Comparison of first-line treatments of peripheral T-cell lymphoma according to regimen: A systematic review and meta-analysis

Peripheral T-cell lymphomas (PTCLs) are known to have an aggressive clinical course and grave prognosis. Several recommended first-line treatment regimens are available, but identification of the superior treatment remain elusive. We conducted a systematic review and meta-analysis to determine which study-level factors and group of regimens affect survival outcomes. The MEDLINE, Embase, and Cochrane databases were searched from inception to January 2021, and phase II or III clinical studies evaluating the efficacy of chemotherapy regimens were included. Random effects models were used to estimate 3-year overall survival rate, complete remission rate, and subgroup differences. Meta-regressions were carried out with adjustments for relevant covariates. Overall, 34 cohorts from 28 studies comprising 1424 PTCL patients were included in the pooled analysis. Chemotherapy regimens were divided into four groups: cyclophosphamide, doxorubicin, vincristine, prednisone (CHOP), CHOP plus etoposide, gemcitabine-based, and others. The pooled 3-year overall survival rate was 0.49 (95% confidence interval [CI] 0.43-0.54) for CHOP, 0.61 (95% CI 0.52-0.70) for CHOP plus etoposide, 0.39 (95% CI 0.30-0.47) for gemcitabine-based, and 0.61 (95% CI 0.44-0.78) for others. CHOP plus etoposide was significantly better than CHOP, with the latter used as a reference (coefficient of 0.11; p = 0.035), with adjustment for the proportion of International Prognostic Index score 4-5 in meta-regression analysis. Although grossly divided groups were pooled and analyzed, among four regimen groups for frontline PTCL treatment CHOP plus etoposide showed better survival than CHOP.