Purpose: In superficial basal cell carcinomas treated with photodynamic therapy with topical y-aminolevulinic acid, we examined effects of light irradiance on photodynamic efficiency and pain. The rate of singlet-oxygen production depends on the product of irradiance and photosensitizer and oxygen concentrations. High irradiance and/or photosensitizer levels cause inefficient treatment from oxygen depletion in preclinical models. Experimental Design: Self-sensitized photobleaching of protoporphyrin IX (PpIX) fluorescence was used as a surrogate metric for photodynamic dose. We developed instrumentation measuring fluorescence and reflectance from lesions and margins during treatment at 633 nm with various irradiances. When PpIX was 90% bleached, irradiance was increased to 150 mW/cm 2 until 200 J/cm 2 were delivered. Pain was monitored. Results: In 33 superficial basal cell carcinomas in 26 patients, photobleaching efficiency decreased with increasing irradiance above 20 mW/cm 2
Rationale and Objectives The treatment of nonmelanoma skin cancer (NMSC) is usually by surgical excision or Mohs micrographic surgery and alternatively may include photodynamic therapy (PDT). To guide surgery and to optimize PDT, information about the tumor structure, optical parameters, and vasculature is desired. Materials and Methods Spatial frequency domain imaging (SFDI) can map optical absorption, scattering, and fluorescence parameters that can enhance tumor contrast and quantify light and photosensitizer dose. High frequency ultrasound (HFUS) imaging can provide high-resolution tumor structure and depth, which is useful for both surgery and PDT planning. Results Here, we present preliminary results from our recently developed clinical instrument for patients with NMSC. We quantified optical absorption and scattering, blood oxygen saturation (StO2), and total hemoglobin concentration (THC) with SFDI and lesion thickness with ultrasound. These results were compared to histological thickness of excised tumor sections. Conclusions SFDI quantified optical parameters with high precision, and multiwavelength analysis enabled 2D mappings of tissue StO2 and THC. HFUS quantified tumor thickness that correlated well with histology. The results demonstrate the feasibility of the instrument for noninvasive mapping of optical, physiological, and ultrasound contrasts in human skin tumors for surgery guidance and therapy planning.
Photodynamic therapy (PDT) using topical 5-aminolevulinic acid (ALA) is currently used as a clinical treatment for nonmelanoma skin cancers. In order to optimize PDT treatment, vascular disruption early in treatment must be identified and prevented. We present blood flow responses to topical ALA-PDT in a preclinical model and basal cell carcinoma patients assessed by diffuse correlation spectroscopy (DCS). Our results show that ALA-PDT induced early blood flow changes and these changes were irradiance dependent. It is clear that there exists considerable variation in the blood flow responses in patients from lesion to lesion. Monitoring blood flow parameter may be useful for assessing ALA-PDT response and planning.
Background and Objective Photodynamic therapy (PDT) with topical δ-aminolevulinic acid (ALA) of non-melanoma skin cancers is often associated with treatment-limiting pain. A previous study on basal cell carcinomas (BCCs) at Roswell Park Cancer Institute evaluated a two-step irradiance scheme as a means of minimizing pain, preserving outcomes, and limiting treatment time. We used an initial low irradiance until 90% of the protoporphyrin IX was photobleached, followed by a high irradiance interval until the prescribed fluence was delivered. Success of this pilot investigation motivated integration of the protocol into routine practice. Here we present a retrospective review of recent clinical experience in a broad patient population. Study Design/Materials and Methods This was a retrospective review of an existing dermatology data base. Fourteen caucasion patients - 9 men and 5 women, ages 18 to 80, with a total of 51 superficial and 73 nodular BCCs, and three Bowen's disease lesions – were included. ALA was applied to each lesion for approximately 4h. Lesions received an initial irradiance of 30 - 50 mW/cm2 for 20 J/cm2, followed by 150 mW/cm2 for a total fluence of 200-300 J/cm2. Pain was assessed using a visual analog scale (VAS). Clinical outcome was determined at 6-12 months. Results Median VAS scores were 1.0 for both irradiances. Five of 127 lesions required pain control with 1% xylocaine. Pain was strongly influenced by lesion location but not by lesion type, number, or size. Complete responses were achieved in 84.1% of BCCs, which compares favorably with reported results for single ALA-PDT treatments. Two of three Bowen's disease lesions showed a complete response. Complete responses for nodular BCCs were 37%, which are also within the range of reported outcomes. Conclusions A two-step irradiance protocol in ALA-PDT effectively minimizes pain, maintains excellent clinical outcomes in superficial lesions, and adds minimal treatment time.
Background Topical photodynamic therapy (PDT) for selected non-melanoma skin cancer, employing 5-aminolevulinic acid (ALA) or methyl aminolevulinate (MAL) has yielded high long-term complete response rates with very good cosmesis. Pain during light activation of the photosensitizer can be a serious adverse event. A two-step irradiance protocol has previously been shown to minimize ALA-PDT pain. Objectives To determine the irradiance-dependent pain threshold for MAL-PDT, to adapt the two-step protocol to an LED light source, and assess clinical response. Methods In this prospective study, 25 superficial basal cell carcinoma (sBCC) received an initial irradiance by laser at 40 or 50 mW/cm2, or LED at 35 mW/cm2 followed by an irradiance at 70 mW/cm2 for a total of 75 J/cm2. Pain levels were recorded for both irradiance steps. Efficacy was assessed at 6, 12 or 24 months. Results Pain was mild in the 40/70 mW/cm2 laser cohort. Three instances of irradiance-limiting pain occurred at 50/70 mW/cm2. Pain was minimal in the 35/70 mW/cm2 LED cohort. Clinical response rates were 80% in the 50/70 mW/cm2 laser cohort and 90% in the 35/70 mW/cm2 LED cohort. Conclusions Topical PDT can be effectively delivered to sBCC with minimal treatment related pain by a two-step irradiance protocol.
Clinical nursing research is an emerging subspecialty that enhances nursing expertise. In an effort to provide a basic educational curriculum on cancer research and clinical trials, a major academic cancer center launched a novel program titled Clinical Research Nursing Grand Rounds that allowed nurses to receive continuing education units. The purpose of the current article is to describe the development and content of the education model, challenges encountered, and implications for oncology nursing education, practice, and research.
To guide intervention planning of nonmelanoma skin cancer (NMSC), information about the tumor depth and thickness as well as functional contrast is desired. The results indicate that ultrasound and spatial frequency domain imaging can provide accurate structural and enhanced contrasts in NMSC. OCIS codes: General (170.0170) Medical optics and biotechnology; (170.3660) Light propagation in tissues; (170.3880) Medical and biological imaging.
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