Histopathology of acneiform eruptions in patients treated with epidermal growth factor receptor inhibitors

Mechanism of Lethal Skin Toxicities Induced by Epidermal Growth Factor Receptor Inhibitors and Related Treatment Strategies

Epidermal growth factor receptor (EGFR) inhibitors are widely used to treat various types of cancers such as non-small cell lung cancer, head and neck cancer, breast cancer, pancreatic cancer. Adverse reactions such as skin toxicity, interstitial lung disease, hepatotoxicity, ocular toxicity, hypomagnesemia, stomatitis, and diarrhea may occur during treatment. Because the EGFR signaling pathway is important for maintaining normal physiological skin function. Adverse skin reactions occurred in up to 90% of cancer patients treated with EGFR inhibitors, including common skin toxicities (such as papulopustular exanthemas, paronychia, hair changes) and rare fatal skin toxicities (e.g., Stevens–Johnson syndrome, toxic epidermal necrolysis, acute generalized exanthematous pustulosis). This has led to the dose reduction or discontinuation of EGFR inhibitors in the treatment of cancer. Recently, progress has been made about research on the skin toxicity of EGFR inhibitors. Here, we summarize the mechanism of skin toxicity caused by EGFR inhibitors, measures to prevent severe fatal skin toxicity, and provide reference for medical staff how to give care and treatment after adverse skin reactions.

Severe and delayed-onset acneiform eruptions as an adverse reaction to regorafenib

Regorafenib is an oral multikinase inhibitor targeting several tyrosine kinase receptors including BRAF and epidermal growth factor receptor (EGFR) and is approved as a third-line treatment for metastatic gastrointestinal stromal tumor (GIST). While acneiform eruptions have been observed in patients receiving other BRAF and EGFR inhibitors, the commonly reported adverse reactions to regorafenib are fatigue and palmar-plantar erythrodysesthesia. Herein, we report, to the best of our knowledge, the first case who presented with a severe acneiform eruption 24 months after beginning regorafenib for the treatment of GIST. A 61-year-old woman developed GIST with multiple liver metastases, and she was treated with imatinib and sunitinib. However, these therapies were discontinued, and regorafenib was administered. Twenty-four months after beginning regorafenib, she developed an acneiform eruption on her back. Histopathologic analysis of a skin biopsy from the back revealed neutrophilic suppurative folliculitis. Therefore, she postponed regorafenib administration for 2 months and was treated with topical application of clindamycin phosphate hydrate, which was effective. Consistent with reported evidence that the presence of acneiform eruption and the efficacy of EGFR inhibitors are positively associated, regorafenib had good anticancer activity in our patient. Ultimately, we found that although regorafenib- associated skin toxicities usually appear within 1 month of treatment, patients potentially can present with delayed-onset acneiform eruptions even 24 months later.

Human skin biomarkers relationship to response to treatment with tyrosine kinase inhibitors in advanced EGFR-mutated lung adenocarcinoma

Background

A relationship between the EGFR signaling pathway expression in skin and the use of targeted cancer therapies has been previously demonstrated. Consistent evidence to support the use of skin biopsies as a surrogate for therapeutic evaluation is needed. The purpose of this study was to establish the relationship between the expression of EGFR signaling pathway markers in skin samples from EGFR‐mutated metastatic lung adenocarcinoma patients and their response to tyrosine kinase inhibitors.

Methods

This was a prospective single blind analysis of 35 skin biopsies from 31 patients with confirmed advanced EGFR‐mutated lung adenocarcinoma. Immunohistochemistry was performed: EGFR, p27, Ki67, STAT3 and MAPK, as well as H&E histopathological analysis, in order to determine their treatment response to tyrosine kinase inhibitors.

Results

EGFR, Ki67, STAT3, stratum corneum thickness (number of layers and millimeters) from skin samples had a statistical correlation with an adequate treatment response (P = 0.025, 0.015, 0.017, 0.041, 0.039 respectively). EGFR, p27 and number of layers of the stratum corneum were related to a better median progression‐free survival (P = 0.025 and P = 0.030).

