Hearing loss in children with brain tumors treated with cisplatin and carboplatin-based high-dose chemotherapy with autologous bone marrow rescue

Ototoxicity of Carboplatin Delivered Locally in a Monkey Brainstem

Ototoxicity is a common side effect of platinum-based chemotherapy. Intratumoral drug delivery theoretically could reduce the ototoxic effects of systemic drug infusions. However, local delivery to central nervous system (CNS) tumors might promote ototoxicity through drug release into cerebrospinal fluid (CSF). This report describes an examination of the cytoarchitecture of vestibular cells of cynomolgus monkeys that had chronic brainstem infusions with the maximum tolerated dose (MTD) of carboplatin. The brainstems of adult monkeys were infused for 30 days at 0.42 μl/h with 0.025 to 0.25 mg/kg (MTD) of carboplatin. The vestibular sensory epithelia of eight drug-treated animals were isolated for microscopic examination of vestibular hair cells and support cells. Local infusions produced chronic elevated CSF levels of platinum, neurological symptoms, and radiographic evidence of pontine injury. Histology revealed significant cell damage at the infusion sites. Microscopic examinations of vestibular support cells and hair cells demonstrate a small reduction in cell counts in the drug-treated monkeys compared to a noninfused control animal. Parametric and nonparametric tests show no effect of dose in predicting the vestibular cell counts. In this single study of eight monkeys, a dose-dependent reduction of vestibular hair cells or support cells was not observed in animals infused with brainstem infusions of 0.025 to 0.25 mg/kg of carboplatin.

The Potential Benefit of Three vs. Six Cycles of Carboplatin, Etoposide, and Vincristine in Postenucleation High-Risk Patients with IRSS Stage I Retinoblastoma

PURPOSE

To compare the clinical effects of different cycles of carboplatin, etoposide, and vincristine (CEV) regimens of adjuvant chemotherapy in postenucleation high-risk patients with IRSS Stage I retinoblastoma (RB).

METHODS

A retrospective analysis of 53 RB patients hospitalized in the Zhongshan Ophthalmic Center of Sun Yat-sen University was performed. All patients had unilateral involvement, received enucleation treatment, were diagnosed as RB by pathology, and had high-risk pathological factors. Patients either refused postoperative chemotherapy or received three or six cycles of CEV regimen chemotherapy. The clinical information, treatment, and results of patients in all groups were compared.

RESULTS

A total of 19 cases refused postenucleation chemotherapy, 18 cases received three cycles, and 16 cases received six cycles of the CEV regimen chemotherapy. The 5-year disease-free survival rate and the overall survival (OS) rate in the chemotherapy group were higher than those in the non-chemotherapy group (97.1% vs. 63.2%, p = 0.001) and were not different between the three-cycle chemotherapy group and the six-cycle chemotherapy group (94.4% vs. 100%, p = 0.35).

CONCLUSION

After eye enucleation for patients with high-risk unilateral RB, the CEV regimen chemotherapy was associated with a higher survival rate. The three-cycle CEV regimen adjuvant chemotherapy was effective and is expected to replace the six-cycle CEV regimen chemotherapy.

Effect of Sensorineural Hearing Loss on Neurocognitive Functioning in Pediatric Brain Tumor Survivors

BACKGROUND

Intensified therapy with platinum-based regimens for pediatric brain tumors has dramatically increased the number of pediatric brain tumor survivors (PBTS) but frequently causes permanent sensorineural hearing loss (SNHL). Although neurocognitive decline in PBTS is known to be associated with radiation therapy (RT), SNHL represents a potential additional contributor whose long-term impact has yet to be fully determined.

METHODS

The neurocognitive impact of significant SNHL (Chang scale ≥ 2b) in PBTS was assessed through a retrospective cohort study of audiograms and neurocognitive testing. Scores for neurocognitive domains and subtest task performance were analyzed to identify specific strengths and weakness for PBTS with SNHL.

RESULTS

In a cohort of PBTS (n = 58) treated with platinum therapy, significant SNHL was identified in more than half (55%, n = 32/58), of which the majority required hearing aids (72%, 23/32). RT exposure was approximately evenly divided between those with and without SNHL. PBTS were 6.7 ± 0.6 and 11.3 ± 0.7 years old at diagnosis and neurocognitive testing, respectively. In multivariate analyses adjusted for RT dose, SNHL was independently associated with deficits in intelligence, executive function, and verbal reasoning skills. Subtests revealed PBTS with SNHL to have poor learning efficiency but intact memory and information acquisition.

CONCLUSIONS

SNHL in PBTS increases the risk for severe therapy-related intellectual and neurocognitive deficits. Additional prospective investigation in malignant brain tumors is necessary to validate these findings through integration of audiology and neurocognitive assessments and to identify appropriate strategies for neurocognitive screening and rehabilitation specific to PBTS with and without SNHL.

Late effects in survivors of childhood CNS tumors treated on Head Start I and II protocols

BACKGROUND

Due to the devastating late effects associated with cranial irradiation in young children with central nervous system (CNS) tumors, treatment for these patients has evolved to include the use of intensive chemotherapy to either avoid or postpone irradiation. While survival outcomes have improved, late effects data in survivors treated on such regimens are needed.

OBJECTIVE

This multi-institutional study comprehensively describes late effects in survivors treated on the Head Start I/II protocols.

METHODS

Survivors of CNS tumors treated on Head Start I/II protocols were enrolled. Late effects data were collected using a validated parent-report questionnaire. Social, emotional, and behavioral functioning and quality of life were assessed using parent-report on the BASC-2 and CHQ-PF50 questionnaires.

