Radiation Pneumonitis in Pediatric Hodgkin Lymphoma Patients receiving Radiotherapy to the Chest

Radiation Pneumonitis in Pediatric Hodgkin Lymphoma Patients receiving Radiotherapy to the Chest

Poster Viewing E569 Volume 99  Number 2S  Supplement 2017 Abstract 3353; Table 1 abnormalities. Age at Radiation Treatment 13 p-value1 1 Percent o...

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Poster Viewing E569

Volume 99  Number 2S  Supplement 2017 Abstract 3353; Table 1 abnormalities. Age at Radiation Treatment <5 5- 13 years >13 p-value1 1

Percent of participants with pulmonary

Any Abnormality 66.7 42.3 20.7 0.022

Diffusing Abnormality 33.3 23.08 13.8 0.202

Obstructive Restrictive 16. 7 7.7 6.9 0.208

33.3 23.1 10.3 0.379

Fisher’s exact test comparing frequencies across all categories

Data collection included age at diagnosis and treatment (radiation, chemotherapy, thoracic surgery), radiation dose and location, spirometry and plethysmography results. PFTs were normalized according to age, gender, height, and ethnicity and transformed into standardized z- scores. Obstructive disease was defined as zFEV1/FVC < -1.645, restrictive as zTLC < -1.645 and abnormal diffusion as zDLCO < -1.645. We determined the incidence of obstructive, restrictive, or diffusing capacity abnormalities in our population and estimated the relative risk of developing pulmonary abnormalities using models adjusted for age, time from radiotherapy (RT), and bleomycin use. Results: At a mean age of 24 years (range 12-31) and time from diagnosis of 9 years (range 1-20), the cumulative incidence of any pulmonary abnormality was 34.4%. The incidence of diffusion abnormalities, obstructive, and restrictive disease was 19.6%, 18% and 8.1% respectively. Patients receiving mantel field or TBI radiation were more likely to have a PFT abnormality compared to those radiated at other lung sites after adjustment for time from RT, age, and bleomycin use [OR 1.20 95%CI (0.94, 1.32) and 2.01 95%CI (0.35, 11.51) respectively]. Those <5 years and 5-13 years had more diffusing, restrictive, and obstructive abnormalities than those >13 years (table 1). Compared to patients >13 years, those < 5 years and 5 - 13 years at radiation treatment had a significantly increased risk of an abnormal PFT as follows: OR 7.71 (95% CI: 1.17, 51.06) and 3.51 (95% CI: 1.06, 11.57) respectively, p<0.035, although statistical significance was lost after adjustment for bleomycin use and time since RT. Further, this association with age remained when examining each type of abnormality (p>0.05). Conclusion: Pulmonary function abnormalities were common among our cohort of childhood cancer survivors treated with lung radiation. Both diffusion and obstructive disease were more common than restrictive disease. Younger age at treatment is associated with an increasing risk of developing pulmonary dysfunction, presumably due to developmental immaturity. Author Disclosure: F. Khan: None. A. Williams: None. D.J. Weiner: None. S. Dhakal: None. L.S. Constine: ; American College of Radiology.

3354 Radiation Pneumonitis in Pediatric Hodgkin Lymphoma Patients receiving Radiotherapy to the Chest G. Lewis,1 J. Agrusa,2,3 B.S. Teh,4 M. Gramatges,2,3 V. Kothari,2,3 C. Allen,2,3 and A.C. Paulino2,5; 1UTMB, Galveston, TX, 2Texas Children’s Hospital, Houston, TX, 3Baylor College of Medicine, Houston, TX, 4 Houston Methodist Hospital, Houston, TX, 5University of Texas MD Anderson Cancer Center, Houston, TX Purpose/Objective(s): Although there is adequate information on the incidence and risk factors for radiation pneumonitis in adults, it is limited in children. One may speculate that children may have better tolerance than adults as they do not have the same risk factors for lung injury such as smoking and asbestos exposure; furthermore, radiotherapy (RT) doses delivered to the chest in pediatric malignancies are lower compared to patients treated for lung cancer. The purpose of this study is to determine the incidence of radiation pneumonitis (RP) in the pediatric population receiving RT for Hodgkin lymphoma (HL). Materials/Methods: A retrospective chart review was conducted of pediatric HL patients who received involved site thoracic RT after induction chemotherapy. The National Cancer Institute Common Terminology

