Long-term outcome of sensorineural hearing loss in nasopharyngeal carcinoma patients: comparison between treatment with radiotherapy alone and chemoradiotherapy

Optimizing Hearing Outcomes in Nasopharyngeal Cancer Survivors in the Era of Modern Radiotherapy and Systemic Therapy

Intensity-modulated radiation therapy (IMRT) improves disease control and reduces treatment-related toxicity in patients with localized nasopharyngeal carcinoma (NPC). However, due to the proximity of the auditory apparatus to the treatment volume and the frequent incorporation of cisplatin-based chemotherapy, treatment-related sensorineural hearing loss (SNHL) remains a common debilitating complication among NPC survivors. The reported crude incidence of SNHL following IMRT for NPC varies widely at 1-46% due to differences in auditory assessment methods and thresholds, follow-up durations, chemotherapy usage, and patient compositions. International guidelines and radiation dosimetric studies have recommended constraining the cochlear mean dose to less than 44-50 Gy, but the risk of SNHL remains high despite adherence to these constraints. Potential strategies to improve hearing outcomes in NPC survivors include cautious de-escalation of radiotherapy dose and volume, individualization of cochlear constraints, optimization of radiotherapy planning techniques, and the use of substitutes or alternative schedules for cisplatin-based chemotherapy. The addition of immune checkpoint inhibitors to chemoradiotherapy did not impact ototoxicity. Prospective studies that employ both objective and patient-reported auditory outcomes are warranted to test the long-term benefits of various approaches. This article aims to provide a comprehensive review of the incidence and radiation dose-toxicity relationship of SNHL in NPC survivors and to summarize potential strategies to optimize hearing outcomes in relation to nuances in radiotherapy planning and the selection of systemic therapy.

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

PURPOSE

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

MATERIALS AND METHODS

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

RESULTS

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

CONCLUSION

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

Complementary acupuncture treatment and reduced risk of sudden sensorineural hearing loss in nasopharyngeal carcinoma patients: a retrospective, nested case-control study

PURPOSE

Hearing loss is a frequently observed comorbidity in patients with nasopharyngeal carcinoma (NPC). Accumulating evidence demonstrated that acupuncture can safely manage cancer and its treatment-related symptoms, but its effect in minimizing the likelihood of experiencing sudden sensorineural hearing loss (SSHL) has not been established. So this work aimed to determine the risk of SSHL among NPC persons with or without acupuncture use.

METHODS

One population-level, nested case-control design within a cohort study is employed. Relevant information on persons aged 20-80 years who were afflicted with NPC between 2000 and 2010 was extracted from a nationwide health claims database. From them, we identified the cases who had the first SSHL diagnosis occurring after NPC, and all of them were randomly matched to two controls without SSHL. Conditional logistic regression was employed to calculate odds ratios (OR) and its respective 95% confidence intervals (CI) for incident SSHL in relation to acupuncture treatment.

RESULTS

Eight hundred eleven SSHL cases were randomly matched to 1452 controls. Those receiving conventional care plus acupuncture use had a reduced adjusted OR of 0.39 (95% CI, 0.25-0.60) for SSHL. We further discovered that the longer usage of acupuncture remarkably correlated with reduction of SSHL risk in a dose-dependent manner.

CONCLUSIONS

Delineation of the benefit from integration of acupuncture into conventional care may be a reference in instituting more appropriate care for NPC subjects.

IMPLICATIONS FOR CANCER SURVIVORS

Patients living with NPC may benefit from a timely integration of acupuncture into routine care to lessen SSHL risk.

