Predicting cisplatin ototoxicity in children: the influence of age and the cumulative dose

Concordance between the chang and the International Society of Pediatric Oncology (SIOP) ototoxicity grading scales in patients treated with cisplatin for medulloblastoma

BACKGROUND

Reporting ototoxicity is frequently complicated by use of various ototoxicity criteria. The International Society of Pediatric Oncology (SIOP) ototoxicity grading scale was recently proposed for standardized use in reporting hearing loss outcomes across institutions. The aim of this study was to evaluate the concordance between the Chang and SIOP ototoxicity grading scales. Differences between the two scales were identified and the implications these differences may have in the clinical setting were discussed.

PROCEDURES

Audiological evaluations were reviewed for 379 patients with newly diagnosed medulloblastoma (ages 3-21 years). Each patient was enrolled on one of two St. Jude clinical protocols that included craniospinal radiation therapy and four courses of 75 mg/m(2) cisplatin chemotherapy. The latest audiogram conducted 5.5-24.5 months post-protocol treatment initiation was graded using the Chang and SIOP ototoxicity criteria. Clinically significant hearing loss was defined as Chang grade ≥2a and SIOP ≥2. Hearing loss was considered serious (requiring a hearing aid) at the level of Chang grade ≥2b and SIOP ≥3.

RESULTS

A strong concordance was observed between the Chang and SIOP ototoxicity scales (Stuart's tau-c statistic = 0.89, 95% CI: 0.86, 0.91). Among those patients diagnosed with serious hearing loss, the two scales were in good agreement. However, the scales deviated from one another in classifying patients with less serious or no hearing loss.

CONCLUSIONS

Although discrepancies between the Chang and SIOP ototoxicity scales exist primarily for patients with no or minimal hearing loss, the scales share a strong concordance overall.

Ototoxicity in children with high-risk neuroblastoma: prevalence, risk factors, and concordance of grading scales--a report from the Children's Oncology Group

PURPOSE

Platinum-based therapy is the mainstay for management of high-risk neuroblastoma. Prevalence of platinum-related ototoxicity has ranged from 13% to 95% in previous reports; variability is attributable to small samples and disparate grading scales. There is no consensus regarding optimal ototoxicity grading. Furthermore, prevalence and predictors of hearing loss in a large uniformly treated high-risk neuroblastoma population are unknown. We address these gaps in our study.

PATIENTS AND METHODS

Audiologic testing was completed after administration of cisplatin alone (< 400 mg/m(2); exposure one) or after cisplatin (400 mg/m(2)) plus carboplatin (1,700 mg/m(2); exposure two). Hearing loss was graded using four scales (American Speech-Language-Hearing Association; Brock; Chang; and Common Terminology Criteria for Adverse Events, version 3 [CTCAEv3]).

RESULTS

Of 489 eligible patients, 333 had evaluable audiologic data. Median age at diagnosis was 3.3 years. Prevalence of severe hearing loss differed by scale. For those in the exposure-one group, prevalence ranged from 8% per Brock to 47% per CTCAEv3 (Brock v CTCAEv3 and Chang, P < .01; CTCAEv3 v Chang, P = .16); for those in the exposure-two group, prevalence ranged from 30% per Brock to 71% per CTCAEv3 (all pair-wise comparisons, P < .01). In patients requiring hearing aids, hearing loss was graded as severe in 49% (Brock), 91% (Chang), and 100% (CTCAEv3). Risk factors for severe hearing loss included exposure to cisplatin and carboplatin compared with cisplatin alone and hospitalization for infection.

CONCLUSION

Severe hearing loss is prevalent among children with high-risk neuroblastoma. Exposure to cisplatin combined with myeloablative carboplatin significantly increases risk. The Brock scale underestimates severe hearing loss and should be used with caution in this setting.

Speech recognition and frequency of hearing loss in patients treated for cancer in childhood

BACKGROUND

The aim of this study was to characterize the audiological profile accompanying oncological treatment in patients who had cancer in childhood and had been free of oncological treatment for at least 8 years. Our main interest lay in identifying the affected frequencies that interfered with speech intelligibility (SI) in those who had acquired hearing loss after treatment.

PROCEDURE

Two hundred patients who had cancer in childhood were evaluated. Diagnosis was made at the mean age of 6 years old, and hearing evaluation was performed at a mean age of 21 years. Fifty-one of these patients received chemotherapy without cisplatin, carboplatin or head and neck radiotherapy; 64 received cisplatin without head and neck radiotherapy; 75 received head and neck radiotherapy without cisplatin; and 10 received both head and neck radiotherapy and cisplatin chemotherapy. All patients underwent pure tone audiometry and speech audiometry.

RESULTS

Patients who had hearing loss primarily had bilateral symmetric sensorineural hearing loss. Although the average SI for ears with hearing loss in the frequency range from 4 to 8 kHz was normal, the Kruskall-Wallis test showed a significant difference between ears without hearing loss and those with hearing loss between 4 and 8 kHz. The average SI score in ears with hearing loss between 1 and 8 kHz was significantly different from all other ears.

CONCLUSIONS

Hearing loss involving frequencies at and above 4 kHz determines a decline in SI.

The role of thiamine pyrophosphate in prevention of cisplatin ototoxicity in an animal model

Objective. The aim of this study was to evaluate the effectiveness of thiamine pyrophosphate against cisplatin-induced ototoxicity in guinea pigs. Materials and Methods. Healthy guinea pigs (n = 18) were randomly divided into three groups. Group 1 (n = 6) received an intraperitoneal injection of saline solution and cisplatin for 7 days, group 2 (n = 6) received an intraperitoneal injection of thiamine pyrophosphate and cisplatin for 7 days, and group 3 (n = 6) received only intraperitoneal injection of saline for 7 days. The animals in all groups were sacrificed under anesthesia, and their cochleas were harvested for morphological and biochemical observations. Results. In group 1, receiving only cisplatin, cochlear glutathione concentrations, superoxide dismutase, and glutathione peroxidase activities significantly decreased (P < 0.05) and malondialdehyde concentrations significantly increased (P < 0.05) compared to the control group. In group 2, receiving thiamine pyrophosphate and cisplatin, the concentrations of enzymes were near those of the control group. Microscopic examination showed that outer hair cells, spiral ganglion cells, and stria vascularis were preserved in group 2. Conclusion. Systemic administration of thiamine pyrophosphate yielded statistically significant protection to the cochlea of guinea pigs from cisplatin toxicity. Further experimental animal studies are essential to determine the appropriate indications of thiamine pyrophosphate before clinical use.

Replication of TPMT and ABCC3 genetic variants highly associated with cisplatin-induced hearing loss in children

Cisplatin is a widely used chemotherapeutic agent for the treatment of solid tumors. A serious complication of cisplatin treatment is permanent hearing loss. The aim of this study was to replicate previous genetic findings in an independent cohort of 155 pediatric patients. Associations were replicated for genetic variants in TPMT (rs12201199, P = 0.0013, odds ratio (OR) 6.1) and ABCC3 (rs1051640, P = 0.036, OR 1.8). A predictive model combining variants in TPMT, ABCC3, and COMT with clinical variables (patient age, vincristine treatment, germ-cell tumor, and cranial irradiation) significantly improved the prediction of hearing-loss development as compared with using clinical risk factors alone (area under the curve (AUC) 0.786 vs. 0.708, P = 0.00048). The novel combination of genetic and clinical factors predicted the risk of hearing loss with a sensitivity of 50.3% and a specificity of 92.7%. These findings provide evidence to support the importance of TPMT, COMT, and ABCC3 in the prediction of cisplatin-induced hearing loss in children.

