18F-FDG-PET/CT response after first-line treatment as a prognostic factor for survival in peripheral T-cell lymphoma: a Spanish retrospective study.

Background: An accurate assessment of tumor viability after first-line treatment is critical for predicting treatment failure in peripheral T-cell lymphomas (PTCLs). ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) positron emission tomography/computed tomography (PET/CT) has been adopted as the preferred assessment method in clinical trials, but its impact in clinical practice should be examined. This study aims to determine the prognostic significance of¹⁸F-FDG-PET/CT for survival following first-line treatment in PTCL patients.

Research design and methods: Retrospective observational study including 175 patients diagnosed with PTCL between 2008 and 2013 in 13 Spanish sites.

Results: Fifty patients were evaluated with¹⁸F-FDG-PET/CT following first-line therapy: 58% were¹⁸F-FDG-PET/CT-negative and 42% were¹⁸F-FDG-PET/CT-positive. Disease progression occurred in 37.9% of¹⁸F-FDG-PET/CT-negative patients and in 80.9% of¹⁸F-FDG-PET/CT-positive patients (p = 0.0037). Median progression-free survival and overall survival were 67 and 74 months for¹⁸F-FDG-PET/CT-negative patients, and 5 (p < 0.0001) and 10 months (p < 0.0001), respectively, in¹⁸F-FDG-PET/CT-positive patients. After multivariate analysis, only B symptoms emerged as a negative predictive factor of complete response (RR 7.08; 95% CI 1.60-31.31; p = 0.001).

Conclusions: ¹⁸F-FDG-PET/CT identifies high-risk PTCL patients who will have poor prognosis and survival following first-line treatment. However, more research is needed to confirm the best treatment options for PTCL patients.