Neurological complications of modern radiotherapy for head and neck cancer

Radiotherapy is one of the mainstay treatment modalities for the management of non-metastatic head and neck cancer (HNC). Notable improvements in treatment outcomes have been observed in the recent decades. Modern radiotherapy techniques, such as intensity-modulated radiotherapy and charged particle therapy, have significantly improved tumor target conformity and enabled better preservation of normal structures. However, because of the intricate anatomy of the head and neck region, multiple critical neurological structures such as the brain, brainstem, spinal cord, cranial nerves, nerve plexuses, autonomic pathways, brain vasculature, and neurosensory organs, are variably irradiated during treatment, particularly when tumor targets are in close proximity. Consequently, a diverse spectrum of late neurological sequelae may manifest in HNC survivors. These neurological complications commonly result in irreversible symptoms, impair patients' quality of life, and contribute to a substantial proportion of non-cancer deaths. Although the relationship between radiation dose and toxicity has not been fully elucidated for all complications, appropriate application of dosimetric constraints during radiotherapy planning may reduce their incidence. Vigilant surveillance during the course of survivorship also enables early detection and intervention. This article endeavors to provide a comprehensive review of the various neurological complications of modern radiotherapy for HNC, summarize the current incidence data, discuss methods to minimize their risks during radiotherapy planning, and highlight potential strategies for managing these debilitating toxicities.

Post-irradiation endolymphatic hydrops vs. post-irradiation sudden deafness

BACKGROUND

Increasing numbers of acute sensorineural hearing loss (SNHL) are recently experienced in irradiated nasopharyngeal carcinoma (NPC) survivors.

AIM

This study adopted MR imaging to differentiate between post-irradiation sudden deafness (PISD) and post-irradiation endolymphatic hydrops (PIEH) in long-term NPC survivors with acute SNHL.

METHODS

From 2012 to 2021, consecutive 10 irradiated NPC survivors with acute SNHL were enrolled. All patients underwent an inner ear test battery and MR imaging using HYDROPS-Mi2 technique. Six patients (11 ears) with positive cochlear hydrops on MR images were diagnosed as PIEH, while another 4 patients (4 ears) without cochlear hydrops on MR images were referred to PISD.

RESULTS

The interval from the onset of NPC to acute SNHL did not significantly differ between the PIEH (10 ± 6 years) and PISD (8 ± 2 years). No significant difference was found between the two disorders from any of the symptomatic, radiotherapeutic, audiological, or vestibular perspective. Interestingly, most (5/6) patients with PIEH had bilateral involvement, while all (4/4) patients with PISD showed unilateral affliction. A significantly declining sequence of abnormality rates in the inner ear test battery was noted in the PIEH patients, running from the audiometry (100%), cervical vestibular-evoked myogenic potential (VEMP) test (100%), ocular VEMP test (73%), to the caloric test (36%). However, such declining trend was not observed in patients with PISD.

CONCLUSION

When facing an NPC survivor who had acute SNHL over a prolonged period after irradiation, MR imaging using HYDROPS-Mi2 technique should be performed to differentiate the PIEH from the PISD, since both disorders have various treatment modalities and hearing outcome.

Definition of an Normal Tissue Complication Probability Model for the Inner Ear in Definitive Radiochemotherapy of Nasopharynx Carcinoma

Background: Definitive radiochemotherapy is the treatment of choice for locally advanced nasopharyngeal carcinoma. Due to the vicinity of the nasopharynx to the inner ear and the use of ototoxic platinum-based chemotherapy, there is a risk for irreversible damage to the auditory system. To avoid or minimize these critical side effects, radiation exposure to each inner ear must be balanced between target volume coverage and toxicity. However, normal tissue complication probability (NTCP) models of the inner ear validated by clinical data are rare. Patients and Methods: This retrospective study investigates the inner ear toxicity of 46 patients who received radio(chemo-)therapy for nasopharyngeal carcinoma at our institution from 2004 to 2021 according to CTCAE 5.0 criteria. For each inner ear, the mean (Dmean) and maximum (Dmax) dose in Gray (Gy) was evaluated and correlated with clinical toxicity data. Based on the data, an NTCP model and a cutoff dose logistic regression model (CDLR) were created. Results: In 11 patients (23.9%) hearing impairment and/or tinnitus was observed as a possible therapy-associated toxicity. Dmean was between 15−60 Gy, whereas Dmax was between 30−75 Gy. There was a dose-dependent, sigmoidal relation between inner ear dose and toxicity. A Dmean of 44 Gy and 65 Gy was associated with inner ear damage in 25% and 50% of patients, respectively. The maximum curve slope (m) was found at 50% and is m=0.013. The Dmax values showed a 25% and 50% complication probability at 58 Gy and 69 Gy, respectively, and a maximum slope of the sigmoid curve at 50% with m=0.025. Conclusion: There is a sigmoidal relation between radiation dose and incidence of inner ear toxicities. Dose constraints for the inner ear of <44 Gy (Dmean) or <58 Gy (Dmax) are suggested to limit the probability of inner ear toxicity <25%.

