Interdisciplinary management of EGFR-inhibitor-induced skin reactions: a German expert opinion

The validity of over-the-counter skin, hair, and nail recommendations for adult patients with cancer: A systematic review

IMPORTANCE

Patients undergoing cancer treatment experience a multitude of skin, hair, and nail adverse events, prompting them to use non-evidence-based and often restrictive over-the-counter (OTC) recommendations to alleviate their symptoms. Comprehensively assessing evidence-based OTC modalities is crucial to enable cancer patients to comfortably resume their lives post-treatment and integrate clinically sound practices into their self-care routines.

OBJECTIVE

Perform a systematic review and assessment of evidence-based OTC skin, hair, and nail care recommendations for adult patients undergoing cancer treatment.

EVIDENCE REVIEW

PubMed, Cochrane, Embase, and Medline databases were searched in March 2023 to identify English articles addressing OTC skin, hair, and nail care recommendations for adult patients before, during, and after cancer chemotherapy or radiation therapy (RT). Quality was assessed with Oxford Centre for Evidence Based Medicine criteria.

FINDINGS

2192 unique articles were screened, of which 77 met inclusion criteria consisting of 54 randomized controlled trials (RCT), 8 non-randomized controlled cohorts, 1 non-randomized controlled clinical trial, 3 controlled prospective cohorts, 4 prospective cohorts, 2 controlled clinical trials, 1 prospective comparative study, 2 case reports, and 2 case series discussing 9322 patients. An additional article outside of our database search was included for a total of 78 articles. OTC skin care treatments with the best quality of evidence included moisturizing creams. Our review revealed a paucity of evidence-based hair and nail care practices.

CONCLUSIONS AND RELEVANCE

This systematic review serves to highlight the efficacy of diverse OTC skin, hair, and nail care recommendations for adult cancer patients while encouraging further clinical trials to establish evidence-based management guidelines.

Multiple drug intolerance in antihypertensive patients: what is known and what is missing

Drug allergy and intolerance are increasingly recognized as significant public health concerns, leading to adverse reactions in patients undergoing pharmacological treatments. Multiple drug intolerance syndrome (MDIS), characterized by adverse reactions to at least three different drug classes without a clear immunological mechanism, poses a substantial challenge, particularly in hypertensive patients. Despite its link to suboptimal adherence and uncontrolled blood pressure, MDIS in the context of hypertension remains insufficiently explored. This review synthesizes existing literature on MDIS, emphasizing clinical characteristics, pathogenesis, and psychiatric comorbidity. Furthermore, it delves into MDIS in the context of hypertension, highlighting the importance of a multidisciplinary approach in diagnosis and management, including innovative therapeutic strategies such as novel therapeutic algorithms or renal denervation. The review concludes by emphasizing the necessity for further research and clinical trials to enhance our understanding and address MDIS, especially in hypertensive patients.

Evaluation of the additional prophylactic effect of topical steroid ointment to systemic minocycline against anti-epidermal growth factor antibody-induced skin toxicities in metastatic colorectal cancer treatment

BACKGROUND

Anti-epidermal growth factor receptor (EGFR) antibodies often cause skin toxicities. Preemptive skin treatments using systemic antibiotics with or without topical steroid are reportedly effective although the most suitable method remains unclear. This study aimed to determine whether combination prophylaxis using systemic minocycline and topical steroid is superior to minocycline alone in a real-world metastatic colorectal cancer (mCRC) treatment.

METHODS

Patients with mCRC (n = 87) who received anti-EGFR monoclonal antibodies were retrospectively assessed. The primary objective was to compare the incidence of grade ≥ 2 overall skin toxicities during all treatment periods between the control group receiving prophylactic minocycline 100 mg/day, and the combination prophylaxis group receiving minocycline 100 mg/day + topical steroid. The incidence of each skin symptom was also evaluated.

RESULTS

The incidence of grade ≥ 2 overall skin toxicities was 63.6% in the control and 56.9% in the combination groups, with no significant difference (P = 0.63). Similarly, the incidence of grade ≥ 2 dry skin, fissures, paronychia, and pruritus did not significantly differ. In addition, incidence of all-grade skin toxicities was not different. However, the incidence of grade ≥ 2 papulopustular rashes was significantly lower in the combination group (23.1% vs. 50.0%, P = 0.03). Propensity score-matched analysis supported these results. Multivariate logistic regression analysis showed no significant association between combination prophylaxis and grade ≥ 2 overall skin toxicities, but it did show a reduction in grade ≥ 2 papulopustular rashes.

CONCLUSION

Adding topical steroids to systemic minocycline did not mitigate grade ≥ 2 overall skin toxicities induced by anti-EGFR antibodies; however, it significantly improved papulopustular rashes.

Acneiform eruption induced by molecularly targeted agents in antineoplastic therapy: A review

BACKGROUND

Various biologic agents targeting specific molecules present new treatment options for various tumors. Acneiform eruption is a very common skin reaction to these agents. Although not life-threatening, acneiform eruption can affect patients' emotional and social lives. In very exceptional cases, it can lead to cancer therapy interruption.

AIMS

The aim of this study was to review the incidence rate, clinical characteristics, pathogenesis, and current management of acneiform eruption induced by molecularly targeted agents.

METHODS

This review was carried out through PubMed, Embase, and Cochrane searching terms 'acneiform eruption', 'papulopustular eruption' or 'acne-like rash' and 'skin toxicity', 'cutaneous toxicity', 'skin reactions', 'dermatological toxicities', 'target therapy,' or 'drug therapy'.

RESULTS

Of the 73 articles matched our search terms, 61 were original articles and 12 were case reports or case series. Acneiform eruption is most commonly observed in patients treated with epidermal growth factor receptor inhibitors and mitogen-activated protein kinase inhibitors. Typical lesions consist of erythematous papules and pustules without comedones, accompanying with burning, pruritus, or xerosis. The pathogenesis involves inflammation and abnormalities of the follicular epithelium, where a disorder in EGFR signaling plays a key role. The treatment of acneiform eruption depends on the severity of the rash.

CONCLUSIONS

Early recognition and effective management of this cutaneous adverse reaction can prevent unnecessary reduction and discontinuation of drug use and improve patient survival and quality of life. Close collaboration between oncologists and dermatologists is important to optimize therapy and improve patient survival.