RESULTS

Twenty-one survivors (medulloblastoma = 13, sPNET = 4, ATRT = 1, ependymoma = 3) were enrolled. Ten (48%) were irradiation-free. Late effects (frequency; median time of onset since diagnosis) included ≥ grade III hearing loss (67%; 3.9 years), vision (67%; 4.1 years), hypothyroidism (33%; 4 years), growth hormone (GH) deficiency (48%; 4.7 years), dental (52%; 7.1 years), and no cases of secondary leukemia. Irradiation-free (vs. irradiated) survivors reported low rates of hypothyroidism (0/10 vs. 7/11; P = 0.004) and GH deficiency (2/10 vs. 8/11; P = 0.03). The BASC-2 and CHQPF-50 mean composite scores were within average ranges relative to healthy comparison norms. Neither age at diagnosis nor irradiation was associated with these scores.

CONCLUSIONS

Irradiation-free Head Start survivors have lower risk of hypothyroidism and GH deficiency. Secondary leukemias are not reported. With extended follow-up, survivors demonstrate quality of life, social, emotional, and behavioral functioning within average ranges.

Hearing loss among survivors of childhood brain tumors treated with an irradiation-sparing approach

BACKGROUND

Intensive, irradiation-sparing chemotherapy regimens for malignant brain tumors have improved survival and neurocognitive outcomes in very young children. Platinum compounds are pivotal to this approach's success but are associated with hearing loss that markedly reduces quality of life for survivors. The purpose of this study was to determine the prevalence and severity of ototoxicity associated with Head Start and similar irradiation-sparing regimens.

PROCEDURE

A retrospective cohort study was conducted of children treated for malignant brain tumors at Children's Hospital Los Angeles using irradiation-sparing regimens. Patient and treatment characteristics were ascertained. Primary outcomes were post-treatment hearing status, need for hearing aids, and hearing threshold change.

RESULTS

Twenty-nine patients were evaluable. The most common diagnosis was medulloblastoma (n = 14). The median age at diagnosis was 2.0 years (range, 0.2-9.2). Median time from diagnosis to most recent hearing assessment was 1.1 years (mean 2.4; range, 0.2-17.5). Cumulative cisplatin and carboplatin dose was 281 ± 88 mg/m(2) and 1,205 ± 277 mg/m(2) , respectively. All patients had aminoglycoside exposure. Following treatment, 18 patients (62.1%) had abnormal hearing and 11 (37.9%) required hearing aids. At 4,000 Hz, statistically significant hearing loss was documented in the range of 30-40 dB.

CONCLUSIONS

While eliminating cranial irradiation has dramatically improved survival and neurocognitive and neuroendocrine outcomes in this population, clinically significant hearing loss is now the leading late effect due to the necessity of platinum-based chemotherapy. Our results document the need for audiometric monitoring and developing otoprotective strategies in this vulnerable population.

Neuropsychological Outcomes of Children Treated for Posterior Fossa Tumours:A Review

The posterior fossa region of the brain is a frequent site for tumour development in children, with over half of all childhood tumours occurring at this site. The principal brain structure implicated at this site is the cerebellum. Children treated for posterior fossa tumours can have a wide range of neurological and psychosocial problems. This paper describes the literature to date that addresses the neuropsychological impact of tumour and treatment in children with posterior fossa tumours. This paper reviews the literature on the causes of morbidity in this group. It discusses the recent research on the role of the cerebellum in outcomes and the studies that identify variables that interact with radiation effects.

Distortion product otoacoustic emissions: An objective technique for the screening of hearing loss in children treated with platin derivatives

In order to develop a sensitive audiometric protocol for identifying ototoxicity in children, a retrospective study of 16 children treated with cisplatin and/or carboplatin was performed. Audiometric testing was done by means of pure-tone threshold audiometry (PTA), high-frequency audiometry (HFA), and distortion product otoacoustic emissions (DPOAEs). Cisplatin caused a sensorineural high-frequency hearing loss in the study group compared to the controls (p < 0.01). Sixty-six percent of the cisplatin patients had a grade 2 or 3 ototoxicity. However, ototoxicity was not found in the patients treated with carboplatin. An excellent correlation was found between DPOAE levels and results obtained by audiometry (r = 0.82). Patients exposed to cisplatin are at significant risk for the development of drug-induced sensorineural hearing loss. Because of the several advantages of DPOAEs (noninvasive, objective, rapid, easy to use, sensitive) this method should be added in the audiological follow-up in infants and toddlers.

Analysis of ototoxicity in young children receiving carboplatin in the context of conservative management of unilateral or bilateral retinoblastoma

BACKGROUND

Carboplatin plays an important role in the conservative management of retinoblastoma, but is associated with risk of ototoxicity in these young children whose sensory prognosis may be also compromised by their loss of vision. This retrospective study analyzed the impact of carboplatin on hearing in the context of conservative management of children with retinoblastoma.

METHODS

Data for 175 children treated at the Institut Curie between 1994 and 2002 were analyzed.

