Role of FDG-PET/CT in Detecting Lymphomatous Bone Marrow Involvement in Patients with Newly Diagnosed Diffuse Large B-Cell Lymphoma

Abstract

5204 Backgrounds: As a bone marrow bopsy (BMB) is a painful and invasive procedure with a restrictive reliability as only a limited area of the bone marrow (BM) can be evaluated, role of FDG-PET/CT to demonstrate lymphomatous BM involvement as an alternative or at least a complementary to BMB is an area of interest. Several previous studies exist but most of them included heterogeneous types of lymphomas with various treatments. Patients and methods: To evaluate the role of FDG-PET/CT in detecting BM involvement, pre-treatment bilateral BMBs and FDG-PET/CT scans of 89 patients with diffuse large B-cell lymphoma (DLBCL) treated with standard immunochemotherapy, rituximab-CHOP were reviewed and analyzed. Uptake more than liver parenchyma intensity on FDG-PET/CT was interpreted as 'with a possibility' of involvement. The final interpretation on the possibility of BM involvement in each patient was reported after discussion among three nuclear medicine physicians and results of BMB were blinded at the time of FDG-PET/CT review. Fourteen patients (15.7%) had lymphomatous involvement based on BMB (BMB+) and 17 patients (19.1%) had the possibility of BM involvement on FDG-PET/CT (FDG-PET/CT+). Seventy-two patients (80.8%) had concordant results between BMB and FDG-PET/CT (7 patients were positive for both and 65 patients were negative for both), but 17 patients (19.2%) had a discordant interpretation (7 patients were BMB+ and FDG-PET/CT-, and 10 for BMB- and FDG-PET/CT+; table 1). Although BMB+ patients had an inferior 2-year EFS (37.0% vs. 79.8%, p < 0.001) and OS (36.3% vs. 81.0%, p < 0.001) compared to BMB- patients, no differences in EFS (62.6% vs. 72.7%, p = 0.185) and OS (59.4% vs. 78.0%, p = 0.146) were shown between FDG-PET/CT+ and FDG-PET/CT- patients. Six of 7 patients with BMB+ and FDG-PET/CT+ had a diffuse involvement on FDG-PET/CT whereas 9 of 10 patients with BMB- and FDG-PET/CT+ had a focal BM involvement on FDG-PET/CT (table 2). Six of 7 patients with diffuse involvement on FDG-PET/CT were BMB+ whereas only 1 of 10 patients with focal BM involvement on FDG-PET/CT were BMB+ (table 2). It is likely therefore that patients with diffuse BM involvement on FDG-PET/CT had higher probability for BMB+ and they might have poorer survival than those with focal BM involvement. Conclusion: The results suggest that FDG-PET/CT had a limited value to detect BM involvement in patients with DLBCL. It may not be justified to upgrade patient's Ann Arbor stage to IV according to focal hypermetabolic BM lesion on FDG-PET/CT. Until additional results on the role of FDG-PET/CT in detecting BM involvement available, FDG-PET/CT should be used as an adjuvant rather than an alternative in detecting BM involvement in patients with newly diagnosed DLBCL. Disclosures: No relevant conflicts of interest to declare.

Use of FDG PET/CT in identification of bone marrow involvement in diffuse large B cell lymphoma and follicular lymphoma: comparison with iliac crest bone marrow biopsy

“…Our findings support those of a recent meta-analysis of seven studies, which demonstrated a pooled sensitivity and specificity of FDG PET/CT of 88.7% and 99.8%, respectively, in newly diagnosed DLBCL (6). Individual studies have found sensitivity of PET/CT in this setting of 70.7–95.8%, with specificity of 99.0–100% (Table 5) (4,13–17).…”

Bone marrow biopsy superiority over PET/CT in predicting progression‐free survival in a homogeneously‐treated cohort of diffuse large B‐cell lymphoma

“…In the setting of B-NHL, and particularly in the DLBCL category, the use of PET/CT and/or BMB for staging purposes is presently one of the most debated issues as different strategies have been proposed according to the divergent results of a number of distinct series or metaanalysis [3][4][5][6][7][8][12][13][14][15], or experience-based recommendations from experts in the field [4,5,[16][17][18][19][20]. With an endeavor to avoid susceptibility and collinearity biases in our study design, we show here the superiority of BMB over PET/CT in predicting PFS in a homogeneously-treated cohort of 203 DLBCL patients.…”

Prognostic value of complete remission status at end‐of‐treatment FDG‐PET in R‐CHOP‐treated diffuse large B‐cell lymphoma: systematic review and meta‐analysis

“…The fact that a negative end-of-treatment FDG-PET fails to predict a favourable outcome in a non-negligible proportion of patients is due to its inherent limitations. First, despite the fact that DLBCL is FDG-avid in the vast majority of cases (Weiler-Sagie et al, 2010) and FDG-PET is thus considered a sensitive staging method in this disease Cheson et al, 2014), recent studies have indicated that FDG-PET is insufficiently accurate for the detection of bone marrow involvement (Hong et al, 2012;Hong & Lee, 2013;Adams et al, 2014a,b). This, in turn, suggests that FDG-PET is not a suitable method to confirm bone marrow remission status.…”