Peripheral T-cell lymphomas in a large US multicenter cohort: prognostication in the modern era including impact of frontline therapy.

BACKGROUND Optimal frontline therapy for peripheral T-cell lymphoma (PTCL) in the modern era remains unclear. PATIENTS AND METHODS We examined patient characteristics, treatment, and outcomes among 341 newly diagnosed PTCL patients from 2000 to 2011. Outcome was compared with a matched cohort of diffuse large B-cell lymphoma (DLBCL) patients, and prognostic factors were assessed using univariate and multivariate analyses. RESULTS PTCL subtypes included PTCL, not otherwise specified (PTCL-NOS) (31%), anaplastic large T-cell lymphoma (ALCL) (26%), angioimmunoblastic T-cell lymphoma (23%), NK/T-cell lymphoma (7%), acute T-cell leukemia/lymphoma (6%), and other (7%). Median age was 62 years (range 18-95 years), and 74% had stage III-IV disease. Twenty-three (7%) patients received only palliative care whereas 318 received chemotherapy: CHOP-like regimens (70%), hyperCVAD/MA (6%), or other (18%). Thirty-three patients (10%) underwent stem-cell transplantation (SCT) in first remission. The overall response rate was 73% (61% complete); 24% had primary refractory disease. With 39-month median follow-up, 3-year progression-free survival (PFS) and overall survival (OS) were 32% and 52%. PFS and OS for PTCL patients were significantly inferior to matched patients with DLBCL. On multivariate analysis, stage I-II disease was the only significant pretreatment prognostic factor [PFS: hazard ratio (HR) 0.54, 95% confidence interval (CI) 0.34-0.85, P = 0.007; OS: HR 0.42, 95% CI 0.22-0.78, P = 0.006]. ALK positivity in ALCL was prognostic on univariate analysis, but lost significance on multivariate analysis. The most dominant prognostic factor was response to initial therapy (complete response versus other), including adjustment for stage and SCT [PFS: HR 0.19, 95% CI 0.14-0.28, P < 0.0001; OS: HR 0.26, 95% CI 0.17-0.40, P < 0.0001]. No overall survival difference was observed based on choice of upfront regimen or SCT in first remission. CONCLUSIONS This analysis identifies early-stage disease and initial treatment response as dominant prognostic factors in PTCL. No clear benefit was observed for patients undergoing consolidative SCT. Novel therapeutic approaches for PTCL are critically needed.