Hearing loss after radiotherapy for pediatric brain tumors: effect of cochlear dose

Ionizing radiation induces neurotoxicity in Xenopus laevis embryos through neuroactive ligand-receptor interaction pathway

Ionizing radiation (IR) poses a significant threat to both the natural environment and biological health. Exposure to specific doses of ionizing radiation early in an organism's development can lead to developmental toxicity, particularly neurotoxicity. Through experimentation with Xenopus laevis (X. laevis), we examined the effects of radiation on early developmental stage. Our findings revealed that radiation led to developmental abnormalities and mortality in X. laevis embryos in a dose-dependent manner, disrupting redox homeostasis and inducing cell apoptosis. Additionally, radiation caused neurotoxic effects, resulting in abnormal behavior and neuron damage in the embryos. Further investigation into the underlying mechanisms of radiation-induced neurotoxicity indicated the potential involvement of the neuroactive ligand-receptor interaction pathway, which was supported by RNA-Seq analysis. Validation of gene expression associated with this pathway and analysis of neurotransmitter levels confirmed our hypothesis. In addition, we further validated the important role of this signaling pathway in radiation-induced neurotoxicity through edaravone rescue experiments. This research establishes a valuable model for radiation damage studying and provides some insight into radiation-induced neurotoxicity mechanisms.

Dosimetric analysis of hearing loss after cranial radiation therapy in children: A single-institution study from the French national registry PediaRT

PURPOSE

To identify dosimetric predictive factors of sensorineural hearing loss (SNHL) in children after cranial radiation therapy (RT) in a single institution using dosimetric data from the French National Registry PediaRT.

METHODS AND MATERIALS

Complete audiological follow-up data were available for 44 children treated with cranial RT between 2014 and 2021 at our institution. The median age at the time of RT initiation was 9 years (range: 2-17 years). No children presented with hearing loss prior to treatment. SNHL was defined as a Chang ototoxicity grade ≥ 1a or higher.

RESULTS

Median audiometric follow-up duration was 51 months. Seven children (16 %) developed SNHL with a median time to occurrence of 33 months (range, 18-46 months). The estimated SNHL cumulative rate at 2 years post-RT was 4,5% ± 3,1% and at 5 years was 21 % ± 7.2 %. Multiple Cox regression models showed that the association of the age at radiotherapy and the dosimetric values to the inner ear canal and cochlea were the most significant predictive factors of SNHL occurrence. No child who received less than 35 Gy on average to both cochleae (n = 26) suffered from SNHL, whereas the 5-year SNHL cumulative incidence for the children who received greater than or equal to 35 Gy on average to either cochlea (n = 18) was 51.8 % ± 15.1 %.

CONCLUSION

Doses received by the inner ear canal and cochlea, associated with the age at RT initiation, are the main predictive factors for radiation-induced SNHL. A median dose to either cochlea over 35 Gy significantly increases the risk of SNHL and justify close audiometric monitoring to detect and equip hearing loss at an early stage.

Risk factors associated with ototoxicity in long-term nasopharyngeal carcinoma survivors

PURPOSE

To investigate patient-reported outcomes among long-term survivors and to analyze their associated risk factors to provide better treatment and symptom management for nasopharyngeal carcinoma patients.

MATERIALS AND METHODS

This retrospective study collected patients diagnosed with nasopharyngeal carcinoma who received radical intensity-modulated radiotherapy in our hospital from June 2009 to June 2016. The patients' disease status and patient-reported outcomes were analyzed by follow-up. The ototoxicity was graded according to CTCAE 5.0.

RESULTS

A total of 223 patients were included in the study. Among the enrolled patients, the median follow-up time was 8.4 (6.0-13.0) years. Based on the patient-reported outcomes, ototoxicity was the most common symptom (52.9 %). After univariable and multivariable logistic regression, age ≥ 50 years old (OR, 4.066; 95 % CI, 1.799-9.190; P = .001), diabetes (OR, 3.520; 95 % CI, 1.442-8.591; P = .006), D2 ≥ 69 Gy (OR, 3.715; 95 % CI, 1.064-12.969; P = . 040) and V35 ≥ 91.5 % (OR, 3.398; 95 % CI, 1.113-10.372; P = .032) were associated with a higher incidence of grade 3-4 ototoxicity. Then, we constructed the individual nomogram and the C index of the graph was 0.815. By univariable logistic regression, we found that grade 3-4 ototoxicity was associated with an increased risk of multiple other symptoms, dysmasesia, tongue dysfunction, hoarseness, dysphagia and ocular toxicity.

CONCLUSION

In long-term survivors of nasopharyngeal carcinoma patients receiving IMRT, the most common patient-reported outcome was ototoxicity. Age ≥ 50 years, diabetes, ear exposure dose of D2 ≥ 69 Gy and V35 ≥ 91.5 % are independent risk factors for grade 3-4 ototoxicity.

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

PURPOSE

The Pediatric Normal Tissue Effects in the Clinic (PENTEC) hearing loss (HL) task force reviewed investigations on cochlear radiation dose-response relationships and risk factors for developing HL. Evidence-based dose-response data are quantified to guide treatment planning.

METHODS AND MATERIALS

A systematic review of the literature was performed to correlate HL with cochlear dosimetry. HL was considered present if a threshold exceeded 20 dB at any frequency. Radiation dose, ototoxic chemotherapy exposure, hearing profile including frequency spectra, interval to HL, and age at radiation therapy (RT) were analyzed.

RESULTS

Literature was systematically reviewed from 1970 to 2021. This resulted in 739 abstracts; 19 met inclusion for meta-analysis, and 4 included data amenable to statistical modeling. These 4 studies included 457 cochleas at risk in patients treated with RT without chemotherapy, and 398 cochlea treated with chemotherapy. The incidence and severity of cochlear HL from RT exposure alone is related to dose and age. Risk of HL was <5% in cochlea receiving a mean dose ≤35 Gy but increased to 30% at 50 Gy. HL risk ranged from 25% to 40% in children under the age of 5 years at diagnosis, declining to 10% in older children for any radiation dose. Probability of similar severe HL occurred at doses 18.3 Gy higher for children <3 versus >3 years of age. High-frequency HL was most common, with average onset occurring 3.6 years (range, 0.4-13.2 years) after RT. Exposure to platinum-based chemotherapies added to the rates of HL at a given cochlear dose level, with 300 mg/m2 shifting the dose response by 7 Gy.

CONCLUSIONS

In children treated with RT alone, risk of HL was low for cochlear dose <35 Gy and rose when dose exceeded 35 Gy without clear RT dose dependence. High-frequency HL was most prevalent, but all frequencies were affected. Children younger than 5 years were at highest risk of developing HL, although independent effects of dose and age were not fully elucidated. Future reports with more granular data are needed to better delineate time to onset of HL and the effects of chemoradiotherapy.

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.

Diffuse intrinsic pontine glioma (DIPG): A review of current and emerging treatment strategies

Diffuse intrinsic pontine glioma (DIPG) is a childhood malignancy of the brainstem with a dismal prognosis. Despite recent advances in its understanding at the molecular level, the prognosis of DIPG has remained unchanged. This article aims to review the current understanding of the genetic pathophysiology of DIPG and to highlight promising therapeutic targets. Various DIPG treatment strategies have been investigated in pre-clinical studies, several of which have shown promise and have been subsequently translated into ongoing clinical trials. Ultimately, a multifaceted therapeutic approach that targets cell-intrinsic alterations, the micro-environment, and augments the immune system will likely be necessary to eradicate DIPG.

The impact of the temporal sequence of cranial radiotherapy and platin-based chemotherapy on hearing impairment in pediatric and adolescent CNS and head-and-neck cancer patients: A report from the PanCareLIFE consortium

The impact of the temporal sequence by which cranial radiotherapy (CRT) and platin-based chemotherapy (PCth) are administered on sensorineural hearing loss (SNHL) in pediatric and adolescent central nervous system (CNS) and head-and-neck (HN) cancer patients has not yet been studied in detail. We examined the ototoxic effects of sequentially applied CRT and PCth. This study included children and adolescents with CNS and HN tumors who participated in the multicountry PanCareLIFE (PCL) consortium. Audiological outcomes were compared between patients who received CRT prior to PCth and those who received it afterwards. The incidence, degree and posttreatment progression of SNHL, defined as Muenster classification grade ≥MS2b, were evaluated in 141 patients. One hundred and nineteen patients were included in a time-to-onset analysis. Eighty-eight patients received CRT prior to PCth (Group 1) and 53 patients received PCth before CRT (Group 2). Over a median follow-up time of 1.6 years, 72.7% of patients in Group 1 experienced SNHL ≥ MS2b compared to 33.9% in Group 2 (P < .01). A time-to-onset analysis was performed for 74 patients from Group 1 and 45 patients from Group 2. Median time to hearing loss (HL) ≥ MS2b was 1.2 years in Group 1 and 4.4 years in Group 2 (P < .01). Thus, audiological outcomes were better for patients who received CRT after PCth than before. This finding should be further evaluated and considered within clinical practice in order to minimize hearing loss in children and adolescents with CNS and HN tumors.