Effect of Hydrogen Inhalation Therapy on Hearing Loss of Patients With Nasopharyngeal Carcinoma After Radiotherapy

Objective

To evaluate the clinical efficacy and safety of hydrogen inhalation in improving hearing loss in patients with long-term survival of nasopharyngeal carcinoma after radiotherapy.

Methods

The eustachian tube dysfunction score, pure tone air conduction threshold, bone conduction threshold, the score of tympanogram and otoscope were prospectively observed in patients with deafness after radiotherapy only or combined radiotherapy and chemotherapy for nasopharyngeal carcinoma. Paired t test and one-way analysis of variance were used to analyze the data before and after treatment.

Results

A total of 17 patients were observed. The median time from radiotherapy to now was 228 months, and the median time from the diagnose of deafness to now was 92 months. After 4 weeks of hydrogen inhalation, the score of eustachian tube dysfunction, air conduction and bone conduction hearing thresholds were significantly reduced, P values were 0.0293, 0.0027, 0.0404, respectively. The mean air-bone gap, the score of otoendoscopy and tympanogram were also decreased, but the differences were not significant (P = 0.2079, P = 0.0536, P = 0.1056). Patients with radiotherapy alone and concurrent chemo-radiotherapy had significantly lower air conduction hearing threshold after hydrogen absorption (P = 0.0142, P = 0.0495). The results of air and bone hearing thresholds before, 4 and 12 weeks after hydrogen inhalation showed a descending trend. The air and bone hearing thresholds before hydrogen inhalation were 74.69 ± 27.03 dB and 45.70 ± 21.58 dB, respectively. At the 12th week, the mean values of air and bone hearing thresholds were the lowest, which were 66.88 ± 20.88 dB and 40.94 ± 18.93 dB, respectively, but there was no significant difference in air and bone hearing thresholds among all groups (P = 0.6755, P = 0.7712). After hydrogen inhalation treatment, no adverse reactions such as nosebleed, chest pain, dyspnea, nausea, vomiting, dizziness, earache and allergic reaction were observed.

Conclusion

This is the first prospective study on the effect of hydrogen inhalation on hearing improvement in patients with deafness after radiotherapy/chemotherapy for nasopharyngeal carcinoma, suggesting that continuous hydrogen inhalation may be an alternative rehabilitation therapy for these patients.

Intensity-modulated proton radiation therapy as a radical treatment modality for nasopharyngeal carcinoma in China: A cost-effectiveness analysis

BACKGROUND

Compared to conventional intensity-modulated photon radiation therapy (IMRT), intensity-modulated proton radiation therapy (IMPT) has potential to reduce irradiation-induced late toxicities while maintaining excellent tumor control in patients with nasopharyngeal carcinoma (NPC). However, the relevant cost-effectiveness remains controversial.

METHODS

A Markov decision tree analysis was performed under the assumption that IMPT offered normal tissue complication probability reduction (NTCP reduction) in long-term dysphagia, xerostomia, and hearing loss, compared to IMRT. Base-case evaluation was performed on T2N2M0 NPC of median age (43 years old). A Chinese societal willingness-to-pay threshold (33558 US dollars [$])/quality-adjusted life-year [QALY]) was adopted.

RESULTS

For patients at median age and having NTCP reduction of 10%, 20%, 30%, 40%, 50%, and 60%, their incremental cost-effectiveness ratios were $102684.0/QALY, $43161.2/QALY, $24134.7/QALY, $13991.6/QALY, $8259.8/QALY, and $4436.1/QALY, respectively; IMPT should provide an NTCP reduction of ≥24% to be considered cost-effective.

CONCLUSIONS

IMPT has potential to be cost-effective for average Chinese NPC patients and should be validated clinically.

Sensorineural Hearing Loss in Nasopharyngeal Carcinoma Survivors in the Modern Treatment Era - The Early and Late Effects of Radiation and Cisplatin

AIMS

Hearing loss is a common debilitating complication in nasopharyngeal carcinoma (NPC) survivors. The aim of the present study was to investigate the impact of inner ear/cochlear radiation dose and cisplatin use on early and late sensorineural hearing loss (SNHL) in NPC patients treated with radiotherapy alone, concurrent chemoradiation (cCRT) and induction chemotherapy followed by cCRT (iCRT) in the intensity-modulated radiotherapy era.