Criteria for Adverse Events (CTCAE) version 4.03 was used to determine the RP grade (Grade 1: asymptomatic, clinical or diagnostic observations only, intervention not indicated, Grade 2: symptomatic, medical intervention needed, Grade 3: severe symptoms, oxygen indicated, Grade 4: life threatening respiratory compromise including tracheotomy and intubation, Grade 5: death). Parameters analyzed included gender, age, bleomycin dose, and RT dosimetric variables such as mean total lung dose, mean individual (right versus left) lung dose, and V5 to V25. Results: From 2008-2016, 54 patients with HL received RT to the chest and had follow-up and dosimetry information. There were 29 females; median age was 15 years (3-18 years). All patients received induction chemotherapy with a regimen that included bleomycin (median dose 60 IU/m2). The most common regimen was ABVE-PC based chemotherapy (n Z 48). All received a prescribed dose of 21 Gy in 14 fractions to part of the chest. Median follow-up from completion of radiotherapy was 39.5 months. Three patients (5.6%) developed RP; two had Grade 1 while one had Grade 2 RP. RP was seen only in patients with individual mean lung dose (MLD) > 13.8 Gy. The incidence of RP according to MLD was 0 of 91 lungs with MLD < 13.7 Gy vs. 3 of 17 (17.6%) with MLD > 13.8 Gy (p < 0.005). RP was seen in 0 of 92 lungs with V20 < 35%, 1 of 7 (14.2%) receiving V20 from 35 to 42%, and 2 of 9 (22.2%) with V20 > 43% (p < 0.005). RP was also more common in lungs with V5 > 75% (p Z0.02), V10 > 64% (p Z 0.02) and V15 > 47% (< 0.005). We did not find any association between age, gender, bleomycin dose and development of RP. Conclusion: RP in pediatric HL patients is an uncommon complication. MLD, V20, V15, V10 and V5 correlated with RP. Further development of pediatric-specific models for RP is necessary as radiation treatment techniques improve. Author Disclosure: G. Lewis: None. J. Agrusa: None. B.S. Teh: None. M. Gramatges: None. V. Kothari: None. C. Allen: None. A.C. Paulino: Royalties for text book; Elsevier Inc.. Rad Onc Written and Oral Board Examinations; ABR.

3355 A Comparison of Pediatric Versus Adult Patients With Rhabdomyosarcoma C. Lin; Department of Radiation Oncology, University of Nebraska Medical Center, Omaha, NE Purpose/Objective(s): Rhabdomyosarcoma (RMS) is a pediatric sarcoma rarely occurring in adults. Adults with RMS have worse outcomes. We hypothesize that the difference in survival between pediatric and adult were not only due to the disease itself but also influenced by discrepancies in the treatment. This study sought to identify differences in prognostic factors in pediatrics and adults, and to examine the differences in treatments and outcomes between groups after matching all prognostic factors. Materials/Methods: Patients (nZ475 pediatric, nZ448 adult) were analyzed using the Surveillance, Epidemiology, and End Results Database from 2004-2013. Between the two groups, demographic, tumor, and treatment characteristics were collated and compared. Chi-squared test was used to determine differences between groups in proportions of the variables. Survival analysis between cohorts (with and without propensitymatched) was done by the Kaplan-Meier method; distributions were compared using the log-rank test. Univariate and multivariate analyses were performed in order to examine variables correlating with overall survival (OS). Results: Pediatrics had a higher odds of having smaller tumor volume, head and neck location, embryonal/spindle histology and receiving radiotherapy (RT) or surgery. Cox regression revealed that factors associated with improved OS were younger age, non-metastasis, smaller tumor volume, embryonal/spindle histology, and receiving RT or surgery. Caucasian and smaller tumor volume were associated with improved OS in pediatrics but not in adults. Pediatric patients positively correlated with OS after adjusting for all potential confounding factors. The median and 5 year OS of the entire population were 49 months and 46%. Median and 5 year OS for pediatrics (Not reached, 63%) were significantly higher than those for adults (20 months, 28%), p <0.0001. Following propensity matching of