Overexpression of the epidermal growth factor receptor (EGFR) is found in many cancers, including those of the head and neck area, non-small-cell lung cancer, and colorectal, cervical, prostate, breast, ovary, stomach, and pancreatic cancer. The EGFR inhibitors are used at present in the treatment of such cancers. Skin lesions that develop during and after cancer treatment may be due to specific cytostatics, molecular-targeted drugs, radiation therapy, complementary therapy, or the cancer itself, and hence knowledge is essential to distinguish between them. The mechanism through which skin toxicity arises during treatment with EGFR inhibitors is not well known, but seems to be due to the modification of the RAS/RAF/MEK/ERK signal path associated with its activation, which results in the similarity between the adverse effects of EGFR inhibitors and the treatment of melanoma with BRAF and MEK inhibitors. The most common side effects are pruritus, xerosis, papulopustular rash, hand-foot skin reaction, alopecia and dystrophy of the hair, and paronychia. This work presents options for prevention and suggestions for managing these adverse events, which are of importance in the care of patients undergoing oncological treatment.

Introduction. Vismodegib is a small-molecule inhibitor of the sonic hedgehog pathway, registered for the treatment of patients with metastatic or locally advanced basal cell carcinoma, who were disqualified from surgical excision or radiotherapy. The full treatment refund from the National Health Fund has been available in Poland since 1 st January 2018. The aim of the study was to analyse the frequency of occurrence of adverse events based on CTCAE and the treatment results based on the RECIST 1.1 criteria, in a group of patients treated for six or 12 months with vismodegib. Material and methods. The patient database was gathered from three sites and consisted of 42 patients, who represented 53.8% of the patients treated with vismodegib in Poland. The duration of the treatment ranged between three weeks and 68 months. The median of the treatment period was 8.25 months (0.75-68); the median of the observation of patients treated for less than 12 months was eight months (6-11), and for those treated for more than 12 months it was 14 months (12-68). Results. The summary of the treatment results after six and 12 months was performed on 29/42 and 17/42 patients accordingly. Complete response was achieved in 3/29 (10.3%) and 3/16 (17.6%) patients after six and 12 months of treatment, respectively, partial response in 13/29 (44.8%) and 5/16 (29.4%) patients, respectively, and stable disease in 13/29 (44.8%) and 8/16 (50.0%) patients, respectively. Progression of the disease was experienced by 7/42 (16.6%) patients within the period of 3-28 months of treatment. One patient with brain metastases died due to the progression of the disease. Adverse events were reported in 31/42 (73.8%) patients, more than one adverse event in a single patient was reported in 22/42 (52.3%) patients. No serious adverse events were observed.