RESULTS

Median age at diagnosis was 8 months (0-60). Carboplatin was administered on 3 days (200 mg/m(2)/day) or 5 days (160 mg/m(2)/day) with etoposide and with diode-laser therapy at the dose of 560 mg/m(2) (chemothermotherapy). Median cumulative dose of carboplatin was 2,880 mg/m(2) (560-6,160). Ototoxicity was investigated by pure-tone audiometry and scored by Brock's grading scale before and after treatment. The median follow-up of hearing assessment was 5 years (1.8-11). Ototoxicity was detected in 8 children: 3 grade 1, 1 grade 2, and 2 grade 4. The two patients with grade 4 hearing-loss required a hearing aid. Two children developed bilateral high frequency hearing-loss, considered to be secondary to carboplatin but with less than Brock grade 1. Ototoxicity was observed for a median cumulative dose of carboplatin of 3,120 mg/m(2) (1,200-5,830). Only one child developed ototoxicity during treatment. All other cases were discovered after the last dose of carboplatin with a median interval of 3.7 years (0-7.6). No other risk factor for ototoxicity was able to account for these lesions.

CONCLUSION

Children receiving carboplatin require long-term audiometric follow-up.

Phase I Study of Weekly Oxaliplatin in Relapsed or Refractory Pediatric Solid Malignancies

Purpose

To explore feasibility, maximum-tolerated dose (MTD), and recommended dose (RD) for phase II studies of weekly oxaliplatin for the treatment of relapsed or refractory pediatric solid malignancies.

Patients and Methods

Eligible patients were 6 months to 21 years old, had a diagnosis of a solid malignancy, and had experienced treatment failure with at least two or more previous lines of therapy. The phase I study was multicentric, open-label, and nonrandomized. It foresaw two phases: a dose-escalation phase (comprising six levels) to find the RD and an extension at the RD to evaluate the cumulative toxicity. Oxaliplatin was administered intravenously over 2 hours on days 1, 8, and 15 of a 28-day cycle.

Results

Forty-five patients were enrolled: 29 patients in the dose-escalation phase and 16 patients in the extension at the RD. Median age was 9.5 years (range, 2.8 to 20.0 years) and 7.8 years (range, 1.8 to 19.2 years), respectively. The dose-limiting toxicities during the first treatment cycle were grade 3 (G3) sepsis at 50 mg/m2, G3 dysesthesia at 90 mg/m2, and G3 dysesthesia and G3 paresthesia at 110 mg/m2, thus the MTD and RD was 90 mg/m2. No case of ototoxicity was reported. Stable disease was reported in seven patients (16.3%), and confirmed partial response was observed in two patients (4.7%), one with neuroblastoma and one with osteosarcoma.

Conclusion

Oxaliplatin administered in a weekly schedule has an acceptable safety profile, different from cisplatin and carboplatin, and shows activity in children with relapsed or refractory solid tumors, suggesting further investigation in pediatric malignancies.

Hearing loss in pediatric oncology patients receiving carboplatin-containing regimens

Carboplatin is a well-established chemotherapeutic agent used to treat a variety of pediatric malignancies. Platinum analogues such as cisplatin are known to be ototoxic, but little is known regarding the ototoxicity of carboplatin. We performed a single institution retrospective chart review of pediatric oncology patients who received platinum-containing regimens from 1993 to 2002. Ninety-nine patients with sufficient medical and audiologic data were identified. Significant hearing loss was defined as a Brock grade 1 or higher. The incidence was compared among 3 treatment groups (carboplatin only, carboplatin and cisplatin, and cisplatin only). Significant hearing loss in patients receiving carboplatin only was rare, observed in only 1/25 (4%) of patients. In contrast, 19/27 (70%) of patients receiving carboplatin and cisplatin possessed significant hearing loss, as did 27/47 (57%) of those patients receiving cisplatin only P<0.001. The difference in hearing loss could not be explained by different cumulative exposures of the platinum agents. Carboplatin, when used without cisplatin, is rarely associated with severe hearing loss, even at high cumulative doses.

A retrospective review of hearing in children with retinoblastoma treated with carboplatin-based chemotherapy

BACKGROUND

Retinoblastoma occurs in approximately 4 per million children per year in the United States, usually before 2 years of age. In developed countries, 95% of children with tumor in one eye can be cured with enucleation, while children with tumor in both eyes require individualized therapy to preserve vision. Although enucleation and radiation are very effective therapies for children with bilateral disease, the resultant visual impairment, cosmetic deformity and risk for new tumors result in morbidity to these children who otherwise have a near normal lifespan. Therefore, since 1994, chemoreduction with vincristine, carboplatin, and etoposide combined with focal treatment, have been used successfully. However, a major concern with the use of carboplatin has been ototoxicity.

PROCEDURES

To determine whether carboplatin, in the doses and schedule used by us and others to treat retinoblastoma (18.6 mg/kg q 4 weeks for six cycles) results in hearing impairment, we reviewed the records of 248 children with retinoblastoma, 164 of whom had received carboplatin. Children generally received carboplatin, vincristine, and etoposide (CEV) for six cycles of chemotherapy.

RESULTS

Hearing evaluations prior to initiating therapy were abnormal in 14 patients (5.6%). No patients with normal initial audiograms were found to have abnormal studies following repeated evaluations.

CONCLUSION

While ototoxicity is a potential concern in this young patient population, carboplatin in the treatment of retinoblastoma does not appear to produce impairment. Screening can identify children who require frequent audiologic follow-up, but children whose hearing is normal prior to therapy do not require routine surveillance following six cycles of standard CEV therapy.