Radiotherapy-associated Sensorineural Hearing Loss in Pediatric Oncology Patients

During the radiotherapeutic treatment of pediatric oncology patients, they would be at a latent risk of developing ionizing radiation-induced ototoxicity when the cochlea or auditory nerve is located within the radiation field. Sensorineural hearing loss (SNHL) is an irreversible late complication of radiotherapy, and its incidence depends on various factors such as the patient's hearing sensitivity, total radiation dose to the cochlea, radiotherapy fractionation regimen, age and chemoradiation. Importantly, this complication exhibits serious challenges to adult survivors of childhood cancer, as it has been linked to impairments in academic achievement, psychosocial development, independent living skills, and employment in the survivor population. Therefore, early detection and proper management can alleviate academic, speech, language, social, and psychological morbidity arising from hearing deficits. In the present review, we have addressed issues such as underlying mechanisms of radiation-induced SNHL, audiometric findings of pediatric cancer patients treated with radiotherapy, and management and protection measures against radiation-induced ototoxicity.

Radiotherapy for Primary Pediatric Central Nervous System Malignancies: Current Treatment Paradigms and Future Directions

BACKGROUND

Central nervous system tumors are the most common solid tumors in childhood. Treatment paradigms for pediatric central nervous system malignancies depend on elements including tumor histology, age of patient, and stage of disease. Radiotherapy is an important modality of treatment for many pediatric central nervous system malignancies.

SUMMARY

While radiation contributes to excellent overall survival rates for many patients, radiation also carries significant risks of long-term side effects including neurocognitive decline, hearing loss, growth impairment, neuroendocrine dysfunction, strokes, and secondary malignancies. In recent decades, clinical trials have demonstrated that with better imaging and staging along with more sophisticated radiation planning and treatment set-up verification, smaller treatment volumes can be utilized without decrement in survival. Furthermore, the development of intensity-modulated radiotherapy and proton-beam radiotherapy has greatly improved conformality of radiation.

KEY MESSAGES

Recent changes in radiation treatment paradigms have decreased risks of short- and long-term toxicity for common histologies and in different age groups. Future studies will continue to develop novel radiation regimens to improve outcomes in aggressive central nervous system tumors, integrate molecular subtypes to tailor radiation treatment, and decrease radiation-associated toxicity for long-term survivors.

The relevance of ototoxicity induced by radiotherapy

BACKGROUND

The risk of ototoxicity, characterized by hearing impairment, tinnitus, or middle ear inflammation, is elevated in both child and adult cancer survivors who have undergone head-neck or brain radiation, or a combination of the two. To provide optimal care for these cancer survivors and minimize subsequent complications, it is crucial to comprehend the relationship between radiotherapy and ototoxicity.

METHODS

A comprehensive search of databases, including the Cochrane Library, PubMed, Embase, and Web of Science, was conducted from the inception of the knowledge base up until January 2023. The metafor-package was employed to compare ototoxicity rates in individuals receiving radiotherapy. Two independent assessors extracted data and analyzed targets using a random-effects model.

RESULTS

Out of the 28 randomized controlled trials (RCTs) included in the analysis, 25 were prospective RCTs. Subgroup analysis revealed that mean cochlear radiation dose, primary tumor location, radiotherapy modality, and patient age significantly influenced total hearing impairment. Intensity-modulated radiotherapy was associated with less ototoxicity than 2D conventional radiotherapy (OR, 0.53; 95% CI, 0.47-0.60; P = 0.73; I² = 0%). Stereotactic radiotherapy appeared to be a superior option for hearing preservation compared to radiosurgery (OR, 1.44; 95% CI, 1.00-2.07; P = 0.69; I² = 0%). Children demonstrated a higher risk of hearing impairment than adults. More than 50% of patients with vestibular neuroadenoma experienced hearing impairment following radiation therapy. A strong association was observed between the average cochlear radiation dose and hearing impairment. Increased cochlear radiation doses may result in a heightened risk of hearing impairment.

CONCLUSION

Several risk factors for radiation-induced hearing impairment were identified in this study. High cochlear radiation doses were found to exacerbate the risk of hearing impairment resulting from radiation therapy.

Precision based approach to tailoring radiotherapy in the multidisciplinary management of pediatric central nervous system tumors

Modern day survivorship from childhood malignancies is estimated to be over 80%. However, central nervous system tumors remain the leading cause of cancer mortality in children and is the most common solid tumor in this population. Improved survivorship is, in part, a result of improved multidisciplinary care, often with a combination of surgery, radiation therapy, and systemic therapy. With improved survival, long term effects of treatment and quality of life impacts have been recognized and pose a challenge to maximize the therapeutic ratio of treatment. It has been increasingly more apparent that precise risk stratification, such as with the inclusion of molecular classification, is instrumental in efforts to tailor radiotherapy for appropriate treatment, generally towards de-intensification for this vulnerable patient population. In addition, advances in radiotherapy techniques have allowed greater conformality and accuracy of treatment for those who do require radiotherapy for tumor control. Ongoing efforts to tailor radiotherapy, including de-escalation, omission, or intensification of radiotherapy, continue to improve as increasing insight into tumor heterogeneity is recognized, coupled with advances in precision medicine employing novel molecularly-targeted therapeutics.

Outcomes of Patients Treated in the UK Proton Overseas Programme: Non-central Nervous System Group

AIMS

The UK Proton Overseas Programme (POP) was launched in 2008. The Proton Clinical Outcomes Unit (PCOU) warehouses a centralised registry for collection, curation and analysis of all outcomes data for all National Health Service-funded UK patients referred and treated abroad with proton beam therapy (PBT) via the POP. Outcomes are reported and analysed here for patients diagnosed with non-central nervous system tumours treated from 2008 to September 2020 via the POP.

MATERIALS AND METHODS

All non-central nervous system tumour files for treatments as of 30 September 2020 were interrogated for follow-up information, and type (following CTCAE v4) and time of onset of any late (>90 days post-PBT completion) grade 3-5 toxicities.

RESULTS

Four hundred and ninety-five patients were analysed. The median follow-up was 2.1 years (0-9.3 years). The median age was 11 years (0-69 years). 70.3% of patients were paediatric (<16 years). Rhabdomyosarcoma (RMS) and Ewing sarcoma were the most common diagnoses (42.6% and 34.1%). 51.3% of treated patients were for head and neck (H&N) tumours. At last known follow-up, 86.1% of all patients were alive, with a 2-year survival rate of 88.3% and 2-year local control of 90.3%. Mortality and local control were worse for adults (≥25 years) than for the younger groups. The grade 3 toxicity rate was 12.6%, with a median onset of 2.3 years. Most were in the H&N region in paediatric patients with RMS. Cataracts (30.5%) were the most common, then musculoskeletal deformity (10.1%) and premature menopause (10.1%). Three paediatric patients (1-3 years at treatment) experienced secondary malignancy. Seven grade 4 toxicities occurred (1.6%), all in the H&N region and most in paediatric patients with RMS. Six related to eyes (cataracts, retinopathy, scleral disorder) or ears (hearing impairment).

CONCLUSIONS

This study is the largest to date for RMS and Ewing sarcoma, undergoing multimodality therapy including PBT. It demonstrates good local control, survival and acceptable toxicity rates.

Medulloblastomas in Pediatric and Adults

Medulloblastoma is the primary malignant embryonic tumor of the cerebellum and the most common malignant tumor of childhood, accounting up to 25% of all CNS tumors in children, but is extremely rare in adults. Despite the fact that medulloblastomas are one of the most malignant human tumors, it is worthy to note that a great breakthrough has been achieved in our understanding of oncogenesis and the development of real methods of treatment. The main objective of surgical treatment is a maximum resection of tumor with minimal impairment of neurological functions, in order to reduce the volume, remove tumor tissue, get the biopsy, and restore the cerebrospinal fluid flow. The progress of surgical techniques (using a microscope, ultrasound suction), anesthesiology, and intensive care has significantly decreased surgical mortality and increased radicality of tumor removal. Postoperative mortality is less than one percent in most studies, while neurological complications have been reported between 5-10%. Radiotherapy is the main method of treatment in patients older than 3 years, which dramatically improved the recurrence-free survival. Nevertheless, the radiation therapy without systemic chemotherapy leads to a high risk of systemic metastases. After the role of chemotherapy was statistically proven, investigations of the optimal combination of different chemotherapy regimens continued around the world. Currently, 80% of patients can already be cured, however, the quality of life of patients in the long-term period remains quite low, which depends on many factors including endocrinological, cognitive, neurological, and otoneurologic aspects. Thus, the main strategic goal of the development of neuro-oncology is to reduce the doses of radiation therapy to the CNS and the main task of international research is to optimize existing protocols and develop fundamentally new ones based on molecular genetic research in order to improve the quality of life.

Patterns of Hearing Loss in Irradiated Survivors of Head and Neck Rhabdomyosarcoma

PURPOSE

The frequency and patterns of HL in a HNRMS survivor cohort were investigated. A dose-effect relationship between the dose to the cochlea and HL was explored.

