Effects of therapy on dentofacial development in long-term survivors of head and neck rhabdomyosarcoma: the memorial sloan-kettering cancer center experience

Long-Term Functional Outcomes in Pediatric Head and Neck Cancer Patients: A Systematic Review

OBJECTIVE

The multimodal treatments for pediatric head and neck (H&N) malignancies can have significant long-term functional consequences for growing patients. This systematic review aims to analyze the current knowledge of functional outcomes for pediatric H&N cancer survivors.

DATA SOURCES

PubMed, Embase, Web of Science.

REVIEW METHODS

Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines were followed, and 1356 papers were reviewed by 3 team members with conflict resolution by a senior member.

RESULTS

Fourteen studies were included. Nine of 14 (64%) papers reported issues with swallowing, characterized as either dysphagia, odynophagia, oropharyngeal fibrosis, esophageal stenosis, xerostomia, trismus, or general issues with the throat and mouth. Six of 14 papers noted nutritional and feeding deficiencies, and 5 of 14 additionally noted issues with speech and voice changes. Four of 14 (29%) reported hearing impairments and/or loss. A majority of papers (9/14) reported long-term functional characteristics as a secondary outcome. Three of 14 (21%) reported a quality of life (QoL) measure. Heterogeneity in methodology and reporting precluded analysis of any relationship between treatment type and functional outcomes. Recommendations include integration of objective measures of feeding support and swallowing, as well as regular measurements of function and QoL parameters during treatment to better understand the evolution of QoL and function throughout care.

CONCLUSION

Relatively few studies focus on functional outcomes following the treatment of pediatric H&N cancer. Swallowing difficulty is the most frequently reported deficit, but objective data is rarely reported. Standardization of functional outcome assessment could improve the quality of evidence for pediatric patients treated for H&N cancer.

Salivary and Dental Complications in Childhood Cancer Survivors Treated With Radiation Therapy to the Head and Neck: A PENTEC Comprehensive Review

PURPOSE

Radiation therapy (RT) to the head and neck (H&N) region is critical in the management of various pediatric malignancies; however, it may result in late toxicity. This comprehensive review from the Pediatric Normal Tissue Effects in the Clinic (PENTEC) initiative focused on salivary dysfunction and dental abnormalities in survivors who received RT to the H&N region as children.

MATERIALS & METHODS

This systematic review was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) method.

RESULTS

Of the 2,164 articles identified through a literature search, 40 were included in a qualitative synthesis and 3 were included in a quantitative synthesis. The dose-toxicity data regarding salivary function demonstrate that a mean parotid dose of 35 to 40 Gy is associated with a risk of acute and chronic grade ≥2 xerostomia of approximately 32% and 13% to 32%, respectively, in patients treated with chemo-radiation therapy. This risk increases with parotid dose; however, rates of xerostomia after lower dose exposure have not been reported. Dental developmental abnormalities are common after RT to the oral cavity. Risk factors include higher radiation dose to the developing teeth and younger age at RT.

CONCLUSIONS

This PENTEC task force considers adoption of salivary gland dose constraints from the adult experience to be a reasonable strategy until more data specific to children become available; thus, we recommend limiting the parotid mean dose to ≤26 Gy. The minimum toxic dose for dental developmental abnormalities is unknown, suggesting that the dose to the teeth should be kept as low as possible particularly in younger patients, with special effort to keep doses <20 Gy in patients <4 years old.

A review of oral pathology in orthodontics. Part 1: Soft-tissue pathology

Orthodontists are well placed to detect soft-tissue disease of the oral cavity and associated structures because of the frequent repeat examinations of their patients. This review describes the clinical manifestations, pathologic features, and treatment of the soft-tissue pathology most likely to be encountered by the orthodontist and uncommon soft-tissue disease with significant implications for the patient. The recognition of soft-tissue disease will allow reassurance, referral, and early intervention when required.

Late Dental Toxicities After Proton Chemoradiation for Rhabdomyosarcoma: A Pediatric Case Report

Purpose

Radiation therapy is an independent risk factor for adverse sequelae to the oral cavity and dentition in childhood cancer survivors. However, dental toxicities after radiation therapy often are underreported and there are minimal published data on disturbances in tooth development after proton beam therapy (PBT). We present the long-term clinical and radiographic dental findings 8 years after treatment completion for a patient treated with PBT and chemotherapy for rhabdomyosarcoma.

