Revisiting the prognostic role of gallium scintigraphy in low-grade non-Hodgkin's lymphoma

The purpose of this study was threefold: to evaluate the role of gallium-67 scintigraphy in the staging of low-grade non-Hodgkin's lymphomas (LGNHL), to assess the relationship between the expression of CD71 on the surface of the neoplastic cells and the Ga-67 uptake by the tumour, and to establish the contribution of Ga-67 scan in defining the prognosis of LGNHL. Forty-eight patients with untreated LGNHL diagnosed in a single institution over a decade were reviewed, The end point of the study was survival of the patients according to the scintigraphic Ga-67 score at diagnosis. In addition to Ga-67 scan, other prognostic variables were studied, relating to the neoplastic burden, the biology of the tumour and the host. Univariate and multivariate analyses were used. Ga-67 scan identified only 116/286 (41%) nodes involved by lymphoma that were detected by clinical examination or computed tomography scan. A scintigraphic scoring system with an arbitrary cut-off value of 3 (high scan score) was able to predict patients with a dismal prognosis: with a mean follow-up of 47 months (range: 1-146 months) the median survival time was 28 months in patients with a high scan score and 74 months in patients with a low scan score (P=0.002), CD71 values were 27.4%+/-14.9% (mean +/-SD) in the former and 8.9%+/-7.2% in the latter (P=0.0001). Only performance status and extranodal sites were significant variables for prognosis in multivariate analysis. It is concluded that Ga-67 scan is inaccurate in staging but might be very important in defining the prognosis in LGNHL, in association with other prognostic variables.