Absorbed doses in the head and oral cavity during total body irradiation

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.

[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.

Disturbed root development of permanent teeth after pediatric stem cell transplantation. Dental root development after SCT

BACKGROUND

Deficient dental root development has been reported after conventional pediatric anticancer therapy, but less information is available on stem cell transplantation (SCT) recipients.

METHODS

Root-crown (R/C) ratios of fully developed permanent teeth were assessed from panoramic radiographs of 52 SCT recipients, who were treated when they were age < 10 years. Using standard deviation scores (SDSs), the authors compared the R/C ratios to the corresponding tooth and gender-specific values in a healthy population. The percentage of affected R/C ratios per individual was examined in a subgroup of 39 (SG39) patients with advanced tooth development. The effects of total body irradiation (TBI) and SCT age on the R/C ratios were studied in TBI and high-dose chemotherapy (HDC = non-TBI) groups and in 3 age groups (< or = 3.0 years, 3.1-5.0 years, > or = 5.1 years).

RESULTS

Per individual, 77% of the fully developed permanent teeth were affected in SG39. At the tooth level, in 77% of the 945 teeth studied (52 patients), the R/C ratios were outside +/-2 SDSs. More teeth were affected in the TBI (85%) than in the non-TBI (55%) group (P < 0.001). The teeth of the patients who were ages 3.1-5.0 years old at SCT presented with the most severe aberrations of the R/C ratio (mean SDS = -4.4) whereas the teeth of the youngest (age < or = 3.0 years) and the oldest (age > or = 5.1 years) patients were equally affected (mean SDSs = -3.1 and -3.0, respectively).

CONCLUSIONS

Disturbances of dental root growth always followed pediatric SCT. HDC alone intensely harmed root growth but TBI further increased the adverse effects that were most extensive in the patients 3.1-5.0 years at SCT. These sequelae should be taken into account during the lifelong dental follow-up to minimize the clinical consequences of dental injuries.