Materials and Methods

Clinical follow-up data of patients treated with PBT within the Proton Overseas Programme (POP) is stored in a National Database and curated by a dedicated outcomes unit at the Christie NHS PBT center. This case report was identified from the extraction and analysis of data for pediatric head and neck cancer patients in this database for a service evaluation project.

Results

The permanent dentition in this patient aged 3.5 years at the time of treatment was severely affected with abnormal dental development first observed 3.5 years after treatment completion. PBT delivered mean doses of 30 Gy(RBE = 1.1) to the maxilla and 25.9 Gy(RBE = 1.1) to the mandible.

Conclusion

Significant dental development abnormalities occurred in this pediatric patient, despite doses in areas being lower than the proposed thresholds in the literature. Improved descriptions of dental toxicities and routine contouring of the maxilla and mandible are needed to correlate dosimetric data. The dose to teeth should be kept as low as reasonably possible in younger patients until the dose thresholds for dental toxicities are known.

Adverse Radiation Therapy Effects in the Treatment of Head and Neck Tumors

Whether used as a single modality or as part of a combined approach, radiation therapy (RT) plays an essential role in the treatment of several head and neck malignancies. Despite the improvement in radiation delivery techniques, normal structures in the vicinity of the target area remain susceptible to a wide range of adverse effects. Given their high incidence, some of these effects are referred to as expected postradiation changes (eg, mucositis, sialadenitis, and edema), while others are considered true complications, meaning they should not be expected and can even represent life-threatening conditions (eg, radionecrosis, fistulas, and radiation-induced neoplasms). Also, according to their timing of onset, these deleterious effects can be divided into four groups: acute (during RT), subacute (within weeks to months), delayed onset (within months to years), and very delayed onset (after several years).The authors provide a comprehensive review of the most important radiation-induced changes related to distinct head and neck sites, focusing on their typical cross-sectional imaging features and correlating them with the time elapsed after treatment. Radiologists should not only be familiar with these imaging findings but also actively seek essential clinical data at the time of interpretation (including knowledge of the RT dose and time, target site, and manifesting symptoms) to better recognize imaging findings, avoid pitfalls and help guide appropriate management. ^© RSNA, 2022.

Long-Term Effect of Anticancer Therapy on Dentition in Childhood Cancer Survivors: An Observational, Cross-Sectional Study

OBJECTIVES

To evaluate the presence of developmental dental anomalies, like microdontia, hypodontia, abnormally shaped teeth (AST), and developmental defects of enamel (DDE) in childhood cancer survivors and compare it with the healthy controls.

METHODS

This cross-sectional analytical study was conducted in 2 groups: childhood cancer survivors (CCS) group including children (> 12 y, m/f) who had undergone anticancer therapy (ACT) before 8 y of age and healthy control group (> 12 y, m/f) without any systemic disease. Pearson chi-square test was used to analyze the difference between the CCS group and the control group for microdontia, hypodontia, AST, DDE and for intragroup analysis in CCS group. Odds ratio was also calculated.

RESULTS

A total of 120 and 121 children were included in CCS and control group, respectively. The prevalence of microdontia, hypodontia, abnormally shaped teeth, and DDE was 17.5% (21), 5% (6), 8.33% (10), and 37.5% (45), respectively in CCS group. It was 8.2% (10), 2.5% (3), 1.65% (2), and 22.3% (27), respectively in the control group. A statistically significant difference was seen in microdontia (p = 0.032), abnormally shaped teeth (p = 0.017) and DDE (p = 0.01). Higher prevalence was seen when ACT began at an early age.

CONCLUSION

An association between developmental dental anomalies and anticancer therapy (ACT) exists with significantly higher difference in microdontia, abnormally shaped teeth and DDE among survivors of childhood cancer as compared to healthy population. These known adverse effects of ACT on developing teeth should be considered during treatment planning of the children having cancers.

