Physiological change in cutaneous toxicity related to epidermal growth factor receptor (EGFR) inhibitors and the efficacy of emollient

Anti-epidermal growth factor receptor treatment strategies, i. e. epidermal growth factor receptor (EGFR) small molecule tyrosine kinase inhibitors, have expanded the effective treatment options for lung cancer. It is widely known that EGFR inhibitor (EGFRI) treatment can often trigger diverse cutaneous toxicities in patients. Managing cutaneous toxicity is crucial as it has been reported that the development of cutaneous lesions may also correlate with treatment benefit. However, little is known of the pathophysiology of this cutaneous toxicity. In the present study, we examined the skin capacitance (which indicates skin hydration or water volume in the stratum corneum) and the clinical symptom of dry skin in 8 patients following the initiation of EGFRI treatment for their small cell lung carcinoma. We also assessed the effects of emollient on dry skin after patients were divided into 2groups (with or without emollient application) at 2weeks after initiating EGFRI treatment. Our pilot study revealed that skin hydration decreased immediately after starting EGFRI therapy. At the same time, the clinical score of dry skin increased with time. Application of emollient improved both skin hydration and dry skin score. These results indicate that dry skin occurs immediately after starting EGFRI therapy and that the use of emollient leads to improvement of this type of cutaneous toxicity.