Modeling the Risk of Hearing Loss From Radiation Therapy in Childhood Cancer Survivors: A PENTEC Comprehensive Review

Awareness about the risk of hearing loss after ototoxic treatments in Swiss childhood cancer survivors

OBJECTIVES

The International Guideline Harmonization Group recommends childhood cancer survivors (CCS) exposed to ototoxic treatments be aware of the risk of hearing loss. We assessed awareness among adult CCS.

METHODS

We identified adults diagnosed with cancer < 20 years who received ototoxic treatments through the Swiss Childhood Cancer Registry (ChCR) and invited them to the HEAR-study. Participants completed a questionnaire and underwent pure-tone audiometry. Cancer and treatment data were obtained from the ChCR. We used logistic regression to explore factors influencing awareness.

RESULTS

Of 424 invited, 105 CCS participated (25 %). Fifty-seven percent did not remember receiving information on hearing loss prior to the study. CCS who remembered being informed were more likely diagnosed after 1995 (OR: 4.5, 95 % CI: 1.3-15.4), reported hearing problems (10.9, 2.6-45.1) and other late effects (4.1, 1.3-13.2), and treated with platinum chemotherapy only (10.8, 2.2-53.2) versus cranial radiotherapy only. 44 % of participants presented clinically relevant hearing loss.

CONCLUSIONS

Over half of CCS exposed to ototoxic treatments were unaware of their risk of hearing loss.

PRACTICE IMPLICATIONS

Educating CCS about potential late effects of ototoxic treatments is important to allow early diagnosis and treatment, especially for those who had cancer longer ago and those exposed to cranial radiation.

Approaches to Reduce Toxicity in Pediatric Brain Tumors

Pediatric central nervous system (CNS) tumor survivors are highly susceptible to long-term toxicity due to tumor location and also the treatment received. Advancements in treatment techniques, risk-adapted approaches to therapy with adjustments to treatment regimens-including de-escalation when feasible-along with the addition of supportive therapy and surveillance in these survivors, serve to minimize and manage late effects of therapy.

Development and Validation of a Novel Prediction Model for Hearing Loss From Cisplatin Chemotherapy

PURPOSE

Cisplatin treats many common tumors but causes permanent and debilitating hearing loss (HL). The objective of this study was to develop and externally validate a predictive model of HL in cisplatin-treated children and adolescent cancer survivors.

METHODS

The Pediatric Holistic Evaluation of Auditory Risk (PedsHEAR) model architecture used several machine learning approaches followed by an ensemble predictor. The primary end point was post-treatment communication-affecting HL (International Society of Pediatric Oncology Ototoxicity Scale [SIOP] Grade ≥2). PedsHEAR was developed from a multicenter data set of cisplatin-exposed patients up to 21 years old (1984-2017) and externally validated using data from the Children's Oncology Group ACCL05C1 study (2007-2012) and two combined institutional cohorts (1988-2022). The model predicts post-treatment HL in each patient (probability [%], 95% CI) and classifies patients as low, intermediate, or high risk for HL (probability HL <0.33, 0.33-0.60, >0.60, respectively).

RESULTS

In the training data set (n = 1,115, median age 6.3 years, SIOP Grade ≥2 HL 44%), PedsHEAR demonstrated excellent discrimination (AUC, 0.93 [95% CI, 0.92 to 0.95]) and then successfully validated within the internal (testing; AUC, 0.79 [95% CI, 0.74 to 0.85]) and two external validation cohorts (AUC, 0.74 and AUC, 0.67). In an aggregate validation cohort (n = 631), the model predicted the probability of HL (AUC, 0.76 [95% CI, 0.72 to 0.79]) and classified 22% (141/631), 71% (447/631), and 7% (43/631) of patients as low, intermediate, or high risk for HL.

CONCLUSION

PedsHEAR predicted SIOP Grade ≥2 HL in pediatric cisplatin-treated patients. This is the first validated model to successfully predict cisplatin-induced HL in a broadly representative population treated with diverse regimens across a range of treatment settings.

Eligibility for Cochlear Implant Candidacy Evaluation in Childhood Cancer Survivors

This cross-sectional study examines the likelihood of meeting the referral criteria for a cochlear implant and the use of hearing aid among childhood cancer survivors with severe hearing loss.

Risk factors for treatment-related sensorineural hearing loss and hearing aid use in medulloblastoma patients: an observational cohort study

PURPOSE

This study aimed to analyze treatment-related risk factors for sensorineural hearing loss (SNHL) and an indication for hearing aids (IHA) in medulloblastoma patients after craniospinal radiotherapy (CSRT) and platin-based chemotherapy (PCth).

METHODS

A total of 58 patients (116 ears) with medulloblastoma and clinically non-relevant pre-treatment hearing thresholds were included. Cranial radiotherapy and PCth were applied sequentially according to the HIT 2000 study protocol or post-study recommendations, the NOA-07 protocol, or the PNET (primitive neuroectodermal tumor) 5 MB therapy protocol. Audiological outcomes up to a maximum post-therapeutic follow-up of 4 years were assessed. The incidence, post-treatment progression, and time-to-onset of SNHL, defined as Muenster classification grade ≥MS2b, were evaluated. Risk factors for IHA were analyzed separately.