Epidemiology and treatment of head and neck malignancies in the AYA generation

The Adolescent and Young Adult (AYA) population refers to the population of young adults and adolescents in the 15-39 years age group. This population subgroup experiences various important life events. Head and neck malignancies are rare tumors, in general, but they are extremely rare in the AYA population. When analyzed by the primary site of the tumors, thyroid gland, soft tissue, and nasopharyngeal malignancies are the most commonly encountered head and neck malignancies in the AYA generation. The most common histopathologic subtypes are carcinomas (thyroid carcinoma, nasopharyngeal carcinoma) and rhabdomyosarcoma. Therefore, in this review, the author discusses these three diseases in the AYA population in detail. Especially, patients with parameningeal rhabdomyosarcoma are at a high risk of dysfunction and facial deformity. Infertility problems may also occur as long-term sequelae of chemotherapy in this population. Radiation therapy might be associated with considerable morbidity. Complications such as cataract, xerostomia, hearing loss, neck fibrosis, and trismus are also common. Head and neck surgeons and medical oncologists should choose the optimal treatment taking into account the curability of the tumors relative to the long-term adverse events of treatment use. Finally, little evidence has been accumulated on head and neck malignancies in the AYA population, and it is urgently necessary to build a high level of evidence for the future.

Acquired Facial, Maxillofacial, and Oral Asymmetries—A Review Highlighting Diagnosis and Management

Facial asymmetry refers to the absence of, or the deviation from the regular mirror image of facial structures, relative to a referenced midline axis. It can be attributed to a wide spectrum of deformities, including congenital, developmental, or acquired conditions, which can originate either prenatally or postnatally. Though highly prevalent, asymmetry commonly goes undiagnosed due to its subtle or relative nature. Among the spectrum of conditions, acquired cases are triggered postnatally, in previously normal individuals, thus subjecting them to sudden, eventful psychological and psychosocial disharmony. When detected early, timely management may help intervene progressive growth of these conditions. This, therefore, emphasizes the need for a thorough diagnostic workup including medical/dental history, clinical examinations, study models, photographic and radiographic records for a case-by-case basis to prevent severe functional and aesthetic complications. Recently, advanced diagnostic procedures, such as stereophotogrammetry, 3D stereolithographic models, skeletal scintigraphy (radionucleotide scans), 3D computed tomographic scans, cone-beam computed tomography, and magnetic resonance imaging, have provided innovative diagnostic instruments for numerous craniofacial defects. This descriptive review aims at focusing on the factors leading to frequently encountered conditions of acquired facial asymmetry and highlights their clinical evaluation, conservative and surgical interventions by a multi-disciplinary team of clinicians.

A Road Map for Important Centers of Growth in the Pediatric Skeleton to Consider During Radiation Therapy and Associated Clinical Correlates of Radiation-Induced Growth Toxicity

With the increasing use of advanced radiation techniques such as intensity modulated radiation therapy, stereotactic radiation therapy, and proton therapy, radiation oncologists now have the tools to mitigate radiation-associated toxicities. This is of utmost importance in the treatment of a pediatric patient. To best use these advanced techniques to mitigate radiation-induced growth abnormalities, the radiation oncologist should be equipped with a nuanced understanding of the anatomy of centers of growth. This article aims to enable the radiation oncologist to better understand, predict, and minimize radiation-mediated toxicities on growth. We review the process of bone development and radiation-induced growth abnormalities and provide an atlas for contouring important growth plates to guide radiation treatment planning. A more detailed recognition of important centers of growth may improve future treatment outcomes in children receiving radiation therapy.

Prosthetic rehabilitation for a patient treated for embryonal rhabdomyosarcoma

A female patient, now aged 17 years, was diagnosed with rhabdomyosarcoma (RMS) in the right pterygopalatine fossa when she was 3 years old. The RMS was successfully treated by excision, but the subsequent radiation and polychemotherapy resulted in the complete anesthesia of the distribution area of the right trigeminal nerve and loss of vision in the right eye. The patient also experienced pain in the mandibular joints and masticatory muscles. Panoramic radiographs displayed a multiple agenesia of the permanent teeth and underdeveloped apices. Treatment involved the fabrication of a complete maxillary denture. A removable device was fabricated to evaluate her response to an occlusal vertical dimension increase of 6 mm and provide a stable intercuspal position. After wearing the prosthesis for 6 months, the patient reported that she was completely free of symptoms.

Facial asymmetry in head and neck rhabdomyosarcoma survivors

INTRODUCTION

Radiotherapy is essential for achieving and maintaining local control in head and neck rhabdomyosarcoma (HNRMS) patients. However, radiotherapy may cause outgrowth disturbances of facial bone and soft tissue, resulting in facial asymmetry. The aim of this study was to develop a method to visualize and measure facial asymmetry in HNRMS survivors using three-dimensional (3D) imaging techniques.

