Estimating differences in volumetric flat bone growth in pediatric patients by radiation treatment method

Early Axial Growth Outcomes of Pediatric Patients Receiving Proton Craniospinal Irradiation

Guidelines on proton craniospinal irradiation (p-CSI) target volume selection in children are lacking. We examined the impact of target volume selection on growth of children receiving p-CSI at a institution. Records of 58 patients who received p-CSI were reviewed. Median age at treatment initiation was 8 years (range, 2 to 18 y). Spinal target volumes included whole vertebral body (WVB) in 67% and partial vertebral body (PVB) in 33%. Height z-scores before and after p-CSI were assessed using Centers for Disease Control and Prevention stature-for-age charts. Maximal Cobb angle and height z-score change were compared for WVB versus PVB p-CSI using a t test. Among 93% of patients with detailed data, median follow-up was 19 months (range, 2 to 58 mo) after radiation therapy initiation. Quantitative growth evaluations were available for 64% of patients. Median change in height z-score was -0.5 (range, -2.1 to +0.7) after treatment, representing a decrease (P<0.001) in age-adjusted height. WVB patients had significantly greater reduction in height z-score versus PVB patients (P=0.004) but no difference in Cobb angle change (P>0.05). Despite reluctance surrounding its use in younger patients, PVB p-CSI was associated with similar spinal curvature and less growth suppression as compared with WVB p-CSI; a trial comparing WVB versus PVB in children may be warranted.

Late toxicity and outcomes following radiation therapy for chest wall sarcomas in pediatric patients

PURPOSE

To investigate the contribution of radiation therapy to acute and late toxicity in pediatric chest wall sarcoma patients and evaluate dosimetric correlates of higher incidence toxicities such as scoliosis and pneumonitis.

METHODS AND MATERIALS

The data from 23 consecutively treated pediatric patients with chest wall sarcomas of various histologies (desmoid, Ewing, rhabdomyosarcoma, nonrhabdomyosarcoma-soft tissue sarcomas) were reviewed to evaluate the relationship between end-organ radiation dose, clinical factors, and the risk of subsequent late effects (scoliosis, pneumonitis). Cobb angles were used to quantify the extent of scoliosis. Doses to the spine and lung were calculated from the radiation treatment plan.

RESULTS

The range of scoliosis identified on follow-up imaging ranged from -47.6 to 64° (median, 2.95°). No relationship was identified between either radiation dose to the ipsilateral or contralateral vertebral body or tumor size and the degree or direction of scoliosis. The extent of surgical resection and number and location of resected ribs affected the extent of scoliosis. The dominant predictor of extent of scoliosis at long-term follow-up was the extent of scoliosis following surgical resection. Radiation pneumonitis was uncommon and was not correlated with mean dose or volume of lung receiving 24 Gy; however, 1 of 3 surviving patients who received whole pleural surface radiation therapy developed significant restrictive lung disease.

CONCLUSIONS

Acute and late radiation therapy-associated toxicities in pediatric chest wall sarcoma patients are modest. The degree of scoliosis following resection is a function of the extent of resection and of the number and location of ribs resected, and the degree of scoliosis at the last follow-up visit is a function of the extent of scoliosis following surgery. Differential radiation therapy dose across the vertebral body does not increase the degree of scoliosis. Severe restrictive pulmonary disease is a late complication of survivors after whole pleural surface radiation therapy.

Children's Oncology Group's 2013 blueprint for research: radiation oncology

Radiation therapy (RT) is used to treat children with CNS tumors, solid tumors or Hodgkin lymphoma. Pediatric radiation oncologists have provided critical input into the development and implementation of concepts for clinical trials to further define the modality's role and test newer methods to reduce side effects or intensify therapy. The quality of pediatric oncology clinical trials that include radiation therapy is linked to the quality of guidelines. Radiation oncology is an adult medical specialty; thus, pediatric radiation oncologists are uniquely positioned to work with adult cancer investigators in the reorganized US National Cancer Institute Clinic Trials Network.