Significance of pleural effusion at diagnosis in pediatric Hodgkin lymphoma: a report from Children’s Oncology Group protocol AHOD0031

BACKGROUND: Pleural effusion at presentation in Hodgkin lymphoma has been associated with inferior outcome but has not been systematically evaluated. OBJECTIVE: To determine whether pleural effusion at presentation in children with Hodgkin lymphoma is a primary indicator of poor prognosis or secondary to associated factors. MATERIALS AND METHODS: Children’s Oncology Group (COG) AHOD0031, a randomized, response-based, centrally reviewed protocol, enrolled 1,712 eligible patients <22 years of age with initial presentation of intermediate risk, biopsy-proven Hodgkin lymphoma; 1,423 had available imaging for retrospective review. We coded effusions as fluid-only or with associated pleural nodule or adjacent lung or bone involvement and correlated this with disease stage, tumor response, large mediastinal adenopathy, and mass effect on the superior vena cava (SVC) and left innominate vein. We recorded change in size and character of effusions post-chemotherapy. RESULTS: Pleural effusions were present in 217, with 204 having fluid-only and 13 having associated solid components. Patients with effusions were more likely to have large mediastinal adenopathy (P<0.0001), be slow early responders (P<0.0001) and have higher relapse rate (P<0.0001). Vascular compression was not significantly correlated with pleural effusion. Of 121 patients with adequate [F-18]2-fluoro-2-deoxyglucose (FDG) positron emission tomography (PET)/CT imaging, no FDG PET avidity was seen in any pleural effusion but was present in solid components. The side of the pleural effusion in those with moderate or large effusions was highly associated with the side of large mediastinal adenopathy (P<0.0001). Statistical analysis indicates that pleural effusion is an independent risk factor for poorer response and relapse. CONCLUSION: Pleural effusion in Hodgkin lymphoma is an important independent poor prognostic indicator for response and relapse.