METHODS

Dutch survivors treated for HNRMS between 1993 and 2017 with no relapse and at least two years after the end of treatment were eligible for inclusion. The survivors were evaluated for HL with pure-tone audiometry. HL was graded according to the Muenster, Common Terminology Criteria for Adverse Events (CTCAE) v4.03 and International Society for Paediatric Oncology (SIOP) classification. We defined deleterious HL as Muenster ≥ 2b, CTCAE ≥ 2, and SIOP ≥ 2. Mixed-effects logistic regression was used to search for the dose-effect relationship between the irradiation dose to the cochlea and the occurrence of HL.

RESULTS

Forty-two HNRMS survivors underwent pure-tone audiometry. The Muenster, CTCAE and SIOP classification showed that 19.0% (n = 8), 14.2% (n = 6) and 11.9% (n = 5) of survivors suffered from HL, respectively. A low-frequency HL pattern with normal hearing or milder hearing loss in the higher frequencies was seen in four survivors. The maximum cochlear irradiation dose was significantly associated with HL (≥Muenster 2b) (p = 0.047). In our series, HL (≥Muenster 2b) was especially observed when the maximum dose to the cochlea exceeded 19 Gy.

CONCLUSION

HL occurred in up to 19% of survivors of HNRMS. More research is needed on HL patterns in HNRMS survivors and on radiotherapy dose-effect relationships.

Hearing Loss in Cancer Patients with Skull Base Tumors Undergoing Pencil Beam Scanning Proton Therapy: A Retrospective Cohort Study

To assess the incidence and severity of changes in hearing threshold in patients undergoing high-dose pencil-beam-scanning proton therapy (PBS-PT). This retrospective cohort study included fifty-one patients (median 50 years (range, 13–68)) treated with PBS-PT for skull base tumors. No chemotherapy was delivered. Pure tone averages (PTAs)were determined before (baseline) and after PBS-PT as the average hearing thresholds at frequencies of 0.5, 1, 2, and 4 kHz. Hearing changes were calculated as PTA differences between pre-and post-PBS-PT. A linear mixed-effects model was used to assess the relationship between the PTA at the follow-up and the baseline, the cochlea radiation dose intensity, the increased age, and the years after PBS-PT. Included patients were treated for chordoma (n = 24), chondrosarcoma (n = 9), head and neck tumors (n = 9), or meningioma (n = 3), with a mean tumor dose of 71.1 Gy (RBE) (range, 52.0–77.8), and a mean dose of 37 Gy (RBE) (range, 0.0–72.7) was delivered to the cochleas. The median time to the first follow-up was 11 months (IQR, 5.5–33.7). The PTA increased from a median of 15 dB (IQR 10.0–25) at the baseline to 23.8 (IQR 11.3–46.3) at the first follow-up. In the linear mixed-effect model, the baseline PTA (estimate 0.80, 95%CI 0.64 to 0.96, p ≤ 0.001), patient’s age (0.30, 0.03 to 0.57, p = 0.029), follow-up time (2.07, 0.92 to 3.23, p ≤ 0.001), and mean cochlear dose in Gy (RBE) (0.34, 0.21 to 0.46, p ≤ 0.001) were all significantly associated with an increase in PTA at follow-up. The applied cochlear dose and baseline PTA, age, and time after treatment were significantly associated with hearing loss after proton therapy.

The Current State of Radiotherapy for Pediatric Brain Tumors: An Overview of Post-Radiotherapy Neurocognitive Decline and Outcomes

Tumors of the central nervous system are the most common solid malignancies diagnosed in children. While common, they are also found to have some of the lowest survival rates of all malignancies. Treatment of childhood brain tumors often consists of operative gross total resection with adjuvant chemotherapy or radiotherapy. The current body of literature is largely inconclusive regarding the overall benefit of adjuvant chemo- or radiotherapy. However, it is known that both are associated with conditions that lower the quality of life in children who undergo those treatments. Chemotherapy is often associated with nausea, emesis, significant fatigue, immunosuppression, and alopecia. While radiotherapy can be effective for achieving local control, it is associated with late effects such as endocrine dysfunction, secondary malignancy, and neurocognitive decline. Advancements in radiotherapy grant both an increase in lifetime survival and an increased lifetime for survivors to contend with these late effects. In this review, the authors examined all the published literature, analyzing the results of clinical trials, case series, and technical notes on patients undergoing radiotherapy for the treatment of tumors of the central nervous system with a focus on neurocognitive decline and survival outcomes.

Toxicity and Clinical Results after Proton Therapy for Pediatric Medulloblastoma: A Multi-Centric Retrospective Study

Medulloblastoma is the most common malignant brain tumor in children. Even if current treatment dramatically improves the prognosis, survivors often develop long-term treatment-related sequelae. The current radiotherapy standard for medulloblastoma is craniospinal irradiation with a boost to the primary tumor site and to any metastatic sites. Proton therapy (PT) has similar efficacy compared to traditional photon-based radiotherapy but might achieve lower toxicity rates. We report on our multi-centric experience with 43 children with medulloblastoma (median age at diagnosis 8.7 years, IQR 6.6, M/F 23/20; 26 high-risk, 14 standard-risk, 3 ex-infant), who received active scanning PT between 2015 and 2021, with a focus on PT-related acute-subacute toxicity, as well as some preliminary data on late toxicity. Most acute toxicities were mild and manageable with supportive therapy. Hematological toxicity was limited, even among HR patients who underwent hematopoietic stem-cell transplantation before PT. Preliminary data on late sequelae were also encouraging, although a longer follow-up is needed.

MRI Correlates of Ototoxicity in the Auditory Pathway in Children Treated for Medulloblastoma

OBJECTIVE

To assess diffusion and perfusion changes of the auditory pathway in pediatric medulloblastoma patients exposed to ototoxic therapies.

STUDY DESIGN

Retrospective cohort study.

SETTING

A single academic tertiary children's hospital.

PATIENTS

Twenty pediatric medulloblastoma patients (13 men; mean age 12.0 ± 4.8 yr) treated with platinum-based chemotherapy with or without radiation and 18 age-and-sex matched controls were included. Ototoxicity scores were determined using Chang Ototoxicity Grading Scale.

INTERVENTIONS

Three Tesla magnetic resonance was used for diffusion tensor and arterial spin labeling perfusion imaging.

MAIN OUTCOME MEASURES

Quantitative diffusion tensor metrics were extracted from the Heschl's gyrus, auditory radiation, and inferior colliculus. Arterial spin labeling perfusion of the Heschl's gyrus was also examined.

RESULTS

Nine patients had clinically significant hearing loss, or Chang grades more than or equal to 2a; 11 patients had mild/no hearing loss, or Chang grades less than 2a. The clinically significant hearing loss group showed reduced mean diffusivity in the Heschl's gyrus (p = 0.018) and auditory radiation (p = 0.037), and decreased perfusion in the Heschl's gyrus (p = 0.001). Mild/no hearing loss group showed reduced mean diffusivity (p = 0.036) in Heschl's gyrus only, with a decrease in perfusion (p = 0.008). There were no differences between groups in the inferior colliculus. There was no difference in fractional anisotropy between patients exposed to ototoxic therapies and controls.

CONCLUSIONS

Patients exposed to ototoxic therapies demonstrated microstructural and physiological alteration of the auditory pathway. The present study shows proof-of-concept use of diffusion tensor imaging to gauge ototoxicity along the auditory pathway. Future larger cohort studies are needed to assess significance of changes in diffusion tensor imaging longitudinally, and the relationship between these changes and hearing loss severity and longitudinal changes of the developing auditory white matter.

Revised clinical and molecular risk strata define the incidence and pattern of failure in medulloblastoma following risk-adapted radiotherapy and dose-intensive chemotherapy: results from a phase III multi-institutional study

BACKGROUND

We characterize the patterns of progression across medulloblastoma (MB) clinical risk and molecular subgroups from SJMB03, a Phase III clinical trial.

METHODS

One hundred and fifty-five pediatric patients with newly diagnosed MB were treated on a prospective, multi-center phase III trial of adjuvant radiotherapy (RT) and dose-intense chemotherapy with autologous stem cell transplant. Craniospinal radiotherapy to 23.4 Gy (average risk, AR) or 36-39.6 Gy (high risk, HR) was followed by conformal RT with a 1 cm clinical target volume to a cumulative dose of 55.8 Gy. Subgroup was determined using 450K DNA methylation. Progression was classified anatomically (primary site failure (PSF) +/- distant failure (DF), or isolated DF), and dosimetrically.

RESULTS

Thirty-two patients have progressed (median follow-up 11.0 years (range, 0.3-16.5 y) for patients without progression). Anatomic failure pattern differed by clinical risk (P = .0054) and methylation subgroup (P = .0034). The 5-year cumulative incidence (CI) of PSF was 5.1% and 5.6% in AR and HR patients, respectively (P = .92), and did not differ across subgroups (P = .15). 5-year CI of DF was 7.1% vs. 28.1% for AR vs. HR (P = .0003); and 0% for WNT, 15.3% for SHH, 32.9% for G3, and 9.7% for G4 (P = .0024). Of 9 patients with PSF, 8 were within the primary site RT field and 4 represented SHH tumors.