Cetuximab severe cutaneous toxicity… a gateway for bacteremia: case report

EGFR inhibitors used in the treatment of metastatic wild-RAS colorectal cancer in combination with chemotherapy are associated with dermatologic side events that are low grade in most cases. We report a case of severe cutaneous toxicity secondary to cetuximab associated with bacterial cellulitis. A 57-year-old woman with metastatic adenocarcinoma of the colon, receiving FOLFIRI and Cetuximab as a first-line treatment, presented with a severe erythematous rash and xerosis resistant to local treatment with moisturizing emollients. Few days later, the patient becomes febrile, and the rash becomes more diffuse with a sandpaper appearance on the face, neck, chest, and flexor creases with exfoliation of large areas of skin. A bacterial cellulitis secondary to a dermatologic severe toxicity of Cetuximab was suspected. The patient started on antibiotics and local treatment with good response. This is a life-threatening cutaneous toxicity of cetuximab with secondary bacterial infection. Early recognition of cutaneous side effects of EGFR inhibitors is important to prevent such type of toxicities.

A pilot randomized controlled study of the effects of an educational training program on skin reactions induced by chemotherapy, Epidermal Growth Factor Inhibitor (EGFRI) treatments, and immunotherapy

PURPOSE

To evaluate the effectiveness of an educational program for cancer patients who developed pruritus, rash or photosensitivity induced by chemotherapy, epidermal growth factor inhibitor (EGFRI) treatments, or immunotherapy.

METHOD

This study is a pilot randomized controlled study. The patients in the experimental pool were assigned to attend the educational program once weekly, for 4 weeks. For the patients in the control group the usual information was provided to them, as with any cancer patient who initiates treatment. Each participant's induction day to the program (symptoms initiation) was considered part of week 0. For the Primary endpoint repeated measurements were taken weekly regarding the grade of skin reaction. For the Secondary endpoint the 36-Item Short Form Survey questionnaire (SF-36) (since week 0) and the Dermatology Life Quality Index (DLQI) questionnaire (since week 1) were recorded.

RESULTS

The study was conducted between January 2019 and December 2020 and included 40 patients. The grades of skin reactions, showed a statistically significant improvement in the intervention group compared to the control (Walds X² = 19,25, p = 0.004). The results from the SF-36 questionnaire, showed that patients in the intervention group presented higher functional health and wellbeing status, although the results did not indicate a significant interaction between Group and Time, for all the questionnaire parameters. The effect size difference between control and intervention groups was higher at week 3 (d = 0.44) according to the results of DLQI questionnaire.

CONCLUSIONS

Further validation of the effectiveness of the educational program over longer periods of time will be required.

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.

Association of dry skin with intercellular lipid composition of stratum corneum after erlotinib administration

PURPOSE

Erlotinib, an inhibitor of the epidermal growth factor receptor tyrosine kinase, causes skin disorders such as dry skin, which impairs the skin barrier function. Stratum corneum (SC) lipids play an important role in skin barrier function; therefore, this study aimed to investigate the relationship between erlotinib-related dry skin and changes in the intercellular lipid composition and structure of the SC.

METHODS

Overall, 21 patients with non-small lung cancer were enrolled in this study. All patients received 150 mg/day erlotinib orally. A SC sample of each patient was collected from the inner forearm using the tape stripping method on days 0, 7, 14, 28, and 56 after erlotinib administration. The intercellular lipid components of ceramide (CER), free fatty acid (FFA), and cholesterol sulfate (CS) in samples extracted from the tape were analyzed using liquid chromatography/time-of-flight/mass spectrometry. SC samples from six healthy subjects were collected as controls on days 0, 28 and 56 and analyzed similarly.

RESULTS

Although total CER and FFA levels were not changed after erlotinib administration, the levels of CER subclasses [AP] and [AH] and hydroxy FFA, which are structural components of CER subclass [A], decreased. In contrast, the CS levels increased after erlotinib administration. Moreover, higher CS levels in the SC correlated with the clinical condition of dry skin. No changes were observed in the SC lipid composition in healthy subjects.

CONCLUSION

Erlotinib-related dry skin was associated with a higher CS level in the SC.

Management of skin adverse reactions in oncology

Chemo and targeted anticancer therapies present significant skin adverse reactions, which impair the patients' quality of life. Cutaneous toxicities lead to poor treatment adherence, drug cessation, and psychosocial distress. This review aims to summarize the current knowledge concerning the prevention and management of skin toxicity arising from these therapies. A systematic literature search on online databases was conducted. The categorization of the main preventive and treatment measures was performed according to the level of evidence. Management of skin adverse reactions of oncology treatments is very heterogeneous, which can be explained by the lack of sound evidence-based treatments. The most studied adverse effects are papulopustular eruption, xerosis, and hand-foot syndrome. Prevention of xerosis stands out as the strategy most supported by level II studies. With respect to treatment, the use of antibiotics in papulopustular eruption resulting from anti-epidermal growth factor receptor agents is the most evidence-based approach. In general, the number of studies published in the literature classified with a level II of evidence (52%) is similar to the ones classified as level IV (33%), making clear the need of more randomized controlled trials regarding the effectiveness of preventive and treatment measures of skin adverse reactions of chemo and targeted anticancer therapies.

Patient-reported symptom burden as a prognostic factor in treatment with first-line cetuximab plus chemotherapy for unresectable metastatic colorectal cancer: Results of Phase II QUACK trial

Background

It remains unclear whether patients’ self‐perceptions of symptoms at baseline clinically impact the prognostic relevance, treatment efficacy, or toxicity profiles in metastatic colorectal cancer (mCRC) patients treated with the first‐line cetuximab and standard chemotherapy.

Methods

The data were collected from a prospective trial that assessed the relationships between quality of life (QOL), treatment efficacy, and adverse events (AEs).

Results

The analysis of 137 mCRC patients revealed a significant association between the presence of baseline tumor‐related symptoms and a lower overall survival (OS) compared to the absence of symptoms (HR, 2.49; 95% CI, 1.37‐4.62; P = .003). The asymptomatic responders had favorable outcomes compared to the symptomatic nonresponders (2‐year OS rates: 83.6% and 35.9%, respectively), while the symptomatic responders had similar outcomes to the asymptomatic nonresponders. The median postprogression survival differed significantly: 10.2 months for the symptomatic patients and 15.9 months for the asymptomatic patients (HR, 2.29; 95% CI, 1.25‐4.29, P = .008). The objective response rates and patient toxicity profiles were similar irrespective of the severity of baseline symptoms.