Intensive chemotherapy followed by consolidative myeloablative chemotherapy with autologous hematopoietic cell rescue (AuHCR) in young children with newly diagnosed supratentorial primitive neuroectodermal tumors (sPNETs): report of the Head Start I and II experience

BACKGROUND

Children with newly diagnosed supratentorial primitive neuroectodermal tumors (sPNET) have poor outcomes compared to medulloblastoma patients, despite similar treatments. In an effort to improve overall survival (OS) and event-free survival (EFS) and to decrease radiation exposure, the Head Start (HS) protocols treated children with newly diagnosed sPNET utilizing intensified induction chemotherapy (ICHT) followed by consolidation with myeloablative chemotherapy and autologous hematopoietic cell rescue (AuHCR).

PROCEDURES

Between 1991 and 2002, 43 children with sPNET were prospectively treated on two serial studies (HS I and II). After maximal safe surgical resection, patients on HS I and patients with localized disease on HS II were treated with five cycles of ICHT (vincristine, cisplatin, cyclophosphamide, and etoposide). Patients on HS II with disseminated disease received high-dose methotrexate during ICHT. If the disease remained stable or in response, patients received a single cycle of high-dose myeloablative chemotherapy followed by AuHCR.

RESULTS

Five-year EFS and OS were 39% (95%CI: 24%, 53%) and 49 (95%CI: 33%, 62%), respectively. Non-pineal sPNET patients faired significantly better than those patients with pineal sPNETs. Metastasis at diagnosis, age, and extent of resection were not significant prognostic factors. Sixty percent of survivors (12 of 20) are alive without exposure to radiation therapy.

CONCLUSIONS

ICHT followed by AuHCR in young patients with newly diagnosed sPNET appears to not only provide an improved EFS and OS for patients who typically have a poor prognosis, but also it successfully permitted deferral and elimination of radiation therapy in a significant proportion of patients.

Outcome for children <4 years of age with malignant central nervous system tumors treated with high-dose chemotherapy and autologous stem cell rescue

BACKGROUND

Children <4 years of age (yo) with malignant central nervous system (CNS) tumors have a dismal prognosis. In an attempt to delay or obviate radiation therapy (XRT) and improve outcome, our institution has treated children <4 yo with newly diagnosed malignant CNS tumors with high-dose chemotherapy (HDC) and autologous stem cell rescue (ASCR) followed by selective XRT.

PROCEDURE

Fifteen children (age 4-38 months) with malignant CNS tumors have completed treatment with HDC/ASCR. All patients received three cycles of induction chemotherapy (cisplatin 3.5 mg/kg- day 0, cyclophosphamide 60 mg/kg- day 1 and 2, etoposide 2.5 mg/kg- day 0-2, vincristine 0.05 mg/kg, day 0, 7, 14) followed by three cycles of HDC (carboplatin 17 mg/kg and thiotepa 6 mg/kg, day 0 and 1) with ASCR. Histology included five medulloblastomas, four primitive neuroectodermal tumors (PNET), five malignant gliomas, and one ependymoma. Outcome and treatment toxicities were evaluated by retrospective chart review.

RESULTS

Median follow-up time of the 15 patients is 22 months (range 8-82 months). The 1- and 2-year progression-free survival (PFS) is 86.1% and 52.2% and overall survival (OS) 91.6% and 72.1%, respectively. Ten patients are alive and disease free 3-77 months (median 18 months) after having completed HDC/ASCR, thereoff five received XRT. Toxicity was primarily myelosuppression. There was no treatment mortality.

CONCLUSIONS

We are encouraged by the outcome of 15 children <4 yo with malignant CNS tumors treated with tandem cycles of HDC and ASCR at our institution. The treatment regimen is relatively well tolerated.

Devastating effects of chemotherapy: deafness and acute renal failure in a patient with epithelial ovarian cancer

Paclitaxel and platinum combination is the standard chemotherapy regimen for patients with advanced epithelial ovarian cancer. The dose-limiting toxicity effects of this combination are myelosuppression and neuropathy. Herein, we report a case of a 71-year-old female with advanced epithelial ovarian cancer who developed bilateral total loss of hearing and acute renal failure related with paclitaxel- and carboplatin-based chemotherapy. Acute renal failure accompanied by complete loss of hearing in patients treated with carboplatin and paclitaxel combination has not been previously reported. This uncommon adverse effect of carboplatin and paclitaxel combination was discussed, and all the literature in English related with the toxicity of paclitaxel and carboplatin were reviewed.

Visual, auditory, sensory, and motor impairments in long-term survivors of hematopoietic stem cell transplantation performed in childhood: results from the Bone Marrow Transplant Survivor study

BACKGROUND

Because of treatment-related toxicity, research is increasingly being focused on long-term sequelae secondary to hematopoietic stem cell transplantation (HSCT) in survivor populations.

METHODS

This study describes the incidence of auditory, sensory, motor, and visual impairments, including cataracts, among 235 individuals who were treated with HSCT during childhood or adolescence. Outcomes were compared with 705 siblings of childhood cancer survivors. Participants completed a survey with questions on posttransplant organ system impairments. Approximately half of survivors were transplanted when younger than 10 years of age. The median length of followup was 11 years.

RESULTS

The cumulative incidence of cataracts was 36% at 15 years post-HSCT, although cataracts occurred only in those who received total body irradiation as an HSCT conditioning agent or head irradiation before transplant. Persistent pain was reported by 21% of survivors. Loss of hearing in one or both ears, and legal blindness in one or both eyes, each occurred after transplant in 2% of survivors. Occurrences were uncommon, but survivors were 4.3 times (95% confidence interval [CI]: 2.0-9.4) more likely to report coordination problems, 7.7 times (95% CI: 3.2-18.5) more likely to report chewing or swallowing problems, and 3.5 times (3.5; 95% CI: 1.6-7.9) more likely to report muscle weakness than those in the comparison group. Muscle weakness was strongly associated with positive history of chronic graft-versus-host disease.