Conclusions

The relationship between EGFR pathway inhibition in the skin and oncological outcomes obtained explains the parallel biological effects of tyrosine kinase inhibitors. We hope that our work incites future research to help validate and assess the use of these markers as potential prognostic and predictive factors.

Clinicopathological differentiation between Pityrosporum folliculitis and acneiform eruption

Distinguishing between Malassezia folliculitis (Pityrosporum folliculitis [P. folliculitis]) and acneiform eruption, based on clinicopathological features, is challenging for clinicians. In the literature, the histopathological differences between P. folliculitis and acneiform eruption lesions have been poorly described. We aimed to determine the clinicopathologic distinctions between P. folliculitis and acneiform eruption by retrospectively analyzing the histology of hematoxylin and eosin stained tissue sections obtained from 52 patients diagnosed with these lesions. The presence of fungal spores in the follicular lumen was most consistent with a P. folliculitis diagnosis (P < 0.001). However, intrafollicular inflammation (P = 0.009), irregular patterns of keratin plugging (P = 0.008), and nuclear dust in the follicular lumen (P < 0.001) favored an acneiform eruption diagnosis. These intrafollicular characteristics and inflammatory differences are believed to be caused by necrotic keratinocytes that lead to vacuolar changes in the follicular wall (P = 0.013). We did not observe any difference between P. folliculitis and acneiform eruption lesions in terms of perifollicular inflammatory cell infiltration. Our study demonstrated that significant differences exist between P. folliculitis and acneiform eruption lesions relative to the presence of necrotic keratinocytes in the follicular wall, intrafollicular characteristics, and inflammatory cell infiltrations. Necrotic keratinocytes are believed to have a key role in these differences. These findings may contribute to an improved understanding of the pathogenesis and differential diagnosis of P. folliculitis and acneiform eruption.

Severe cutaneous adverse reactions induced by targeted anticancer therapies and immunotherapies

With the increasing use of targeted anticancer drugs and immunotherapies, there have been a substantial number of reports concerning life-threatening severe cutaneous adverse reactions (SCARs), including Stevens–Johnson syndrome (SJS), toxic epidermal necrolysis (TEN), drug rash with eosinophilia and systemic symptoms, drug-induced hypersensitivity syndrome, and acute generalized exanthematous pustulosis. Although the potential risks and characteristics for targeted anticancer agent- and immunotherapy-induced SCAR were not well understood, these serious adverse reactions usually result in morbidity and sequela. As a treatment guideline for this devastating condition is still unavailable, prompt withdrawal of causative drugs is believed to be a priority of patient management. In this review, we outline distinct types of SCARs caused by targeted anticancer therapies and immunotherapies. Also, we discuss the clinical course, latency, concomitant medication, tolerability of rechallenge or alternatives, tumor response, and mortality associated with these devastating conditions. Imatinib, vemurafenib, and rituximab were the top three offending medications that most commonly caused SJS/TEN, while EGFR inhibitors were the group of drugs that most frequently induced SJS/TEN. For drug rash with eosinophilia and systemic symptoms/drug-induced hypersensitivity syndrome and acute generalized exanthematous pustulosis, imatinib was also the most common offending drug. Additionally, we delineated 10 SCAR cases related to innovative immunotherapies, including PD1 and CTLA4 inhibitors. There was a wide range of latency periods: 5.5–91 days (median). Only eight of 16 reported patients with SCAR showed clinical responses. Targeted anticancer drugs and immunotherapies can lead to lethal SCAR (14 deceased patients were identified as suffering from SJS/TEN). The mortality rate of TEN was high: up to 52.4%. The information compiled herein will serve as a solid foundation to formulate ideas for early recognition of SCAR and to discontinue offending drugs for better management.