METHODS

Facial deformity was evaluated in a multidisciplinary clinical assessment of 75 HNRMS survivors, treated with external beam radiotherapy (EBRT, n = 26) or Ablative surgery, MOulage brachytherapy, and REconstruction (AMORE, n = 49). Individual facial asymmetry was measured using 3D photogrammetry and expressed in a raw asymmetry index and a normalized sex-age-ethnicity-matched asymmetry signature weight. Facial asymmetry was also compared between British and Dutch controls and between survivors and their matched controls.

RESULTS

Facial asymmetry was more pronounced with increasing age (P < 0.01) in British controls compared with Dutch controls (P = 0.04). Survivors developed more facial asymmetry than matched controls (P < 0.001). The clinical assessment of facial deformity correlated with the raw asymmetry index (r = 0.60, P < 0.001).

DISCUSSION

3D imaging can be used for objective measurement of facial asymmetry in HNRMS survivors. The raw asymmetry index correlated with a clinical assessment of facial deformity. Comparisons between treatment groups seemed inappropriate given the differences in facial asymmetry between British and Dutch controls. In future studies, pretreatment images could act as matched controls for posttreatment evaluation.

Trismus in patients with head and neck cancer: etiopathogenesis, diagnosis and management

BACKGROUND

Trismus indicates severely restricted mouth opening of any aetiology. A mouth opening of 35 mm or less should be regarded as trismus. Aim of this study was to review the etiopathogenesis, incidence, treatment and prevention of trismus in patients with head and neck cancer.

OBJECTIVE OF REVIEW

Trismus is frequently seen in patients suffering from malignant tumours of the head and neck. The reported prevalence of trismus in those patients varies considerably in the literature and ranges from 0 to 100% depending on the tumour site and extension. Trismus may worsen or remain the same over time, or the symptoms may reduce, even in the absence of treatment. When a patient presents with trismus after tumour treatment, it is important to determine whether the trismus is the result of the treatment, or is the first sign of a recurrence. Restricted mouth opening may impede inspection of the oral cavity as needed for dental care, and particularly for oncologic follow-up.

CONCLUSIONS

Mouth opening after radiotherapy (RT) decreases on average by approximately 20% compared to mouth opening prior to RT. The prevalence of trismus increases with increasing doses of RT to mastication structures. The use of intensity-modulated RT seems to lower the percentage and severity of RT-induced trismus. Treatment of trismus can be conservative (with either medical or physical therapy) or surgical. Exercise therapy is the mainstay of treatment and exercise should start as soon as possible after treatment. The prevention of trismus, rather than its treatment, is the most important objective.

Long-term effect of chemotherapy-intensity-modulated radiation therapy (chemo-IMRT) on dentofacial development in head and neck rhabdomyosarcoma patients

Dentofacial developmental abnormalities have been reported in head and neck rhabdomyosarcoma (HNRMS) patients treated with conventional radiotherapy technique and chemotherapy. This current study investigates dentofacial long-term effects among HNRMS survivors managed with intensity-modulated radiotherapy (IMRT) and chemotherapy. In general, IMRT is a more effective 3D-conformal radiotherapy technique, which delivers high doses of radiation to the tumor target while minimizing doses received by the surrounding normal tissues. The medical records and radiographs of thirteen patients were reviewed to identify the following: 1. Facial asymmetry and jaw hypoplasia. 2. Effects on the dental tissue causing tooth agenesis/hypodontia, root agenesis/stunting/malformation, and/or enamel hypoplasia. 3. Trismus, hyposalivation/xerostomia. Seven patients presented with facial asymmetry and jaw hypoplasia, 9 patients presented with effects on the dental tissue [root agenesis/stunting/malformation (9), tooth agenesis/hypodontia (7) and enamel hypoplasia (3)] and 7 patients developed trismus and /or xerostomia. All patients with facial asymmetry and jaw hypoplasia also developed dental abnormalities. Patients with dentofacial developmental abnormalities were ≤7 years of age at treatment. Our study shows that dentofacial developmental abnormalities are still a burden in the era of IMRT and as prognosis of childhood malignancy improves and more patients survive, these late dentofacial sequelae among childhood cancer survivors will become more common. Dental oncologists should be integral members in the management of children with head and neck cancers.

Dental Care for Survivors of Adolescent and Young Adult Cancer: Special Considerations

PURPOSE

Oral health is important for quality of life, but may be undermanaged for survivors of cancer. We examine dental care use and barriers among long-term survivors of adolescent and young adult (AYA) cancer in comparison to individuals without a history of cancer.