Conclusion

Baseline symptoms were associated with worse OS but not with impaired treatment efficacy or more frequent AEs in mCRC patients treated with cetuximab in addition to chemotherapy.

Relationships between quality of life and skin toxicities of epidermal growth factor receptor inhibitors in cancer patients: A literature review

AIM

Epidermal growth factor receptor (EGFR) inhibitors are used as treatments for various cancers, but the associated skin toxicities affect quality of life (QoL). The aim of this review is to document the relationship between skin toxicity and QoL of cancer patients, and to identify implications for clinical practice and subjects for future studies.

METHODS

Electronic databases were searched systematically and all studies examining aspects of health-related QoL in patients receiving EGFR inhibitor treatments for cancer.

RESULTS

A total of 25 published studies met the criteria for inclusion. Some cancer patients maintained their health conditions by recognizing that skin toxicities are correlated with the efficacy of EGFR inhibitor therapy, yet QoL declined in all functional evaluations. In particular, QoL was low in patients above 81 years of age and in those under 50 years of age.

CONCLUSION

Improved understanding of the pain due to skin toxicity is required in all age groups, particularly in elderly and young cancer patients. In addition, further studies are required to define long-term changes in QoL among patients receiving EGFR inhibitors for cancer. Healthcare professionals need to help patients to maintain subjective health conditions by understanding relationships between skin toxicity and therapeutic effects. To this end, assessments of patients who are prone to QoL decline due to skin toxicity are critical so that skin management can be started during early stages.

A technical appraisal of guidelines for the management of skin rash in patients on chemotherapy and targeted therapy

BACKGROUND

Skin rash remains one of the most prevalent and troublesome clinical problems experienced by patients on chemotherapy and targeted therapy. To ensure high-quality care, guidelines are seen as the best guidance. Considering the quality of guidelines varies greatly, a systematical appraisal of the methodological quality of guidelines for the management of skin rash in patients on chemotherapeutic drugs and targeted anticancer therapies was undertaken, in order to identify appropriate ones for healthcare professionals.

METHODS

A systematic search of databases and Internet was conducted to obtain pertinent guidelines. Two reviewers independently assessed the eligibility of guidelines according to the inclusion criteria. Then the guidelines included were appraised by three researchers with the methodological quality of eligible guideline using Appraisal of Guidelines for Research and Evaluation II (AGREEII).

RESULTS

Totally nineteen guidelines met the inclusion criteria. The quality ranged from good to acceptable in scope and purpose (mean: 78.80%, range: 66.67-94.44%) and clarity of presentation domains (mean: 85.38%, 75.00-91.67%), but not in stakeholder involvement (mean: 50.15%, range: 36.11-75.00%), rigor of development (mean: 23.65%, range: 6.25-70.83%), applicability (mean: 23.96%, range: 4.17-52.08%), and editorial independence domains (mean: 45.18%, range: 0.00-87.50%). Overall, two guidelines were classified as "recommended".

CONCLUSIONS

Only two guidelines were recommended to manage skin rash in patients on chemotherapy and targeted therapies, most guidelines issued were of low to moderate quality. Thus, more attention should be paid to the methodological quality of guideline development in this field.

Management of skin toxicities during panitumumab treatment in metastatic colorectal cancer

BACKGROUND

Anti-epidermal growth factor receptor therapy is associated with skin adverse events not previously reported with conventional chemotherapy. Prophylactic actions are recommended, but routine clinical management of these toxicities and their impact on quality of life remain unknown.

AIM

To assess the dermatological toxicities reported after panitumumab initiation, their impact on the quality of life and the clinical practices for their management.

METHODS

Patients included in this prospective multicenter observational study were over 18 years of age and began treatment with panitumumab for wild-type KRAS metastatic colorectal cancer. The incidence of dermatological toxicities, clinical practices for their management and impact on quality of life were recorded during a 6-mo follow-up.

RESULTS

Overall, 229 patients (males, 57.6%; mean age, 66.2 years) were included. At day 15, 59.3% of patients had dermatological toxicity; the rate peaked at month 2 (74.7%) and decreased at month 6 (46.5%). The most frequent dermatological toxicities were rash/acneiform rash, xerosis and skin cracks. At least one preventive treatment was administered to 65.9% of patients (oral antibiotics, 84.1%; emollients, 75.5%; both, 62.9%). The rates of patients who received at least one curative treatment peaked at month 2 (63.4%) and decreased at month 6 (44.8%). The impact of the dermatological toxicities on quality of life was limited as assessed with Dermatology Life Quality Index scores and inconvenience visual analogic scale score. The rates of topical corticosteroids administration and visits to specialists were low.

CONCLUSION

The rates of the different skin toxicities peaked at various times and were improved at the end of follow-up. Nevertheless, their clinical management could be optimized with a better adherence to current recommendations. The impact of skin toxicities on patient’s quality of life appeared to be limited.

Update review of skin adverse events during treatment of lung cancer and colorectal carcinoma with epidermal growth receptor factor inhibitors

The past decades have witnessed a rapid increase in the use of molecularly targeted therapies. One class of agents includes the epidermal growth factor receptor inhibitors (EGFRIs), which afford patients longer progression-free survival (PFS) times, especially among non-small cell lung cancer (NSCLC) and metastatic colorectal carcinoma (mCRC). Certain adverse effects, particularly skin toxicity, are mainly manifested as rash, xerosis, pruritus, nails changes, hair changes and mucositis. Previous studies reported the adverse events occurred based on the cutaneous inflammation reaction. Treatment recommended glucocorticoids and antibiotics. It is suggested that skin toxicity is an important issue because it usually affects patients' quality of life (QoL) and still causes dose reduction or discontinuation of targeted therapies. For these reasons, more and more oncologists and dermatologists recognize the importance of recognition and management of skin toxicities with the expansion in availability of EGFRIs. In this review, we conducted a systematic review of recent data to examine the types and frequencies of dermatologic toxicities associated with anti-epidermal growth factor receptor (EGFR) therapies in NSCLC and mCRC. In addition, we would like to explore the management and treatment options currently used by clinicians based on the possible mechanism.

