Biomedical subjects

Peter K Lee

Publications and source records attributed to Peter K Lee.

6 recordsLinked to original sources

PubMed2006

Treatment of dermatofibroma with a 600 nm pulsed dye laser.

BACKGROUND: Dermatofibroma (DF) is one of the most basic and common dermatologic diseases treated by practicing dermatologists on a daily basis. Although benign, it can be pruritic or tender. Furthermore, it is difficult to treat effectively with optimal cosmetic outcomes. OBJECTIVE: We report a safe, effective, and cosmetically superior method of treating DF with the 600 nm pulsed dye laser (PDL). METHODS: We used a 600 nm PDL to treat 20 lesions from 18 Caucasian patients. The laser parameter was set at a fluence of 7 J/cm2, a spot size of 7 mm and a pulse duration of 1.5 ms. Each lesion was treated three times at a 6- to 8-week interval. For each treatment, the lesion was double pulsed with a 20 to 30% overlap. Clinical improvement was graded by a single examiner in evaluating three clinical parameters: color, size/volume, and symptoms. For each parameter, improvement was ranked as no improvement, partial improvement, and complete response. RESULTS: All 18 patients (17 women) completed the study. For the volume/size parameter, 15 of 20 lesions (75%) showed complete response. For improvement in color, 12 of 20 patients (60%) showed complete response. Only six lesions were symptomatic (i.e., tender and irritating), and all six lesions showed complete resolution of symptoms after the PDL treatments. After each treatment, all patients experienced blistering, crusting, and purpura that usually resolved after 10 days. CONCLUSIONS: We have demonstrated for the first time that PDL (600 nm and 1.5 ms pulse duration) is an effective and safe treatment of DF. It may provide superior cosmetic outcomes compared with other modalities such as surgical excision.

Adult↗

PubMed2006

Mohs micrographic surgery for lentigo maligna and lentigo maligna melanoma using Mel-5 immunostaining: University of Minnesota experience.

BACKGROUND: Mohs micrographic surgery (MMS) continues to become a more common and accepted treatment for lentigo maligna (LM) and lentigo maligna melanoma (LMM). The primary difficulty encountered lies in the accurate identification of atypical single melanocytes to determine tumor-free margins. Numerous methods have been used to better visualize single melanocytes, with varying results. We present our experience using Mel-5 immunostaining in MMS of LM and LMM. METHODS: Two hundred patients with primary or recurrent LM or LMM were treated using MMS from 1999 to 2003 at the University of Minnesota. The initial clinical margins were determined by Wood's light examination, and an initial debulk specimen was taken and sent for formalin fixation and later reviewed by a dermatopathologist. The first Mohs layer was then taken, and staining with hemotoxylin and eosin as well as Mel-5 immunostaining was performed. All patients were followed up to evaluate for recurrence, with a mean follow-up time of 38.4 months. RESULTS: Of the 200 patients treated, only one recurrence was noted. This patient had been treated with excision followed by radiation before MMS. Use of Mel-5 immunostaining added approximately 40 minutes to each stage. Use of the Autostainer Immunostaining System (DAKO, Carpenterina, CA, USA) shortened the added time to 20 minutes. CONCLUSIONS: MMS with Mel-5 immunostaining yielded excellent results in the treatment of LM and LMM, with only one recurrence noted in 200 patients. When an automated immunostainer was used, minimal time was added to each Mohs stage.

Adult↗

PubMed2005

Long-term clinical outcomes following treatment of actinic keratosis with imiquimod 5% cream.

BACKGROUND: The results from four phase III, randomized, vehicle-controlled studies showed that imiquimod 5% cream (imiquimod) was safe and effective in the treatment of actinic keratosis (AK). Patients applied imiquimod or vehicle cream to AK lesions on the face or balding scalp, dosing three times per week or two times per week for 16 weeks. OBJECTIVE: To obtain long-term safety follow-up data and estimate AK recurrence in patients who completely cleared their AK lesions in the treatment area at the 8-week post-treatment visit in the phase III studies. METHODS: One hundred forty-six patients from 30 study centers in the United States were evaluated for clinical evidence of AK, and safety data were collected. RESULTS: After a median follow-up period of 16 months, 24.7% (19 of 77) of the patients administered imiquimod three times per week and 42.6% (23 of 54) of the patients administered imiquimod two times per week had a recurrence of AK (the appearance of at least one AK lesion) in the original treatment area. The median number of AK lesions present was one lesion for both patients receiving imiquimod three times and those receiving imiquimod two times per week compared with a median of six lesions at baseline in the combined three times per week and two times per week phase III studies. There were no long-term safety issues, and the skin quality seen in the imiquimod-treated patients at the end of the phase III studies was maintained. CONCLUSION: One and a half years following treatment, imiquimod continued to provide a long-term clinical benefit in a majority of patients who experienced complete clearance of their AK lesions.

