Hearing loss after childhood cancer treatment.

Strebel, Sven (2023). Hearing loss after childhood cancer treatment. (Unpublished). (Dissertation, University of Bern, Faculty of Medicine and Faculty of Human Sciences)

Full text not available from this repository.

Background of my PhD thesis: Hearing loss is a potential adverse event in children and adolescents
treated for cancer, particularly after platinum-based chemotherapy and cranial radiation. Platinum
compounds (mostly cisplatin) damage hair cells of the cochlea in the inner ear. This manifests clinically
as binaural, irreversible high-frequency hearing loss. Depending on severity, high-frequency hearing
loss can lead to neurocognitive difficulties, impaired speech and language development, and poorer
school performance. Only few studies have investigated severity, risk factors, and longitudinal change of
hearing loss after platinum-based chemotherapy using detailed audiogram data from medical records.
In addition, it is not known how auditory adverse events, such as hearing loss and tinnitus, influence
quality of life in long-term childhood cancer survivors (CCS).

Aims of my PhD thesis: The overall aim of my PhD thesis was to cover relevant knowledge gaps
about hearing loss after childhood cancer treatment and what impact it has on quality of life. Specifically
I aimed to 1) examine severity and associated risk factors of hearing loss after platinum-based
chemotherapy; 2) assess the influence of vincristine on platinum-induced hearing loss; 3) describe how
hearing function changes over time after completion of platinum-based chemotherapy; and 4) evaluate
the impact of tinnitus and hearing loss on health-related quality of life (HRQoL).

Methods my PhD thesis: To address the aims of my PhD thesis, I analyzed data from a national and
international cohort of CCS. The national cohort consisted of CCS who were treated with platinumbased
chemotherapy at age ≤ 18 between 1990-2014 in Switzerland and had detailed treatment and
audiogram data from medical records available. The international cohort consisted of long-term CCS
who participated in the European-based PanCareLIFE study, were diagnosed with cancer at age ≤ 18
years, survived ≥ 5 years, and aged 25-44 years at study. All included CCS had information on cancer
diagnosis and treatment available, as well as questionnaire data on hearing and HRQoL (measured with
the short form 36 questionnaire).

Results of my PhD thesis: My PhD project resulted in 4 original research articles (1 published, 1
accepted for publication, 1 submitted & under review, and 1 in the status of an early draft). The main
findings are summarized below:
Publication I: Hearing loss was present to a clinically relevant degree in about half of included CCS.
Identified risk factors were young age at cancer diagnosis, higher dose of cisplatin, and exposure to
additional ototoxic treatments such as cranial radiation or hematopoietic stem cell transplantation.
Publication II: Neurotoxic vincristine was associated with a higher risk for platinum-induced hearing
loss. Prevalence of hearing loss was twice as high in CCS treated with platinum-based chemotherapy
and additional vincristine compared with CCS treated with platinum-based chemotherapy alone.
Publication III: Preliminary results suggest that hearing does not deteriorate further after completion of
platinum-based chemotherapy. However, we observed a large variability in longitudinal hearing function
trajectories between individual CCS.
Publication IV: Auditory adverse events were associated with decreased HRQoL. We observed a particularly
strong decrease of HRQoL in CCS who reported hearing loss and additional tinnitus compared with
CCS who reported only hearing loss.

Conclusion of my PhD thesis: In summary, the burden of hearing loss after platinum-based chemotherapy
is high in Switzerland. We identified clinical factors that increase the risk of hearing loss, including
the neurotoxic vincristine. However, these factors do not explain all of the variability in our
cohort and there may be other determinants, such as genetic predisposition, which play a role. We
also found that hearing function neither worsened nor improved after completion of platinum-based
chemotherapy and that hearing loss was associated with impaired quality of life. This emphasizes the
importance of preventive measures to reduce avoidable risk factors for additional hearing loss—such
as other ototoxic drugs or increased noise exposure—as part of follow-up care.

Item Type:	Thesis (Dissertation)
Division/Institute:	04 Faculty of Medicine > Pre-clinic Human Medicine > Institute of Social and Preventive Medicine (ISPM)
Graduate School:	Graduate School for Health Sciences (GHS)
UniBE Contributor:	Strebel, Sven, Kühni, Claudia
Subjects:	600 Technology > 610 Medicine & health 300 Social sciences, sociology & anthropology > 360 Social problems & social services
Language:	English
Submitter:	Doris Kopp Heim
Date Deposited:	10 Jul 2023 11:32
Last Modified:	10 Jul 2023 11:32
Additional Information:	PhD in Health Sciences (Clinical Epidemiology and Biostatistics)
URI:	https://boris.unibe.ch/id/eprint/184626