An Update of Efficacy and Safety of Cetuximab in Metastatic Colorectal Cancer: A Narrative Review

Colorectal cancer is the second most common cancer, representing 13% of all diagnosed cancers. Cetuximab is a recombinant chimeric monoclonal IgG1 antibody and epidermal growth factor receptor (EGFR) inhibitor. Cetuximab is approved for the first-line treatment in combination with chemotherapy or as a single agent in patients who have failed or are intolerant to chemotherapy in patients with EGFR-expressing, RAS wild-type metastatic colorectal cancer. Cetuximab efficacy emerged from studies that were conducted to approve the drug. Cetuximab is well tolerated; its toxicities are caused by its mechanism of action and the most common adverse reaction is skin toxicity. The main purpose of this manuscript is to present an update on the evidence-based summary of efficacy and safety and on the cost-effectiveness of cetuximab. Furthermore, it suggests a management of adverse drug reactions to improve the tolerability of the drug.

Therapeutic developments in pancreatic cancer: current and future perspectives

The overall 5-year survival for pancreatic cancer has changed little over the past few decades, and pancreatic cancer is predicted to be the second leading cause of cancer-related mortality in the next decade in Western countries. The past few years, however, have seen improvements in first-line and second-line palliative therapies and considerable progress in increasing survival with adjuvant treatment. The use of biomarkers to help define treatment and the potential of neoadjuvant therapies also offer opportunities to improve outcomes. This Review brings together information on achievements to date, what is working currently and where successes are likely to be achieved in the future. Furthermore, we address the questions of how we should approach the development of pancreatic cancer treatments, including those for patients with metastatic, locally advanced and borderline resectable pancreatic cancer, as well as for patients with resected tumours. In addition to embracing newer strategies comprising genomics, stromal therapies and immunotherapies, conventional approaches using chemotherapy and radiotherapy still offer considerable prospects for greater traction and synergy with evolving concepts.

Clinical impact of minocycline on afatinib-related rash in patients with non-small cell lung cancer harboring epidermal growth factor receptor mutations

BACKGROUND

The management of skin toxicity is crucial for efficient afatinib treatment, but the role of tetracycline class antibiotics (TCs) in managing these rashes is relatively unknown.

METHODS

We reviewed the clinical records of patients who were administered afatinib for the treatment of non-small cell lung cancer harboring epidermal growth factor receptor mutations between October 2014 and November 2016. Twenty-five patients, who received TCs for the management of afatinib-related skin disorders, were enrolled.

RESULTS

Minocycline was administered orally to participants. Afatinib-related toxic effects, such as rash, diarrhea, and paronychia, were observed in 92%, 92%, and 40% of cases, respectively. Although 24% of diarrhea and 4% of paronychia cases were rated grade 3 or higher, no severe cases of rash were observed during afatinib treatment. Of the 18 afatinib dose reductions, 14 (78%), three (17%), and one (6%) resulted from diarrhea, paronychia, and stomatitis, respectively; no patients required a dose reduction because of rash. When minocycline treatment started, 21 patients (84%) had a rash of grade 1 or less, and three patients had a grade 2 rash. A response to afatinib was observed in 18 patients (72%) and the median duration of afatinib administration was 501 days. An adverse event related to minocycline (grade 1 nausea) was observed in one patient.

CONCLUSIONS

A large proportion of the study patients started minocycline before grade 2 rash development and the severity of afatinib-related rash was lower than that previously reported. Oral TCs may be beneficial, especially if started early.

Dermatologic Toxicity Occurring During Anti-EGFR Monoclonal Inhibitor Therapy in Patients With Metastatic Colorectal Cancer: A Systematic Review

Monoclonal antibody inhibitors of the epidermal growth factor receptor (EGFR) have been shown to improve outcomes for patients with metastatic colorectal cancer (mCRC) without RAS gene mutations. However, treatment with anti-EGFR agents can be associated with toxicities of the skin, nails, hair, and eyes. Because these dermatologic toxicities can result in treatment discontinuation and affect patient quality of life, their management is an important focus when administering anti-EGFR monoclonal antibodies. The present systematic review describes the current data reporting the nature and incidence of, and management and treatment options for, dermatologic toxicities occurring during anti-EGFR treatment of mCRC. A search of the National Library of Medicine PubMed database from January 1, 2009, to August 18, 2016, identified relevant reports discussing dermatologic toxicity management among patients with mCRC receiving anti-EGFR therapy. The studies were grouped by type and rated by level of evidence using the GRADE approach developed by the Agency for Healthcare Research and Quality. Overall, 269 reports were reviewed (nonrandomized trials, n = 120; randomized trials, n = 31; retrospective studies, n = 15; reviews, n = 39). Dermatologic toxicity of any grade occurs in most patients who receive anti-EGFR therapy; approximately 10% to 20% of patients experienced grade 3/4 toxicity. The most common dermatologic toxicities include papulopustular/acneiform rash, xerosis, and pruritus; however, nail changes, hair abnormalities, and ocular conditions also occur. Guidance for managing these toxicities includes the use of inexpensive emollient ointments and moisturizers, avoidance of sun exposure, avoidance of irritants, and the use of short showers. Several studies also found that preemptive treatment was more effective than reactive treatment at limiting the incidence and severity of skin toxicity. With appropriate treatment, the dermatologic toxicities associated with anti-EGFR monoclonal antibody therapy can be managed, minimizing patient discomfort and the need for therapy interruption and/or discontinuation. Additionally, preemptive treatment can reduce dermatologic toxicity severity, ultimately yielding better quality of life.

Assessment of demodex presence in acne-like rash associated with cetuximab

CONTEXT

Cetuximab is an epidermal growth factor receptor inhibitor. It is frequently used in the treatment of solid tumors. However, it has a high potential to cause acne-like rash. Demodex mites, which are known to increase in number in immunosuppressive circumstances, are closely related to the acneiform lesions.

OBJECTIVE

The aim of this study is to evaluate the presence of demodex mites in acne-like rash that appears under the treatment of Cetuximab.

METHODS

We reviewed the medical records of patients who applied to our clinic with cetuximab induced papulopustular rashes between November 2014 and March 2016. Demodex sampling was performed by standardized skin surface biopsy (SSSB) in a total of 11 patients (eight males and three females). Infestation was defined as at least 5 living parasites/cm² of skin.

RESULTS

Upon the SSSB examination in 10 out of the 11 patients, no demodex mites were detected. Demodex mites were found in only one of the patients. This patient, in whom two dead Demodex folliculorums were found through facial sampling, was also regarded as negative since his demodex density was under the threshold limit value.

