Application of the International Prognostic Index in a study of Chinese patients with non-Hodgkin's lymphoma and a high incidence of primary extranodal lymphoma

BACKGROUND. Chemotherapy containing anthracycline is the standard initial treatment for aggressive non-Hodgkin's lymphoma (NHL), and the international Prognostic Index (IPI) is widely accepted as the standard tool for determining the prognosis of patients with this disease. However, the data on which the IPI was based primarily came from studies conducted in Western countries. It may not be directly applicable to Asian populations, in which the incidence of primary extranodal lymphoma (PENL) is known to be high. METHODS. The authors conducted a retrospective study of 218 patients with aggressive NHL who were treated with chemotherapy. They analyzed the distribution of stage and pathology, prognostic factors, toxicity, and treatment outcome. The IPI was then applied and its ability to identify distinct prognostic groups tested. RESULTS. Eighty-six patients (39.4%) had lymph node lymphoma (LNL) and 132 (60.6%) had primary extranodal lymphoma (defined as non-Hodgkin's lymphoma with primary presentation, bulk of disease, and histologic confirmation at an extranodal site). The most common primary extranodal sites were the stomach (22%) and Waldeyer's tonsillar ring (18.9%). The complete response rate of PENL patients to chemotherapy containing anthracycline was 52%, as compared with 64% of the LNL group. The 5-year survival rates for patients with LNL and PENL were 57.4% and 52.1%, respectively. The toxicity in the two patient groups was similar. Four of the prognostic factors in the IPI-age, serum LDH, performance status, and disease stage-predicted significantly different survival for PENL and LNL patients. However, the number of extranodal sites involved was not a significant predictive variable in PENL. CONCLUSIONS. The IPI was applicable to this Chinese population in which the incidence of PENL was high, although the number of extranodal sites did not achieve statistical significance as a risk factor. A proposal for modification was made. Chemotherapy containing anthracycline was an effective treatment for both PENL and LNL patients. (C) 1998 American Cancer Society.