CONCLUSIONS

The low incidence of PSF following conformal primary site RT is comparable to prior studies using larger primary site or posterior fossa boost volumes. Distinct anatomic failure patterns across MB subgroups suggest subgroup-specific treatment strategies should be considered.

Hearing Loss After Radiation and Chemotherapy for CNS and Head-and-Neck Tumors in Children

PURPOSE

Hearing loss (HL) is a serious secondary effect of treatment for CNS and head-and-neck tumors in children. The goal of this study was to evaluate incidence and risk factors for HL in patients with multiple ototoxic exposures.

PATIENTS AND METHODS

We evaluated 340 ears from 171 patients with CNS or head-and-neck tumors treated with radiation, with or without chemotherapy, who had longitudinal audiologic evaluation. International Society of Pediatric Oncology-Boston grades were assigned to 2,420 hearing assessments. Multivariable weighted ordinal logistic regression was fitted to evaluate the effect of clinicopathologic features on HL.

RESULTS

Mean cochlea dose (odds ratio [OR] 1.04 per Gy, P < .001), time since radiotherapy (RT; OR 1.21 per year, P < .001), cisplatin dose (OR 1.48 per 100 mg/m², P < .001), and carboplatin dose (OR 1.41 per 1,000 mg/m², P = .002) were associated with increasing International Society of Pediatric Oncology-Boston grade of HL. There was no synergistic effect of RT and cisplatin (interaction term, P = .53) or RT and carboplatin (interaction term, P = .85). Cumulative incidence of high-frequency HL (> 4 kHz) was 50% or greater at 5 years after RT if mean cochlea dose was > 30 Gy, while incidence of HL across all frequencies continued to increase beyond 5 years after RT.

CONCLUSION

Children treated with radiation and chemotherapy experience a high incidence of HL over time, with associations found between more severe HL and cisplatin or carboplatin dose as well as mean cochlea dose. Mean cochlea dose of ≤ 30 Gy is proposed as a goal to reduce the risk of HL; a lower threshold (20-25 Gy) may be considered in patients receiving platinum chemotherapy to reduce cumulative HL burden.

Normal tissue complication probability modeling to guide individual treatment planning in pediatric cranial proton and photon radiotherapy

PURPOSE

Proton therapy (PT) is broadly accepted as the gold standard of care for pediatric patients with cranial cancer. The superior dose distribution of PT compared to photon radiotherapy reduces normal tissue complication probability (NTCP) for organs at risk. As NTCPs for pediatric organs are not well understood, clinics generally base radiation response on adult data. However, there is evidence that radiation response strongly depends on the age and even sex of a patient. Furthermore, questions surround the influence of individual intrinsic radiosensitivity (α/β ratio) on pediatric NTCP. While the clinical pediatric NTCP data is scarce, radiobiological modeling and sensitivity analyses can be used to investigate the NTCP trends and its dependence on individual modeling parameters. The purpose of this study was to perform sensitivity analyses of NTCP models to ascertain the dependence of radiosensitivity, sex, and age of a child and predict cranial side-effects following intensity-modulated proton therapy (IMPT) and intensity-modulated radiotherapy (IMRT).

METHODS

Previously, six sex-matched pediatric cranial datasets (5, 9, and 13 years old) were planned in Varian Eclipse treatment planning system (13.7). Up to 108 scanning beam IMPT plans and 108 IMRT plans were retrospectively optimized for a range of simulated target volumes and locations. In this work, dose-volume histograms were extracted and imported into BioSuite Software for radiobiological modeling. Relative-Seriality and Lyman-Kutcher-Burman models were used to calculate NTCP values for toxicity endpoints, where TD50, (based on reported adult clinical data) was varied to simulate sex dependence of NTCP. Plausible parameter ranges, based on published literature for adults, were used in modeling. In addition to sensitivity analyses, a 20% difference in TD50 was used to represent the radiosensitivity between the sexes (with females considered more radiosensitive) for ease of data comparison as a function of parameters such as α/β ratio.

RESULTS

IMPT plans resulted in lower NTCP compared to IMRT across all models (p < 0.0001). For medulloblastoma treatment, the risk of brainstem necrosis (> 10%) and cochlea tinnitus (> 20%) among females could potentially be underestimated considering a lower TD50 value for females. Sensitivity analyses show that the difference in NTCP between sexes was significant (p < 0.0001). Similarly, both brainstem necrosis and cochlea tinnitus NTCP varied significantly (p < 0.0001) across tested α/β as a function of TD50 values (assumption being that TD50 values are 20% lower in females). If the true α/β of these pediatric tissues is higher than expected (α/β ∼ 3), the risk of tinnitus for IMRT can significantly increase (p < 0.0001).

CONCLUSION

Due to the scarcity of pediatric NTCP data available, sensitivity analyses were performed using plausible ranges based on published adult data. In the clinical scenario where, if female pediatric patients were 20% more radiosensitive (lower TD50 value), they could be up to twice as likely to experience side-effects of brainstem necrosis and cochlea tinnitus compared to males, highlighting the need for considering the sex in NTCP models. Based on our sensitivity analyses, age and sex of a pediatric patient could significantly affect the resultant NTCP from cranial radiotherapy, especially at higher α/β values.

Ototoxicity in cancer survivors: Experience and proposal of a surveillance protocol

INTRODUCTION

Ototoxicity occurs in different percentages in patients after treatment with platinum-based chemotherapy or cranial radiation therapy. The aim of this study was to present our experience in ototoxicity monitoring.

MATERIAL AND METHODS

A review was made of the registry of paediatric cancer patients referred to the Children's Hearing Loss Unit from 1999 to 2019.

RESULTS

Of the 46 patients referred to this unit, 41 had received platinum as part of their treatment, 17 patients underwent neurosurgery, and 18 patients received cranial radiation therapy. An anamnesis and otoscopy were performed on all of them, and the monitoring was carried out with tone-verbal audiometry and/or distortion products. Hearing loss was observed in eight patients (21.05% of patients referred for audiological follow-up) as a consequence of the treatment. It was impossible to determine the audiological situation in eight patients at the end of treatment. Hearing aid adaption was necessary in two patients. In coordination with Paediatric Oncology, a change from cisplatin to carboplatin due to bilateral grade two ototoxicity was considered appropriate during treatment in one patient.

CONCLUSION

Adequate coordination with Paediatric Oncology is essential to carry out active surveillance for ototoxicity and to modify, if possible, the dosage or type of chemotherapy in case hearing is affected. In our experience, and following current recommendations, a pre-treatment assessment is usually performed, as well as monitoring during treatment, at the end of treatment, and annually thereafter due to the risk of a later development of hearing loss.

The cumulative incidence of cisplatin-induced hearing loss in young children is higher and develops at an early stage during therapy compared with older children based on 2052 audiological assessments

BACKGROUND

Ototoxicity is a common adverse event of cisplatin treatment. The authors investigated the development of cisplatin-induced hearing loss (CIHL) over time in children with cancer by age and examined the influence of other clinical characteristics on the course of CIHL.

METHODS

Data from Canadian patients with childhood cancer were retrospectively reviewed. Hearing loss was graded according to International Society of Pediatric Oncology criteria. The Kaplan-Meier method was applied to estimate the cumulative incidence of CIHL for the total cohort and according to age. Cox regression models were used to explore the effects of independent variables on CIHL development up to 3 years after the start of therapy.

RESULTS

In total, 368 patients with 2052 audiological assessments were included. Three years after initiating therapy, the cumulative incidence of CIHL was highest in patients aged ≤5 years (75%; 95% confidence interval [CI], 66%-84%), with a rapid increase observed to 27% (95% CI, 21%-35%) at 3 months and to 61% (95% CI, 53%-69%) at 1 year, compared with patients aged >5 years (48%; 95% CI, 37%-62%; P < .001). The total cumulative dose of cisplatin at 3 months (per 100 mg/m² increase: hazard ratio [HR], 1.20; 95% CI, 1.01-1.41) vincristine (HR, 2.87; 95% CI, 1.89-4.36) and the total duration of concomitantly administered antibiotics (>30 days: HR, 1.85; 95% CI, 1.17-2.95) further influenced CIHL development over time.

CONCLUSIONS

In young children, the cumulative incidence of CIHL is higher compared with that in older children and develops early during therapy. The course of CIHL is further influenced by the total cumulative dose of cisplatin and other ototoxic (co-)medication. These results highlight the need for audiological monitoring at each cisplatin cycle.

Hearing loss and intellectual outcome in children treated for embryonal brain tumors: Implications for young children treated with radiation sparing approaches

Purpose

We investigate the impact of severe sensorineural hearing loss (SNHL) and for the first time evaluate the effect of unilateral versus bilateral SNHL on intellectual outcome in a cohort of children with embryonal brain tumors treated with and without radiation.