Mechanisms of cisplatin ototoxicity: theoretical review

Introduction:

Cisplatin is an effective chemotherapeutic agent commonly used in the treatment of malignant tumours, but ototoxicity is a significant side effect.

Objectives:

To discuss the mechanisms of cisplatin ototoxicity and subsequent cell death, and to present the results of experimental studies.

Material and methods:

We conducted a systematic search for data published in national and international journals and books, using the Medline, SciELO, Bireme, LILACS and PubMed databases.

Results:

The nicotinamide adenine dinucleotide phosphate oxidase 3 isoform (also termed NOX3) seems to be the main source of reactive oxygen species in the cochlea. These reactive oxygen species react with other molecules and trigger processes such as lipid peroxidation of the plasma membrane and increases in expression of the transient vanilloid receptor potential 1 ion channel.

Conclusion:

Cisplatin ototoxicity proceeds via the formation of reactive oxygen species in cochlear tissue, with apoptotic cell death as a consequence.

Cisplatin-induced ototoxicity in pediatric solid tumors: the role of glutathione S-transferases and megalin genetic polymorphisms

Cisplatin-induced ototoxicity, an important dose-limiting side effect, has proven high interindividual variability. Glutathione S-transferases (GSTs) are isoenzymes involved in cellular detoxification processes. Megalin has been demonstrated to bind aminoglycosides, known to be similar to cisplatin for their ototoxicity. The GSTs and megalin expression is genetically polymorphic, which might be responsible for the variability in cisplatin-induced ototoxicity. The genotyping of GSTM1, GSTT1 polymorphisms, and 2 nonsynonymous single nucleotide polymorphisms (SNPs) at megalin genes, rs2075252 and rs2228171, were performed in 68 children diagnosed with solid tumors who received cisplatin-based chemotherapy. After the end of treatment, audiometry demonstrated hearing loss in 79.4% of patients according to Brock classification. The cumulative cisplatin dose >400 mg/m is associated with increased risk of cisplatin-induced ototoxicity [odds ratio (OR), 17.5; 95% confidence interval (CI), 3.09-98.62]. GSTT1 wild genotype and C-allele of rs2228171 SNPs of megalin gene occurred with higher frequency in patients with ototoxicity (P=0.023; OR, 10; 95% CI, 1.80-56.00 and P=0.034; OR, 2.67; 95% CI, 1.22-5.82, respectively). In conclusion, our results suggested that GSTT1 wild genotype and C-allele of rs2228171 SNPs might be risk factors for ototoxicity. The cumulative cisplatin dose <400 mg/m should be beneficial in order to ameliorate ototoxicity.

The mechanism of mesna in protection from cisplatin-induced ovarian damage in female rats

Objective

Cisplatin is a widely used chemotherapeutic agent in the treatment of cancers in clinic; but it often induces adverse effects on ovarian functions such as reduced fertility and premature menopause. Mesna could attenuate the cisplatin-induced ovarian damages; however, the underlying mechanism is still unknown. This study aimed to figure out the underlying mechanism of the protection of mesna for ovaries against cisplatin therapy in cancers.

Methods

We performed female adult Sprague-Dawley rats into normal saline control (NS), low-dose cisplatin (C_L), high-dose cisplatin (C_H), C_L plus mesna (C_L+M), and C_H plus mesna (C_H+M) groups and detected anti-Müllerian hormone (AMH)-positive follicle, oxidative stress status and anti-oxidative capability in ovaries.

Results

AMH-positive follicles were significantly decreased after cisplatin administration, which was significantly reversed when mesna was co-administered with cisplatin. The end product of lipid peroxidation, malondialdehyde (MDA), was significantly increased, but the anti-oxidative enzymatic activity of superoxide dismutase (SOD) and glutathione (GSH) were significantly decreased in cisplatin groups when compared with NS group. In contrast, after co-administration of cisplatin with mesna, MDA was significantly decreased whereas the activity of SOD and the concentration of GSH were increased. Moreover, mesna did not decrease the anti-tumor property of cisplatin in HePG2 cell lines.

Conclusion

Cisplatin damages the granulosa cells by oxidative stress to deplete the ovarian reserve and mesna could protect ovarian reserve through anti-oxidation. These results might highlight the mechanism of the protection of mesna for ovarian reserve and open an avenue for the application of mesna as a protective additive in cisplatin chemotherapy in clinical practise.

Glutathione S-transferase P1 single nucleotide polymorphism predicts permanent ototoxicity in children with medulloblastoma

BACKGROUND

Glutathione S-transferase (GST) enzymes are involved in detoxifying chemotherapy and clearing reactive oxygen species formed by radiation. We explored the relationship between the host GSTP1 105 A > G polymorphism (rs1695), tumor GSTpi protein expression, and clinical outcomes in pediatric medulloblastoma. We hypothesized that the GSTP1 105 G-allele and increased tumor GSTpi expression would be associated with lower progression-free survival and fewer adverse events.

PROCEDURE

The study included 106 medulloblastoma/primitive neuroectodermal tumor (PNET) patients seen at Texas Children's Cancer Center. Genotyping was performed using an Illumina HumanOmni1-Quad BeadChip and GSTpi expression was assessed using immunohistochemistry. We used the Kaplan-Meier method for survival analyses and logistic regression for toxicity comparisons.

RESULTS

Patients with a GSTP1 105 AG/GG genotype (vs. AA) or who had received high dose craniospinal radiation (≥34 Gy vs. <26 Gy) had a greater risk of requiring hearing aids than their counterparts (OR 4.0, 95% CI 1.2-13.6, and OR 3.1, 95% CI 1.1-8.8, respectively, n = 69). Additionally, there was a statistically significant interaction between these variables. Compared with the lowest risk group (GSTP1 105 AA-low dose radiation), patients with a GSTP1 105 AG/GG genotype who received high dose radiation were 8.4 times more likely to require hearing aids (95% CI 1.4-49.9, p-trend = 0.005, n = 69). When adjusted for age, cumulative cisplatin dose, and amifostine use, the association remained.

CONCLUSIONS

The GSTP1 105 G-allele is associated with permanent ototoxicity in pediatric medulloblastoma/PNET and strongly interacts with radiation dose. Patients with this allele should be considered for clinical trials employing radiation dose modifications and cytoprotectant strategies.

Is there a role for carboplatin in the treatment of malignant germ cell tumors? A systematic review of adult and pediatric trials

BACKGROUND

While cisplatin is considered superior to carboplatin for the treatment of malignant germ cell tumors (MGCTs) in adults, pediatric oncology collaborative groups still remain concerned about the late effects of cisplatin in children.

METHODS

We performed a literature search to identify randomized controlled trials (RCTs) that used carboplatin for MGCTs in adults. Since no RCTs were available in children, we identified cohort studies of pediatric MGCTs treated with carboplatin. We compared the adult and pediatric studies in terms of characteristics, doses of chemotherapy, and outcomes.