CONCLUSION

In this study, it has been concluded that acne-like rash that develops under the treatment of cetuximab is not related to the presence of demodex mites. Papulopustular eruptions that develop under cetuximab treatment should not be directly correlated with the presence of demodex; first SSSB and demodex presence should be evaluated.

Dermatologic events from EGFR inhibitors: the issue of the missing patient voice

Purpose

As epidermal growth factor receptor (EGFR) inhibitors are associated with a variety of dermatologic adverse events (dAEs), the purpose of this study was to develop an overview of current knowledge of dAEs associated with EGFR inhibitors and to identify knowledge gaps regarding incidence, treatment, impact on quality of life (QOL), and patient acceptance.

Method

A structured literature search was conducted using MEDLINE/PubMed (January 1983 to January 2014). In total, 71 publications published from 2004 to 2014 were identified for consideration in the final evidence review.

Results

The majority of published articles concentrate on the incidence of skin reactions, duration, treatment, and prevention strategies. Different grading systems based on the symptoms of skin rash or on health-related QOL (HRQOL) are used. An additional topic is the possible correlation between acneiform rash and efficacy of EGFR inhibitors. Knowledge gaps identified in the literature were how dAEs impact QOL compared with other AEs from a patient’s perspective, patients’ acceptance of dAEs (willingness to tolerate), and the impact of physician-patient communication on treatment decisions.

Conclusions

Research is needed on the impact of dAEs on patients’ acceptance of cancer treatments. Systematic studies are missing that compare the impact of dAEs with other toxicities on therapy decisions from both physician’s and patient’s view, and that investigate the balance between efficacy and avoidance of acneiform rash in treatment decisions. Such studies could provide deeper insights into the acceptance of the risk of untoward dermatologic events by both physicians and patients when treating advanced cancers.

Electronic supplementary material

The online version of this article (doi:10.1007/s00520-016-3419-4) contains supplementary material, which is available to authorized users.

Expert Consensus on the Management of Adverse Events from EGFR Tyrosine Kinase Inhibitors in the UK

Epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) such as gefitinib, erlotinib, and afatinib are standard-of-care for first-line treatment of EGFR-mutant advanced non-small cell lung cancer (NSCLC). These drugs have a proven benefit in terms of higher response rate, delaying progression and improvement of quality of life over palliative platinum-based chemotherapy. The most common adverse events (AEs) are gastrointestinal (GI) (diarrhoea and stomatitis/mucositis) and cutaneous (rash, dry skin and paronychia). These are usually mild, but if they become moderate or severe, they can have a negative impact on the patient’s quality of life (QOL) and lead to dose modifications or drug discontinuation. Appropriate management of AEs, including prophylactic measures, supportive medications, treatment delays and dose reductions, is essential. A consensus meeting of a UK-based multidisciplinary panel composed of medical and clinical oncologists with a special interest in lung cancer, dermatologists, gastroenterologists, lung cancer nurse specialists and oncology pharmacists was held to develop guidelines on prevention and management of cutaneous (rash, dry skin and paronychia) and GI (diarrhoea, stomatitis and mucositis) AEs associated with the administration of EGFR-TKIs. These guidelines detail supportive measures, treatment delays and dose reductions for EGFR-TKIs. Although the focus of the guidelines is to support healthcare professionals in UK clinical practice, it is anticipated that the management strategies proposed will also be applicable in non-UK settings.

A case of successfully treated recalcitrant EGFR inhibitor-induced acneiform eruption following non-ablative fractional laser

Epidermal growth factor receptor (EGFR) inhibitor, a targeted therapy in the field of oncology, is a new drugs suggested for the cause of acneiform eruptions. The unresponsiveness to conventional acne therapy is a pivotal reason of seeking alternatives to treat drug-induced acneiform eruptions. A 30-year-old female treated with cetuximab, EGFR inhibitor presented with numerous sized erythematous papules and pustules on her face. All responses of oral medications and topical application were poor. She was treated with two passes of non-ablative 1550 nm fractional erbium glass laser with topical clindamycin. After three laser sessions, the skin lesions improved dramatically without any side effects. There is currently no single effective treatment for acneiform eruption. This report shed light on the possibility that non-ablative fractional laser can be an alternative for recalcitrant drug-induced acneiform eruptions.

Skin problems and EGFR-tyrosine kinase inhibitor

Epidermal growth factor receptor inhibition is a good target for the treatment of lung, colon, pancreatic and head and neck cancers. Epidermal growth factor receptor-tyrosine kinase inhibitor was first approved for the treatment of advanced lung cancer in 2002. Epidermal growth factor receptor-tyrosine kinase inhibitor plays an essential role in the treatment of cancer, especially for patients harbouring epidermal growth factor receptor activating mutation. Hence, skin toxicity is the most concerning issue for the epidermal growth factor receptor-tyrosine kinase inhibitor treatment. Skin toxicity is bothersome and sometimes affects the quality of life and treatment compliance. Thus, it is important for physicians to understand the background and how to manage epidermal growth factor receptor-tyrosine kinase inhibitor-associated skin toxicity. Here, the author reviewed the mechanism and upfront preventive and reactive treatments for epidermal growth factor receptor inhibitor-associated skin toxicities.

Atypical skin reaction in a patient treated with gefitinib for advanced lung cancer: A case report and review of the literature

Gefitinib is a selective epidermal growth factor receptor tyrosine kinase inhibitor utilized for the treatment of advanced non-small cell lung carcinoma. The most commonly reported adverse event during gefitinib therapy is skin rash, particularly a papulopustular acne-like eruption. Cutaneous toxicities can affect treatment compliance and the quality of life of the patient. The present study reports a case of gefitinib-induced atypical skin reaction in a 73-year-old woman with advanced non-small cell lung cancer, who developed a squamous-crusted eruption on her face after 4 weeks of oral treatment with gefitinib at a dose of 250 mg/day. The patient was treated with 100 mg minocyclin (2 tablets/day, orally) and with ryfamicin topically. A complete resolution of the lesions was observed 2 weeks later. The present case report explored the pathogenesis of this skin manifestation, focusing on the underlying immunological mechanisms. A review of the literature concerning skin reactions to gefitinib was also conducted.

Risk of mucocutaneous toxicities in patients with solid tumors treated with lapatinib: a systematic review and meta-analysis

BACKGROUND

We performed a systematic review and meta-analysis to determine the risk of mucocutaneous adverse events associated with lapatinib.