METHODS

The 2008-2012 Medical Expenditure Panel Survey (MEPS) identified 1216 individuals diagnosed with cancer at AYA ages (15-39 years), who were at least 5 years from diagnosis. A comparison group was matched using age, sex, and other factors. We evaluated self-reported dental visits in the previous 12 months, and inability and delay in receiving necessary dental care among survivors and the comparison group. Furthermore, individual factors associated with dental care use were identified using multivariable logistic regressions.

RESULTS

Of survivors, 60.86% reported no dental visits in the previous year compared to 51.96% of the comparison individuals (p < 0.001). Survivors were more likely to report inability (10.71% vs. 6.29%, p = 0.001) and delay (8.12% vs. 4.45%, p = 0.001) in getting necessary dental care than the comparison group. Notably, survivors without dental insurance were more likely to report inability and delay. Female survivors were more likely to use dental care than males (odds ratio = 1.76, 95% confidence interval 1.15-2.71, p = 0.01). Hispanic survivors, those diagnosed at younger ages, and uninsured survivors were less likely to have at least one dental visit.

CONCLUSION

Survivors of AYA cancer need timely surveillance to manage late effects, including dental complications. Yet, these survivors, particularly those who are uninsured, delay dental care more often than individuals from the general population. Survivor-specific interventions are needed to reduce dental care barriers.

Survivors of childhood and adolescent cancer: life-long risks and responsibilities

Survival rates for most paediatric cancers have improved at a remarkable pace over the past four decades. In developed countries, cure is now the probable outcome for most children and adolescents who are diagnosed with cancer: their 5-year survival rate approaches 80%. However, the vast majority of these cancer survivors will have at least one chronic health condition by 40 years of age. The burden of responsibility to understand the long-term morbidity and mortality that is associated with currently successful treatments must be borne by many, including the research and health care communities, survivor advocacy groups, and governmental and policy-making entities.

Construction of conditional lentivirus-mediated shRNA vector targeting the human Mirk gene and identification of RNAi efficiency in rhabdomyosarcoma RD cells

Rhabdomyosarcoma is the most common malignant soft tissue tumor in children. It has been demonstrated that Mirk as an activated protein kinase is overexpressed in rhabdomyosarcoma cells, which may be correlated with tumorigenesis. The aim of the present study was to explore the possibility of Mirk gene as a therapeutic target for the treatment of rhabdomyosarcoma, and the use of RNA interference in a temporally and spatially restricted manner to study the function of the target gene would be highly beneficial. To address this problem, a conditional lentivirus-mediated short hairpin RNA targeting human Mirk gene was constructed and employed to reduce endogenous Mirk expression in the rhabdomyosarcoma RD cell line in vitro. The expression of Mirk shRNA in RD cells transduced with this recombinant vector could be tracked with the expression of red fluorescent protein by the administration of doxycycline. A stable transgenic RD line was generated by transducing RD lines with the packaging viral particles. Quantitative PCR and western blot analysis indicated that the mRNA and protein levels of Mirk in the transgenic RD cells were significantly lower compared to those in the controls. In addition, the increasing apoptosis of RD cells induced by silencing of the Mirk gene was also observed. Overall, the results demonstrated that this recombinant vector-based RNAi expression system is an efficient approach to knockdown Mirk gene expression in the rhabdomyosarcoma RD cell line, which could, thereby, provide both a protocol to study the role of Mirk gene in tumor cells and a safer gene therapy in the clinic.

Hypodontia and hypoplasia of mandible: A rare defect caused by combination therapy

Hypodontia is defined as the developmental absence of one or more tooth and it can present in varying degrees of severity and severe hypodontia has been defined as the absence of six teeth, excluding third molars. Radiation plays an important role in the treatment of head and neck cancer, in spite of its benefits, radiation has several side-effects in the head and neck region. This article highlights a case report, where hypodontia, hypoplasia of mandible, stunded permanent teeth roots, microdontia, inversion of tooth bud were observed in 19 years old patient who was diagnosed with Langerhans cell histiocytosis at her age of 3 years she had received a combination of radiotherapy and chemotherapy for a period of 1 year and radiation of 50 Gy was used in the head and neck region. Radiographs were taken and it revealed abnormal changes in growth and development of bone and teeth.

[Children who received a radiotherapy treatment of the cranio-cervico-facial region: appraisal of the orthodontic treatment need]

INTRODUCTION

Currently, 1 out of 900 adults from the ages of 16 to 44 is a survivor of childhood cancer. The global rate of survival for all types of childhood cancer is close to 80% and progress in treatment and care continues to offer promising results. In the years following treatment, these children, just like other healthy children, should have access to orthodontic care in spite of their chronic health problems.

