Surgical scar remodelling after photodynamic therapy using aminolaevulinic acid or its methylester: a retrospective, blinded study of patients with field cancerization.

BACKGROUND: Photodynamic therapy (PDT) is a nonsurgical alternative to conventional tumour excision for nonmelanoma skin cancers (NMSCs). OBJECTIVES: We evaluated whether patients with field cancerization (multiple NMSCs) treated with aminolaevulinic acid (ALA) or its methylester (MAL) for that indication had PDT-induced changes in surgical scars in the treatment field. METHODS: Six adult patients with multiple NMSCs and a total of 21 scars from previous excisions were studied in a retrospective blinded evaluation from clinical photographs of scar response to ALA/MAL-PDT. After a 3-h application of topical 20% ALA or 16·8% MAL under occlusion, each field was irradiated with 635-nm light-emitting diode light at the fluence of 200Jcm(-2) . Patients underwent one to three PDT sessions per field at ∼1month intervals, to fields that included scars on the back, thigh, arms and neck. Pre- and post-treatment digital photographs of scars were combined into 92 pairs that were independently and blindly evaluated by three board-certified dermatologists. This study was performed at our academic practice at the Massachusetts General Hospital. RESULTS: PDT produced a statistically significant improvement in scar appearance. The degree of improvement correlated with the number of treatment sessions (two or three treatments; P<0·05). Improvement after a single treatment was not statistically different from baseline ratings (P=0·99). CONCLUSIONS: Surgical scar remodelling and clinical improvement may be accomplished via ALA/MAL-PDT, but may require repeated treatment sessions. Larger, prospective studies are necessary to confirm the effectiveness of PDT for this indication.

Enhanced uptake and photoactivation of topical methyl aminolevulinate after fractional CO2 laser pretreatment.

BACKGROUND AND OBJECTIVES: Photodynamic therapy (PDT) of thick skin lesions is limited by topical drug uptake. Ablative fractional resurfacing (AFR) creates vertical channels that may facilitate topical PDT drug penetration and improve PDT-response in deep skin layers. The purpose of this study was to evaluate whether pre-treating the skin with AFR before topically applied methyl aminolevulinate (MAL) could enable a deep PDT-response. MATERIALS AND METHODS: Yorkshire swine were treated under general anesthesia with a fractional CO(2) laser using stacked single pulses of 3 milliseconds, 91.6 mJ per pulse and subsequent topical MAL application for 3 hours (Metvix®). Red light (LED arrays) was then delivered at fluences of 37 and 200 J/cm(2). Fluorescent photography and microscopy was used to quantify MAL-induced porphyrin distribution and PDT-induced photobleaching at the skin surface and five specific depths down to 1,800 µm. RESULTS: Laser-ablated channels were approximately 1,850 µm deep, which significantly increased topical MAL-induced porphyrin fluorescence (hair follicles, dermis, P < 0.0001) and PDT response, both superficially and deep, versus topical MAL application alone. The fraction of porphyrin fluorescence lost by photobleaching was slightly less after 37 J/cm(2) than after 200 J/cm(2) (overall median values 67-90%; 37 vs. 200 J/cm(2), P > 0.05 for all but one comparison). Photobleaching was steady throughout skin layers and did not vary significantly with skin depth at either LED fluence (P > 0.05). CONCLUSIONS: AFR greatly facilitates topical MAL-induced porphyrins and the fraction of photobleached porphyrins is similar for superficial and deep skin. These observations are consistent with AFR-enhanced uptake of MAL, increased porphyrin synthesis, and photodynamic activation of deep porphyrins even at the lower fluence of 37 J/cm(2), widely used in clinical practice. AFR appears to be a clinically practical means for improving PDT deep into the skin. Clinical studies are suggested to evaluate selectivity in targeting dysplastic cell types.

Cutaneous T-cell lymphoma with HTLV-I infection: clinical overlap with adult T-cell leukemia/lymphoma.

Adult T-cell leukemia/lymphoma (ATLL) is a malignant proliferation of mature helper T lymphocytes,(1) and is caused by human T-lymphotropic virus type I (HTLV-I);(2) an HTLV-I infection endemic in the Caribbean, south-western Japan, South America and Africa.(3,4) Seroepidemiological studies suggest that it is also endemic in Brazil.(5) Although carriers of HTLV-I show polyclonal integration of virus in T lymphocytes, only patients with ATLL of various subtypes show monoclonal integration of HTLV-I in tumor cells.(6,7) Cutaneous T-cell lymphomas (CTCL) are a group of primary cutaneous lymphoproliferative diseases(8) with unknown etiology.(9) The two most common presentations of CTCL are mycosis fungoides (MF) and Sézary syndrome (SS).(10-13) However, both CTCL categories can easily resemble ATLL. Therefore, in HTLV-I endemic areas, differentiation between ATLL and CTCL must be performed, as they have different prognoses and treatment approaches.(14).