THE ROLE OF THE GALLIUM SCAN IN PRIMARY EXTRANODAL LYMPHOMA

The purpose of this study was to examine the factors influencing galli um scan positivity for patients with primary extranodal lymphoma and t o examine the role of the gallium scan in staging the disease and asse ssing response to initial treatment. Methods: Ninety-two patients with extranodal lymphoma who had a gallium scan were reviewed. The influen ces of tumor site, size, grade and the presence of clinically detectab le disease after biopsy on the rate of gallium scan positivity were an alyzed. The role of the gallium scan in staging and selecting treatmen t was assessed. Nineteen patients had a gallium scan to assess their r esponse to treatment, and its predictive value was reviewed. Results: The overall gallium scan positivity (sensitivity) rate was 70%. This r ate was low in patients whose extranodal lymphoma occurred in skin, in testine and testis, or was low grade (0%-25%). When these patients wer e excluded, the rate rose to 88%. Gallium scan positivity was not rela ted to the presence of clinically detectable disease after biopsy and there was insufficient data about tumor size to determine a relationsh ip. The gallium scan increased the disease stage in six patients (7%) and changed the initial treatment in six patients (7%). The gallium sc an became negative in 15 (79%) of those patients who had a gallium sca n to assess their response to treatment. All but two of these patients remain alive with a median follow-up of 3.75 yr. Conclusion: The gall ium scan was rarely positive for patients with skin, intestinal, testi cular and low-grade lymphomas, but was otherwise comparable to lymphom a arising in lymph nodes. The result affected staging or treatment in seven patients (8%). After treatment, an initially-positive gallium sc an usually became negative, a conversion associated with a favorable o utcome.