OBJECTIVES

A transverse epidemiological study was conducted at the Leon Bernard Cancer Treatment Center in Lyon in order to respond to these requests and to assist orthodontists with the therapeutic difficulties presented by these patients. Our objective was to identify the orthodontic treatment required for children 7 years old or older who received antineoplastic therapy with radiation of the cranio-cervico-facial region.

RESULTS

The results show that children who received radiation therapy in the cranio-facial region presented delayed growth, facial asymmetry in 74% of the cases, overbite and overjet increased respectively in 70% and 61% of the cases. Dental discrepancies in development were present in 83% of the patients who presented with stunted teeth, premature closing of the apices and hypoplasias. We found sialopathy such as reduced saliva flow rate. Finally, considerable treatment was necessary in 61% of the cases and moderate treatment for 17% of the cases, because of missing teeth, retained deciduous teeth or an increased overjet.

A low-grade myofibroblastic sarcoma in the abdominal cavity

Background

Rhabdomyosarcoma is the most common malignant tumor in the nasal and paranasal sinus area at childhood. Multimodal treatment for this disorder has severe side effects due to normal tissue damage. As a result of this treatment, facial growth retardation and oral abnormalities such as malformation of teeth and microstomia can cause esthetic and functional problems.

Case reports

Two cases are presented of patients with severe midfacial hypoplasia and reduced oral function as a result of treatment of rhabdomyosarcoma of the nasopharyngeal and nasal–tonsil region. With a combined surgical (osteotomy, distraction osteogenesis, implants) and prosthetic (implant-based overdenture) treatment, esthetics and function were improved.

A systematic review of dental disease in patients undergoing cancer therapy

INTRODUCTION

This purpose of this systematic review was to evaluate the literature and update our current understanding of the impact of present cancer therapies on the dental apparatus (teeth and periodontium) since the 1989 NIH Development Consensus Conference on the Oral Complications of Cancer Therapies.

REVIEW METHOD

A systematic literature search was conducted with assistance from a research librarian in the databases MEDLINE/PubMed and EMBASE for articles published between 1 January 1990 and 31 December 2008. Each study was independently assessed by two reviewers. Taking into account predetermined quality measures, a weighted prevalence was calculated for the prevalence of dental caries, severe gingival disease, and dental infection. Data on DMFT/dmft, DMFS/dmfs, plaque, and gingival indexes were also gathered. The level of evidence, recommendation, and guideline (if possible) were given for published preventive and management strategies.

RESULTS

Sixty-four published papers between 1990 and 2008 were reviewed. The weighted overall prevalence of dental caries was 28.1%. The overall DMFT for patients who were post-antineoplastic therapy was 9.19 (SD, 7.98; n = 457). The overall plaque index for patients who were post-antineoplastic therapy was 1.38 (SD, 0.25; n = 189). The GI for patients who were post-chemotherapy was 1.02 (SD, 0.15; n = 162). The weighted prevalence of dental infections/abscess during chemotherapy was reported in three studies and was 5.8%.

CONCLUSIONS

Patients who were post-radiotherapy had the highest DMFT. The use of fluoride products and chlorhexidine rinses are beneficial in patients who are post-radiotherapy. There continues to be lack of clinical studies on the extent and severity of dental disease that are associated with infectious complications during cancer therapy.

Chiari I malformation after cranial radiation therapy in childhood: a dynamic process associated with changes in clival growth

OBJECT

The small posterior fossa is believed to be relevant to the development of Chiari I malformation (CMI). In this study, we evaluated children with supratentorial tumors developing CMI after radiation therapy (RT) that involved the skull base. Changes in clivus and supraocciput growth rate were correlated with tonsillar herniation.

METHODS

Ten children who underwent RT for supratentorial tumors at St. Jude Children's Research Hospital (1994-2008) developed CMI on follow-up magnetic resonance imaging (MRI). Four other patients with supratentorial tumor and CMI who did not receive RT were identified. Length of the supraocciput, basisphenoid, and basichondrium and extent of tonsillar herniation were measured on serial midsagittal MRI.