PATIENTS AND METHODS

Eligible studies included randomized phase II and III trials of patients with solid tumors on lapatinib; describing events of stomatitis, skin rash, hand foot syndrome, pruritus and alopecia.

RESULTS

Our search strategy yielded 380 potentially relevant citations on lapatinib from PubMed/Medline, CENTRAL Cochrane Registry and ASCO Meeting Library. After exclusion of ineligible studies, a total of 19 clinical trials were considered eligible for the meta-analysis. The RRs of all-grade skin rash, stomatitis, hand foot syndrome and pruritus were 3.04 (95% CI 2.33-3.96; p < 0.00001), 1.67 (95% CI 1.02-2.3; p < 0.04), 4.45 (95% CI 1.15-17.19; p = 0.03), and 2.02 (95% CI 1.46-2.8; p < 0.0001), respectively. Exploratory subgroup analysis showed no effect of treatment regimen on the RRs of the relevant adverse events.

CONCLUSIONS

Our meta-analysis has demonstrated that lapatinib is associated with a significantly increased risk of all-grade skin rash, hand foot skin reaction and pruritus. Clinicians should be aware of these risks and perform regular clinical monitoring.

[Effect and significance of BH3-only protein in targeted therapy of non-small cell lung cancer]

肺癌死亡率居全球恶性肿瘤死亡之首，非小细胞肺癌是肺癌中最常见的类型。在传统的抗肺癌治疗中，促进细胞凋亡是非小细胞肺癌治疗的一个重要组成部分，但抗肿瘤药物存在毒副作用大和耐药性等问题。因此，寻找新的抗肿瘤药物作用靶点成为非小细胞肺癌治疗的重点之一。BH3-only蛋白在凋亡的启动及凋亡通路的沟通中发挥极其重要的作用。BIM是BH3-only蛋白家族中的核心成员。以BIM为靶点的治疗在非小细胞肺癌的治疗中具有不可取代的作用。本文简单介绍了BCL-2家族和其中的BH3-only促凋亡蛋白，并且阐述了BIM、BH3-only蛋白在非小细胞肺癌靶向治疗中的重要作用。

Dermatological toxicity associated with targeted therapies in cancer: optimal management

Targeted therapies have developed rapidly over the last few years in the field of oncology thanks to a better understanding of carcinogenesis. They target pathways involved in signal transduction (EGFR, HER2, HER3, HER4, FLT3, RAS, RAF, MEK, KIT, RET, mTOR, SRC, EPH, SCF), tumor angiogenesis (VEGFR, TIE2), and tumor microenvironment (PDGFR, FGFR). They rarely cause the systemic adverse reactions generally associated with chemotherapy, but frequently cause disabling and specific skin toxicity. The impact on patient quality of life can be important both in terms of symptoms caused and of potentially aesthetic consequences. Inappropriate management can increase the risk of dose reduction or discontinuation of the cancer treatment. In this review, we will discuss skin toxicity associated with the main drug classes-EGFR, BRAF, MEK, mTOR, c-KIT, CTLA4, and SMO inhibitors, and anti-angiogenic agents. Targeted therapy-induced skin toxicities will be detailed in terms of symptoms, frequency, evolution, complications, and topical and oral treatments in order to improve their diagnosis and management.

[Safety of reintroduction of erlotinib at low doses following hand-foot syndrome induced by erlotinib treatment for a Pancoast-Tobias tumour]

INTRODUCTION

Erlotinib, an epidermal growth factor receptor tyrosine kinase inhibitor (EGFR-TKI), is a targeted therapy used in first, second or third line treatment of non-small cell lung carcinoma. Several cutaneous toxicities after the use of EGFR-TKI are well-described.

OBSERVATION

After 13 days of erlotinib treatment, an 82-year-old man, diagnosed with squamous cell lung carcinoma, developed an acneiform rash in parallel with hand-foot syndrome (HFS). This led to the interruption of his treatment because of the patient's distress. However, for the first time and after a total recovery of the toxidermia, we reintroduced the therapy at very low doses without any HFS recurrence being observed.

DISCUSSION

The HFS is a dose-dependent toxidermia appearing within the first week following administration of the triggering cytotoxic agents (chemotherapies or target therapies). It appears that a specific pathogenic mechanism exists for each cytotoxic agent triggering the skin damage, resulting in different clinical presentations. A major aspect of HFS treatment involves the reduction or withdrawal of the treatment.

CONCLUSIONS

We describe what is to our knowledge, the third case of erlotinib-induced HFS, a new secondary undesirable skin pathology for which, currently, exist few direct causal explanations or drug monitoring. This observation highlights the importance of broadening our knowledge of the exact mechanisms linking EGFR-TKI to the appearance of HFS in order to optimize treatment.

1,4-naphthoquinones: from oxidative damage to cellular and inter-cellular signaling

Naphthoquinones may cause oxidative stress in exposed cells and, therefore, affect redox signaling. Here, contributions of redox cycling and alkylating properties of quinones (both natural and synthetic, such as plumbagin, juglone, lawsone, menadione, methoxy-naphthoquinones, and others) to cellular and inter-cellular signaling processes are discussed: (i) naphthoquinone-induced Nrf2-dependent modulation of gene expression and its potentially beneficial outcome; (ii) the modulation of receptor tyrosine kinases, such as the epidermal growth factor receptor by naphthoquinones, resulting in altered gap junctional intercellular communication. Generation of reactive oxygen species and modulation of redox signaling are properties of naphthoquinones that render them interesting leads for the development of novel compounds of potential use in various therapeutic settings.

Barrier protective use of skin care to prevent chemotherapy-induced cutaneous symptoms and to maintain quality of life in patients with breast cancer

Purpose

Chemotherapy with anthracyclines, taxanes, or alkylating agents often causes cutaneous side effects. Nonspecific inhibition of the proliferative activity of keratinocytes has antidifferentiation effects that lead to defects in the barrier function and, thus, to dry, itchy, and irritable skin. These cutaneous symptoms reduce the quality of life of the patients considerably. Conditioning with topical application of niacinamide uses the cytoprotective and barrier stabilizing effect of vitamin B₃.

Patients and methods

A multicenter randomized crossover study investigated the influence of the test preparation on the quality of life compared to standard care for 73 patients with breast cancer undergoing adjuvant or neoadjuvant cytostatic therapy. Primary target parameter was the Dermatology Life Quality Index with its respective subscales after 6 weeks of a twice-daily application of the respective preparations. Additionally, specific symptoms such as pruritus, dryness, and irritability have been assessed using visual analog scales.