RESULTS

Of 2,131 publications retrieved, five RCTs in adults (1,340 patients) and four cohort studies in children (219 patients) met criteria for inclusion. All adult RCTs evaluated carboplatin versus cisplatin regimens in men with good-prognosis metastatic MGCTs. Carboplatin regimens had a higher risk of events (RR 2.51, P < 0.001) and of deaths (RR 2.21, P < 0.001) than cisplatin regimens. Across all five RCTs, 497/654 (76%) of adults who received carboplatin remained event-free. Compared to the adult trials, three pediatric studies used carboplatin at a higher dose, frequency, and number of cycles. Across these three studies, 158/179 (88%) of children remained event-free.

CONCLUSIONS

Cisplatin is superior to carboplatin at the studied doses for the treatment of adult metastatic MGCTs. However, we observe that carboplatin is associated with good outcomes for children with MGCT when used at the higher doses. We hypothesize that a risk-adapted approach utilizing both platinum agents may achieve the optimal balance between cure and late effects.

Cancer pharmacogenomics in children: research initiatives and progress to date

Over the last few decades, cure rates for pediatric cancer have increased dramatically, and now over 80 % of children with cancer are cured of their disease. This improvement in cure has come with a significant cost, with many children suffering irreversible, life-threatening, or long-lasting toxicities due to the medications required during their treatment. In the last 2 decades, major technological advances in genomics and the mapping of the human genome have made it possible to identify genetic differences between children in order to investigate differing responses to cancer therapy and to help explain why children treated with the same medications can have different outcomes. The emerging field of pharmacogenomics has had many important findings in pediatric cancer. The focus of this review is drug toxicity in pediatric cancer and the use of pharmacogenomics to reduce these adverse drug reactions, with a specific focus on thiopurines, methotrexate, cisplatin, vincristine and anthracyclines. Future areas of research and the need for international collaboration are discussed.

Protective role of bilberry extract against Cisplatin induced ototoxicity in rats

To investigate the potential preventive effect of bilberry extract in cisplatin-induced ototoxicity. Thirty-five 3-3.5-month healthy adult female Sprague-Dawley rats were randomly divided into three groups and treated as follows: Both, group 1 (n = 10) and group 2 (n = 15) subjects received a single dose of 12 mg/kg cisplatin intraperitoneally; while in group 2, bilberry extract was also administered via gavage feeding for 15 days. Group 3 (n = 10), received no cisplatin or bilberry extract. Baseline distortion product otoacoustic emissions testing were performed in all subjects prior to administration of any medication. The test was repeated at 15th day following administration of any medication. The distortion product otoacoustic emissions were evaluated at 1.5, 2, 3, 4, 5, 6, 7, 8, 10 and 12 kHz. Histopathological changes in the cochlea of rats were observed by light microscopy. There was no statistically significant difference in apical turn between three groups but there was a statistically significant difference in basal and mid turn external ciliated cells number. Stria vascularis changes were statistically significant between three groups. The median score for stria vascularis injury and spiral ganglion cells changes were significantly greater in group 1 than in group 2. The initial distortion product otoacoustic emissions measurement results gave similar statistically insignificant values in the three groups (p > 0.05). In contrast to initial measurements statistically significant differences were recorded between day 0 and 15 otoacoustic thresholds (p < 0.05). Bilberry extract group had a significantly higher DP-gram except for 1.5 and 2 kHz frequencies when compared to cisplatin group. The analyses of the results revealed statistically significant differences between two groups (p < 0.05), suggesting that bilberry extract had shown a protective effect against cisplatin ototoxicity. The results of our study revealed that treatment with bilberry extract affords significant protection to the cochlea from cisplatin toxicity and thus, oral experimental dose of bilberry extract administration may have a protective effect against cisplatin ototoxicity in rats.

The use of high-frequency audiometry increases the diagnosis of asymptomatic hearing loss in pediatric patients treated with cisplatin-based chemotherapy

BACKGROUND

Cisplatin may cause permanent cochlear damage by changing cochlear frequency selectivity and can lead to irreversible sensorineural hearing loss. High-frequency audiometry (HFA) is able to assess hearing frequencies above 8,000 Hz; hence, it has been considered a high-quality method to monitor and diagnose early and asymptomatic signs of ototoxicity in patients receiving cisplatin.

PROCEDURE

Forty-two pediatric patients were evaluated for hearing loss induced by cisplatin utilizing HFA, and its diagnostic efficacy was compared to that of standard pure-tone audiometry and distortion-product otoacoustic emissions (DPOAEs). The patient population consisted of those who signed an informed consent form and had received cisplatin chemotherapy between 1991 and 2008 at the Hospital de Clínicas de Porto Alegre Pediatric Unit, Brazil.

RESULTS

Forty-two patients were evaluated. The median age at study assessment was 14.5 years (range 4-37 years). Hearing loss was detected in 24 patients (57%) at conventional frequencies. Alterations of DPOAEs were found in 64% of evaluated patients and hearing loss was observed in 36 patients (86%) when high-frequency test was added. The mean cisplatin dose was significantly higher (P = 0.046) for patients with hearing impairment at conventional frequencies.

CONCLUSION

The results suggest that HFA is more effective than pure-tone audiometry and DPOAEs in detecting hearing loss, particularly at higher frequencies. It may be a useful tool for testing new otoprotective agents, beside serving as an early diagnostic method for detecting hearing impairment.

Ten challenges in the management of neuroblastoma

Neuroblastoma is a complex disease with many contradictions and challenges. It is, by and large, a cancer of babies and preschool children, but it does occur, albeit increasingly rarely, in older children, adolescents and young adults. The prognosis is very variable, with outcome related to age, stage and molecular pathology. Neuroblastoma may behave in an almost benign way, with spontaneous regression in some infants, but the majority of older patients have high-risk disease, which is usually fatal, despite best current treatments. As a rare disease, international collaboration is essential to run clinical trials of adequate statistical power to answer important questions in a reasonable time frame. High-risk disease requires multimodality therapy including chemotherapy, surgery and radiotherapy as well as biological and immunological treatments for optimal outcomes. Innovative treatment approaches, sometimes associated with appreciable toxicity, offer hope for the future but, despite parental wishes, cannot be generally implemented without adequate assessment in clinical trials.

Early cisplatin induced ototoxicity profile may predict the need for hearing support in children with medulloblastoma

BACKGROUND

Cisplatin (CDDP) ototoxicity is a significant side effect of the current treatment of medulloblastoma (MB). Cumulative dose of CDDP and age are recognized risk factors for hearing loss, but inter-individual susceptibility limits our ability to identify patients at risk for hearing loss. We describe the kinetics of early audiometric changes during therapy and identify profiles associated with a higher risk of needing hearing aids.

PROCEDURE

Serial audiometric evaluations were performed during and after completion of therapy in children with average risk (AR) and high-risk (HR) MB. Each audiogram was scored according to five grading systems. Variations of pure tone thresholds were analyzed at each frequency for each consecutive audiogram. CDDP dose modifications and hearing outcome were recorded.

RESULTS

A total of 258 audiograms from 35 patients (22 AR, 13 HR) were analyzed. Eighteen AR patients (81.3%) required dose reduction and the median cumulative dose of CDDP administered was 412.5 mg/m(2) (150-600), corresponding to 68% of the intended dose. Three HR patients (23.0%) required dose reduction. At a median follow-up of 67 months (11-117), nine patients (25.7%) required hearing support: After two cycles of CDDP (150 mg/m(2) ), the average hearing loss at 8,000 Hz was twice higher in the group that eventually required hearing support.

