Dermatologic irAEs induced by PD-1 or PD-L1 blockade therapy rarely result in significant morbidity or permanent discontinuation of treatment. However, early recognition and appropriate management are crucial for restricting dose-limiting toxicities.

Targeted therapies and immunotherapies are associated with a wide range of dermatologic adverse events (dAEs) resulting from common signaling pathways involved in malignant behavior and normal homeostatic functions of the epidermis and dermis. Dermatologic toxicities include damage to the skin, oral mucosa, hair, and nails. Acneiform rash is the most common dAE, observed in 25–85% of patients treated by epidermal growth factor receptor and mitogen-activated protein kinase kinase inhibitors. BRAF inhibitors mostly induce secondary skin tumors, squamous cell carcinoma and keratoacanthomas, changes in pre-existing pigmented lesions, as well as hand-foot skin reactions and maculopapular hypersensitivity-like rash. Immune checkpoint inhibitors (ICIs) most frequently induce nonspecific maculopapular rash, but also eczema-like or psoriatic lesions, lichenoid dermatitis, xerosis, and pruritus. Of the oral mucosal toxicities observed with targeted therapies, oral mucositis is the most frequent with mammalian target of rapamycin (mTOR) inhibitors, followed by stomatitis associated to multikinase angiogenesis and HER inhibitors, geographic tongue, oral hyperkeratotic lesions, lichenoid reactions, and hyperpigmentation. ICIs typically induce oral lichenoid reactions and xerostomia. Targeted therapies and endocrine therapy also commonly induce alopecia, although this is still underreported with the latter. Finally, targeted therapies may damage nail folds, with paronychia and periungual pyogenic granuloma distinct from chemotherapy-induced lesions. Mild onycholysis, brittle nails, and a slower nail growth rate may also be observed. Targeted therapies and immunotherapies often profoundly diminish patients’ quality of life, which impacts treatment outcomes. Close collaboration between dermatologists and oncologists is therefore essential.

Taxanes (docetaxel and paclitaxel) are among the most commonly prescribed anticancer drugs approved for the treatment of metastatic or locally advanced breast, non-small cell lung, prostate, gastric, head and neck, and ovarian cancers, as well as in the adjuvant setting for operable node-positive breast cancers. Although the true incidence of dermatological adverse events (AEs) in patients receiving taxanes is not known, and has never been prospectively analysed, they clearly represent one of the major AEs associated with these agents. With an increase in the occurrence of cutaneous AEs during treatment with novel targeted and immunological therapies when used in combination with taxanes, a thorough understanding of reactions attributable to this class is imperative. Moreover, identification and management of dermatological AEs is critical for maintaining the quality of life in cancer patients and for minimizing dose modifications of their antineoplastic regimen. This analysis represents a systematic review of the dermatological conditions reported with the use of these drugs, complemented by experience at comprehensive cancer centres. The conditions reported herein include skin, hair, and nail toxicities. Lastly, we describe the dermatological data available for the new, recently FDA-and EMA- approved, solvent-free nab-paclitaxel.

Development of biological targeted therapies and immune checkpoint inhibitors has redefined the treatment for many cancers; however, the increasing use of new protocols has led to physicians observing a new spectrum of toxicities. To date, oral adverse events induced by these new anticancer therapies have been mainly reported using nonspecific terminology (Bstomatitis,^Bmucosal inflammation,^Bmucositis^) and remain poorly characterized, with the exception of mammalian target of rapamycin (mTOR) inhibitor-associated stomatitis. Oral toxicities of targeted therapies often display very characteristic features which clearly differ from classic oral injuries observed with cytotoxic chemotherapy and/or radiotherapy. In addition, they frequently affect more than 20% of treated patients and can lead to a significant morbidity or permanent treatment discontinuation. Oral mucosal toxicities described in this review include mTOR inhibitor-associated stomatitis (mIAS); stomatitis, benign migratory glossitis, and osteonecrosis of the jaw associated with multi-targeted kinase inhibitors of the VEGF and PDGF receptors; mucositis induced by EGFR inhibitors (in monotherapy or in combination with head and neck radiotherapy and/or chemotherapy); hyperkeratotic lesions with BRAF inhibitors; pigmentary changes and lichenoid reactions secondary to imatinib; and more recent data on the BOsler-Weber-Rendu-like syndrome^described with the antibody-drug conjugate, TDM-1. Finally, we provide, to our knowledge, the first available structured data on oral toxicities induced by the new recently FDA-and EMA-approved monoclonal antibodies targeting PD-1. Clinical management of these targeted therapy-related oral changes is also discussed.

No abstract