CONCLUSIONS

Increased risks were found for motor impairments, hearing loss, vision loss, and persistent pain among study participants. Cataracts were a frequent adverse effect, suggesting that close monitoring with appropriate intervention for preservation of vision, particularly among those who received total body irradiation, should be a primary goal in survivors of HSCT performed in childhood.

Assessment of hearing in very young children receiving carboplatin for retinoblastoma

Children with retinoblastoma have increasingly been treated with carboplatin in the past decade. Ototoxicity is a known, possible, side-effect of carboplatin. Since retinoblastoma patients are very young and frequently have impaired vision, the evaluation of hearing loss is very important. The hearing status of 25 children with retinoblastoma treated with carboplatin (median cumulative dose 2,240 mg/m(2)) was evaluated in detail. Median age at first carboplatin administration was 7 months. The evaluation of hearing loss was performed by an age-appropriate measurement protocol consisting of tympanometry, otoacoustic emission measurements, auditory brainstem responses and (high-frequency) visual reinforcement audiometry (VRA) or play-audiometry. The median follow-up time after last carboplatin dose was 25 months (range 1-94 months). In none of the children was hearing loss detected after carboplatin administration. A measurement protocol that includes tympanometry, distortion product otoacoustic emission measurements and high-frequency VRA is recommended for young children receiving carboplatin or other ototoxic drugs.

Ototoxicity from high-dose use of platinum compounds in patients with neuroblastoma

BACKGROUND

The young age of neuroblastoma patients makes them especially prone to the ototoxic effects of widely used treatments that feature aggressive use of platinum compounds. We present data defining the extent of the problem in a large series of neuroblastoma patients whose induction included high-dose cisplatin/etoposide (HD-P/E) as used in both the Memorial Sloan-Kettering Cancer Center N7 regimen and the Children's Oncology Group A3973 study.

METHODS

N7/A3973 patients were divided into 3 groups: Group 1 had hearing tested after induction, that included 2 cycles of HD-P/E (cumulative cisplatin = 400 mg/m(2)); Group 2 had hearing tested after induction, that included 3 cycles of HD-P/E (cumulative cisplatin = 600 mg/m(2)); and Group 3 had hearing tested following carboplatin-containing myeloablative therapy administered after induction, that included 2 cycles of HD-P/E. Ototoxicity was scored by the Brock method.

RESULTS

All 3 groups had similar clinical characteristics, including median age at diagnosis of about 3 years. Little or no hearing loss in the speech range (Grade 0/1) was documented in 21 (32%) of the 65 Group 1 patients, 5 (10%) of the 50 Group 2 patients, and 9 (15.5%) of the 58 Group 3 patients. Severe (Grade 3/4) deficits affected 25% of Group 1, 54% of Group 2, and 50% of Group 3 patients. Patients < 5 years at diagnosis had greater ototoxicity than older patients had, with adolescents/adults being the least affected. Findings were stable in repeated assessments over 2 or more years.

CONCLUSIONS

Ototoxicity is a serious and pervasive problem in this patient population. Strategies to ameliorate ototoxicity without compromising on antitumor activity of treatments are urgently needed.

Amino acid concentrations in chinchilla cochlear nucleus at different times after carboplatin treatment

Amino acid concentrations were measured in the cochlear nucleus for a group of 20 chinchillas: four each of control and 4, 8, 29, and 85 days after treatment with the ototoxic anti-tumor drug carboplatin (100 mg/kg, i.p.). The treated chinchillas showed various extents of inner hair cell loss, generally more complete at longer survival times, but little loss of outer hair cells. Aspartate concentration in rostral anteroventral cochlear nucleus (AVCN) showed a decline to 28% less than the control value at 29 and 85 days after treatment, whereas glutamate concentration showed little change through 29 days, then dropped by 22% at 85 days after treatment. In caudal posteroventral cochlear nucleus (PVCN), the aspartate concentration decreased by 32% at 29 days, in animals with significant inner hair cell loss, and 48% at 85 days after treatment, while the glutamate concentration showed no decrease through 29 days and 40% decrease at 85 days. The concentration of gamma-aminobutyrate (GABA) was about 18% lower than control in caudal PVCN at all survival times. Significant correlations were found between the proportion of inner hair cells remaining and glutamate and aspartate concentrations in PVCN and AVCN, but not GABA or other amino acids.

Platinum Compound-Related Ototoxicity in Children: Long-Term Follow-Up Reveals Continuous Worsening of Hearing Loss

OBJECTIVES

The purpose of this study was to evaluate the severity of hearing loss after cisplatin and/or carboplatin treatment in young children and to analyze its evolution and its relation to different therapy schedules.

METHODS

One hundred twenty patients treated in the Pediatrics Department at the Institut Gustave-Roussy from 1987 to 1997 for neuroblastoma, osteosarcoma, hepatoblastoma, or germ cell tumors were analyzed. Median age at diagnosis was 2.6 (range 0-17) years. Median follow-up was 7 (1-13) years. Chemotherapy regimens contained cisplatin and/or carboplatin. Three patients also received high-dose carboplatin. Cisplatin was administered at a dose of 200 mg/m/course in 72% of cases. The median cumulative dose was 400 mg/m for cisplatin and 1,600 mg/m for carboplatin. Hearing loss of grade 2 or above, according to Brock's grading scale, was revealed with pure tone audiometry and behavioral techniques.

