We evaluated the predictive value of interim positon emission tomography (I-PET) after one course of chemoimmunotherapy in patients with newly diagnosed diffuse large B-cell lymphoma (DLBCL). One hundred and twelve patients with DLBCL were enrolled. All patients had PET/computed tomography (CT) scans performed after one course of chemotherapy (PET-1). I-PET scans were categorized according to International Harmonization Project criteria (IHP), Deauville 5-point scale (D 5PS) with scores 1-3 considered negative (D 5PS > 3) and D 5PS with scores 1-4 considered negative (D 5PS = 5). Ratios of tumor maximum standardized uptake value (SUVmax) to liver SUVmax were also analyzed. We found no difference in progression-free survival (PFS) between PET-negative and PET-positive patients according to IHP and D 5PS > 3. The 2-year PFS using D 5PS = 5 was 50.9% in the PET-positive group and 84.8% in the PET-negative group (p = 0.002). A tumor/liver SUVmax cut-off of 3.1 to distinguish D 5PS scores of 4 and 5 provided the best prognostic value. PET after one course of chemotherapy was not able to safely discriminate PET-positive and PET-negative patients in different prognostic groups.
Routine imaging for diffuse large B-cell lymphoma (DLBCL) in first complete remission (CR) is controversial and plays a limited role in detecting relapse. This population-based study compared the survival of Danish and Swedish patients with DLBCL for whom traditions for routine imaging have been different.
Patients from the Danish and Swedish lymphoma registries were included according to the following criteria: newly diagnosed DLBCL from 2007 to 2012, age 18 to 65 years, and CR after R-CHOP/CHOEP. Follow-up for Swedish patients included symptom assessment, clinical examinations, and blood tests at 3- to 4-month intervals for 2 years, with longer intervals later in follow-up. Imaging was only recommended when relapse was clinically suspected. Follow-up for Danish patients was similar but included routine imaging (usually computed tomography every 6 months for 2 years).
Danish (n = 525) and Swedish (n = 696) patients with DLBCL had comparable baseline characteristics. Cumulative 2-year progression rate after CR was 6% (95% CI, 4 to 9) for International Prognostic Index (IPI) = 2 versus 21% (95% CI, 13 to 28) for IPI > 2. Age > 60 years (hazard ratio [HR], 2.3; 95% CI, 1.6 to 3.4), elevated lactate dehydrogenase (HR, 2.3; 95% CI, 1.4 to 3.8), B symptoms (HR, 1.7; 95% CI, 1.1 to 2.5), and Eastern Cooperative Oncology Group performance status = 2 (HR, 1.8; 95% CI, 1.0 to 3.0) were associated with worse post-CR survival. Imaging-based follow-up strategy had no impact on survival, neither for all patients nor for IPI-specific subgroups.
DLBCL relapse after first CR is infrequent, and the widespread use of routine imaging in Denmark did not translate into better survival. This favors follow-up without routine imaging and, more generally, a shift of focus from relapse detection to improved survivorship.
Comment In: J Clin Oncol. 2015 Dec 1;33(34):3983-426438116