In Vivo Fluorescence Immunohistochemistry: Localization of Fluorescently Labeled Cetuximab in Squamous Cell Carcinomas

Anti-EGFR (epidermal growth factor receptor) antibody based treatment strategies have been successfully implemented in head and neck squamous cell carcinoma (HNSCC). Unfortunately, predicting an accurate and reliable therapeutic response remains a challenge on a per-patient basis. Although significant efforts have been invested in understanding EGFR-mediated changes in cell signaling related to treatment efficacy, the delivery and histological localization in (peri-)tumoral compartments of antibody-based therapeutics in human tumors is poorly understood nor ever made visible. In this first in-human study of a systemically administered near-infrared (NIR) fluorescently labeled therapeutic antibody, cetuximab-IRDye800CW (2.5 mg/m², 25 mg/m², and 62.5 mg/m²), we show that by optical molecular imaging (i.e. denominated as In vivo Fluorescence Immunohistochemistry) we were able to evaluate localization of fluorescently labeled cetuximab. Clearly, optical molecular imaging with fluorescently labeled antibodies correlating morphological (peri-)tumoral characteristics to levels of antibody delivery, may improve treatment paradigms based on understanding true tumoral antibody delivery.

Mechanisms underlying skin disorders induced by EGFR inhibitors

The epidermal growth factor receptor (EGFR) is a receptor tyrosine kinase that is frequently mutated or overexpressed in a large number of tumors such as carcinomas or glioblastoma. Inhibitors of EGFR activation have been successfully established for the therapy of some cancers and are more and more frequently being used as first or later line therapies. Although the side effects induced by inhibitors of EGFR are less severe than those observed with classic cytotoxic chemotherapy and can usually be handled by out-patient care, they may still be a cause for dose reduction or discontinuation of treatment that can reduce the effectiveness of antitumor therapy. The mechanisms underlying these cutaneous side effects are only partly understood. Important questions, such as the reasons for the correlation between the intensity of the side effects and the efficiency of treatment with EGFR inhibitors, remain to be answered. Optimized adjuvant strategies to accompany anti-EGFR therapy need to be found for optimal therapeutic application and improved quality of life of patients. Here, we summarize current literature on the molecular and cellular mechanisms underlying the cutaneous side effects induced by EGFR inhibitors and provide evidence that keratinocytes are probably the optimal targets for adjuvant therapy aimed at alleviating skin toxicities.

Skin/nail infections with the addition of pertuzumab to trastuzumab-based chemotherapy

We report a series of breast cancer patients with invasive skin and nail infections with Staphylococcus species that we attribute to the addition of pertuzumab to trastuzumab-based therapy. With the suspicion of an increased incidence of cutaneous infection in patients treated with pertuzumab and trastuzumab-based chemotherapy, treating medical oncologists identified patients receiving therapy who experienced infection. Between March and October 2014, 18 patients treated with pertuzumab and trastuzumab-based chemotherapy were found to have 21 separate skin/nail infections. Treatment was administered as neoadjuvant therapy in 12 (67 %) patients, adjuvant therapy in four (22 %) patients, and for metastatic disease in two (11 %) patients. Granulocyte growth factors were administered in 11 (61 %) patients and no patients were documented to be neutropenic. New skin and nail lesions developed as early as cycle 1 and as late as 8 months from initial therapy. The 21 separate infections documented were folliculitis and “bite-like” lesions (10), abscess (6), paronychia (3), and cellulitis (2). The appearance of these lesions was distinct from typical EGFR-associated skin changes. When cultures were obtained, Staphylococcus species were isolated. Quantitative immunoglobulins were assessed in 14 (78 %) patients and were abnormally low in six (43 %) of these patients. The skin infections resulted in treatment delay in two (11 %) patients and premature discontinuation of therapy in one patient. We believe that the skin/nail infections reported here in patients treated with the combination of pertuzumab and trastuzumab represent a previously unrecognized toxicity of adding pertuzumab to trastuzumab-based therapies.