CONCLUSION

Early alteration of high-frequency thresholds may help identify individuals who will require hearing support. In the MB population, alternative strategies should be developed to limit the cumulative dose of CDDP to prevent significant ototoxicity.

Prospective evaluation of cisplatin- and carboplatin-mediated ototoxicity in paediatric and adult soft tissue and osteosarcoma patients

Platinum-compound chemotherapy is known to have ototoxic side-effects. However, there is a paucity of literature examining hearing function prospectively and longitudinally in cohorts containing paediatric and adult patients treated within the same cisplatin- or carboplatin-containing treatment trial protocols. In Germany, Austria and Switzerland, late effects of treatment for osteosarcoma and soft tissue sarcoma have been prospectively and longitudinally registered by the Late Effects Surveillance System since 1998. The aim of this study was to analyse cisplatin- and carboplatin-induced ototoxity in a group of 129 osteosarcoma and soft tissue sarcoma patients treated within the COSS-96, CWS-96 and CWS-2002P treatment trials. The cohort consisted of 112 children and 17 adults. The median age at diagnosis was 13.56 (IQR, 10.26-16.27) years. Follow-up was 6.97 (IQR, 0.87-15.63) months. Hearing function was examined by audiometry before and after platinum treatment. A total of 108 patients were treated with cisplatin with a median cumulative dose of 360 mg/m(2). Thirteen patients received carboplatin with a median cumulative dose of 1500 mg/m(2) and 8 patients were treated with both platinum compounds (median cisplatin dose, 240 mg/m(2); IQR, 240-360 mg/m(2) and median carboplatin dose: 1200 mg/m(2); IQR, 600-3000 mg/m(2)). Following cessation of therapy, 47.3% of the patients demonstrated a hearing impairment, namely 55 children (49.1%) and 6 adults (42.1%). Out of thirteen children treated with carboplatin with a cumulative dose of 1500 mg/m(2), six revealed a significant hearing impairment. Although ototoxicity caused by platinum compounds is considered irreversible, we identified hearing improvements over time in 11 children (9.8%) and 3 adults (17.6%). None of these patients received irradiation to the head. We conclude that hearing loss is frequent in children treated with protocols containing platinum compounds and recommend prospective testing via audiometry.

Yield of screening for long-term complications using the children's oncology group long-term follow-up guidelines

PURPOSE

The Children's Oncology Group Long-Term Follow-Up (COG-LTFU) Guidelines use consensus-based recommendations for exposure-driven, risk-based screening for early detection of long-term complications in childhood cancer survivors. However, the yield from these recommendations is not known.

METHODS

Survivors underwent COG-LTFU Guideline-directed screening. Yield was classified as negligible/negative (< 1%), intermediate (≥ 1% to < 10%), or high (≥ 10%). For long-term complications with high yield, logistic regression was used to identify subgroups more likely to screen positive.

RESULTS

Over the course of 1,188 clinic visits, 370 childhood cancer survivors (53% male; 47% Hispanic; 69% leukemia/lymphoma survivors; median age at diagnosis, 11.1 years [range, 0.3 to 21.9 years]; time from diagnosis, 10.5 years [range, 5 to 55.8 years]) underwent 4,992 screening tests. High-yield tests included thyroid function (hypothyroidism, 10.1%), audiometry (hearing loss, 22.6%), dual-energy x-ray absorptiometry scans (low bone mineral density [BMD], 23.2%), serum ferritin (iron overload, 24.0%), and pulmonary function testing/chest x-ray (pulmonary dysfunction, 84.1%). Regression analysis failed to identify subgroups more likely to result in high screening yield, with the exception of low BMD (2.5-fold increased risk for males [P = .04]; 3.3-fold increased risk for nonobese survivors [P = .01]). Screening tests with negligible/negative (< 1%) yield included complete blood counts (therapy-related leukemia), dipstick urinalysis for proteinuria and serum blood urea nitrogen/creatinine (glomerular defects), microscopic urinalysis for hematuria (hemorrhagic cystitis, bladder cancer), ECG (anthracycline-related conduction disorder), and hepatitis B and HIV serology.

CONCLUSION

Screening tests with a high yield are appropriate for risk groups targeted for screening by the COG-LTFU Guidelines. Elimination of screening tests with negligible/negative yield should be given consideration.

Survival trends and long-term toxicity in pediatric patients with osteosarcoma

Background. This study was conducted to investigate the clinical characteristics and treatment results of osteosarcoma in pediatric patients during the past 30 years. Trends in survival rates and long-term toxicity were analyzed. Procedure. 130 pediatric patients under the age of 20 years with primary localized or metastatic high-grade osteosarcoma were analyzed regarding demographic, treatment-related variables, long-term toxicity, and survival data. Results. Comparison of the different time periods of treatment showed that the 5-year OS improved from 58.6% for children diagnosed during 1979–1983 to 78.6% for those diagnosed during 2003–2008 (P = 0.13). Interestingly, the basic treatment agents including cisplatin, doxorubicin, and methotrexate remained the same. Treatment reduction due to acute toxicity was less frequent in patients treated in the last era (7.1% versus 24.1% in patients treated in 1979–1983; P = 0.04). Furthermore, late cardiac effects and secondary malignancies can become evident many years after treatment. Conclusion. We elucidate the prevalence of toxicity to therapy of patients with osteosarcoma over the past 30 years. The overall improvement in survival may in part be attributed to improved supportive care allowing regimens to be administered to best advantage with higher tolerance of chemotherapy and therefore less chemotherapy-related toxicity.

Utilisation of nanoparticle technology in cancer chemoresistance

The implementation of cytotoxic chemotherapeutic drugs in the fight against cancer has played an invariably essential role for minimizing the extent of tumour progression and/or metastases in the patient and thus allowing for longer event free survival periods following chemotherapy. However, such therapeutics are nonspecific and bring with them dose-dependent cumulative adverse effects which can severely exacerbate patient suffering. In addition, the emergence of innate and/or acquired chemoresistance to the exposed cytotoxic agents undoubtedly serves to thwart effective clinical efficacy of chemotherapy in the cancer patient. The advent of nanotechnology has led to the development of a myriad of nanoparticle-based strategies with the specific goal to overcome such therapeutic hurdles in multiple cancer conditions. This paper aims to provide a brief overview and recollection of all the latest advances in the last few years concerning the application of nanoparticle technology to enhance the safe and effective delivery of chemotherapeutic agents to the tumour site, together with providing possible solutions to circumvent cancer chemoresistance in the clinical setting.

Time-frequency analysis of transient-evoked otoacoustic emissions in children exposed to carboplatin chemotherapy

The aims of this study were to characterize and quantify time-frequency changes in transient-evoked otoacoustic emissions (TEOAEs) recorded in children diagnosed with retinoblastoma who were receiving carboplatin chemotherapy. A signal processing technique, the wavelet transform (WT), was used to analyze TEOAE waveforms in narrow-band frequency components. Ten children (aged 3-72 months) diagnosed with unilateral or bilateral retinoblastoma were enrolled in the study. TEOAEs were acquired from the children with linear sequences of 70 dB peak equivalent SPL clicks. After WT analysis, TEOAE energy, latency and normalized energy in the narrow-band frequency components were compared before and during carboplatin chemotherapy treatment (average dose 1693 mg/m2). On a group basis, no significant differences (p>0.05) in the TEOAE energy, latency or normalized energy before and after carboplatin treatment were observed. There were decreases in normalized energy on an individual basis in 10 out of 18 ears in the sample. Exposure to carboplatin chemotherapy did not cause significant changes in TEOAE energy, latency and normalized energy during treatment. However, long-term monitoring of hearing with measurements of TEOAEs is warranted, given the risks of delayed hearing loss in some children receiving carboplatin chemotherapy.

