Restaging with gallium scan identifies chemosensitive patients and predicts survival of poor-prognosis mediastinal Hodgkin's disease patients

Following treatment of mediastinal Hodgkin's disease (HD), residual masses are frequent and gallium scanning has proven to be of value in the evaluati on of their specificity (fibrosis or active disease). This study assessed, for relapse and survival, the predictive Value of restaging gallium scan of patients with a residual mass on computed tomography scan after induction chemotherapy. Between 1/89 and 12/97, in 53 newly diagnosed HD patients wit h a residual mediastinal mass, a gallium scan was performed after chemother apy (3 or 4 courses) and always before consolidative radiotherapy. Characte ristics at diagnosis were: nodular sclerosis histology, 89%; bulky mediasti nal disease, 79%; B-symptoms, 51%. Results: gallium scan was positive in 16 patients (30%) and negative in 37 (70%). At median follow-up period of 36 months, freedom-from-progression rate was 86% versus 19% (P<0.0001) for pat ients with negative vs positive gallium scans, respectively. The 5-year ove rall survival (OS) rate was 68% and differed significantly (P< 0.0001) betw een negative (91%) and positive (25%) gallium scanning groups. The specific ity of gallium scanning was 91% and the sensitivity 72% with a positive pre dictive value of 81% and a negative predictive Value of 86%. Evaluation wit h gallium scan after induction chemotherapy identifies chemosensitive patie nts among those with poor-prognosis mediastinal HD. Although relapse may oc cur in patients with negative gallium scan, a postive gallium scan is highl y predictive of failure and poor outcome, and treatment should thus be modi fied.