Patterns of Involved-Field Radiation Therapy (IFRT) Protocol Deviations in Pediatric versus Adolescent and Young Adults with Hodgkin Lymphoma: A Report from the Children’s Oncology Group (COG) AHOD0031

Publication date: Available online 6 January 2018
Source:International Journal of Radiation Oncology*Biology*Physics
Author(s): A. Parzuchowski, Rizvan Bush, Qinglin Pei, D.L. Friedman, T.J. FitzGerald, S.L. Wolden, K.V. Dharmarajan, L.S. Constine, F. Laurie, S.K. Kessel, B. Appel, K. Fernandez, A. Punnett, C.L. Schwartz, J. Cox, S.A. Terezakis
BackgroundThis protocol for pediatric intermediate-risk Hodgkin Lymphoma (IRHL) evaluated the use of a dose-intensive chemotherapy regimen (ABVE-PC) with response-based therapy augmentation (addition of DECA) or therapy reduction (elimination of radiation). Central review of radiotherapy data for quality assurance (QA) was performed, and the association between radiation protocol deviation (RPD) and relapse was assessed in pediatric (<15) and AYA (≥15-21) groups.ProcedureIFRT treatment planning was reviewed prior to the start of treatment and at the completion of treatment. Records were reviewed through the Quality Assurance Review Center's (QARC) central review to identify RPD, classified according to dose (DD), volume (VD), under-treatment (UT), and over-treatment (OT). DD and VD were further classified as major or minor.ResultsOf the 1,712 patients enrolled, 1,155 received IFRT and 216 (18.7%) had RPD. DD and VD patterns were similar between pediatric and AYA groups. Minor VD was most common. UT RPD accounted for 69% in the pediatric group and 75% in the AYA group. Of 35 relapses and RPD, 29 had an under-treatment RPD. Among the patients who received IFRT, there was a significant difference in the cumulative incidence rates of relapse between pediatric and AYA groups (p=0.03) but no significant difference between patients with and without RPD (p=0.2).ConclusionsThe majority of RPD were minor and under-treatments in both the AYA and pediatrics population. There was no observed difference in RPD between the pediatric and AYA patients. Thus, in a well-defined and standardized protocol, RPD distributions for AYA patients are similar to the pediatrics population. However, the increased cumulative incidence of relapse in the AYA population who received IFRT compared to the pediatrics population needs to be further explored given the potential differences in clinical outcomes in the AYA population.

Teaser

As ******** is the largest phase III study to date on intermediate-risk Hodgkin Lymphoma in pediatric patients, we investigated the patterns of radiation protocol deviation and relapse between the pediatric and adolescent and young adult patient cohorts. We demonstrate that there were no statistically significant differences in deviation patterns between the two cohorts, though of those that received IFRT, there was a significant difference in cumulative incidence rates of relapse between the two groups.


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