RESULTS

Carboplatin alone was not ototoxic. Deterioration of hearing of grade 2 or above was observed in 37% of patients treated with cisplatin and 43% of patients treated with cisplatin plus carboplatin (P = NS). Fifteen percent of patients experienced grade 3 or 4 ototoxicity. Ototoxicity was most often observed after a total cisplatin dose of at least 400 mg/m. No improvement was observed with time; on the contrary, worsening or progression of hearing loss at lower frequencies was detected during follow-up. Only 5% of audiograms showed toxicity of at least grade 2 before the end of therapy; in contrast, this level was observed in 11% of early post-therapy evaluations and in 44% after more than 2 years of follow-up.

CONCLUSIONS

Children treated with cisplatin at cumulative doses approaching 400 mg/m require long-term surveillance to avoid overlooking hearing deficits. Carboplatin, at a standard dose, does not appear to be a significant risk factor for ototoxicity even in patients who have already been treated with cisplatin.

Tobramycin Pharmacokinetics in Children with Febrile Neutropenia Undergoing Stem Cell Transplantation: Once-Daily versus Thrice-Daily Administration

STUDY OBJECTIVE

To describe the pharmacokinetic disposition of tobramycin in children undergoing stem cell transplantation (SCT) after intravenous administration either every 24 hours or every 8 hours, and to use this information to create initial dosing guidelines for administration every 24 hours in this patient population.

DESIGN

Pharmacokinetic analysis of a randomized controlled trial.

SETTING

The Hospital for Sick Children, Toronto, Ontario, Canada.

PATIENTS

Sixty children (< 18 yrs) with febrile neutropenia undergoing stem cell transplantation.

INTERVENTION

Patients were randomized to receive intravenous tobramycin either every 24 hours (29 patients) or every 8 hours (31 patients). Initially, they received either 2.5 mg/kg/dose every 8 hours or weight-based doses by age group (< 5 yrs, 9 mg/kg/dose; 5 to < 12 yrs, 8 mg/kg/dose; > or = 12 yrs, 7 mg/kg/dose) every 24 hours.

MEASUREMENTS AND MAIN RESULTS

Serum tobramycin concentrations were obtained at 2 and 8 hours after the first dose. Initial guidelines for dosing every 24 hours were derived using the parameters from all patients to achieve a maximum serum concentration (Cmax) of 20-22.5 mg/L and a drug-free interval (time during dosing interval when the tobramycin concentration was < 1 mg/L) of at least 4 hours. After the first tobramycin dose, the elimination rate constant (kel) and volume of distribution (Vd) observed in the every-8-hour group (23 patients) were 0.34 +/- 0.09 hours(-1) and 0.48 +/- 0.21 L/kg, respectively. The kel and Vd in the every-24-hour group (22 patients) were 0.43 +/- 0.12 hr(-1) and 0.43 +/- 0.26 L/kg, respectively. Tobramycin Vd varied with age. Initial doses of tobramycin every 24 hours recommended to achieve the target parameters are 10 mg/kg/dose for patients aged 6 months to less than 9 years, 8 mg/kg/dose for those aged 9 to less than 12 years, and 6 mg/kg/dose for those aged 12 years or older.

CONCLUSION

Children undergoing SCT who receive tobramycin every 24 hours should receive an initial dose based on age. Further validation of the proposed dosing guidelines is required.

Randomized controlled trial of once- versus thrice-daily tobramycin in febrile neutropenic children undergoing stem cell transplantation

BACKGROUND

The benefits of aminoglycoside antibiotics, such as tobramycin, administered as a once-daily dose to manage febrile neutropenia, have been demonstrated in many patient populations. However, toxicity and safety data are lacking for pediatric stem cell transplant recipients, who are at especially high risk for aminoglycoside-related toxicity and infectious morbidity. In particular, the relative nephrotoxicity and efficacy of tobramycin administered as a single daily dose or as three daily doses among this patient population is not known.

METHODS

We conducted a randomized, double-blind controlled study of tobramycin dosing among children 18 years or younger who had fever and neutropenia while undergoing stem cell transplantation. From October 2000 through November 2002, 60 children were randomly assigned to receive intravenous tobramycin, as either a single daily dose (n = 29) or every 8 hours (n = 31), in combination with either piperacillin or ceftazidime (intravenous). Tobramycin doses were adjusted to achieve pharmacokinetic targets. The primary outcome was nephrotoxicity, as represented by the maximal percent increase in serum creatinine concentration throughout the episode of febrile neutropenia relative to the baseline serum creatinine concentration. Efficacy was a secondary outcome and was defined as survival of the episode without modification of the antibacterial regimen. All statistical tests were two-sided.

RESULTS

In a modified intent-to-treat analysis, the mean maximal percent increase in serum creatinine concentration was 32% (N = 26) in the once daily dose group and 51% (N = 28) in the every 8 hours dose group (difference = 19%, 95% confidence interval [CI] = 0% to 38%; P =.054). Among patients evaluable for efficacy, 12 (46%) of 26 patients in the once daily dose group and five (19%) of 27 patients in the every 8 hours dose group survived the episode of febrile neutropenia without requiring antibacterial treatment modification (difference = 27%, 95% CI = 4% to 52%; P =.03). There was one death in each group.