Methods

Data were from 94 childhood survivors of posterior fossa (PF) embryonal brain tumors who were treated with either: (1) chemotherapy alone (n = 16, 7.11 [3.41] years, 11M/5F), (2) standard‐dose craniospinal irradiation (CSI) and/or large boost volumes (n = 44, 13.05 [3.26] years, 29M/15F), or (3) reduced‐dose CSI with a boost restricted to the tumor bed (n = 34, 11.07 [3.80] years, 19M/15F). We compared intellectual outcome between children who: (1) did and did not develop SNHL and (2) developed unilateral versus bilateral SNHL. A Chang grade of ≥2b that required the use of a hearing aid was considered severe SNHL. Comparisons were made overall and within each treatment group separately.

Results

Patients who developed SNHL had lower full scale IQ (p = 0.007), verbal comprehension (p = 0.003), and working memory (p = 0.02) than patients without SNHL. No differences were observed between patients who had unilateral versus bilateral SNHL (all p > 0.05). Patients treated with chemotherapy alone who developed SNHL had lower mean working memory (p = 0.03) than patients who did not develop SNHL. Among patients treated with CSI, no IQ indices differed between those with and without SNHL (all p > 0.05).

Conclusions

Children treated for embryonal brain tumors who develop severe SNHL have lower intellectual outcome than patients with preserved hearing: this association is especially profound in young children treated with radiation sparing approaches. We also demonstrate that intellectual outcome is similarly impaired in patients who develop unilateral versus bilateral SNHL. These findings suggest that early intervention to preserve hearing is critical.

Recommendations for Age-Appropriate Testing, Timing, and Frequency of Audiologic Monitoring During Childhood Cancer Treatment: An International Society of Paediatric Oncology Supportive Care Consensus Report

Importance

Ototoxicity is an irreversible direct and late effect of certain childhood cancer treatments. Audiologic surveillance during therapy as part of the supportive care pathway enables early detection of hearing loss, decision-making about ongoing cancer treatment, and, when applicable, the timely use of audiologic interventions. Pediatric oncologic clinical practice and treatment trials have tended to be driven by tumor type and tumor-specific working groups. Internationally accepted standardized recommendations for monitoring hearing during treatment have not previously been agreed on.

Objective

To provide standard recommendations on hearing loss monitoring during childhood cancer therapy for clinical practice.

Methods

An Ototoxicity Task Force was formed under the umbrella of the International Society of Paediatric Oncology, consisting of international audiologists, otolaryngologists, and leaders in the field of relevant pediatric oncology tumor groups. Consensus meetings conducted by experts were organized, aimed at providing standardized recommendations on age-directed testing, timing, and frequency of monitoring during cancer treatment based on literature and consensus. Consensus statements were prepared by the core group, adapted following several videoconferences, and finally agreed on by the expert panel.

Findings

The consensus reached was that children who receive ototoxic cancer treatment (platinum agents, cranial irradiation, and/or brain surgery) require a baseline case history, monitoring of their middle ear and inner ear function, and assessment of tinnitus at each audiologic follow-up. As a minimum, age-appropriate testing should be performed before and at the end of treatment. Ideally, audiometry with counseling before each cisplatin cycle should be considered in the context of the individual patient, specific disease, feasibility, and available resources.

Conclusions and Relevance

This is an international multidisciplinary consensus report providing standardized supportive care recommendations on hearing monitoring in children undergoing potentially ototoxic cancer treatment. The recommendations are intended to improve the care of children with cancer and facilitate comparative research on the timing and development of hearing loss caused by different cancer treatment regimens.

Clinical and genetic risk factors for radiation-associated ototoxicity: A report from the Childhood Cancer Survivor Study and the St. Jude Lifetime Cohort

BACKGROUND

Cranial radiation therapy (CRT) is associated with ototoxicity, which manifests as hearing loss and tinnitus. The authors sought to identify clinical determinants and genetic risk factors for ototoxicity among adult survivors of pediatric cancer treated with CRT.

METHODS

Logistic regression evaluated associations of tinnitus (n = 1991) and hearing loss (n = 2198) with nongenetic risk factors and comorbidities among CRT-treated survivors in the Childhood Cancer Survivor Study. Genome-wide association studies (GWASs) of CRT-related tinnitus and hearing loss were also performed.

RESULTS

Males were more likely to report CRT-related tinnitus (9.4% vs 5.4%; P = 5.1 × 10^-4 ) and hearing loss (14.0% vs 10.7%; P = .02) than females. Survivors with tinnitus or hearing loss were more likely to experience persistent dizziness or vertigo (tinnitus: P < 2 × 10^-16 ; hearing loss: P = 6.4 × 10^-9 ), take antidepressants (tinnitus: P = .02; hearing loss: P = .01), and report poorer overall health (tinnitus: P = 1.5 × 10^-6 ; hearing loss: P = 1.7 × 10^-6 ) in comparison with controls. GWAS of CRT-related tinnitus revealed a genome-wide significant signal in chromosome 1 led by rs203248 (P = 1.5 × 10^-9 ), whereas GWAS of CRT-related hearing loss identified rs332013 (P = 5.8 × 10^-7 ) in chromosome 8 and rs67522722 (P = 7.8 × 10^-7 ) in chromosome 6 as nearly genome-wide significant. A replication analysis identified rs67522722, intronic to ATXN1, as being significantly associated with CRT-related hearing loss (P = .03) and de novo hearing loss (P = 3.6 × 10^-4 ).

CONCLUSIONS

CRT-associated ototoxicity was associated with sex, several neuro-otological symptoms, increased antidepressant use, and poorer self-reported health. GWAS of CRT-related hearing loss identified rs67522722, which was supported in an independent cohort of survivors.

LAY SUMMARY

Hearing loss and subjective tinnitus (the perception of noise or ringing in the ear) are long-term side effects of cancer treatment and are common in children treated with radiation to the brain. These toxicities can affect childhood development and potentially contribute to serious learning and behavioral difficulties. This study's data indicate that males are at greater risk for hearing loss and tinnitus than females after radiation therapy to the brain. Those who develop these toxicities are more likely to use antidepressants and report poorer overall health. Health care providers can improve the management of survivors by informing patients and/or their parents of these risks.

Normal tissue tolerance amongst paediatric brain tumour patients- current evidence in proton radiotherapy

BACKGROUND

Proton radiotherapy (PT) is used increasingly for paediatric brain cancer patients. However, as demonstrated here, the knowledge on normal tissue dose constraints, to minimize side-effects, for this cohort is limited.

METHODS

A search strategy was systematically conducted on MEDLINE® database. 65 papers were evaluated ranging from 2013 to 2021.

RESULTS

Large variations in normal tissue tolerance and toxicity reporting across PT studies makes estimation of normal tissue dose constraints difficult, with the potential for significant late effects to go unmeasured. Mean dose delivered to the pituitary gland varies from 20 to 30 Gy across literature. Similarly, the hypothalamic dose delivery ranges from 20 to 54.6 Gy for paediatric patients.

CONCLUSION

There is a significant lack of radiobiological data for paediatric brain cancer patients undergoing proton therapy, often using data from x-ray radiotherapy and adult populations. The way forward is through standardisation of reporting in order to validate relevant dose constraints.

Late effects of radiation therapy in pediatric patients and survivorship

Advances in multimodality therapy have led to childhood cancer cure rates over 80%. However, surgery, chemotherapy, and radiotherapy may lead to debilitating or even fatal long-term effects among childhood survivors beyond those inflicted by the primary disease process. It is critical to understand, mitigate, and prevent these late effects of cancer therapy to improve the quality of life of childhood cancer survivors. This review summarizes the various late effects of radiotherapy and acknowledges the Pediatric Normal Tissue Effects in the Clinic (PENTEC), an international collaboration that is systematically analyzing the association between radiation treatment dose/volume and consequential organ toxicities, in developing children as a basis to formulate recommendations for clinical practice of pediatric radiation oncology. We also summarize initiatives for survivorship and surveillance of late normal tissue effects related to radiation therapy among long-term survivors of childhood cancer treated in the past.

Hearing Loss Risk in Pediatric Patients Treated with Cranial Irradiation and Cisplatin-Based Chemotherapy

PURPOSE

Cranial radiation therapy (RT) and cisplatin-based chemotherapy are essential to treating many pediatric cancers but cause significant ototoxicity. The objective of this study is to determine the relationship between the RT dose and the risk of subsequent hearing loss in pediatric patients treated with cisplatin.

METHODS AND MATERIALS

This retrospective study of cisplatin-treated pediatric patients examined ototoxicity from cranial RT. Ototoxicity was graded for each ear according to the International Society of Pediatric Oncology (SIOP) consensus ototoxicity scale. The RT dose to the cochlea was calculated using the mean, median, maximum, and minimum dose received to determine the most predictive parameter for hearing loss. Multivariable logistic regression models then examined risk factors for hearing loss.