MATERIALS AND METHODS

The study included 81 NPC patients treated with intensity-modulated radiotherapy between 2014 and 2016. Pure tone audiometry was carried out at baseline and follow-up. The effects of cochlear/inner ear radiation and cisplatin doses on early (<12 months) and late (≥24 months) SNHL were analysed using multivariable regression after adjusting for important predictors.

RESULTS

In total, 156 ears were examined. In early SNHL (n = 136), cisplatin use predicted the incidence of early high-frequency SHNL (HF-SNHL) (odds ratio 6.4, 95% confidence interval 1.7-23.9, P = 0.005). Ninety ears were analysed for late SNHL (median follow-up 38 months). Inner ear/cochlear radiation and cisplatin doses and better pre-treatment hearing were independent predictors of threshold change at 4 kHz. Every 10 Gy increase in inner ear/cochlear Dmean resulted in 5-dB and 6-dB threshold changes, respectively (cochlear Dmean: B = 0.005, 95% confidence interval 0.0004-0.009, P = 0.031; inner ear Dmean: B = 0.006, 95% confidence interval 0.001-0.010, P = 0.014). Cisplatin use was associated with late HF-SNHL (odds ratio 3.74, 95% confidence interval 1.1-12.3, P = 0.031). In the cCRT and iCRT subgroups, no cisplatin dose-dependent ototoxicity was observed. Severe (≥30 dB) late HF-SNHL occurred in 14% and 25% of the patients when the cochlear dose constraints were 40 Gy and 44 Gy, respectively. The radiotherapy-alone group did not develop severe late HF-SNHL.

CONCLUSION

Cochlear/inner ear radiation dose and cisplatin use showed differential and independent ototoxicity in early and late SNHL. As cochlear/inner ear dose-dependent ototoxicity was demonstrated, the cochlear dose constraint should be as low as reasonably achievable, especially when cisplatin is also administered.

[Concurrent chemoradiotherapy for head neck cancers. Should organs at risk dose constraints be revisited ?]

Concurrent chemoradiotherapy improves the outcome of locally advanced head and neck cancers and the current reference chemotherapy is cisplatin. These results are obtained at the cost of increased toxicities. To limit the risk of toxicity, organ at riskdose constraints have been established starting with 2D radiotherapy, then 3D radiotherapy and intensity-modulated radiotherapy. Regarding grade ≥3 acute toxicities, the scientific literature attests that concurrent chemoradiotherapy significantly increases risks of mucositis and dysphagia. Constraints applied to the oral mucosa volume excluding the planning target volume, the pharyngeal constrictor muscles and the larynx limit this adverse impact. Regarding late toxicity, concurrent chemoradiotherapy increases significantly the risk of postoperative neck fibrosis and hearing loss. However, for some organs at risk, concurrent chemotherapy appears to increase late radiation induced effect, even though the results are less marked (brachial plexus, mandible, pharyngeal constrictor muscles, parotid gland). This additional adverse impact of concomitant chemotherapy may be notable only when organs at risk receive less than their usual dose thresholds and this would be vanished when those thresholds are exceeded as seems to be the situation for the parotid glands. Until the availability of more robust data, it seems appropriate to apply the principle of delivering dose to organs at risk as low as reasonably achievable.

Vestibulotoxicity Associated With Platinum-Based Chemotherapy in Survivors of Cancer: A Scoping Review

Background: Cochleotoxicity following the treatment with platinum-based chemotherapy is well documented. The potential for vestibulotoxicity is still unclear. This scoping review examined the extent of current research literature, summarized research findings and identified research gaps regarding vestibular-related adverse effects associated with platinum-based chemotherapy in survivors of cancer.

Methods: Inclusion criteria followed the PICO principles: Participants, adult, and pediatric cancer patients of any cancer type; Intervention, platinum-based chemotherapy (such as cisplatin, carboplatin, and oxaliplatin); Control, none or any; Outcomes, vestibular-related adverse effects. English language articles published since 1978 were retrieved. Seventy-five eligible studies were identified from a systematic literature search, and relevant data were charted, collated, and summarized.

