Diagnostic role of gallium scanning in the management of lymphoma with mediastinal involvement

Background and Objective. Therapy of both Hodgkin's disease (HD) and aggres sive non-Hodgkin's lymphoma (NHL) with mediastinal presentation at the time of diagnosis is frequently followed by radiological detection of residual masses. Computed tomography (CT) scanning is generally unable to detect the differences between tumor tissue and fibrosis. Gallium-67-citrate single p hoton emission ((GaSPECT)-Ga-67) can potentially differentiate residual act ive tumor tissue from fibrosis. Design and Methods. Seventy-five patients with HD or aggressive NHL present ing mediastinal involvement (64% with a bulky mass) were studied with CT an d (GaSPECT)-Ga-67 at the end of combined modality therapy (chemo- and radia tion therapy). Results. After treatment, 3/3 (100%) patients with positive (GaSPECT)-Ga-67 and negative CT scan relapsed while only 1/18 (6%) patients with both nega tive (GaSPECT)-Ga-67 and CT scan did so. At the same time, 54 patients had a positive restaging CT scan (abnormal mass < 10% of size of initial mass). Of these patients, 13 had a positive (GaSPECT)-Ga-67, 10 of whom (77%) rel apsed; 41 had a negative (GaSPECT)-Ga-67 of whom 5 (12%) relapsed. The 4-ye ar actuarial relapse-free survival rate was 90% for those with negative sca ns compared with 23% for gallium-positive patients (p<0.000000). Interpretation and Conclusions. In lymphoma patients with mediastinal invol vement, (GaSPECT)-Ga-67 should be considered, at least in patients who are CT positive, the Imaging technique of choice for monitoring and differentia ting the nature of any residual masses. (C) 1999, Ferrata Storti Foundation .