Ototoxicity in pediatric cancer patients
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Platinum-based chemotherapy, including cisplatin, carboplatin, oxaliplatin or a combination of these, is used in the treatment of different types of childhood cancer. The alkylating platinum chemotherapeutics are the mainstay of therapy for several types of childhood and adolescent cancers, despite their toxicities. The most common childhood cancers treated with cisplatin include medulloblastoma, osteosarcoma, hepatoblastoma, neuroblastoma and germ cell tumors1.
Although these life-threatening illnesses affect a relatively small number of children and adolescents each year, the impact on children and their families is significant. Platinum chemotherapeutics and other free-radical inducing therapies, such as radiotherapy, can cause multiple systemic and neurological side effects. One of the most important side effects of platinum chemotherapy is hearing loss. This can occur not only during treatment but also years after the end of treatment. Although it is not life-threatening, the loss of hearing, especially during the first three years of life, may lead to difficulties with school performance and psychosocial functioning. Prevention of platinum-induced hearing loss is thus very important and might improve the quality of life of children undergoing cancer treatment and those who have survived treatment with platinum-based chemotherapy2.
In children, ototoxicity is the primary toxicity of cisplatin chemotherapy. The prevalence of cisplatin-induced ototoxicity, measured with standard audiometry to 8 kHz, is approximately 60–70% in pediatric patients3. Carboplatin is significantly less ototoxic but hearing loss can occur with high-dose treatment. When both drugs are used in combination, ototoxicity approaches 80–90%.
So how does platinum ototoxicity manifest? The hearing loss caused by cisplatin and carboplatin is due to degeneration of the cochlear hair cells and supporting cells. The outer hair cells are damaged before the inner hair cells, and platinum initially affects hair cells at the base of the cochlea, where high-frequency sounds are encoded. This results in loss of hearing sensitivity. In addition to loss of hearing sensitivity, damage to cochlear hair cells impacts one’s ability to recognize subtle differences in sound frequency; this results in difficulty understanding speech, especially in noise.
Hearing loss acquired from ototoxic therapy may negatively impact a child’s language development and communication, speech development, socialization, cognition, learning, lifetime earnings and quality of life. Therefore, it is critical to subject patient to audiologic monitoring for platinum ototoxicity. Audiologic monitoring can help in (1) informing treatment management and (2) informing family members/care takers about changes in hearing so that communication strategies can be recommended, and intervention can be initiated as soon as possible. Besides, children treated with platinum therapy or radiation should have long-term follow-up evaluations to monitor for late onset and progressive hearing loss. In addition to monitoring hearing status, audiological counselling can be provided to help children and young adults understand their hearing status, its impact on communication and learning, hearing conservation, and their options for ongoing management.
References
- Beth Brooks & Kristin Knight (2018) Ototoxicity monitoring in children treated with platinum chemotherapy, International Journal of Audiology, 57:sup4, S62-S68, DOI: 10.1080/14992027.2017.1355570
- Van As JW, Van den Berg H, Van Dalen EC. Medical interventions for the prevention of platinum-induced hearing loss in children with cancer. Cochrane Database of Systematic Reviews 2019, Issue 5. Art. No.: CD009219. DOI: 10.1002/14651858.CD009219.pub5
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Rajput at el. Ototoxicity-induced hearing loss and quality of life in survivors of paediatric cancer. International Journal of Pediatric Otorhinolaryngology.
Volume 138, November 2020, 110401
