Incidence and correlates of radiation pneumonitis in pediatric patients with partial lung irradiation.
OBJECTIVE
To provide a radiation pneumonitis risk estimate and investigate the correlation of clinical and dosimetric factors in pediatric patients receiving chest irradiation.


METHODS
A total of 122 patients diagnosed with sarcoma or Hodgkin lymphoma who received radiotherapy to the chest were evaluated for symptomatic radiation pneumonitis (Common Toxicity Criteria Grade 1 with respiratory symptom or higher grade). Pneumonitis data were collected from either prospective toxicity screenings as part of a clinical trial or through chart review. Dosimetric parameters including V(10)-V(25), mean lung dose, binned lung dose, and tissue complication probability models were used, as well as clinical features to correlate with the development of pneumonitis.


RESULTS
The 1- and 2-year cumulative incidence of symptomatic radiation pneumonitis for all patients was 8.2% and 9.1%, respectively. Nine patients experienced symptomatic Grade 1 toxicity, and 2 experienced Grade 2. From univariate analysis, chemotherapy containing bleomycin (chi(2) test, p = 0.027) and V(24) (logistic regression, p = 0.019) were the clinical and dosimetric factors that resulted in statistically significant differences in the occurrence of pneumonitis. The probability of pneumonitis increased more dramatically with increasing V(24) in patients receiving bleomycin than in those who did not. Adult tissue complication models did not differentiate pediatric patients with radiation pneumonitis from those without.


CONCLUSIONS
The incidence of symptomatic radiation pneumonitis in pediatric patients is low and its severity mild. Parameters frequently used in adult radiation oncology provide some guidance as to risk, but pediatric patients warrant their own specific models for risk assessment, incorporating dosimetry and clinical factors.
Hua
Chiaho
C
Department of Radiological Sciences, St Jude Children's Research Hospital, Memphis, TN 38105-3678, USA. Chia-Ho.Hua@stjude.org
Hoth
Kelly A
KA
Wu
Shengjie
S
Kun
Larry E
LE
Metzger
Monika L
ML
Spunt
Sheri L
SL
Xiong
Xiaoping
X
Krasin
Mathew J
MJ
D000293:Adolescent; D000704:Analysis of Variance; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use; D001859:Bone Neoplasms / Q000188:drug therapy / Q000532:radiotherapy*; D002648:Child; D002675:Child, Preschool; D005260:Female; D006689:Hodgkin Disease / Q000188:drug therapy / Q000532:radiotherapy*; D006801:Humans; D015994:Incidence; D008168:Lung / Q000528:radiation effects; D008297:Male; D015233:Models, Statistical; D017564:Radiation Pneumonitis / Q000453:epidemiology* / Q000209:etiology; D011879:Radiotherapy Dosage; D018570:Risk Assessment; D012509:Sarcoma / Q000188:drug therapy / Q000532:radiotherapy*; D012983:Soft Tissue Neoplasms / Q000188:drug therapy / Q000532:radiotherapy*; D055815:Young Adult