Expert guidance on prophylaxis and treatment of dermatologic adverse events with Tumor Treating Fields (TTFields) therapy in the thoracic region

Tumor Treating Fields (TTFields) are electric fields, delivered via wearable arrays placed on or near the tumor site, that exert physical forces to disrupt cellular processes critical for cancer cell viability and tumor progression. As a first-in-class treatment, TTFields therapy is approved for use in newly diagnosed glioblastoma, recurrent glioblastoma, and pleural mesothelioma. Additionally, TTFields therapy is being investigated in non-small cell lung cancer (NSCLC), brain metastases from NSCLC, pancreatic cancer, ovarian cancer, hepatocellular carcinoma, and gastric adenocarcinoma. Because TTFields therapy is well tolerated and delivery is locoregional, there is low risk of additive systemic adverse events (AEs) when used with other cancer treatment modalities. The most common AE associated with TTFields therapy is mild-to-moderate skin events, which can be treated with topical agents and may be managed without significant treatment interruptions. Currently, there are no guidelines for oncologists regarding the management of TTFields therapy-related skin AEs in the thoracic region, applicable for patients with pleural mesothelioma or NSCLC. This publication aims to provide guidance on preventing, minimizing, and managing dermatologic AEs in the thoracic region to help improve patient quality of life and reduce treatment interruptions that may impact outcomes with TTFields therapy.

Prevention and Management of Dermatologic Adverse Events Associated With Tumor Treating Fields in Patients With Glioblastoma

Importance: Tumor Treating Fields (TTFields) are an anti-mitotic treatment approved for treating newly diagnosed and recurrent glioblastoma, and mesothelioma. TTFields in glioblastoma comprise alternating electric fields (200 kHz) delivered continuously, ideally for ≥18 h/day, to the tumor bed via transducer arrays placed on the shaved scalp. When applied locoregionally to the tumor bed and combined with systemic temozolomide chemotherapy, TTFields improved overall survival vs. temozolomide alone in patients with newly diagnosed glioblastoma. Improved efficacy outcomes with TTFields were demonstrated, while maintaining a well-tolerated and manageable safety profile. The most commonly-reported TTFields–associated adverse events (AEs) are beneath-array dermatologic events. Since survival benefit from TTFields increases with duration-of-use, prevention and management of skin AEs are critical to maximize adherence. This paper describes TTFields-associated dermatological AEs and recommends prevention and management strategies based on clinical trial evidence and real-world clinical experience.

Observations: TTFields–associated skin reactions include contact dermatitis (irritant/allergic), hyperhidrosis, xerosis or pruritus, and more rarely, skin erosions/ulcers and infections. Skin AEs may be prevented through skin-care and shifting (~2 cm) of array position during changes. TTFields–related skin AE management should be based on clinical phenotype and severity. Depending on diagnosis, recommended treatments include antibiotics, skin barrier films, moisturizers, topical corticosteroids, and antiperspirants. Water-based lotions, soaps, foams, and solutions with minimal impact on electrical impedance are preferred with TTFields use over petroleum-based ointments, which increase impedance.

Conclusions: Early identification, prophylactic measures, and symptomatic skin AE management help patients maximize TTFields usage, while maintaining quality-of-life and optimizing therapeutic benefit.

Implications for practice: TTFields confer a survival benefit in patients with glioblastoma that correlates positively with duration of daily use. Skin events (rash) are the primary treatment-related AE that can limit duration of use. The recommendations described here will help healthcare professionals to recognize, prevent, and manage dermatologic AEs associated with TTFields treatment. These recommendations may improve cutaneous health and support adherence to therapy, both of which would maximize treatment outcomes.