Early stage nasal NK/T-cell lymphoma: clinical outcome, prognostic factors, and the effect of treatment modality. 
To determine the clinical outcome, prognostic factors, and effect of adding combination chemotherapy to radiation therapy on disease control and survival in early stage nasal natural killer (NK)/T-cell lymphoma.  A retrospective "intent to treat" analysis was carried out on 79 patients treated consecutively with curative intent between 1977 and June 2001.  They all had early stage (Ann Arbor Stage I(E): 63, II(E):16) nasal NK/T-cell lymphoma.  Sixty-one were planned for combined modality treatment (CMT); radiotherapy alone (RT) was intended for 18.  Three to 6 cycles of anthracycline-containing regimens were aimed at for patients intended for CMT.  Patients selected for RT were generally older or treated during the earlier part of the study period.  The overall complete response (CR) rate was 68.4% (54/79), of whom 44.4% (24/54) relapsed after 54.9 months median follow-up of the survivors.  The 5-year disease-free survival (DFS) and overall survival (OS) rates were 35.5% and 37.9%, respectively.  On multivariate analysis, good performance status (Eastern Cooperative Oncology Group [ECOG] <2) was shown to be a significant favorable factor for DFS (p = 0.011), whereas good performance status (ECOG <2) and Ann Arbor Stage I(E) disease were shown to be significant favorable factors for OS (p = 0.001 and p = 0.013, respectively).  The type of intended treatment was not a significant factor for DFS (5-year DFS CMT vs. RT = 35.8% vs. 30.5%, p = 0.795) or OS (5-year OS CMT vs. RT = 40.3% vs. 29.8%, p = 0.693) though only 2 of the 16 Stage II(E) patients were intended for RT alone.  Resistance to treatment, especially to chemotherapy, was common.  Of 61 patients intended to be given CMT, 31 showed disease progression while receiving chemotherapy, of whom 17 progressed locoregionally.  Nine of the latter group were rendered CR by salvage radiotherapy.  The overall outcome in early stage nasal NK/T-cell lymphoma is poor.  Performance status and Ann Arbor stage are significant factors influencing DFS and OS.  The addition of anthracycline-containing chemotherapy to radiotherapy does not appear to confer any survival benefit in Stage I(E) patients.  Therefore, radiation therapy remains the mainstay of treatment for this lymphoma type.