504 Dual parameter predictive model utilizing skin temperature and diffuse reflectance spectroscopy facilitates the diagnosis of cellulitis

Abstract

Background: Hyperproliferative cutaneous lesions, such as non-melanoma and melanoma skin cancers, are the most commonly diagnosed cancers in the United States. While surgery remains the gold standard, treatment can be costly and complications can include pain, scarring, infections. Hyperthermia (40-44 C) has been utilized for many years to treat various cancer types as it induces localized cell toxicity. Combining local anesthetics, such as lidocaine, with hyperthermia has been shown in vitro to enhance cell death. Objective: We investigated whether the combination of hyperthermia with lidocaine enhanced cell toxicity in cutaneous cell lines and whether the effect is specific for rapidly proliferating cells. Methods: We exposed normal skin cell lines (fibroblasts, keratinocytes), skin cancer cell lines (melanoma, basal cell carcinoma), and a mucosal cancer cell line (cervical carcinoma) to various concentrations of lidocaine (0.0-0.4%) over a range of temperatures (37-44 C) for 10 minutes. Cell viability was assessed with an MTT assay and cell cycle with propidium iodide and flow cytometry. Results: We demonstrate that cancer cell lines show significantly increased cell toxicity at a moderate temperature (42 C) and lidocaine concentration (0.2%) compared to normal skin cells (p<0.05). Further, we show that cancer cell lines have a higher percentage of cells in S-phase (28-57%) compared to normal skin cell lines (13-19%), which directly correlated with cell toxicity from combined hyperthermia and lidocaine (R-square 0.6752). Conclusions: In the future, combined mild hyperthermia with lidocaine may provide a non-invasive alterative to treatment of skin cancer. This treatment demonstrates selectivity for rapidly dividing cancer cells compared to normal skin cells. Further, lidocaine can be applied specifically to cutaneous lesions to potentially minimize unwanted side effects on the surrounding tissue. Additional investigation via clinical trials are needed to confirm these in vitro data.