Results: Testing for vestibulotoxicity predominately featured functional evaluation of the horizontal semicircular canal using the caloric and rotational tests. The rate of abnormal vestibular function test results after chemotherapy administration varied from 0 to 50%. The results of objective testing did not always correspond to patient symptoms. There is tentative support for patients with pre-existing loss of vestibular function to be more likely to experience vestibular toxicity after dosing with cisplatin.

Conclusions: A number of studies reported significant evidence of vestibular toxicities associated with platinum-based chemotherapy, especially cisplatin. This scoping review emphasizes that vestibular toxicity needs more attention and comprehensive evaluation. Specifically, studies that analyse cumulative dose of platinum-based chemotherapy, affected sites of lesion in vestibular end organs, and the correlation and temporal patterns of cochlear and vestibular toxicity are needed.

Time course and clinical characterization of cisplatin-induced ototoxicity after treatment for nasopharyngeal carcinoma in a South East Asian population

BACKGROUND

The purpose of this study was to characterize the clinical course of hearing loss in patients with nasopharyngeal carcinoma (NPC) and the clinical factors affecting its severity.

METHODS

The time course of hearing loss in patients with NPC was assessed using threshold shift from baseline and Common Terminology Criteria for Adverse Events (CTCAE) grade.

RESULTS

In the chemoradiotherapy (CRT) groups, the threshold shift was significantly higher from 3 months at 4 kHz (P = 2.30 × 10^-9 , concurrent CRT only) but not within 2 years posttreatment in the radiotherapy (RT) group. The CRT groups had worse CTCAE grades than the RT group (percentage of latest CTCAE grade ≥1: 64.9% vs 29.0%, respectively). Cumulative cisplatin dose and cochlear RT dose significantly affects threshold shifts, especially at high frequencies.

CONCLUSION

Although cisplatin led to high frequency hearing impairment from about 3 months posttreatment, RT conferred no significant hearing impairment in the first 2 years.

Impact of radiation technique, radiation fraction dose, and total cisplatin dose on hearing : Retrospective analysis of 29 medulloblastoma patients

PURPOSE

To analyze the incidence and degree of sensorineural hearing loss (SNHL) resulting from different radiation techniques, fractionation dose, mean cochlear radiation dose (D_mean), and total cisplatin dose.

MATERIAL AND METHODS

In all, 29 children with medulloblastoma (58 ears) with subclinical pretreatment hearing thresholds participated. Radiotherapy (RT) and cisplatin had been applied sequentially according to the HIT MED Guidance. Audiological outcomes up to the latest follow-up (median 2.6 years) were compared.

RESULTS

Bilateral high-frequency SNHL was observed in 26 patients (90%). No significant differences were found in mean hearing threshold between left and right ears at any frequency. A significantly better audiological outcome (p < 0.05) was found after tomotherapy at the 6 kHz bone-conduction threshold (BCT) and left-sided 8 kHz air-conduction threshold (ACT) than after a combined radiotherapy technique (CT). Fraction dose was not found to have any impact on the incidence, degree, and time-to-onset of SNHL. Patients treated with CT had a greater risk of SNHL at high frequencies than tomotherapy patients even though D_mean was similar. Increase in severity of SNHL was seen when the total cisplatin dose reached above 210 mg/m², with the highest abnormal level found 8-12 months after RT regardless of radiation technique or fraction dose.

CONCLUSION

The cochlear radiation dose should be kept as low as possible in patients who receive simultaneous cisplatin-based chemotherapy. The risk of clinically relevant HL was shown when D_mean exceeds 45 Gy independent of radiation technique or radiation regime. Cisplatin ototoxicity was shown to have a dose-dependent effect on bilateral SNHL, which was more pronounced in higher frequencies.

