significant at the 24-month follow-up. The recurrence rate was significantly lower with AFL-PDT (12.5%) than with MAL-PDT (63.6%) at 24 months (P = .006). AFL-PDT and MAL-PDT did not differ significantly with respect to the cosmetic outcomes, adverse events, or pain intensity. Conclusions and Relevance AFL-PDT can be used as an alternative treatment option for patients with microinvasive SCC who are not suitable for surgical treatment. Trial Registration clinicaltrials.gov Identifier: NCT02666534

Prognostic and Clinicopathologic Associations of BRAF Mutation in Primary Acral Lentiginous Melanoma in Korean Patients: A Preliminary Study

Background In the majority of melanomas, the RAS/RAF/MEK/ERK signaling pathway is constitutively activated, due to oncogenic mutations in the BRAF and NRAS genes. The BRAF mutation has been mainly described in Caucasian melanomas. However, there is a lack of study evaluating the status, and the clinical significance, of BRAF mutation in the Asian population. Objective This study was aimed to determine the frequency of BRAF mutation, and to evaluate the correlation of BRAF status with clinicopathologic features and outcomes, in Korean primary acral lentiginous melanoma (ALM) patients. Methods ALM samples (n=36) were analyzed for the BRAF V600E mutation, by dual-priming oligonucleotide (DPO) based real-time polymerase chain reaction. The clinicopathologic features and prognosis of the patients were analyzed with BRAF mutation status. Results The incidence of BRAF V600E mutation was 19.4% (7/36). The BRAF V600E mutations were not associated with clinicopathologic features, except for the age factor. All of the BRAF-mutant patients survived without recurrence or metastasis, and have a better clinical outcome than BRAF wild-type patients. Conclusion In Korean primary ALM, a low frequency of BRAF mutation was shown; and BRAF mutation presented with a favorable prognosis. These results indicate that other distinctive genetic mechanisms may have more important roles in the development and progression of disease. Further multicenter study with large sample size is firmly needed, to confirm the results of our preliminary study.