RESULTS

While 39 patients received conventionally fractionated RT (CFRT; group 1), 19 patients received hyperfractionated RT (HFRT; group 2). Over a median follow-up of 40 months, 69.2% of ears in group 1 experienced SNHL ≥MS2b compared to 89.5% in group 2 (p = 0.017). In multivariable Cox regressions analysis, younger age and increased mean cochlear radiation dose calculated as the equivalent dose in 2‑Gy fractions (EQD2) were associated with time-to-onset of SNHL ≥MS2b (p = 0.019 and p = 0.023, respectively) and IHA (p < 0.001 and p = 0.016, respectively). Tomotherapy and supine positioning were associated with a lower risk for IHA in univariable modelling only (p = 0.048 and p = 0.027, respectively).

CONCLUSION

Young age and cochlear EQD2 Dmean ≥40 Gy are significant risk factors for the incidence, degree, and time-to-event of SNHL as well as for IHA in medulloblastoma patients.

The cochlear dose and the age at radiotherapy predict severe hearing loss after passive scattering proton therapy and cisplatin in children with medulloblastoma

BACKGROUND

Hearing loss (HL) is associated with worse neurocognitive outcomes among patients with medulloblastoma. We aimed to identify risk factors associated with severe HL and to evaluate the generalizability of a published HL calculator among patients treated with passive scattering proton therapy (PSPT) and cisplatin.

METHODS

We identified patients aged 3-21 years who were treated at our centers between 2007 and 2022. Audiograms were graded using the International Society of Pediatric Oncology (SIOP) Boston scale. Time to grades 3-4 HL was evaluated using Kaplan-Meier and multivariable Cox models to estimate hazard ratios and 95% confidence intervals (CI).

RESULTS

Seventy-nine patients were treated with PSPT at a median age of 7.5 years (range: 3.1-21.1). The mean cochlear dose (Dmc) (±SD) was 31.5 ± 8.5 Gy, and the cumulative cisplatin dose was 295 ± 50 mg/m2. Fifty-nine patients (75%) received amifostine. Patients completed a median of 9 audiograms (range: 4-22) with a median audiogram follow-up of 49 months (range: 6-177). Twenty-seven patients (34%) had grades 3-4 HL. In adjusted Cox models, only higher Dmc (HR = 1.12, 95% CI:1.06-1.18) was associated with grades 3-4 HL. The predicted 3-year incidence of grades 3-4 HL was 40.0% (95% CI: 21.3-66.3) and 66.7% (95% CI: 35.4-93.7) for children with Dmc ≥36 Gy and age at radiotherapy ≥7 and <7 years, respectively (P = .042). It was 8.9% (95% CI: 2.3-31.6) and 15.6% (95% CI: 5.3-41.1) for children with Dmc <36 Gy and age at radiotherapy ≥7 and <7 years, respectively (P = .78).

CONCLUSIONS

Children <7 years at radiotherapy with a Dmc ≥36 Gy are at higher risk for HL.

Improving Pediatric Normal Tissue Radiation Dose-Response Modeling in Children With Cancer: A PENTEC Initiative

The development of normal tissue radiation dose-response models for children with cancer has been challenged by many factors, including small sample sizes; the long length of follow-up needed to observe some toxicities; the continuing occurrence of events beyond the time of assessment; the often complex relationship between age at treatment, normal tissue developmental dynamics, and age at assessment; and the need to use retrospective dosimetry. Meta-analyses of published pediatric outcome studies face additional obstacles of incomplete reporting of critical dosimetric, clinical, and statistical information. This report describes general methods used to address some of the pediatric modeling issues. It highlights previous single- and multi-institutional pediatric dose-response studies and summarizes how each PENTEC taskforce addressed the challenges and limitations of the reviewed publications in constructing, when possible, organ-specific dose-effect models.

Reporting Standards for Complication Studies of Radiation Therapy for Pediatric Cancer: Lessons From PENTEC

The major aim of Pediatric Normal Tissue Effects in the Clinic (PENTEC) was to synthesize quantitative published dose/-volume/toxicity data in pediatric radiation therapy. Such systematic reviews are often challenging because of the lack of standardization and difficulty of reporting outcomes, clinical factors, and treatment details in journal articles. This has clinical consequences: optimization of treatment plans must balance between the risks of toxicity and local failure; counseling patients and their parents requires knowledge of the excess risks encountered after a specific treatment. Studies addressing outcomes after pediatric radiation therapy are particularly challenging because: (a) survivors may live for decades after treatment, and the latency time to toxicity can be very long; (b) children's maturation can be affected by radiation, depending on the developmental status of the organs involved at time of treatment; and (c) treatment regimens frequently involve chemotherapies, possibly modifying and adding to the toxicity of radiation. Here we discuss: basic reporting strategies to account for the actuarial nature of the complications; the reporting of modeling of abnormal development; and the need for standardized, comprehensively reported data sets and multivariate models (ie, accounting for the simultaneous effects of radiation dose, age, developmental status at time of treatment, and chemotherapy dose). We encourage the use of tools that facilitate comprehensive reporting, for example, electronic supplements for journal articles. Finally, we stress the need for clinicians to be able to trust artificial intelligence models of outcome of radiation therapy, which requires transparency, rigor, reproducibility, and comprehensive reporting. Adopting the reporting methods discussed here and in the individual PENTEC articles will increase the clinical and scientific usefulness of individual reports and associated pooled analyses.