RESULTS

Over the median follow-up of 85.5 months, basisphenoid annual growth rate was significantly lower in children receiving RT for suprasellar tumor (n=8) than those who did not (p=0.04). Growth of clivus and basisphenoid was significantly lower in the first 12 months after RT in children who received RT for suprasellar tumor (p=0.03 and p=0.04, respectively). In these patients, tonsillar herniation increased over 24 months after RT, reaching maximal descent at a mean of 20.2 months; this resolved as clival growth returned to normal. No patient was symptomatic.

CONCLUSIONS

In these children, restriction of clival growth occurred after RT for suprasellar tumors. Changes in clival growth were associated with changes in the extent of tonsillar herniation. This supports the importance of the small posterior fossa and reduced clival length in the etiology of CMI.

Treatment of Nonmetastatic Cranial Parameningeal Rhabdomyosarcoma in Children Younger Than 3 Years Old: Results From International Society of Pediatric Oncology Studies MMT 89 and 95

Purpose

To explore a strategy by which radiotherapy (RT) could be avoided in the treatment of young children with parameningeal rhabdomyosarcoma (PM RMS).

Patients and Methods

Fifty-nine children (median age, 2 years 3 months) with nonmetastatic cranial PM RMS were treated in the International Society of Pediatric Oncology MMT 89 and 95 trials between 1989 and 2003.

Results

Five-year EFS and OS rates were 46% and 54%, respectively, for the whole group. No standard clinical or pathologic variables had prognostic impact. Fifty (85%) of 59 patients achieved complete local control either with (n = 28) or without (n = 22) RT administered as part of their primary treatment. Nine patients (15%) did not achieve local control (four of whom had had RT), and all died. Patients who received RT had a significantly superior 5-year EFS rate compared with patients who did not receive RT (59% v 28%, respectively). Twenty-three patients (48%) experienced relapse at a median interval of 15 months. Ultimately, only seven patients (12%) were cured without RT, although this represented 32% of those who achieved local control with initial chemotherapy.

Conclusion

Despite concerns about the late effects of its use in young children, cure of PM RMS remains unlikely without systematic use of RT. The accurate prediction of the small subset of patients who achieve local control without RT and who do not experience relapse would provide an opportunity for a minority of patients to avoid RT.

Radiation-induced craniofacial bone growth disturbances

Multimodality treatment, including radiotherapy, chemotherapy, and surgery, is required for the management of head and neck cancer in pediatric patients. Despite the modern advances in radiation dosing and targeting techniques, the radiation damage to the growing craniofacial skeleton in children remains a significant clinical problem. The first part of this review summarizes the clinical effects of radiotherapy on craniofacial bone growth in children. Experimental evidence on therapeutic radiation effects on bone growth in in vivo and in vitro models is reviewed. The second part of this review focuses on prevention of radiation-induced craniofacial bone growth inhibition using radioprotective agents.

Symptomatic Chiari type I malformation after radiation therapy in an infant: case report

OBJECTIVE

One previous case report has described the development of a Chiari I malformation in a child after fractionated radiation therapy to the anterior cranial base. The authors present an additional case of a 17-month-old girl treated for an isolated, malignant, rhabdoid tumor of the right neck with neoadjuvant chemotherapy, surgical exploration, and radiation therapy.

CLINICAL PRESENTATION

The patient developed a Chiari I malformation and cervical syringomyelia 1.5 years after the treatment. The patient experienced two episodes of unresponsiveness before diagnosis, and the malformation was then identified on magnetic resonance imaging scans.

INTERVENTION

Suboccipital decompressive craniectomy, and C1 laminectomy with autologous duraplasty were performed.

RESULTS

Postoperative magnetic resonance imaging scans revealed reconstitution of cerebrospinal fluid at the foramen magnum and ascent of the cerebellar tonsils. The patient remains asymptomatic 5.5 years after treatment.

CONCLUSION

The importance of this association is discussed in the context of the increasing use of radiation therapy in young children and infants.

Rhabdomyosarcoma of the mandible in a 6-year-old boy

INTRODUCTION

Rhabdomyosarcoma is an aggressive malignant tumour composed of neoplastic mesenchymal cells that infiltrate surrounding tissue structures, making their precise site of origin unclear. Although rare, this is highly aggressive and the most common soft-tissue neoplasm of the head and neck in children. Regrettably by the time most cases are initially seen, the patients already have large tumours, due to rapid tumour growth and delayed medical consultation.

CASE REPORT

This report describes a 6-year-old presenting with just such symptoms of facial swelling and pain but elicitation of further information and findings, including tooth mobility of 3 days duration, led to prompt referral and early treatment of an embryonal rhabdomyosarcoma.