The effectiveness of myringotomy and ventilation tube insertion versus observation in post-radiation otitis media with effusion

To compare the effectiveness of myringotomy and ventilation tube insertion versus observation in post-radiation otitis media with effusion (OME) in nasopharyngeal carcinoma (NPC). NPC patients who finished radiotherapy and had persistent OME were randomized to myringotomy and ventilation tube insertion and observation groups. The resolution rate of OME and hearing outcomes were evaluated. Forty three patients (23 in control group and 20 in intervention group) were analyzed. One patient in the control group obtained a resolution of OME. The remaining patients in the control group had persistent middle ear fluid. Fourteen patients in the intervention group had retained ventilation tubes without otorrhea. Ventilation tubes had spontaneously extruded in the remaining six patients and all of these patients had recurrent OME. Mean air-pure tone average in the control group was 52.04 dB (SD 11.61), significantly different from the intervention group [38.15 dB (SD 19.10); p = 0.01]. Mean air-bone gap in the control and intervention groups were 27.30 dB (SD 9.11) and 9.30 dB (SD 9.59) respectively (p < 0.001). Mean air-pure tone average and mean air-bone gap improvement was significantly improved in the intervention group (p < 0.001). Two patients in the intervention group (10%) developed complications, one patient suffering suppurative otitis media whilst another had otorrhea, which resolved after 1-week course of antibiotic treatment. Post-radiation OME is common in patients with NPC and tends to persist long-term. Conservative management is safe, however, is plagued by frustrating effects of hearing impairment and aural fullness. Myringotomy with ventilation tube insertion leads to hearing improvement with few complications.

A human Fab exclusively binding to the extracellular domain of LMP2A

In the areas of North Africa, Southeast Asia as well as South China, Nasopharyngeal carcinoma (NPC) is among the most widespread cancers. Plenty of research findings confirmed that Epstein-Barr virus (EBV) played a crucial role in NPC. EBV-encoded Latent membrane protein 2A (LMP2A) which continuously expressed in cell membrane protein induced an epithelial-mesenchymal transition and increased the number of side population stem-like cancer cells in NPC. This reveals that LMP2A could contribute to the development and recurrence in NPC. Above evidences suggest that LMP2A could be the potential target molecule in the treatment of NPC. In the current study, a novel human antibody Fab (Fab29) against the extracellular domain of LMP2A was produced with success. Through immunofluorescence experiment it was proved that human antibody Fab29 exclusively combined the surface of SUNE cells (LMP2A-positive). Then flow cytometry result exhibited that the fluorescent intensities of SUNE cells and CNE cells were distinct (96.89% and 0.02% respectively). After that, it was shown by affinity test that the Fab29 fragment had high affinity (KD (M) 1.79E-09) with LMP2A. It was also revealed by immunohistochemical analysis that the Fab29 fragment could combine with LMP2A-positive human NPC tissues in comparison with the control group. Finally, the MTT result indicated that the Fab29 fragment could inhibit the proliferation of LMP2A-positive NPC cells. The inhibiting rate to SUNE cell proliferation reached a peak by Fab29 (19.67%) compared with unrelated Fab and CNE with Fab29 at a concentration of 500 μg/L in first 24 h and in the next 24 h the inhibition rate grew to 22.54%. In brief, it was shown that Fab29, a characteristic human antibody, could recognize LMP2A protein and inhibit the proliferation of LMP2A-expressing NPC cells in vitro.

Sensorineural Hearing Loss after Combined Intensity Modulated Radiation Therapy and Cisplatin-Based Chemotherapy for Nasopharyngeal Carcinoma

PURPOSE

The incidence of sensorineural hearing loss (SNHL) after treatment with combination of intensity-modulated radiation therapy (IMRT) and cisplatin-based chemotherapy in nasopharyngeal carcinoma (NPC) patients was evaluated, and relationships of SNHL with host factors, treatment-related factors, and radiation dosimetric parameters were investigated.

METHODS

Fifty-one NPC patients treated with IMRT from 2004 to 2009 were analyzed. All patients received neoadjuvant, concurrent, or adjuvant use of cisplatin. Pure tone audiometry was performed during the follow-up period with a median time of 60months, ranging from 28 to 84months. Correlation of SNHL at low frequencies (pure tone average, 0.5-2kHz) with a series of factors was analyzed.

