Mandibular third molar development after mantle radiation in long-term survivors of childhood Hodgkin's disease

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 systematic review of dental late effects in survivors of childhood cancer

Survivors of childhood cancer are at risk for dental late effects. This systematic review summarizes associations between treatment exposures and dental late effects among survivors of childhood cancer. We included investigations with at least 20 study participants conducted for 2 or more years after completion of childhood, adolescent, or young adult cancer therapy. This review suggests both independent and additive effects of radiotherapy and chemotherapy on dental complications, and identifies vulnerable groups with specific host and treatment characteristics. This summary provides information that will assist clinicians to prevent, detect, and facilitate early intervention for dental late effects.

The chronology of third molar mineralization in the Austrian population—a contribution to forensic age estimation

The aim of the present study was to determine the chronology of third molar mineralization and to establish Austrian reference data. Therefore, a cross-sectional study was undertaken by evaluating 610 panoramic radiographs in order to assess the mineralization status of the mandibular third molars of Austrian male and female individuals (275 males and 335 females) between the ages of 12 and 24. The evaluation was carried out using the eight grade scheme of Demirjian et al. (1973). Mean ages, standard deviations, standard errors and percentile distributions are presented for each stage of development. Significant differences between the left and right mandibular third molars were not found. Males reach the developmental stages earlier than females, statistically significant differences were noted in stages E and F. Both mandibular third molars were observed in the majority of the individuals of the Austrian sample (477 individuals, 78.2%). For medicolegal purposes the likelihood of whether an Austrian individual is older than 18 years or not was determined.

Treatment planning with protons for pediatric retinoblastoma, medulloblastoma, and pelvic sarcoma: How do protons compare with other conformal techniques?

PURPOSE

To calculate treatment plans and compare the dose distributions and dose-volume histograms (DVHs) for photon three-dimensional conformal radiation therapy (3D-CRT), electron therapy, intensity-modulated radiation therapy (IMRT), and standard (nonintensity modulated) proton therapy in three pediatric disease sites.

METHODS AND MATERIALS

The tumor volumes from 8 patients (3 retinoblastomas, 2 medulloblastomas, and 3 pelvic sarcomas) were studied retrospectively to compare DVHs from proton therapy with 3D-CRT, electron therapy, and IMRT. In retinoblastoma, several planning techniques were analyzed: A single electron appositional beam was compared with a single 3D-CRT lateral beam, a 3D-CRT anterior beam paired with a lateral beam, IMRT, and protons. In medulloblastoma, three posterior fossa irradiation techniques were analyzed: 3D-CRT, IMRT, and protons. Craniospinal irradiation (which consisted of composite plans of both the posterior fossa and craniospinal components) was also evaluated, primarily comparing spinal irradiation using 3D-CRT electrons, 3D-CRT photons, and protons. Lastly, in pelvic sarcoma, 3D-CRT, IMRT, and proton plans were assessed.

RESULTS

In retinoblastoma, protons resulted in the best target coverage combined with the most orbital bone sparing (10% was the mean orbital bone volume irradiated at > or =5 Gy for protons vs. 25% for 3D-CRT electrons, 69% for IMRT, 41% for a single 3D lateral beam, 51% for a 3D anterolateral beam with a lens block, and 65% for a 3D anterolateral beam without a lens block). A single appositional electron field was the next best technique followed by other planning approaches. In medulloblastoma, for posterior fossa and craniospinal irradiation, protons resulted in the least dose to the cochlea (for only posterior fossa irradiation at > or =20 Gy, 34% was the mean cochlear volume irradiated for protons, 87% for IMRT, 89% for 3D-CRT) and hypothalamus-pituitary axis (for only posterior fossa irradiation at > or =10 Gy, 21% was the mean hypothalamus-pituitary volume irradiated for protons, 81% for IMRT, 91% for 3D-CRT); additional dose reductions to the optic chiasm, eyes, vertebrae, mandible, thyroid, lung, kidneys, heart, and liver were seen. Intensity-modulated radiotherapy appeared to be the second best technique for posterior fossa irradiation. For spinal irradiation 3D-CRT electrons were better than 3D-CRT photons in sparing dose to the thyroid, heart, lung, kidney, and liver. With pelvic sarcoma, protons were superior in eliminating any dose to the ovaries (0% of mean ovarian volume was irradiated at > or =2 Gy with protons) and to some extent, the pelvic bones and vertebrae. Intensity-modulated radiotherapy did show more bladder dose reduction than the other techniques in pelvic sarcoma irradiation.