"Accelerated ear-age": a new measure of chemotherapy-induced ototoxicity

Currently, there are several different scales that grade chemotherapy-induced ototoxicity. This report highlights how the implications of the conclusions drawn from each scale differ and compare these prior scales to a more functionally based scale developed at Children's Hospital Boston. Additionally, this report introduces the concept of "ear-age," akin to the age at which one would expect the observed decrease in hearing as a consequence of normative aging (but documented in a child or young adult following chemotherapy).

Cisplatin and aminoglycoside antibiotics: hearing loss and its prevention

This review introduces the pathology of aminoglycoside antibiotic and the cisplatin chemotherapy classes of drugs, discusses oxidative stress in the inner ear as a primary trigger for cell damage, and delineates the ensuing cell death pathways. Among potentially ototoxic (damaging the inner ear) therapeutics, the platinum-based anticancer drugs and the aminoglycoside antibiotics are of critical clinical importance. Both drugs cause sensorineural hearing loss in patients, a side effect that can be reproduced in experimental animals. Hearing loss is reflected primarily in damage to outer hair cells, beginning in the basal turn of the cochlea. In addition, aminoglycosides might affect the vestibular system while cisplatin seems to have a much lower likelihood to do so. Finally, based on an understanding the mechanisms of ototoxicity pharmaceutical ways of protection of the cochlea are presented.

New ways to detect adverse drug reactions in pediatrics

Adverse drug reactions (ADRs) complicate at least 5% of all courses of therapy for children. Dealing with an ADR requires a stepwise approach in appreciation of the possibility of an ADR, assessment of whether the adverse event in question is drug-related, assessment of causality, assistance in treating the symptoms of the ADR, and dealing with the aftermath of the event. Several new developments likely will improve the ability to assess, evaluate, treat, and prevent ADRs in children. These developments include tools to evaluate causality, laboratory tests to diagnose ADRs, pharmacogenomic approaches to prevent ADRs, and new insights into treating serious ADRs.

Risk factors for cisplatin-associated ototoxicity in pediatric oncology patients

BACKGROUND

Cisplatin is an effective chemotherapy agent against several pediatric malignancies. One of its side effects is irreversible sensorineural hearing damage that is highly variable with a reported incidence of 22-70%. The aim of this study was to evaluate the incidence and identify clinical predictors of cisplatin-related ototoxicity.

PROCEDURES

We performed a retrospective chart review of 102 pediatric patients who had completed cisplatin therapy for osteosarcoma, neuroblastoma, hepatoblastoma, or germ cell tumor. Patients were diagnosed at Riley Hospital for Children between January 1995 and June 2008, were less than 18 years old at diagnosis, and had normal hearing prior to therapy. Audiograms were scored using the Brock scale (0-4), a validated grading system for cisplatin-related hearing loss.

RESULTS

Forty-two percent of the patients experienced hearing loss and 28% had moderate to severe ototoxicity (Brock score ≥2). Males were at significantly greater risk for developing hearing loss than were females (P = 0.005, OR 4.812). Age at cancer diagnosis was inversely related to severity of ototoxicity. Patients who suffered Brock grade 3 ototoxicity had a mean age of 4.5 years versus 11.5 years and 7.2 years for grades 1 and 2, respectively (P = 0.02). Cumulative cisplatin dose was also identified as a risk factor for development of ototoxicity (P = 0.03).

CONCLUSIONS

Gender and cumulative dose are important clinical biomarkers of cisplatin ototoxicity. Severity of ototoxicity may be inversely related to age at time of exposure, with very young patients exhibiting higher grades of hearing loss following cisplatin therapy.

Development and validation of a cisplatin dose-ototoxicity model

BACKGROUND

Cisplatin is effective in the treatment of several cancers but is a known ototoxin resulting in shifts to hearing sensitivity in up to 50-60% of patients. Cisplatin-induced hearing shifts tend to occur first within an octave of a patient's high frequency hearing limit, termed the sensitive range for ototoxicity (SRO), and progress to lower frequencies. While it is currently not possible to know which patients will experience ototoxicity without testing their hearing directly, monitoring the SRO provides an early indication of damage. A tool to help forecast susceptibility to ototoxic-induced changes in the SRO in advance of each chemotherapy treatment visit may prove useful for ototoxicity monitoring efforts, patient counseling, and therapeutic planning.

PURPOSE

This project was designed to (1) establish pretreatment risk curves that quantify the probability that a new patient will suffer hearing loss within the SRO during treatment with cisplatin and (2) evaluate the accuracy of these predictions in an independent sample of Veterans receiving cisplatin for the treatment of cancer.

STUDY SAMPLE

Two study samples were used. The Developmental sample contained 23 subjects while the Validation sample consisted of 12 subjects.

DATA COLLECTION AND ANALYSIS

Risk curve predictions for SRO threshold shifts following cisplatin exposure were developed using a Developmental sample comprised of data from a total of 155 treatment visits obtained in 45 ears of 23 Veterans. Pure-tone thresholds were obtained within each subject's SRO at each treatment visit and compared with baseline measures. The risk of incurring an SRO shift was statistically modeled as a function of factors related to chemotherapy treatment (cisplatin dose, radiation treatment, doublet medication) and patient status (age, pre-exposure hearing, cancer location and stage). The model was reduced so that only statistically significant variables were included. Receiver-operating characteristic (ROC) curve analyses were then used to determine the accuracy of the risk curve predictions in an independent Validation sample of observations from over 62 treatment visits obtained in 24 ears of 12 Veterans.

RESULTS

Only cumulative cisplatin dose and pre-exposure hearing were found to be significantly related to the risk for hearing shift. The dose-ototoxicity risk curve predictions developed from the Developmental sample yielded area under the ROC curve accuracy estimates of 0.85 when applied to an independent Validation sample.

CONCLUSIONS

Cumulative cisplatin dose in combination with pre-exposure hearing provides an indication of whether hearing will shift in the SRO in advance of cisplatin administration. The validated dose-ototoxicity risk curves described herein can be used before and during treatment to anticipate hearing loss. While having such a tool would not replace serial hearing testing, it would be of great benefit to an ototoxicity monitoring program. It would promote relevant pretreatment counseling. Furthermore, for those found to be at risk of SRO shifts within the speech frequencies, the oncology treatment plan could incorporate anticipated dosing adjustments that could stave off the impact that ototoxicity might bring.

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.

Medical interventions for the prevention of platinum-induced hearing loss in children with cancer

BACKGROUND

Platinum-based therapy, including cisplatin, carboplatin and/or oxaliplatin, is used to treat a variety of paediatric malignancies. Unfortunately, one of the most important adverse effects is the occurrence of hearing loss or ototoxicity. In an effort to prevent this ototoxicity, different otoprotective medical interventions have been studied.

OBJECTIVES

The primary objective was to assess the efficacy of different otoprotective medical interventions in preventing hearing loss in children with cancer treated with platinum-based therapy. Secondary objectives were to determine possible effects of these interventions on anti-tumour efficacy, toxicities other than hearing loss and quality of life.

