¹⁸FDG positron emission tomography versus ⁶⁷Ga scintigraphy as prognostic test during chemotherapy for non‐Hodgkin's lymphoma

Abstract

Summary. A prospective study was performed, comparing gallium scintigraphy ( 67 Ga) and positron emission tomography (PET) using fluorine-18 fluorodeoxyglucose ( 18 FDG), to monitor the response of aggressive non-Hodgkin's lymphoma during treatment. 67 Ga and 18 FDG scans were performed in 26 patients after two cycles of CHOP (cyclophosphamide, doxorubicin, vincristine, prednisone) therapy. The scans were reviewed independently by four experienced nuclear physicians, who were blinded for the alternative scan technique and follow-up. Eleven out of 26 patients remained free from progression with a mean follow up of 25 ± 5 months, whereas 14 patients relapsed, and one died of lung cancer. Interobserver variation was significantly greater for 67 Ga than for 18 FDG PET. Some 64% of patients who had a negative early restaging 18 FDG PET remained free from progression versus 50% of patients with negative 67 Ga scans. Only 25% of patients with a positive PET remained disease free versus 42% of 67 Gapositive patients. Time to progression was associated with 18 FDG PET results, but not with those by 67 Ga. 18 FDG PET had better test characteristics than 67 Ga for the evaluation of early response in aggressive non-Hodgkin's lymphoma patients.

Imaging and PET — PET/CTimaging

“…A major indication for FDG-PET imaging is the evaluation of treatment response after completion of therapy, especially in those patients with residual masses, where it is unclear whether these masses represent tumor persistence (32,33). In comparison to other nuclear medicine studies, FDG-PET shows a significant higher site and patient sensitivity than Ga-67 scintigraphy in staging as well as early therapy evaluation (34,35). To date, results regarding the use of FDG PET/CT in staging and restaging HD and NHL are limited (36,37).…”

18F-FDG PET in Non-Hodgkin's Lymphoma: Qualitative or Quantitative?

“…In the studies reported so far, the positive predictive value (PPV) and negative predictive value (NPV) of early 18 F-FDG PET for progressionfree survival are quite variable. Data for PPVs range from 44% to 100% (5)(6)(7)(8)(9)(10)(11)(12)15). Conversely, NPVs ranging from 50% to 100% have been reported.…”

“…Although the use of 18 F-FDG PET for assessment of tumor response after completion of therapy is well established in HL and aggressive NHL, more recent studies have indicated that 18 F-FDG PET may also allow prediction of tumor response and patient outcome early in the course of therapy-that is, after 1 or 2 cycles of chemotherapy (5)(6)(7)(8)(9)(10)(11)(12). The ability to predict tumor response early in the course of therapy would be very valuable clinically, as it would allow intensification of treatment in patients who are unlikely to respond to first-line chemotherapy.…”

The usefulness of 18F‐fluorodeoxyglucose positron emission tomography (18F‐FDG‐PET) and a comparison of 18F‐FDG‐pet with 67gallium scintigraphy in the evaluation of lymphoma

“…[15][16][17][18] However, those studies were not systematic, and they involved relatively small numbers of patients. [9][10][11][12][13][14] Comparisons between 18 F-FDG-PET and conventional imaging modalities using large numbers of patients would help to further our understanding of the biologic differences between lymphoma cell types, establish guidelines for the selection of appropriate clinical management, and verify the clinical relevance of lymphoma classification systems. 1,2,6 The distinction between indolent and aggressive lymphomas is important clinically, because the choice of treatment is influenced by histologic subtype.…”

“…18 F-FDG-PET has several advantages over 67 Ga, including sameday results and high resolution. 1,2 There have been several reports comparing the usefulness of 18 F-FDG-PET with conventional imaging modalities, such as computed tomography (CT) and 67 Ga for detecting tumors, [10][11][12][13] and examining the relations between 18 F-FDG-PET and histologic subtypes based on the World Health Organization (WHO) classification system. [15][16][17][18] However, those studies were not systematic, and they involved relatively small numbers of patients.…”