Results

Regarding the total score of the Dermatology Life Quality Index, no relevant differences could be observed. However, the results for the “symptoms and feelings” subscale show a significant advantage in favor of the test preparation. Significant superiority of the test preparation could also be observed in the secondary target parameters, the visual analog scales (P<0.05).

Conclusion

The results show for the first time a significant superiority of prophylactic application of niacinamide for maintaining quality of life while undergoing cytostatic treatment.

Acneiform eruptions

Is it acne or is it not? When this question arises, we can presume that we have crossed the boundaries of "acneiform eruptions" of the face. Although acne may be considered a condition fairly easy to diagnose, it is not rare for the practicing dermatologist or the general physician to wonder when faced with an acneiform eruption before establishing a diagnosis. In this review, we address facial acneiform eruptions in children and in adults, including perioral dermatitis, granulomatous periorificial dermatitis, nevus comedonicus, acne cosmetica, rosacea, demodicosis, folliculitis, acneiform presentation of cutaneous lymphomas, and drug-induced [epidermal growth factor receptor (EGFR) inhibitors, steroids, etc.] acneiform eruptions, along with their diagnosis and therapeutic approaches. The major distinguishing factor in acneiform eruptions is that, in contrast to acne, there are no comedones (whiteheads or blackheads).

Randomized double-blind trial of prophylactic topical Evozac(®) Calming Skin Spray for gefitinib-associated acne-like eruption

Background

“Gefitinib” is a first-generation epidermal growth factor receptor tyrosine-kinase inhibitor. More than half of patients receiving gefitinib develop acne-like eruption. Evozac^® Calming Skin Spray (Evaux Laboratoires, Évaux-les-Bains, France) is made of Évaux thermal spring water and commonly used for the treatment of dermatological toxicities caused by anti-epidermal growth factor receptor therapy. The aim of the study reported here was to test the effect of Evozac Calming Skin Spray on the prevention of rash in patients receiving gefitinib.

Methods

Non-small-cell lung cancer patients preparing to initiate gefitinib therapy were randomly assigned to apply Evozac Calming Skin Spray or physiological saline to the face three times a day. The treatment was started on the same day as initiation of gefitinib therapy and continued for 4 weeks.

Results

A total of 51 patients in the Evozac Calming Skin Spray group and 50 patients in the physiological saline group completed the study per the protocol. The number of facial lesions peaked at the end of 3 weeks in both groups. There were significantly fewer lesions in the Evozac Calming Skin Spray group than in the physiological saline group at the end of 1 week (0.25 versus [vs] 1.10, P=0.031) and 3 weeks (6.67 vs 12.26, P=0.022). Patients from the Evozac Calming Skin Spray group also developed fewer facial lesions at the end of 2 weeks and 4 weeks, however, the difference was not statistically significant. At the end of 4 weeks, fewer patients from the Evozac Calming Skin Spray group developed rash of grade 2 or greater severity (17.6% vs 36.0%, P=0.037), or experienced rash-associated symptoms (13.7% vs 34.0%, P=0.017).

Conclusion

Prophylactic treatment with Evozac Calming Skin Spray appears to decrease the number of facial lesions at the peak of the rash, reduce the incidence of grade 2 or more severe rash and relieve rash-associated symptoms.

Epidermal growth factor receptor signalling in keratinocyte biology: implications for skin toxicity of tyrosine kinase inhibitors

The epidermal growth factor receptor (EGFR) and its ligands have been long recognized as centrally involved in the growth and repair process of epithelia, as well as in carcinogenesis. In addition, the EGFR has been demonstrated to be importantly involved in the control of inflammatory responses. During this last decade, a number of highly specific agents targeting this system have become an integral component of pharmacologic strategies against many solid malignancies. These drugs have led to increased patient survival and made therapy more tolerant when compared to conventional cytotoxic drugs. Nonetheless, their use is associated with a constellation of toxic effects on the skin, including follicular pustules, persistent inflammation, xerosis and pruritus, and enhanced susceptibility to infections. This dramatic impairment of skin homoeostasis underscores the centrality of the EGFR-ligand system in the whole skin immune system. So far, no mechanism-based approaches are available to specifically counteract the adverse effects of anti-EGFR drugs or any other class of tyrosine kinase inhibitors. Only the knowledge of the cellular and molecular events underlying these adverse effects in humans, combined with in vitro/in vivo models able to mimic these toxic responses, may guide the development of mechanism-based treatment or prevention strategies.

Randomized controlled trial to evaluate the effects of ethyl-2-cyanoacrylate on pain intensity and quality of life in head and neck cancer patients suffering from cetuximab-induced rhagades during radioimmunotherapy: the support trial

Background

Cetuximab is a chimeric monoclonal antibody against the epidermal growth factor receptor (EGFR). Skin reactions are the most common side effects of cetuximab. Rhagades of the tips of the fingers and toes, the heels and especially the interphalangeal joints are one of the most frightening and painful dermatological side effects that may develop from EGFR-inhibitor therapy. Rhagades are characterized by pain, severe tenderness and poor healing response. They are challenging to treat. Thus, rhagades often poses the most significant threat to the quality of life (QoL) for these patients. Ethyl-2-cyanoacrylate (ECA), an ethyl ester of the 2-cyano-2-propenoic acid, is often used as adhesive in a variety of different work settings in industry, i.e. as a component in nail-care products such as nail glue. In addition, ECA is used for various medical indications, such as for liquid bandages and for suture-less surgery. Wound healing can be accelerated with ECA. The purpose of the SUPPORT trial is to investigate the efficacy of ECA for the treatment of cetuximab-induced rhagades and to assess the clinical usefulness of the SUPO score, a new classification system for rhagades induced by EGFR-inhibitor therapy.

Methods/Design

The SUPPORT trial is an open-label, prospective, randomized, national multicenter intervention study to evaluate the effectiveness of ECA versus the standard treatment of each institution on the pain intensity and QoL in patients with locally advanced head and neck cancer suffering from painful cetuximab-induced rhagades during radioimmunotherapy. Primary endpoint is the assessment of the pain intensity 24 hours after application of ECA or the standard treatment quantified by the visual analogue scale (VAS). Secondary endpoints are the evaluation of QoL assessed by the EORTC-QoL-C30 questionnaire and the Dermatological Life Quality Index (DLQI).