RESULTS

In 96 children (161 ears) treated with RT + cisplatin, the minimum cochlear RT dose was most predictive of hearing loss. A higher cochlear RT dose was associated with increased hearing loss (odds ratio per 10 Gy dose increase = 1.64; P = .043), with an added risk in those receiving an autologous bone marrow transplantation (hazard ratio = 10.47; P < .001).

CONCLUSIONS

This research supports further testing of the minimum cochlear RT dose as a more predictive dose parameter for risk of ototoxicity. The cochlear RT dose was additive to the risk of hearing loss from underlying cisplatin-based chemotherapy. Exposure to autologous bone marrow transplantation was the strongest predictor of developing hearing loss, placing these children at particularly high risk for hearing loss across all cochlear doses. Future prospective studies are crucial to further inform RT dose thresholds and minimize the risk of hearing loss in childhood cancer survivors.

Outcomes of stereotactic radiosurgery for pilocytic astrocytoma: an international multiinstitutional study

OBJECTIVE

The current standard initial therapy for pilocytic astrocytoma is maximal safe resection. Radiation therapy is considered for residual, recurrent, or unresectable pilocytic astrocytomas. However, the optimal radiation strategy has not yet been established. Here, the authors describe the outcomes of stereotactic radiosurgery (SRS) for pilocytic astrocytoma in a large multiinstitutional cohort.

METHODS

An institutional review board-approved multiinstitutional database of patients treated with Gamma Knife radiosurgery (GKRS) between 1990 and 2016 was queried. Data were gathered from 9 participating International Radiosurgery Research Foundation (IRRF) centers. Patients with a histological diagnosis of pilocytic astrocytoma treated using a single session of GKRS and with at least 6 months of follow-up were included in the analysis.

RESULTS

A total of 141 patients were analyzed in the study. The median patient age was 14 years (range 2-84 years) at the time of GKRS. The median follow-up was 67.3 months. Thirty-nine percent of patients underwent SRS as the initial therapy, whereas 61% underwent SRS as salvage treatment. The median tumor volume was 3.45 cm3. The tumor location was the brainstem in 30% of cases, with a nonbrainstem location in the remainder. Five- and 10-year overall survival rates at the last follow-up were 95.7% and 92.5%, respectively. Five- and 10-year progression-free survival (PFS) rates were 74.0% and 69.7%, respectively. On univariate analysis, an age < 18 years, tumor volumes < 4.5 cm3, and no prior radiotherapy or chemotherapy were identified as positive prognostic factors for improved PFS. On multivariate analysis, only prior radiotherapy was significant for worse PFS.

CONCLUSIONS

This represents the largest study of single-session GKRS for pilocytic astrocytoma to date. Favorable long-term PFS and overall survival were observed with GKRS. Further prospective studies should be performed to evaluate appropriate radiosurgery dosing, timing, and sequencing of treatment along with their impact on toxicity and the quality of life of patients with pilocytic astrocytoma.

Clinical outcomes and quality of life in children and adolescents with primary brain tumors treated with pencil beam scanning proton therapy

BACKGROUND

Long-term treatment-related toxicity may substantially impact well-being, quality of life (QoL), and health of children/adolescents with brain tumors (CBTs). Strategies to reduce toxicity include pencil beam scanning (PBS) proton therapy (PT). This study aims to report clinical outcomes and QoL in PBS-treated CBTs.

PROCEDURE

We retrospectively reviewed 221 PBS-treated CBTs aged <18 years. Overall-free (OS), disease-free (DFS), and late-toxicity-free survivals (TFS), local control (LC) and distant (DC) brain/spinal control were calculated using Kaplan-Meier estimates. Prospective QoL reports from 206 patients (proxies only ≤4 years old [yo], proxies and patients ≥5 yo) were descriptively analyzed. Median follow-up was 51 months (range, 4-222).

RESULTS

Median age at diagnosis was 3.1 years (range, 0.3-17.7). The main histologies were ependymoma (n = 88; 39.8%), glioma (n = 37; 16.7%), craniopharyngioma (n = 22; 10.0%), atypical teratoid/rhabdoid tumor (ATRT) (n = 21; 9.5%) and medulloblastoma (n = 15; 6.8%). One hundred sixty (72.4%) patients received chemotherapy. Median PT dose was 54 Gy(relative biological effectiveness) (range, 18.0-64.8). The 5-year OS, DFS, LC, and DC (95% CI) were 79.9% (74-85.8), 65.2% (59.8-70.6), 72.1% (65.4-78.8), and 81.8% (76.3-87.3), respectively. Late PT-related ≥G3 toxicity occurred in 19 (8.6%) patients. The 5-year ≥G3 TFS was 91.0% (86.3-95.7). Three (1.4%) secondary malignancies were observed. Patients aged ≤3 years at PT (P = .044) or receiving chemotherapy (P = .043) experienced more ≥G3 toxicity. ATRT histology independently predicted distant brain failure (P = .046) and death (P = .01). Patients aged ≥5 years self-rated QoL higher than their parents (proxy assessment). Both reported lower social functioning and cognition after PT than at baseline, but near-normal long-term global well-being. QoL was well below normal before and after PT in children ≤4 years.

CONCLUSIONS

The outcome of CBTs was excellent after PBS. Few patients had late ≥G3 toxicity. Patients aged <5 years showed worse QoL and toxicity outcomes.

Impact of proton radiotherapy on treatment timing in pediatric and adult patients with CNS tumors

BACKGROUND

Despite putative benefits associated with proton radiotherapy in the setting of CNS tumors, numerous barriers limit treatment accessibility. Given these challenges, we explored the association of proton use with variations in treatment timing.

METHODS

Pediatric and adult patients with histologically confirmed CNS tumors were identified from the National Cancer Database (2004-2015). Univariable and multivariable regression models were constructed to assess factors impacting radiation timing. Multivariable Cox regression was used to evaluate the effect of treatment delay on survival.

RESULTS

A total of 76 157 patients received photon or proton radiotherapy. Compared to photons, time to proton administration was longer in multiple pediatric (embryonal, ependymal, nonependymal glial, and other) and adult (ependymal, nonependymal glial, meningeal, other) tumor histologies. On adjusted analysis, proton radiotherapy was associated with longer delays in radiotherapy administration in pediatric embryonal tumors (+3.00 weeks, P = .024) and in all adult tumors (embryonal [+1.36 weeks, P = .018], ependymal [+3.15 weeks, P < .001], germ cell [+2.65 weeks, P = .024], glial [+2.15 weeks, P < .001], meningeal [+5.05 weeks, P < .001], and other [+3.06 weeks, P < .001]). In patients with high-risk tumors receiving protons, delays in adjuvant radiotherapy were independently associated with poorer survival (continuous [weeks], adjusted hazard ratio = 1.09, 95% CI = 1.02-1.16).

CONCLUSIONS

Proton radiotherapy is associated with later radiation initiation in pediatric and adult patients with CNS tumors. In patients with high-risk CNS malignancies receiving protons, delayed adjuvant radiotherapy is associated with poorer survival. Further studies are needed to understand this discrepancy to maximize the potential of proton radiotherapy for CNS malignancies.

Hearing and Other Neurologic Problems

Ototoxicity and other neurologic toxicities are potential consequences of exposure to common therapeutic agents used during treatment of childhood cancer, including platinum and vinca alkaloid chemotherapy, cranial radiation, surgery involving structures critical to cochlear and neurologic function, and supportive care medications such as aminoglycoside antibiotics and loop diuretics. This article provides an overview of ototoxicity and other neurologic toxicities related to childhood cancer treatment, discusses the challenges that these toxicities may pose for survivors, and presents an overview of current recommendations for surveillance and clinical management of these potentially life-altering toxicities in survivors of childhood cancers.

Comparison of radiation and chemoradiation-induced sensorineural hearing loss in head and neck cancer patients

Aim

The purpose of this study was to assess and compare the incidence and severity of sensorineural hearing loss (SNHL) in head-and-neck patients undergoing radiotherapy (RT) and concurrent cisplatin-based chemoradiotherapy (CRT).

Materials and Methods

Pure tone audiometry (PTA) was performed at 0.25-12 kHz on 35 RT and 25 CRT patients after 12-month followed up. The hearing loss was evaluated according to the Common Terminology Criteria for Adverse Events (CTCAE) criteria.

Results

SNHL increased to 84% in patients who had received CRT, compared with 26% increasing in patients who had treated with RT. There was an increased risk of SNHL at all frequencies for ears received a cochlear mean dose >50 Gy in RT group, compared to those receiving cochlear mean dose >30 Gy in CRT group. SNHL was more severe at higher frequencies in both patient groups.

Conclusion

Characteristic of radiation-induced SNHL is different from CRT-induced SNHL, especially in threshold radiation dose and PTA frequency.

[Ototoxicity in cancer survivors: experience and proposal of a surveillance protocol]

INTRODUCTION

Ototoxicity occurs in different percentages in patients after treatment with platinum-based chemotherapy or cranial radiation therapy. The aim of this study was to present experience in ototoxicity monitoring.

MATERIAL AND METHODS

A review was made of the registry of paediatric cancer patients referred to the Children's Hearing Loss Unit from 1999 to 2019.

