Postchemotherapy PET evaluation correlates with patient outcome in paediatric Hodgkin's disease

Abstract

Aim: To evaluate the role of postchemotherapy FDG PET and compare it with other predictive factors in paediatric Hodgkin's disease (HD).

Materials and methods: In this retrospective study, 98 paediatric patients with HD (enrolled in eight Italian centres) were analysed. Their mean age was 13.8 years (range 5-19 years). A PET scan was performed at the end of chemotherapy and reported as positive or negative on the basis of visual and/or semiquantitative analysis. True outcome was defined as remission or disease on the basis of combined criteria (clinical, instrumental and/or histological) with a mean follow-up period of 25 months. Statistical analyses were performed for the postchemotherapy PET results and other potential predictive factors (age cut-off, stage, presence of bulky masses and therapeutic group) with respect to patient outcome and progression-free survival (PFS).

Results: Overall the patients had a mean PFS of 23.5 months (range 4-46 months): 87 achieved remission (88.8%) and 11 showed disease. Of the 98 patients, 17 were positive on postchemotherapy PET . Seven patients (41%) showed disease during follow-up, and relapse occurred in only four out of the 81 patients who were negative on PET (p = 0.0001). Kaplan-Meier analysis demonstrated significant correlations between PFS and the postchemotherapy PET result (p = 0.0001) and a cut-off age at diagnosis of 13.3 years (p = 0.0337), whereas disease stage (p = 0.7404), therapeutic group (p = 0.5240) and presence of bulky masses (p = 0.2208) were not significantly correlated with PFS. Multivariate analysis confirmed a statistically significant correlation with PFS only for the postchemotherapy PET findings (p = 0.0009).

Conclusion: In paediatric HD, age at diagnosis and postchemotherapy PET results are the main predictors of patient outcome and PFS, with FDG PET being the only independent predictive factor for PFS.