Discussion

During treatment with EGFR inhibitors it is necessary to recognize and manage side effects promptly to assure better patient QoL. The SUPPORT trial is the first randomized clinical trial evaluating a new treatment option for painful cetuximab-induced rhagades. Furthermore, the new SUPO score will be prospectively assessed in terms of clinical usefulness for classification of EGFR inhibitor-induced rhagades.

Trial registration

Current Controlled Trials NCT01693159.

Hot flashes are not predictive for serum concentrations of tamoxifen and its metabolites

Background

Tamoxifen has dramatically reduced the recurrence and mortality rate of estrogen receptor positive breast cancer. However, the efficacy of tamoxifen varies between individuals and 40% of patients will have a recurrence despite adjuvant tamoxifen treatment. Factors that predict tamoxifen efficacy would be helpful for optimizing treatment. Serum concentrations of the active metabolite, endoxifen, may be positively related to treatment outcome. In addition, hot flashes are suggested to be positively associated with tamoxifen treatment outcome.

Methods

We investigated in a series of 109 patients whether the frequency and severity of hot flashes were related to concentrations of tamoxifen and its metabolites. A serum sample of all patients was analyzed for the concentration of tamoxifen, N-desmethyltamoxifen, endoxifen and 4-hydroxytamoxifen, as well as for estradiol concentrations and several single nucleotide polymorphisms in CYP2D6. Additionally, these patients completed a questionnaire concerning biometric data and treatment side effects.

Results

We found no evidence supporting an association between concentrations of tamoxifen or metabolites and either the frequency or severity of hot flashes in the covariate unadjusted analyses. However, including interactions with menopausal status and pre-treatment hot flash (PTHF) history indicated that post-menopausal women with PTHF experienced an increasing frequency of hot flashes with increasing serum concentrations of tamoxifen and its metabolites. This finding was not altered when adjusting for potential confounding factors (duration of tamoxifen treatment, CYP2D6 phenotype, estradiol serum concentration, age and body mass index). In addition we observed a positive association between body mass index and both hot flash frequency (p = 0.04) and severity (p < 0.0001). We also observed that patients with lower estradiol levels reported more severe hot flashes (p = 0.02).

Conclusions

No univariate associations were observed between concentrations of active tamoxifen metabolites and either the frequency or severity of hot flashes during treatment. However, the frequency of hot flashes may be exacerbated by higher serum concentrations of tamoxifen and its metabolites in post-menopausal women with a history of hot flashes prior to tamoxifen treatment.

Hazards and risks in oncology: radiation oncology

Adverse effects and hazards which have their origin from radiation using conventional techniques like 3-D conformal radiotherapy and total radiation doses are well known. However little is known about the sprectum of especially late toxicity after radiation using new technologies like intensity modulated radiotherapy (IMRT) combined with novel target volume and dose concepts. Since IMRT allows for selective protection of the large salivary glands this technique improves the intermediate term quality of life and is the standard of care despite many details need further prospective evaluation. Combining cytotoxic drugs and radiotherapy yield improved survival in well-defined high risk patients. However morbidity and mortality of these protocols are high and deserve special expertise and supportive therapy. EGF-receptor antibodies have gained well defined indications, albeit specific toxicities in combination with irradiation deserve prospective studies and special attention.

Pilot clinical trial on the efficacy of prophylactic use of vitamin K1-based cream (Vigorskin) to prevent cetuximab-induced skin rash in patients with metastatic colorectal cancer

BACKGROUND

Cetuximab is an effective option for the treatment of metastatic colorectal cancer in the first and subsequent lines of treatment; among its side effects, acneiform skin rash is one of the major causes of treatment delay, reduction, or interruption, with a negative effect on quality of life. No effective strategy to prevent skin rash induced by epidermal growth factor receptor inhibitors is available; however, encouraging results have come from vitamin K1, phytomenadione, applied as a topical formulation. Available studies have been conducted in heterogeneous populations and are mainly focused on the use of vitamin K1-based cream for the treatment, rather than the prophylaxis, of acneiform rash.

PATIENTS AND METHODS

Forty-one consecutive patients from a single center all affected by metastatic colorectal cancer and receiving cetuximab, alone or combined with chemotherapy, applied vitamin K1-based cream to prevent the occurrence of acneiform skin rash. The cream was applied twice a day on the face and trunk from the first day of administration of cetuximab.

RESULTS

The application of the cream was well tolerated. No grade 4 rash was reported. The proportion of grade 3 skin rash in the first 8 weeks of treatment in this population was 15%, at the lower limit of values reported in the literature, and the proportion of patients with grade 2 rash was reduced (22.5%).

CONCLUSION

This experience confirms available data in a homogeneous population, suggesting a possible benefit of topical vitamin K1 as prophylaxis for cetuximab-induced skin rash in patients with metastatic colorectal cancer.

Tyrosine kinase inhibitors: their on-target toxicities as potential indicators of efficacy

Tyrosine kinase inhibitors (TKIs) have revolutionized the treatment of certain forms of cancers, raising hopes for many patients with otherwise unresponsive tumours. While these agents are generally well tolerated, clinical experience with them has highlighted their unexpected association with serious toxic effects on various organs such as the heart, lungs, liver, kidneys, thyroid, skin, blood coagulation, gastrointestinal tract and nervous system. Many of these toxic effects result from downstream inhibition of vascular endothelial growth factor or epidermal growth factor signalling in cells of normal organs. Many of these undesirable effects such as hypertension, hypothyroidism, skin reactions and possibly proteinuria are on-target effects. Since tyrosine kinases are widely distributed with specific functional roles in different organs, this association is not too surprising. Various studies suggest that the development of these on-target effects indicates clinically desirable and effective inhibition of the corresponding ligand-mediated receptor linked with oncogenesis. This is reflected as improved efficacy in the subgroup of patients who develop these on-target adverse effects compared with those who do not. Inevitably, issues arise with respect to the regulatory assessment of efficacy and risk/benefit of the TKIs as well as the clinical approach to managing patients who develop these effects. Routine subgroup analysis of efficacy data from clinical trials (patients with and without on-target toxicity) may enable more effective clinical use of TKIs since (i) discontinuing or reducing the dose of the TKI has a negative impact if the tumour is TKI-responsive; and (ii) it is usually possible to manage these undesirable on-target effects with conventional clinical approaches. Prospective studies are needed to investigate this proposition further.