RESULTS

Of the 46 patients referred to this unit, 41 had received platinum as part of their treatment, 17 patients underwent neurosurgery, and 18 patients received cranial radiation therapy. An anamnesis and otoscopy were performed on all of them, and the monitoring was carried out with tone-verbal audiometry and/or distortion products. Hearing loss was observed in eight patients (21.05% of patients referred for audiological follow-up) as a consequence of the treatment. It was impossible to determine the audiological situation in eight patients at the end of treatment. Hearing aid adaption was necessary in two patients. In coordination with Paediatric Oncology, a change from cisplatin to carboplatin due to bilateral grade two ototoxicity was considered appropriate during treatment in one patient.

CONCLUSION

Adequate coordination with Paediatric Oncology is essential to carry out active surveillance for ototoxicity and to modify, if possible, the dosage or type of chemotherapy in case hearing is affected. In our experience, and following current recommendations, a pre-treatment assessment is usually performed, as well as monitoring during treatment, at the end of treatment, and annually thereafter due to the risk of a later development of hearing loss.

Association of Hearing Impairment With Neurocognition in Survivors of Childhood Cancer

Importance

Despite advancements in cancer therapy and supportive care, childhood cancer survivors remain at risk for chronic morbidities associated with disease and treatment, such as hearing impairment (HI) and neurocognitive deficits. This study, to our knowledge, is the first to objectively measure hearing and neurocognitive function in a large cohort of long-term survivors of childhood cancer stratified by treatment exposures.

Objective

To assess the association of HI with neurocognitive function and the factors in HI that mediate neurocognitive outcomes in survivors of childhood cancer.

Design, Setting, and Participants

Data analyzed in this cross-sectional study were collected for the period April 25, 2007, to June 30, 2017, from participants in the St. Jude Lifetime Cohort Study (SJLIFE), an ongoing study that quantifies the long-term health outcomes of survivors of childhood cancer. Participants included those treated at St. Jude Children's Research Hospital (Memphis, Tennessee) for childhood cancer who survived 5 or more years after their original diagnosis and who were eligible for audiologic and neurocognitive testing. Hearing outcomes were coded using the Chang Ototoxicity Grading Scale. Data analysis was performed from March 22, 2019, to March 5, 2020.

Main Outcomes and Measures

Hearing and neurocognitive function. Survivors were grouped by hearing sensitivity (normal hearing [Chang grade 0], mild HI [Chang grades 1a, 1b, and 2a], or severe HI [Chang grade ≥2b]) and stratified by treatment exposure (platinum-only exposure group [treated with cisplatin and/or carboplatin chemotherapy], cochlear radiotherapy [RT] exposure group [treated with cochlear RT with or without platinum-based chemotherapy], or no exposure group [no platinum-based chemotherapy or cochlear RT]). Multivariable log-binomial models were adjusted for age at diagnosis, time since diagnosis, sex, and relevant treatment exposures.

Results

A total of 1520 survivors of childhood cancer were analyzed, among whom 814 were male survivors (53.6%), the median (interquartile range [IQR]) age was 29.4 (7.4-64.7) years, and the median (IQR) time since diagnosis was 20.4 (6.1-53.8) years. Prevalence and risk of severe HI among survivors were higher in survivors in the platinum-only (n = 107 [34.9%]; relative risk [RR], 1.68 [95% CI, 1.20-2.37]) or cochlear RT (n = 181 [38.3%]; RR, 2.69 [95% CI, 2.02-3.57) exposure group compared with those in the no exposure group (n = 65 [8.8%]). Severe HI was associated with deficits in verbal reasoning skills (no exposure group RR, 1.11 [95% CI, 0.50-2.43]; platinum-only exposure group RR, 1.93 [95% CI, 1.21-3.08]; cochlear RT exposure group RR, 2.00 [95% CI, 1.46-2.75]), verbal fluency (no exposure group RR, 1.86 [95% CI, 1.19-2.91]; platinum-only exposure group RR, 1.83 [95% CI, 1.24-2.71]; cochlear RT exposure group RR, 1.45 [95% CI, 1.09-1.94]), visuomotor speed (no exposure group RR, 1.87 [95% CI, 1.07-3.25]; platinum-only exposure group RR, 3.10 [95% CI, 1.92-4.99]; cochlear RT exposure group RR, 1.40 [95% CI, 1.11-1.78]), and mathematics skills (no exposure group RR, 1.90 [95% CI, 1.18-3.04]; platinum-only exposure group RR, 1.63 [95% CI, 1.05-2.53]; cochlear RT exposure group RR, 1.58 [95% CI, 1.15-2.18]), compared with survivors with normal hearing or with mild HI.

Conclusions and Relevance

Results of this study suggest that severe HI in childhood cancer survivors is associated with neurocognitive deficits independent of the neurotoxic treatment received. Early screening and intervention for HI may facilitate the development and maintenance of neurocognitive function and identify individuals at risk for impairment.

Modern Radiotherapy for Pediatric Brain Tumors

Cancer is a leading cause of death in children with tumors of the central nervous system, the most commonly encountered solid malignancies in this population. Radiotherapy (RT) is an integral part of managing brain tumors, with excellent long-term survival overall. The tumor histology will dictate the volume of tissue requiring treatment and the dose. However, radiation in developing children can yield functional deficits and/or cosmetic defects and carries a risk of second tumors. In particular, children receiving RT are at risk for neurocognitive effects, neuroendocrine dysfunction, hearing loss, vascular anomalies and events, and psychosocial dysfunction. The risk of these late effects is directly correlated with the volume of tissue irradiated and dose delivered and is inversely correlated with age. To limit the risk of developing these late effects, improved conformity of radiation to the target volume has come from adopting a volumetric planning process. Radiation beam characteristics have also evolved to achieve this end, as exemplified through development of intensity modulated photons and the use of protons. Understanding dose limits of critical at-risk structures for different RT modalities is evolving. In this review, we discuss the physical basis of the most common RT modalities used to treat pediatric brain tumors (intensity modulated radiation therapy and proton therapy), the RT planning process, survival outcomes for several common pediatric malignant brain tumor histologies, RT-associated toxicities, and steps taken to mitigate the risk of acute and late effects from treatment.

Long-Term Incidence and Predictors of Significant Hearing Loss Requiring Hearing Assistive Devices Among Childhood Cancer Survivors: A Population-Based Study

PURPOSE

Hearing loss is a significant late effect among childhood cancer survivors. Recent guidelines note insufficient evidence to quantify its natural history or risk associated with specific exposures. We examined the long-term incidence and predictors of hearing loss requiring hearing amplification devices (HADs) using population-based health care data.

METHODS

In Ontario, Canada, HAD costs are subsidized by the Assistive Devices Program (ADP). Ontario children < 18 years of age at cancer diagnosis between 1987 and 2016 were identified and linked to ADP claims. Cumulative HAD incidence was compared between cases and matched controls. Patient, disease, and treatment predictors of HAD were examined.

RESULTS

We identified 11,842 cases and 59,210 controls. Cases were at higher risk for HAD (hazard ratio [HR], 12.8; 95% CI, 9.8 to 16.7; P < .001). The cumulative incidence of HAD among survivors was 2.1% (95% CI, 1.7% to 2.5%) at 20 years and 6.4% (95% CI, 2.8% to 12.1%) at 30 years post-diagnosis. The 30-year incidence was highest in neuroblastoma (10.7%; 95% CI, 3.8% to 21.7%) and hepatoblastoma (16.2%; 95% CI, 8.6% to 26.0%) survivors. Predictors of HAD in multivariable analyses included age 0-4 years at diagnosis (v 5-9 years; HR, 2.2; 95% CI, 1.4-3.3; P < .001). Relative to no cisplatin exposure, patients receiving < 200 mg/m² were not at greater risk, unlike those receiving higher cumulative doses. Relative to no cranial or facial radiation, those who had received ≤ 32.00 Gy were at no higher risk, unlike those who had received > 32.00 Gy. Carboplatin exposure was not associated with HAD.

CONCLUSION

Childhood cancer survivors are at elevated risk for requiring HAD, which continues to increase between 20 and 30 years after diagnosis. Thresholds of cisplatin and radiation exposure exist, above which risk substantially increases. Prolonged monitoring and trials of otoprotective agents are warranted in high-risk populations.

Assessment and Management of Platinum-Related Ototoxicity in Children Treated for Cancer

Platinum compounds are a group of chemotherapeutic agents included in many pediatric and adult oncologic treatment protocols. The main platinum compounds are cisplatin, carboplatin, and oxaliplatin. Their use in clinical practice has greatly improved long-term survival of pediatric patients, but they also cause some toxic effects: ototoxicity, myelosuppression, nephrotoxicity, and neurotoxicity. Hearing damage is one of the main toxic effects of platinum compounds, and it derives from the degeneration of hair cells of the ear, which, not having self-renewal capacity, cannot reconstitute themselves. Hearing loss from platinum exposure is typically bilateral, sensorineural, and permanent, and it is caused by the same mechanisms with which platinum acts on neoplastic cells. According to available data from the literature, the optimal timing for the audiological test during and after treatment with platinum compounds is not well defined. Moreover, no substances capable of preventing the onset of hearing loss have been identified.