CONCLUSIONS

In febrile neutropenic children undergoing stem cell transplantation, tobramycin may be less nephrotoxic and more efficacious when administered as a once daily dose than when administered every 8 hours.

Distortion product otoacoustic emissions test is useful in children undergoing cisplatin treatment

BACKGROUND

Cisplatin is a widely used chemotherapy agent that has several adverse effects, such as ototoxicity. Evaluation of hearing loss due to cisplatin therapy in children is difficult. The purpose of this study was to compare the validity of distortion product otoacoustic emissions (DPOAEs) with pure tone audiometry (PTA) in assessing hearing loss in children under cisplatin therapy.

METHODS

We reviewed the files of 26 children aged between 2 and 15 years; 14 were girls. All were under treatment with cisplatin for malignancy. PTA and DPOAEs were obtained at the same session. Three subjects were studied twice; thus, there were 29 sets of studies.

RESULTS

Determining a cut-off point at 45 dB HL for PTA and 4 dB SPL difference for DPOAEs, diagnostic specificity for the latter was 0.97 while sensitivity was 0.57.

CONCLUSIONS

DPOAEs represent a highly valuable test for evaluating hearing loss due to cisplatin treatment. DPOAEs is a quick and objective hearing assessment method not requiring much cooperation from children.

Round window application of D-methionine provides complete cisplatin otoprotection

OBJECTIVE

Cisplatin is a widely used, very effective chemotherapeutic agent that can cause severe ototoxicity. In this study, D-methionine was tested as an otoprotectant via round window membrane (RWM) application in the chinchilla.

METHODS

A minute amount of cisplatin alone, or D-methionine followed by cisplatin, was applied topically directly to the intact RWM of anesthetized adult chinchillas. Auditory brainstem responses were measured before and 1 week after topical round window application. Animals were killed, and the cochleas were examined.

RESULTS

The ears pretreated with D-methionine were completely protected from hearing loss and hair cell loss in the organ of Corti compared with controls. The ears receiving cisplatin without D-methionine protection sustained nearly complete hearing loss with threshold shifts of >60 dB, with extensive outer hair cell loss throughout the organ of Corti but particularly in the basal turn.

CONCLUSION

These results demonstrate that topical D-methionine provides excellent otoprotection against cisplatin-induced ototoxicity both electrophysiologically and structurally.

Effects of carboplatin on amino acid chemistry in chinchilla cochlear nucleus

Carboplatin, a drug widely used against solid head and neck tumors, selectively destroys cochlear inner hair cells and type I auditory nerve fibers in chinchilla. This should affect neurotransmitter chemistry, involving amino acids, where the type I auditory nerve fibers terminate in the cochlear nucleus. Using microdissection combined with high-performance liquid chromatography, amino acid concentrations were mapped in the cochlear nuclei of chinchillas injected intraperitoneally 6-8 weeks earlier with 100 mg/kg carboplatin and in those of control animals. Glutamate concentrations were 23% lower in the anteroventral cochlear nucleus (AVCN) and 40% lower in the posteroventral cochlear nucleus (PVCN) of carboplatin-injected chinchillas as compared to controls, while aspartate concentrations were 18% lower in AVCN and 27% lower in PVCN. Using a fluorometric assay, activities of glutaminase, an enzyme which catalyzes glutamate synthesis, were 30% lower in AVCN and 38% lower in PVCN of carboplatin-injected chinchillas. Concentrations of glutamine, gamma-aminobutyrate, and glycine were also lower in some ventral and dorsal cochlear nucleus regions of treated animals. These changes probably result mainly from both primary and later effects of reduced type I auditory nerve fiber input to the cochlear nucleus.

Feasibility of four consecutive high-dose chemotherapy cycles with stem-cell rescue for patients with newly diagnosed medulloblastoma or supratentorial primitive neuroectodermal tumor after craniospinal radiotherapy: results of a collaborative study

PURPOSE

This study was designed to determine the feasibility and safety of delivering four consecutive cycles of high-dose cyclophosphamide, cisplatin, and vincristine, each followed by stem-cell rescue, every 4 weeks, after completion of risk-adapted craniospinal irradiation to children with newly diagnosed medulloblastoma or supratentorial primitive neuroectodermal tumor (PNET).

PATIENTS AND METHODS

Fifty-three patients, 19 with high-risk disease and 34 with average-risk disease, were enrolled onto this study. After surgical resection, high-risk patients were treated with topotecan in a 6-week phase II window followed by craniospinal radiation therapy and four cycles of high-dose cyclophosphamide (4,000 mg/m2 per cycle), with cisplatin (75 mg/m2 per cycle), and vincristine (two 1.5-mg/m2 doses per cycle). Support with peripheral blood stem cells or bone marrow and with granulocyte colony-stimulating factor was administered after each cycle of high-dose chemotherapy. Treatment of average-risk patients consisted of surgical resection and craniospinal irradiation, followed by the same chemotherapy given to patients with high-risk disease. The expected duration of the chemotherapy was 16 weeks, with a cumulative cyclophosphamide dose of 16,000 mg/m2 and a planned dose-intensity of 1,000 mg/m2/wk.

