GALLIUM SCANS IN THE EVALUATION OF RESIDUAL MASSES AFTER CHEMOTHERAPYFOR SEMINOMA

Purpose: To assess the ability of gallium scans to determine whether r esidual masses consist of viable tumor or necrotic fibrous tissue afte r chemotherapy for seminoma. Patients and Methods: Thirty-two patients were enrolled and 27 were assessable. Patients receiving first-line o r salvage chemotherapy had gallium scans performed during their first and last scheduled course of chemotherapy and results were compared wi th restaging computed tomographic (CT) scans and subsequent clinical o utcome. Results: Of 27 assessable patients, 22 received first-line che motherapy (group A) and five salvage chemotherapy (group B). Eight pat ients were not gallium-avid before chemotherapy despite obvious clinic al and radiographic evidence of metastatic seminoma, Eighteen of 19 ga llium-positive patients had a persistent mass postchemotherapy on abdo minal CT, Of 16 patients in group A whose tumors were gallium-avid, al l 16 had normalized gallium scans after chemotherapy. However, two of these 16 patients recurred in their original disease site, In group B, there were three patients with gallium-avid rumors and all three had normalized scans postchemotherapy. Two patients who were not gallium-a vid (one each in group A and B) also developed recurrent disease. Twen ty-four of 27 patients ore alive with no evidence of active disease at a median follow-up time of 18 months, including 20 with more than 1 y ear of follow-up data. Conclusion: Eight of 27 patients had false-nega tive gallium scans at the time of diagnosis, All nineteen gallium scan s that were initially positive reverted to normal after chemotherapy, Two of 19 patients' follow-up gallium scans were false-negative, We th erefore feel that gallium scans have minimal value in the prechemother apy or postchemotherapy evaluation of metastatic seminoma. (C) 1995 by American Society of Clinical Oncology.