CONCLUSIONS

In the diseases studied, using various techniques of 3D-CRT, electrons, IMRT, and protons, protons are most optimal in treating retinoblastomas, medulloblastomas (posterior fossa and craniospinal), and pelvic sarcomas. Protons delivered superior target dose coverage and sparing of normal structures. As dose-volume parameters are expected to correlate with acute and late toxicity, proton therapy should receive serious consideration as the preferred technique for the treatment of pediatric tumors.

Dental abnormalities in children treated for neuroblastoma

PURPOSE

To determine the frequency and types of dental abnormalities among children treated at a young age for cancer, as represented by neuroblastoma.

PATIENTS AND METHODS

We retrospectively reviewed the dental records and panoramic radiographs of 542 children who were treated for neuroblastoma at our institution over a 31-year period. Patients in our study had to meet the following criteria: they were treated on an institutional protocol, they had undergone panoramic radiography, and their dental follow-up continued for at least 2 years after diagnosis. We evaluated the frequency of clinically or radiographically apparent microdontia, excessive caries, root stunting, hypodontia, and enamel hypoplasia in our study population.

RESULTS

Of the 52 patients who met the study criteria, 71% developed dental abnormalities, comprising microdontia in 38%, excessive caries in 29%, root stunting in 17%, hypodontia in 17%, and enamel hypoplasia in 17%. In nearly half (23) of our patients, neuroblastoma was diagnosed on or before their first birthday.

CONCLUSION

Children treated for neuroblastoma are at high risk for abnormal dental development. The abnormalities in these patients may require extensive dental care and can compromise their quality of life. Frequent dental examinations and an intense oral hygiene program before, during, and after treatment may improve overall dental health.

Assessment and treatment of facial deformity resulting from radiation to the orbital area in childhood

Children who receive radiation for malignant tumors in the orbital area frequently develop widespread craniofacial deformities. These affect the skull, orbit, maxilla, and mandible. When these patients seek treatment at a later age, they require careful assessment using cephalometrics and three-dimensional imaging. It is recommended that the four levels of skeletal deformity be corrected in a single procedure, that is frontotemporal expansion with repositioning of the skull base area, orbital expansion and repositioning together with maxillary and mandibular surgery. Bone grafts should be inlay rather than onlay and soft tissue should be supplied by free-tissue transfer. This counteracts any residual ischemia related to the previous radiation therapy. The second surgical stage is designed to reconstruct the socket and the eyelids to allow more satisfactory rehabilitation with an ocular prosthesis. In patients who have a globe present, the usual enophthalmos can be corrected by repositioning of the eye as part of the first procedure by reducing the anteroposterior dimensions of the socket. In bilateral cases, the deformity is hourglass in nature and requires correction in the frontal and temporal area with lateral displacement of the orbits. A bimaxillary procedure is also indicated. It is emphasized that to formulate a satisfactory operative plan an in-depth three-dimensional analysis of the deformity is mandatory.

Dental abnormalities in long-term survivors of head and neck rhabdomyosarcoma

To define the long-term dental sequelae of therapy for childhood rhabdomyosarcoma of the head and neck, and to identify factors in their development, we retrospectively reviewed the serial panoramic radiographs and clinical records of 22 survivors of head or neck rhabdomyosarcoma who had been followed for at least 5 years. Patients were divided into four groups based upon age at the time of therapy and three groups based upon radiation doses. All patients had received similar multiagent chemotherapy. Dental sequelae of oncotherapy occurred in over half of the long-term survivors of head and neck rhabdomyosarcoma. The abnormalities comprised root stunting in 54%, microdontia in 23%, and hypodontia in 50% of patients; 36% had multiple abnormalities. Microdontia and multiple abnormalities were more prevalent in patients treated at the earliest age, and abnormalities tended to be more prevalent with increasing doses of radiation. Five patients (23%) developed severe cosmetic and/or functional sequelae necessitating surgical and/or orthodontic intervention. The high frequency of dental sequelae we observed suggests that meticulous long-term dental and radiographic follow-up are needed. Early detection and treatment of the complications of therapy will expedite their correction and minimize morbidity.

Micrognathia after radiation therapy for childhood facial tumors. Report of two cases with long-term follow-up

As the survival duration and cure rate of children with malignant conditions improve, awareness of long-term side effects is crucial. Two case reports demonstrate long-term changes in dentition and orofacial development in children who had been treated for facial malignant conditions. Changes induced mandibular and maxillary hypoplasia, partial anodontia, microdontia, altered eruption pattern, root stunting, and altered amelogenesis.