RESULTS

Fifty of the 53 patients commenced high-dose chemotherapy, and 49 patients completed all four cycles. The median length of chemotherapy cycles one through four was 28, 27, 29, and 28 days, respectively. Engraftment occurred at a median of 14 to 15 days after infusion of stem cells or autologous bone marrow. The intended dose-intensity of cyclophosphamide was 1,000 mg/m2/wk; the median delivered dose-intensity was 1,014, 1,023, 974, and 991 mg/m2/wk for cycles 1 through 4, respectively; associated median relative dose-intensity was 101%, 102%, 97%, and 99%. No deaths were attributable to the toxic effects of high-dose chemotherapy. Early outcome analysis indicates a 2-year progression-free survival of 93.6% +/- 4.7% for the average-risk patients. For the high-risk patients, the 2-year progression-free survival is 73.7% +/- 10.5% from the start of therapy and 84.2% +/- 8.6% from the start of radiation therapy.

CONCLUSION

Administering four consecutive cycles of high-dose chemotherapy with stem-cell support after surgical resection and craniospinal irradiation is feasible in newly diagnosed patients with medulloblastoma/supratentorial PNET with aggressive supportive care. The early outcome results of this approach are very encouraging.

Ototoxicity after high-dose chemotherapy with cyclophosphamide, thiotepa and carboplatin followed by stem cell transplantation in patients with breast cancer

Our purpose was to determine the risk of ototoxicity in breast cancer patients receiving a myeloablative regimen consisting of cyclophosphamide 6000 mg/m2, thiotepa 500 mg/m2 and carboplatin 800 mg/m2 (CTCb) followed by stem cell transplantation. Fourteen consecutive patients with breast cancer were treated with high dose chemotherapy consisting of the CTCb regimen followed by stem cell transplantation. A pretransplant complete hearing study was obtained which consisted of hearing case history, audiometry and tympanometry. In addition, DPOAE (Distortion Product Otoaccoustic Emissions) was done to evaluate measurable changes in the cochlear (outer hair cell) functioning. Pre-transplant, all patients had no clinical evidence of hearing impairment and hearing studies were normal. Eleven patients had hearing studies and a telephone interview posttransplant. One patient was lost to follow-up and two patients died. One of the 11 patients tested had an abnormal post-transplant hearing study but none of them had clinically detectable hearing impairment. In our prospective study of breast cancer patients treated with the CTCb regimen, we did not observe clinically detectable hearing impairment in any of the patients tested.

Glutathione S-transferase genetic polymorphisms and individual sensitivity to the ototoxic effect of cisplatin

One of the side effects of cisplatin therapy in malignant neoplasms is ototoxicity. This effect shows a wide inter-individual range which is more variable than the pharmacokinetic parameters. Oxidative stress has been implicated in cisplatin ototoxicity. The glutathione S-transferase (GST) supergene family encodes isoenzymes that appear to be critical in protection against oxidative stress. Certain GST loci are polymorphic, demonstrating alleles that are null (GSTM1 and GSTT1), encode low-activity variants (GSTP1) or are associated with variable inducibility (GSTM3). The aim of our study was to investigate genetic risk factors involved in the ototoxicity of cisplatin and to determine whether the polymorphisms in five GST genes affect the individual risk of ototoxicity by cisplatin. Two groups of patients were analyzed in this study: group H, 20 patients early and highly sensitive to the ototoxicity of cisplatin; and group N, 19 patients with no hearing impairment under comparable doses of the drug. We found a protective effect for the GSTM3*B allele with a frequency of 0.18 in the group with normal hearing after therapy versus 0.025 in the group with hearing impairment. (chi2=5.37; p=0.02).

Intracochlear infusion of buthionine sulfoximine potentiates carboplatin ototoxicity in the chinchilla

The aim of this experiment was to determine if buthionine sulfoximine (BSO), an inhibitor of glutathione (GSH) synthesis, enhances the ototoxicity of carboplatin. Osmotic pumps were used to infuse BSO into the right cochleas of 12 adult chinchillas for 14 days. The left cochleas served as controls. Animals were assigned to three groups: a drug control group that did not receive carboplatin, a group that received a single dose of carboplatin (25 mg/kg i.p.), and a group that received a double dose of carboplatin (25 mg/kg i.p. x 2), with 4 days between injections. Carboplatin was administered after three days of BSO pre-treatment. Ototoxicity was assessed with evoked potentials recorded from electrodes implanted in the inferior colliculi (ICPs), distortion product otoacoustic emissions (DPOAEs), and cochleograms. BSO infusion itself caused no long-term functional or morphological changes. One of four animals treated with it single dose of carboplatin showed a significant loss of inner hair cells (IHCs), with greater loss in the BSO-treated ear. All animals in the double-dose carboplatin group showed marked differences between BSO-treated and control ears. Average IHC losses were 59% in BSO-treated ears vs. 18% in control ears. Moreover, BSO-treated ears sustained significantly greater outer hair cell (OHC) losses than control ears (37% vs. 2%, respectively). ICP and DPOAE response amplitudes were reduced slightly in BSO-treated ears relative to control ears, consistent with their greater hair cell loss. The results clearly show that BSO can enhance carboplatin ototoxicity in the chinchilla, supporting a role of GSH and reactive oxygen species in platinum ototoxicity.

The monitoring of potential long-term comlications in treated adult cancer patients

A wide variety of long-term complications may be noted following conventional cancer treatment. These include overwhelming postsplenectomy sepsis syndrome, central and peripheral nervous system toxicity, cardiovascular complications, chronic liver damage, and secondary malignancy. Follow-up monitoring usually incorporates both physical examination and the result of radiological and laboratory investigations. Primary care physicians will often be responsible for the majority of the follow-up monitoring involving cured cancer patients and need to be aware of possible long-term therapy-related problems, especially those that present years after successful treatment of the original malignancy.