CONCLUSION

General dental practitioners are frequently presented with a child with a swollen face and pain. Experience would suggest a dental abscess to be the most likely cause with treatment as appropriate. However, all swellings in children, should be thoroughly investigated and reviewed as particularly in this age group, tumour growth is rapid while early diagnosis allows successful treatment with multimodality therapy.

Late effects of pelvic rhabdomyosarcoma and its treatment in female survivors

PURPOSE

To document the spectrum and severity of late effects in female survivors of pelvic rhabdomyosarcoma.

PATIENTS AND METHODS

We reviewed the demographic, diagnostic, treatment, and outcome data of the 26 females treated for pelvic rhabdomyosarcoma at our institution between March 1962 and December 1996 who survived free of disease for 5 or more years. Adverse effects that occurred 5 or more years after diagnosis were graded according to the National Cancer Institute Common Terminology Criteria for Adverse Events, version 3.0.

RESULTS

The most common tumor sites were vagina (n = 7), pelvis/retroperitoneum (n = 6), and bladder (n = 4). All patients received chemotherapy (alkylating agent, n = 23; doxorubicin, n = 16); 22 received radiotherapy (median dose, 46 Gy). Median follow-up of the 23 survivors was 20.3 years. Late effects occurred in 24 patients, 23 of whom had grade 3/4 late effects (median grade 3/4 late effects per patient, three; range, zero to 14). Fourteen patients (54%) required surgery for late complications. The 22 patients who had received radiotherapy had a greater median number of late effects per patient than did the remaining four (9.5 v one; P = .002). The median number of late effects per patient was higher in the 12 patients treated during or after 1984 than in the 14 treated earlier (12.5 v 6.5; P = .041).

CONCLUSION

The burden of late effects in girls treated for pelvic rhabdomyosarcoma is significant and does not seem to be diminishing with advances in treatment. Prospective studies are needed to better assess the impact of these late effects on quality of life and functional outcome, and to refine the treatment approach to pelvic rhabdomyosarcoma.

The effects of external beam irradiation on the growth of flat bones in children: modeling a dose-volume effect

PURPOSE

To model the effects of external beam irradiation on the developing flat bones of pediatric patients undergoing radiation therapy (RT) for tumors involving the musculoskeletal system.

METHODS AND MATERIALS

Patients with image-guided RT plans including areas adjacent to facial or pelvic flat bones underwent retrospective contouring of nontumor involved flat bones ipsilateral and contralateral to the treatment side. Radiation dose-volume information and bone volume data (initial and the most recent follow-up) were analyzed in 15 paired flat bones from 10 patients (ages 1.0-17.0 years). The models to predict bone growth after completion of RT (v(post)) were based on initial bone volume (v(pre)), the patient's age, time to follow-up (t), and the dose-volume parameter (v(Int35+)).

RESULTS

We developed a dose effects model as follows: Log (v(post) / v(pre)) = beta(time)t + beta(age group)t + beta(dose)t v(Int35). The dose-volume parameter v(Int35) predicted significantly for alterations in growth in younger patients, but not for older patients. The predictability of the fitted model for relative change in bone growth improved in the younger age group with the addition of the dose-volume term v(Int35) (correlation coefficient of r = 0.5510 to r = 0.6760 with the addition v(Int35)).

CONCLUSIONS

Our model accurately predicted flat bone growth and is notable for the inclusion of radiation dose-volume information, which is now available in the image-guided RT era. Further refinement of this model in a prospective patient population is underway.

Update in management of head and neck sarcoma

PURPOSE OF REVIEW

This update addressing head and neck sarcoma presents new data published after January 2003. This new information is presented following review of contemporary management principles established before 2003.

RECENT FINDINGS

The application of advances in molecular and genetic techniques to characterize individual sarcomas has improved classification schemes and hopefully will lead to individually tailored therapy. Maturation and refinements of large tumor registries are permitting more detailed analysis of larger contemporary series of the rare head and neck sarcomas. Improved long-term survival of patients treated for sarcoma in their childhood has allowed study of the morbidity induced by treatment. Novel treatment strategies are under study to decrease morbidity without diminishing the chance for cure.

SUMMARY

Progress in improving the treatment of sarcoma of the head and neck has been slow due to the lack of a large clinical experience with this rare neoplasm. Advances continue and are anticipated to be most striking in the study of genetic mechanisms.