Peripheral T-cell lymphomas,not otherwise specified constitutes 25.9% of Peripheral T-cell lymphomas and over 15% of all lymphomas by the World Health Organization classification. Because of the rare presentation and evident heterogeneity of PTCL-NOS, optimal frontline therapy for this disease in the modern era remains unclear. Patients have traditionally been treated with anthracycline-containing chemotherapy such as CHOP or CHOP-like regimen used in B-cell NHLs. This strategy is associated with an overall response rate higher than 60%, but the 5-year PFS and OS rates have been reported to be as low as approximately 20-30%.Better therapeutic regimens are in highly need to improve the survival outcome of these patients. The investigators' previous study reported an ORR of 64% in relapsed/refractory PTCL-NOS patients. Therefore, the investigators design this study to evaluate the efficacy and safety of GDP chemotherapy as frontline treatment in patients with PTCL-NOS.