RESULTS

Among 102 ears, 12.7% had low-frequency SNHL and 42.2% had high-frequency (4kHz) SNHL. The incidence of low-frequency SNHL was greater in patients with age>40, with T-stage 4, or who received cumulative cisplatin dose (CCD)>200mg/m(2) (P=.034, .011, and .003, respectively) and in ears with secretory otitis media (SOM) (P=.002). Several dosimetric parameters were found to be correlated with SNHL. Univariate analysis showed that the minimum radiation dose to 0.1ml highest dose volume (D0.1ml) of the cochlea was the best radiation-related predictive parameter. Multivariate analysis indicated that CCD, SOM, and D0.1ml of cochlea (P=.035, .012, and .022, respectively) were the factors associated with SNHL.

CONCLUSION

For NPC patients treated with IMRT and chemotherapy, the incidence of treatment-related SNHL was associated with CCD, D0.1ml of cochlea, and SOM.

Methylprednisolone use during radiotherapy extenuates hearing loss in patients with nasopharyngeal carcinoma

OBJECTIVES/HYPOTHESIS

To investigate the hearing protective effects of methylprednisolone use during radiotherapy in patients with nasopharyngeal carcinoma.

STUDY DESIGN

Prospective, controlled clinical study.

METHODS

Fifty-three patients with nasopharyngeal carcinoma (106 ears). Twenty-five patients (50 ears) received radiotherapy with intravenous methylprednisolone for 14 days, and another 28 patients (56 ears) received radiotherapy alone. Pure tone audiometry, distortion product otoacoustic emission (DPOAE), and auditory brainstem responses (ABR) results were reviewed before and 1 year after radiotherapy.

RESULT

One year after radiotherapy, the air-and-bone conduction pure tone hearing thresholds increased, and the DPOAE levels decreased in the control group. There was no difference in the ABR wave I, III, and V latencies and the I to V interwave latencies before and 1 year after radiotherapy. The pure tone air conduction thresholds decreased, and the DPOAE levels increased in the treatment group compared with the control group.

CONCLUSION

Early sensorineural hearing loss after radiotherapy primarily affected the outer hair cells. The use of methylprednisolone during radiotherapy can extenuate early sensorineural hearing loss caused by irradiation.

SmartArc-based volumetric modulated arc therapy can improve the middle ear, vestibule and cochlea sparing for locoregionally advanced nasopharyngeal carcinoma: a dosimetric comparison with step-and-shoot intensity-modulated radiotherapy

OBJECTIVE

Radiation-induced sensorineural hearing loss is a common complication after radiotherapy in patients with nasopharyngeal carcinoma (NPC) that significantly affects their quality of life. The goal of this study was to compare SmartArc-based volumetric modulated arc therapy (VMAT-S) with step-and-shoot intensity-modulated radiation therapy (IMRT) for patients with locoregionally advanced NPC with regard to the sparing effect on middle ear, vestibule and cochlea.

METHODS

20 patients with non-metastatic Stage III or IV NPC were selected to have planning with VMAT-S and IMRT [using Philips Pinnacle Planning System (Philips, Fitchburg, WI) for Varian accelerator] for dosimetric comparison. Mean middle ears, vestibule and cochlea doses for the two planning techniques were compared using a paired t-test. Target coverage and dose homogeneity were evaluated by calculating conformity index (CI) and homogeneity index (HI) values.

RESULTS

VMAT-S had significantly improved homogeneity and conformity compared with IMRT. Mean HI of planning target volume of gross tumour volume (PGTV) was better with VMAT-S (1.05 ± 0.02) than IMRT (1.09 ± 0.03) (p < 0.001). Mean CI of PGTV is also better with VMAT-S (0.59 ± 0.12) than IMRT (0.54 ± 0.12) (p < 0.001). Mean doses to the left cochleas were 43.8 ± 3.6 and 47.8 ± 4.0 (p < 0.001) for VMAT-S and IMRT plans, respectively. Mean doses to the right cochleas were 42.7 ± 4.7 and 47.6 ± 5.4 (p < 0.001) for VMAT-S and IMRT plans, respectively. VMAT-S also significantly reduced the mean doses to middle ears (p < 0.001 for both) and vestibule (p < 0.001 for both).

CONCLUSION

Our results indicate that VMAT-S provides better sparing of hearing apparatus in locoregionally advanced NPC.

ADVANCES IN KNOWLEDGE

VMAT-S can improve the middle ear, vestibule and cochlea sparing in patients with locoregionally advanced NPC.