SEARCH METHODS

We searched the electronic databases Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2011, Issue 4), MEDLINE (PubMed) (1945 to 22 December 2011) and EMBASE (Ovid) (1980 to 22 December 2011). In addition, we handsearched reference lists of relevant articles and the conference proceedings of the International Society for Paediatric Oncology (2006 to 2011), the American Society of Pediatric Hematology/Oncology (2007 to 2011) and the International Conference on Long-Term Complications of Treatment of Children and Adolescents for Cancer (2010). We scanned the International Standard Randomized Controlled Trial Number (ISRCTN) Register and the National Institute of Health Register for ongoing trials (www.controlled-trials.com) (searched on 20 December 2011).

SELECTION CRITERIA

Randomized controlled trials (RCTs) or controlled clinical trials (CCTs) evaluating platinum-based therapy together with an otoprotective medical intervention versus platinum-based therapy with placebo, no additional treatment or another protective medical intervention in children with cancer.

DATA COLLECTION AND ANALYSIS

Two review authors independently performed the study selection, risk of bias assessment of included studies and data extraction, including adverse effects. Analyses were performed according to the guidelines of the Cochrane Handbook for Systematic Reviews of Interventions.

MAIN RESULTS

We identified two RCTs and one CCT (total number of patients 149) evaluating the use of amifostine versus no additional treatment. Two studies included children with osteosarcoma, the other study included children with hepatoblastoma. Patients received cisplatin only or a combination of cisplatin and carboplatin, either administered intra-arterially or intravenously. All studies had methodological limitations. Unfortunately, pooling of the results of included studies was not possible. However, in all individual studies no significant difference was identified in symptomatic ototoxicity only (that is grade 2 or higher) and combined asymptomatic and symptomatic ototoxicity (that is grade 1 or higher) between children treated with or without amifostine. Only one study, including children with osteosarcoma treated with intra-arterial cisplatin, provided information on tumour response, defined as the number of patients with a good or partial remission. The 'available data' analysis (data were missing for one patient), 'best case scenario' analysis and 'worst case scenario' analysis all showed a difference in favour of amifostine, but this difference was significant only in the 'worst case scenario' analysis (P = 0.04). No information on survival was available for any of the included study populations. Only one study, including children with osteosarcoma treated with intra-arterial cisplatin, provided data on the number of patients with adverse effects other than ototoxicity grade 3 or higher. There was a significant difference in favour of the control group in the occurrence of vomiting grade 3 or 4 (RR 9.04; 95% CI 1.99 to 41.12; P = 0.004). No significant difference was identified between treatment groups for cardiotoxicity and renal toxicity grade 3 or 4. None of the studies evaluated quality of life. No eligible studies were found for possible otoprotective medical interventions other than amifostine and other types of malignancies.

AUTHORS' CONCLUSIONS

At the moment there is no evidence from individual studies in children with osteosarcoma and hepatoblastoma treated with different platinum analogues and dosage schedules which underscores the use of amifostine as an otoprotective intervention as compared to no additional treatment. Since pooling of results was not possible and all studies had serious methodological limitations, no definitive conclusions can be made. It should be noted that 'no evidence of effect', as identified in this review, is not the same as 'evidence of no effect'. Based on the currently available evidence, we are not able to give recommendations for clinical practice. For other possible otoprotective medical interventions and other types of malignancies no eligible studies were identified, so no conclusions can be made about their efficacy in preventing ototoxicity in children treated with platinum-based therapy. More high quality research is needed.

Using germline genomics to individualize pediatric cancer treatments

The amazing successes in cure rates for children with cancer over the last century have come in large part from identifying clinical, genetic, and molecular variables associated with response to therapy in large cooperative clinical trials and stratifying therapies according to the predicted risk of relapse. There is an expanding interest in identifying germline genomic variants, as opposed to genetic variants within the tumor, that are associated with susceptibility to toxicity and for risk of relapse. This review highlights the most important germline pharmacogenetic and pharmacogenomic studies in pediatric oncology. Incorporating germline genomics into risk-adapted therapies will likely lead to safer and more effective treatments for children with cancer.

siRNA-mediated knock-down of NOX3: therapy for hearing loss?

Cisplatin is a widely used chemotherapeutic agent that causes significant hearing loss. Previous studies have shown that cisplatin exposure is associated with increase in reactive oxygen species (ROS) in the cochlea. The inner ear expresses a unique isoform of NADPH oxidase, NOX3. This enzyme may be the primary source of ROS generation in the cochlea. The knockdown of NOX3 by pretreatment with siRNA prevented cisplatin ototoxicity, as demonstrated by preservation of hearing thresholds and inner ear sensory cells. Trans-tympanic NOX3 siRNA reduced the expression of NOX3 and biomarkers of cochlear damage, including transient receptor vanilloid 1 (TRPV1) channel and kidney injury molecule-1 (KIM-1) in cochlear tissues. In addition, siRNA against NOX3 reduced apoptosis as demonstrated by TUNEL staining, and prevented the increased expression of Bax and abrogated the decrease in Bcl2 expression following cisplatin administration. Trans-tympanic administration of siRNA directed against NOX3 may provide a useful method of attenuating cisplatin ototoxicity. In this paper, we review recent publications dealing with the role of NOX3 in ototoxicity and the effects of siRNA against cisplatin-induced hearing loss.

Platinum-induced ototoxicity in children: a consensus review on mechanisms, predisposition, and protection, including a new International Society of Pediatric Oncology Boston ototoxicity scale

PURPOSE

The platinum chemotherapy agents cisplatin and carboplatin are widely used in the treatment of adult and pediatric cancers. Cisplatin causes hearing loss in at least 60% of pediatric patients. Reducing cisplatin and high-dose carboplatin ototoxicity without reducing efficacy is important.

PATIENTS AND METHODS

This review summarizes recommendations made at the 42nd Congress of the International Society of Pediatric Oncology (SIOP) in Boston, October 21-24, 2010, reflecting input from international basic scientists, pediatric oncologists, otolaryngologists, oncology nurses, audiologists, and neurosurgeons to develop and advance research and clinical trials for otoprotection.

RESULTS

Platinum initially impairs hearing in the high frequencies and progresses to lower frequencies with increasing cumulative dose. Genes involved in drug transport, metabolism, and DNA repair regulate platinum toxicities. Otoprotection can be achieved by acting on several these pathways and generally involves antioxidant thiol agents. Otoprotection is a strategy being explored to decrease hearing loss while maintaining dose intensity or allowing dose escalation, but it has the potential to interfere with tumoricidal effects. Route of administration and optimal timing relative to platinum therapy are critical issues. In addition, international standards for grading and comparing ototoxicity are essential to the success of prospective pediatric trials aimed at reducing platinum-induced hearing loss.

CONCLUSION

Collaborative prospective basic and clinical trial research is needed to reduce the incidence of irreversible platinum-induced hearing loss, and optimize cancer control. Wide use of the new internationally agreed-on SIOP Boston ototoxicity scale in current and future otoprotection trials should help facilitate this goal.