Adjuvants, Immunologic↗

PubMed2004

Photodynamic therapy of multiple nonmelanoma skin cancers with verteporfin and red light-emitting diodes: two-year results evaluating tumor response and cosmetic outcomes.

BACKGROUND: Efficient treatment of patients with multiple synchronous nonmelanoma skin cancers represents a therapeutic challenge. OBJECTIVE: To study the safety and efficacy of photodynamic therapy (PDT) with verteporfin and red light in the treatment of multiple nonmelanoma skin cancers. DESIGN: Open-label, randomized, multicenter, dose-ranging phase 2 study conducted at 4 North American university-based dermatology clinics. PATIENTS: Fifty-four patients with 421 multiple nonmelanoma skin cancers including superficial and nodular basal cell carcinoma and squamous cell carcinoma in situ (Bowen disease). METHODS: A single intravenous infusion of 14 mg/m(2) of verteporfin followed 1 to 3 hours later by exposure of tumors to 60, 120, or 180 J/cm(2) of red light (688 +/- 10 nm) from a light-emitting diode panel. MAIN OUTCOME MEASURES: Pathologic response of treated sites was assessed at 6 months. Clinical and cosmetic responses were assessed and graded at 6 weeks, 3 months, and 6 months after verteporfin PDT, with optional follow-up visits at 12, 18, and 24 months. RESULTS: The histopathologic response, defined as absence of tumor on biopsy specimens 6 months after verteporfin PDT, ranged from 69% at 60 J/cm(2) to 93% at 180 J/cm(2). At 24 months of follow-up (276 tumors in 31 patients), the clinical complete response rate ranged from 51% at 60 J/cm(2) to 95% at 180 J/cm(2). No significant systemic adverse events were observed; most events occurred at the treated tumor sites and included events such as pain. Overall, 65% (95% confidence interval, 58%-71%) of tumors were judged to have good to excellent cosmesis at 24 months. CONCLUSION: A single course of verteporfin PDT showed treatment benefit for patients with multiple nonmelanoma skin cancers.

Adult↗

PubMed2004

Imiquimod 5% cream for the treatment of actinic keratosis: results from two phase III, randomized, double-blind, parallel group, vehicle-controlled trials.

BACKGROUND: The immune system plays a critical role in the development and pathogenesis of actinic keratosis (AK). Imiquimod has been shown to stimulate the cutaneous immune response and be effective for the treatment of nonmelanoma skin cancers. OBJECTIVE: Two phase III, randomized, double-blind, vehicle-controlled studies evaluated the efficacy of imiquimod 5% cream compared with vehicle in the treatment of AK lesions on the face and balding scalp. METHODS: A total of 436 participants at 24 centers in the United States and Canada were randomized to either imiquimod 5% or vehicle cream. Study cream was applied one time per day, 2 days per week for 16 weeks. Clearance of AK lesions was clinically assessed at an 8-week posttreatment visit. RESULTS: The complete clearance rate was 45.1% for the imiquimod group and 3.2% for the vehicle group. The difference in complete clearance rates (imiquimod minus vehicle) was 41.9% with a 95% confidence interval of 34.9% to 49%. The partial (> or =75%) clearance rate was 59.1% for the imiquimod group and 11.8% for the vehicle group. The difference in partial clearance rates (imiquimod minus vehicle) was 47.3% with a 95% confidence interval of 39.5% to 55.1%. The median percent reduction in AK lesions was 83.3% for the imiquimod group and 0% for the vehicle group. Local skin reactions were common. Severe erythema was reported by 17.7% of participants who received imiquimod and 2.3% of participants who received vehicle. Overall, imiquimod was very well tolerated. CONCLUSION: Imiquimod 5% cream used 2 times per week for 16 weeks is an effective and well-tolerated treatment for AK.

Adjuvants, Immunologic↗

PubMed2004

Common skin cancers.

Skin cancers are the most common types of all cancers, and the most commonly occurring skin cancers are basal cell carcinoma, squamous cell carcinoma, and malignant melanoma, in that order. This article discusses the clinical presentations and subtypes of these 3 types of cancer and the current state of treatments for them. Also discussed are precursor lesions to these malignancies, including actinic keratosis, a squamous cell carcinoma precursor, and atypical or dysplastic nevus, a potential precursor of malignant melanoma.

Basal Cell Carcinoma↗