Prognostic importance of restaging gallium scans following induction chemotherapy for advanced Hodgkin's disease

This study was intended to assess the ability of restaging gallium scanning to distinguish between patients with residual radiographic abnormalities who still have active Hodgkin's disease (HD) and those who are truly complete responders. Early identification of the former patients might increase the success of secondary salvage therapy. The charts of all patients with advanced HD treated at Duke University Medical Center during the years 1983 to 1991 who underwent gallium scanning were reviewed. Thirty-three patients were identified who had gallium scans performed as part of restaging following induction combination chemotherapy; no patient had other signs or symptoms of active or progressive HD. Thirteen of 33 patients had positive restaging gallium scans; 20 patients had negative scans. The 4-year actuarial relapse-free survival (RFS) rate was 75% for patients with negative restaging gallium scans compared with 8% for those with positive restaging scans (P < .001). The 4-year actuarial overall survival (OS) rate was 100% for those with negative scans compared with 51% for gallium-positive patients (P = .001). Twenty-four patients had residual chest x-ray or computed tomographic scan abnormalities. Calculated negative and positive predictive values for gallium scanning are 92% and 90%, respectively, compared with values of 48% and 83% for computed tomographic scanning. Restaging gallium scans separate complete responders from induction failures with a high degree of accuracy. Gallium scanning is clearly superior to computed tomography in this regard. Patients with advanced HD who have positive restaging gallium scans after induction chemotherapy should be classified as induction failures and are highly unlikely to be cured with involved-field low-dose radiotherapy.