Prediction of copper transport protein 1 (CTR1) genotype on severe cisplatin induced toxicity in non-small cell lung cancer (NSCLC) patients

BACKGROUND

Cisplatin toxicity severely obstacles successful chemotherapy in lung cancer patients. Cisplatin uptake is considered as one of the major factors contributing to the side effects of cisplatin. Genetic variances of core genes also affect cisplatin toxicity. It has been identified that CTR1, copper transporter protein 1, plays an essential role in cisplatin uptake. The purpose of this study is to investigate whether CTR1 polymorphism is associated with platinum toxicity in non-small cell lung cancer (NSCLC) patients.

METHOD

204 incident NSCLC patients from three different institutions were enrolled and followed up. These patients were histologically confirmed with non-small cell lung cancer. All patients have accepted cisplatin-based chemotherapy for at least two cycles. Twenty SNPs of CTR1 were detected in these patients.

RESULT

CTR1 rs10981694 A>C polymorphism is associated with cisplatin induced severe toxicity in NSCLC patients. C-carrier subjects presented poorer tolerance to ototoxicity (p<0.05). The survival times of patients with different rs10981694 genetic polymorphism were not significantly different.

CONCLUSION

NSCLC patients carrying C allele of CTR1 rs10981694 presented more sensitivity to ototoxicity after cisplatin treatment. CTR1 plays an essential role in cisplatin toxicity and could be considered as a predictor for pretreatment evaluation in lung cancer patients.

Carboplatin-associated ototoxicity in children with retinoblastoma

PURPOSE

Carboplatin-induced ototoxicity remains poorly defined but is of potential great consequence in children with retinoblastoma. We retrospectively assessed the incidence of ototoxicity and its risk factors in children with retinoblastoma who were treated with carboplatin.

PATIENTS AND METHODS

We reviewed the audiologic test results of 60 patients with retinoblastoma who received front-line treatment with systemic carboplatin and vincristine according to the St Jude RET-3 protocol (n = 23) or best clinical management (n = 37). Ototoxicity was evaluated by three different grading systems.

RESULTS

Twelve patients (20%) developed ototoxicity at some time after treatment initiation; however, ototoxicity resolved in two patients, and thus,10 patients (17%) had sustained hearing loss as documented at their most recent audiologic evaluation. Nine of these 10 patients had grade 3 or 4 ototoxicity, and nine patients were less than 6 months of age at the start of chemotherapy. Age at the start of chemotherapy was the only risk factor identified as a significant predictor of sustained hearing loss. Younger age was associated with an increased incidence of hearing loss. The different ototoxicity grading systems showed good overall agreement in the identification of patients with ototoxicity. Agreement was greatest between the Brock and Children's Cancer Group systems.

CONCLUSION

We found that young patients with retinoblastoma who were treated with systemic carboplatin had a higher incidence of ototoxicity than previously reported. Younger patients (< 6 months of age at the start of treatment) were more likely to have ototoxicity than were older patients. Children treated with carboplatin should routinely undergo thorough, long-term audiologic monitoring.

Protective role of resveratrol against cisplatin induced ototoxicity in guinea pigs

OBJECTIVE

The aim of this study was to evaluate the effectiveness of systemic administration of resveratrol against cisplatin-induced ototoxicity in guinea pigs.

MATERIALS AND METHODS

Healthy guinea pigs (n=24) were randomly divided into four groups. Group 1 (n=6) received resveratrol+cisplatin, group 2 (n=6) received 4% ethanol+cisplatin, group 3 (n=6) received cisplatin, and group 4 (n=6) received saline. Cisplatin was administered at a dose of 10mg/kg/day on days 14 and 15 of the study. Resveratrol (10mg/kg/day), 4% ethanol, and saline were administered throughout the study. Baseline auditory brainstem responses (ABR) (4 kHz, 8 kHz, and click stimulus) were determined for all groups. ABR was repeated 72 h after the last dose of cisplatin in order to record the threshold shifts. The ABR threshold shifts for the click stimulus, 4-kHz- and 8-kHz-frequency stimuli were compared after drug administration. After follow-up ABRs the animals sacrificed under deep sedation and their cochleae were removed. Left cochleae were immediately harvested for measurement of level of reactive oxygen species (ROS). Right cochleae were prepared for histological changes which were observed by scanning electron microscopy (SEM).

RESULTS

For the all stimulus, there was a significant threshold difference among the groups (p<0.01). Group 3 had a significantly higher threshold shift at all stimuli when compared with groups 1 and 4. There was no significant threshold shifts in all stimuli between groups 2 and 3. The resveratrol-treated group 1 showed preservation of threshold in ABR (p ≤ 0.05). SEM showed that inner and outer hair cells were preserved in the group 1. Level of reactive oxygen species (ROS) were significantly higher in groups 2 and 3 compared with groups 1 and 4 (p ≤ 0.05).

CONCLUSION

These results indicated that systemic administration of resveratrol afforded statistically significant protection to the cochlea of guinea pigs from cisplatin toxicity. Experimental dose of resveratrol injections may have a protective effect against cisplatin ototoxicity in guinea pigs.

Role of genetic susceptibility in development of treatment-related adverse outcomes in cancer survivors

Clear and unambiguous associations have been established between therapeutic exposures and specific complications. However, considerable interindividual variability is observed in the risk of developing an outcome for a given therapeutic exposure. Genetic predisposition and especially its interaction with therapeutic exposures can potentially exacerbate the toxic effect of treatment on normal tissues and organ systems, and can possibly explain the interindividual variability. This article provides a brief overview of the current knowledge about the role of genomic variation in the development of therapy-related complications. Relatively common outcomes with strong associations with therapeutic exposures, including cardiomyopathy, obesity, osteonecrosis, ototoxicity, and subsequent malignancies are discussed here. To develop a deeper understanding of the molecular underpinnings of therapy-related complications, comprehensive and near-complete collection of clinically annotated samples is critical. Methodologic issues such as study design, definition of the endpoints or phenotypes, identification of appropriate and adequately sized study population together with a reliable plan for collecting and maintaining high-quality DNA, and selection of an appropriate approach or platform for genotyping are also discussed. Understanding the etiopathogenetic pathways that lead to the morbidity is critical to developing targeted prevention and intervention strategies, optimizing risk-based health care of cancer survivors, thus minimizing chronic morbidities and improving quality of life.

Evaluation of ototoxicity in children treated for retinoblastoma: preliminary results of a systematic audiological evaluation

BACKGROUND

The objective of this study was to identify the ocurrence of hearing loss in children treated for retinoblastoma using a multidisciplinary approach.

PATIENTS AND METHODS

Thirty-two children were evaluated pre- and post-treatment. Eleven children were treated exclusively with enucleation, fifteen with carboplatin and six with cisplatin. Otoacoustic emissions were performed with the ILO 88, before and after the treatment.

RESULTS

In our study we found 5 children (24%) with hearing loss among the 21 evaluated. However in the group of children treated with carboplatin (N=15), 1 case (6.6%) presented hearing loss, while among those treated with cisplatin (N=6) we found 4 cases (66.6%) with hearing loss (p=0.0114).

CONCLUSION

We concluded that patients who are treated with cisplatin are at risk for developing hearing loss.