Margin-Free Fractionated Stereotactic Radiation Therapy for Pediatric Brain Tumors

PURPOSE

Conventional radiation therapy (RT) to pediatric brain tumors exposes a large volume of normal brain to unwarranted radiation causing late toxicity. We hypothesized that in well demarcated pediatric tumors lacking microscopic extensions, fractionated stereotactic RT (SRT), without target volume expansions, can reduce high dose normal tissue irradiation without affecting local control.

METHODS AND MATERIALS

Between 2008 and 2017, 52 pediatric patients with brain tumors were treated using the CyberKnife (CK) with SRT in 180 to 200 cGy per fraction. Thirty representative cases were retrospectively planned for intensity modulated RT (IMRT) with 4-mm PTV expansion. We calculated the volume of normal tissue within the high or intermediate dose region adjacent to the target. Plan quality and radiation dose-volume dosimetry parameters were compared between CK and IMRT plans. We also reported overall survival, progression-free survival (PFS), and local control.

RESULTS

Tumors included low-grade gliomas (n = 28), craniopharyngiomas (n = 16), and ependymomas (n = 8). The volumes of normal tissue receiving high (≥80% of prescription dose or ≥40 Gy) or intermediate (80% > dose ≥50% of the prescription dose or 40 Gy > dose ≥25 Gy) dose were significantly smaller with CK versus IMRT plans (P < .0001 for all comparisons). With a median follow-up of 3.7 years (range, 0.1-9.0), 3-year local control was 92% for all patients. Eight failures occurred: 1 craniopharyngioma (marginal), 2 ependymomas (both in-field), and 5 low-grade gliomas (2 in-field, 1 marginal, and 2 distant).

CONCLUSIONS

Fractionated SRT using CK without target volume expansion appears to reduce the volume of irradiated tissue without majorly compromising local control in pediatric demarcated brain tumors. These results are hypothesis generating and should be tested and validated in prospective studies.

Effect of sensorineural hearing loss on neurocognitive and adaptive functioning in survivors of pediatric embryonal brain tumor

PURPOSE

Survivors of pediatric embryonal brain tumors (BT) are at high risk for sensorineural hearing loss (SNHL) associated with neurocognitive decline. However, previous studies have not assessed the relationship between SNHL and adaptive functioning. We examined neurocognitive and adaptive functioning in patients with and without SNHL.

METHODS

Participants included 36 patients treated for an embryonal BT with craniospinal irradiation (CSI) and cisplatin chemotherapy who were assessed 6.7 years post-treatment on average. The impact of SNHL on neurocognitive performance and parent-rated adaptive functioning was assessed in univariate and multivariate analyses.

RESULTS

There were 17 cases with SNHL (mean age at evaluation = 14.4) and 19 cases with NH (mean age at evaluation = 13.8). After accounting for age at diagnosis and additional covariates in multivariable analyses, SNHL was associated with worse overall intellectual functioning (p = 0.027) and perceptual reasoning (p = 0.016) performance. There was no effect of SNHL on adaptive functioning in multivariable models. Age at diagnosis and sex were associated with performance on neurocognitive measures.

CONCLUSIONS

SNHL in pediatric embryonal BT is associated with increased risk for neurocognitive deficits in conjunction with other demographic and treatment-related factors.

Medulloblastoma has a global impact on health related quality of life: Findings from an international cohort

Background

Understanding the global impact of medulloblastoma on health related quality of life (HRQL) is critical to characterizing the broad impact of this disease and realizing the benefits of modern treatments. We evaluated HRQL in an international cohort of pediatric medulloblastoma patients.

Methods

Seventy‐six patients were selected from 10 sites across North America, Europe, and Asia, who participated in the Medulloblastoma Advanced Genomics International Consortium (MAGIC). The Health Utilities Index (HUI) was administered to patients and/or parents at each site. Responses were used to determine overall HRQL and attributes (ie specific subdomains). The impact of various demographic and medical variables on HRQL was considered—including molecular subgroup.

Results

The majority of patients reported having moderate or severe overall burden of morbidity for both the HUI2 and HUI3 (HUI2 = 60%; HUI3 = 72.1%) when proxy‐assessed. Self‐care in the HUI2 was rated as higher (ie better outcome) for patients from Western versus Eastern sites, P = .02. Patients with nonmetastatic status had higher values (ie better outcomes) for the HUI3 hearing, HUI3 pain, and HUI2 pain, all P < .05. Patients treated with a gross total resection also had better outcomes for the HUI3 hearing (P = .04). However, those who underwent a gross total resection reported having worse outcomes on the HUI3 vision (P = .02). No differences in HRQL were evident as a function of subgroup.

Conclusions

By examining an international sample of survivors, we characterized the worldwide impact of medulloblastoma. This is a critical first step in developing global standards for evaluating long‐term outcomes.

Genetic Determinants of Ototoxicity During and After Childhood Cancer Treatment: Protocol for the PanCareLIFE Study

Background

Survival rates after childhood cancer now reach nearly 80% in developed countries. However, treatments that lead to survival and cure can cause serious adverse effects with lifelong negative impacts on survivor quality of life. Hearing impairment is a common adverse effect in children treated with cisplatin-based chemotherapy or cranial radiotherapy. Ototoxicity can extend from high-tone hearing impairment to involvement of speech frequencies. Hearing impairment can impede speech and language and neurocognitive development. Although treatment-related risk factors for hearing loss following childhood cancer treatment have been identified, the individual variability in toxicity of adverse effects after similar treatment between childhood cancer patients suggests a role for genetic susceptibility. Currently, 12 candidate gene approach studies have been performed to identify polymorphisms predisposing to platinum-induced ototoxicity in children being treated for cancer. However, results were inconsistent and most studies were underpowered and/or lacked replication.

Objective

We describe the design of the PanCareLIFE consortium’s work packages that address the genetic susceptibility of platinum-induced ototoxicity.

Methods

As a part of the PanCareLIFE study within the framework of the PanCare consortium, we addressed genetic susceptibility of treatment-induced ototoxicity during and after childhood cancer treatment in a large European cohort by a candidate gene approach and a genome-wide association screening.

Results

This study included 1124 survivors treated with cisplatin, carboplatin, or cranial radiotherapy for childhood cancer, resulting in the largest clinical European cohort assembled for this late effect to date. Within this large cohort we defined a group of 598 cisplatin-treated childhood cancer patients not confounded by cranial radiotherapy. The PanCareLIFE initiative provided, for the first time, a unique opportunity to confirm already identified determinants for hearing impairment during childhood cancer using a candidate gene approach and set up the first international genome-wide association study of cisplatin-induced direct ototoxicity in childhood cancer patients to identify novel allelic variants. Results will be validated in an independent replication cohort. Patient recruitment started in January 2015 and final inclusion was October 2017. We are currently performing the analyses and the first results are expected by the end of 2019 or the beginning of 2020. 

Conclusions

Genetic factors identified as part of this pan-European project, PanCareLIFE, may contribute to future risk prediction models that can be incorporated in future clinical trials of platinum-based therapies for cancer and may help with the development of prevention strategies.

International Registered Report Identifier (IRRID)

DERR1-10.2196/11868

Asymmetric sensorineural hearing loss is a risk factor for late-onset hearing loss in pediatric cancer survivors following cisplatin treatment

BACKGROUND

Ototoxicity is a significant complication of cisplatin treatment. Hearing loss can be symmetric or asymmetric, and may decline after therapy. This study examined the risks of asymmetric and late-onset hearing loss (LOHL) in cisplatin-treated pediatric patients with cancer.

METHODS

A retrospective review of 993 patients' medical and audiological charts from August 1990 to March 2015 was conducted using stringent criteria to characterize patients with asymmetric hearing loss (AHL) or LOHL. Audiologic data were reviewed for 248 patients that received cisplatin to assess cisplatin-induced sensorineural hearing loss and its associated risk factors.

RESULTS

Of the patients evaluable for AHL, 26% exhibited this finding. Of those evaluable for LOHL, 42% of the patients' hearing worsened more than 6 months after therapy completion. Radiation and type of cancer diagnosis were major risk factors for both AHL and LOHL. Furthermore, LOHL was linked to age of diagnosis, noncranial radiation, and longer audiologic follow-up. AHL was strongly associated with LOHL-60% of patients with AHL also had LOHL. Logistic regression analysis revealed that patients with AHL (OR 6.3, 95% CI: 2.2-17.8, P = 0.0005) or those receiving radiation (OR 3.2, 95% CI: 1.2-8.6, P = 0.02) were at greatest risk for LOHL.

CONCLUSION

Children receiving cisplatin therapy are at risk for developing AHL and LOHL. Those that have received radiation and/or with AHL are at increased risk for further hearing decline. Long-term monitoring of these patients is important for early intervention as hearing diminishes.