Cisplatin ototoxicity in rat cochlear organotypic cultures

Ototoxicity is a dose-limiting side effect of chemotherapeutic treatment with cisplatin. In a series of experiments on neonatal rat cochlear organotypic cultures, the extent of damage induced by a broad range of cisplatin treatment concentrations was examined. Paradoxically, it was found that hair cell loss was greater following 48 h exposure to low (10, 50 and 100 μM) versus high (400 and 1000 μM) concentrations of cisplatin; these findings indicate that hair cells possess intrinsic resistance to high levels of extracellular cisplatin. Using cisplatin conjugated to Alexa Fluor 488, it was found that cisplatin is readily taken up by hair cells at low concentrations, but is largely excluded at high concentrations. Recent studies indicate that the major influx of cisplatin into hair cells occurs via the copper transporter, Ctr1, whereas ATP7A and ATP7B are copper pumps responsible for cisplatin sequestration and efflux. Using immunolabeling procedures for these copper trafficking proteins, it was found that Ctr1 and ATP7B were localized in the hair cells, whereas ATP7A showed extensive labeling in the pillar cells in the organ of Corti. Additional experiments confirmed the protective effect of copper sulfate and cimetidine in attenuating cisplatin-induced hair cell loss. However, because neither copper sulfate nor cimetidine provided complete protection against cisplatin, and high levels of copper sulfate itself were found to be ototoxic, it is suggested that future therapeutic efforts may benefit from a combination of pharmacological treatments which seek to not only limit the uptake of cisplatin into cochlear cells but also increase its efflux.

Cisplatin ototoxicity affecting cochlear implant benefit

OBJECTIVE

Report a case of loss of cochlear implant benefit after cisplatin therapy to treat osteosarcoma. Examine the implications for the loci of cisplatin-associated cochleotoxicity.

STUDY DESIGN

Retrospective case review.

SETTING

Tertiary referral center.

PATIENTS

Single case study.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Cochlear implant programming levels.

RESULTS

Increase in cochlear implant programming T- and C-levels after cisplatin therapy.

CONCLUSION

Cisplatin therapy likely affects spiral ganglion cells. It seems that auditory cells other than outer hair cells in the organ of Corti are affected by cisplatin because the hearing sensitivity of this patient with nonfunctioning outer hair cells declined after receiving chemotherapy. Implications of these findings are discussed.

Survival and long-term outcomes in children with hepatoblastoma treated with continuous infusion of cisplatin and doxorubicin

Despite high survival rates, many survivors of hepatoblastoma develop late effects including ototoxicity and cardiomyopathy. With the goal of minimizing long-term toxicities, our institution treated hepatoblastoma with continuous infusion of doxorubicin and cisplatinum (PLADO), rather than short infusion or bolus dosing as used in other treatment protocols. This retrospective cohort study includes consecutive patients diagnosed between 1985 and 2007. Patients were scheduled for treatment with 6 cycles of continuous infusion of PLADO with resection after the third or fourth cycle. Audiograms and echocardiograms were obtained at baseline, after every 2 chemotherapy cycles and yearly after the completion of therapy. Fifty-five patients were treated (34 localized; 21 metastatic). Fifty-one patients received at least 1 cycle of PLADO. Median follow-up was 7.0 years (range, 0.11 to 17.8 y). Event-free and overall survival for these 51 patients were 72.2% (standard error 6.3%) and 75.6% (standard error 6.2%) respectively. Of the 38 survivors treated with cisplatin who had an audiogram during follow-up, 4 (11%) demonstrated severe (Brock grade 3/4) and 13 (34%) mild (Brock grade 1/2) hearing loss. At a median of 10.0 years (range, 5.0 to 13.0 y) after therapy, 2 of 41 (5%) patients who were still alive had evidence of cardiac dysfunction. Overall, continuous infusion of PLADO therapy resulted in survival rates consistent with those observed in intergroup studies, but rates of chronic cardiac and ototoxicity did not differ sufficiently from those observed after shorter infusion of PLADO therapy to warrant the use of continuous infusions.

Advances in the understanding of constitutional and somatic genomic alterations in neuroblastoma

Advances in the field of genomics have led to multiple recent discoveries in the understanding of genetic predisposition and molecular pathogenesis of the childhood cancer neuroblastoma. Neuroblastoma is the most common extracranial solid tumor of childhood and is responsible for 10% of childhood cancer related mortality. The genetic etiology of rare families with hereditary neuroblastoma is now largely understood, with the majority having activating mutations in the anaplastic lymphoma kinase (ALK) gene. Genome-wide association studies have identified multiple common, low penetrance genetic polymorphisms that are associated with a predisposition to sporadic neuroblastoma, and these associations are disease phenotype specific. While many of the discoveries related to variations in the host genome that predispose to neuroblastoma are recent, there is a long and robust history of investigation of tumor cell genomics, leading to the identification of multiple biomarkers of tumor aggressiveness. Current patient risk stratification algorithms utilize key genomic features for therapy assignment. Microarray-based tumor DNA and RNA profiling techniques and next generation sequencing efforts may further refine these risk groups and identify new tractable therapeutic targets. Moving forward, integrative genomics efforts will be needed to discover how the interaction of germline genetic variations influence oncogenesis in neuroblastoma-both initiation and progression. In this review, we summarize the recent advances in the understanding of germline predisposition and molecular pathogenesis of neuroblastoma.

Auditory complications in childhood cancer survivors: a report from the childhood cancer survivor study

BACKGROUND

Studies have found associations between cancer therapies and auditory complications, but data are limited on long-term outcomes and risks associated with multiple exposures.

PROCEDURE

The Childhood Cancer Survivor Study is a retrospective cohort investigating health outcomes of long-term survivors (5+ years) diagnosed and treated between 1970 and 1986 compared to a randomly selected sibling cohort. Questionnaires were completed by 14,358 survivors of childhood cancer and 4,023 sibling controls. Analysis determined the first occurrence of four auditory conditions in two time periods: diagnosis to 5 years post-diagnosis, and ≥ 5 years post-diagnosis. Multivariable analyses determined the relative risks (RR) and 95% confidence interval (CI) of auditory conditions by treatment exposure.

RESULTS

Five or more years from cancer diagnosis, survivors were at increased risk of problems hearing sounds (RR = 2.3; 95% CI: 1.8-2.8), tinnitus (RR = 1.7; 95% CI: 1.4-2.1), hearing loss requiring an aid (RR = 4.4; 95% CI: 2.8-6.9), and hearing loss in 1 or both ears not corrected by a hearing aid (RR = 5.2; 95% CI: 2.8-9.5), when compared to siblings. Temporal lobe and posterior fossa radiation was associated with these outcomes in a dose-dependent fashion. Exposure to platinum compounds was associated with an increased risk of problems hearing sounds (RR = 2.1; 95% CI: 1.3-3.2), tinnitus (RR = 2.8; 95% CI: 1.9-4.2), and hearing loss requiring an aid (RR = 4.1; 95% CI: 2.5-6.7).

CONCLUSIONS

Childhood cancer survivors are at risk of developing auditory complications. Radiation and platinum compounds are determinants of this risk. Follow-up is needed to evaluate the impact of auditory conditions on quality of life.

Pharmacogenomics of cisplatin-induced ototoxicity

Cisplatin ototoxicity affects different individuals in a widely variable manner. These variations are likely to be explained by genetic differences among those affected. It would be highly advantageous to identify genetic variants that predispose to cisplatin ototoxicity in order to minimize the risk to susceptible subgroups. Although this area of research is very important, only a few studies have rigorously examined the genetic basis for cisplatin-induced susceptibility to hearing loss. This article addresses recent progress in clarifying the incidence of cisplatin ototoxicity and the risk factors and controversies regarding the identification of genetic variants associated with cisplatin-induced hearing loss.