PROGNOSTIC FACTORS AND A PREDICTIVE MODEL OF FOLLICULAR LYMPHOMA - A 25-YEAR STUDY AT A SINGLE INSTITUTION IN JAPAN

The incidence of follicular lymphoma in Japan is far lower than that i n western countries, and no large-scale clinicopathologic studies on t his neoplasm have been conducted in Japan. We reviewed histopathologic al specimens from 118 of 135 patients who had been diagnosed as having follicular lymphoma between 1968 and 1993. Prognostic factors influen cing survival were analyzed using univariate and multivariate analyses . Factors that were independently significant upon multivariate analys is were incorporated into a predictive model. Ninety-three patients (7 8.8%) had a confirmed diagnosis of follicular lymphoma. Twenty-one of the remaining 25 patients were categorized as having other lymphoma su btypes, and four patients showed indefinite findings or those suggesti ng diseases other than lymphoma. Major characteristics of the 93 patie nts with follicular lymphoma were a median age of 53 years (20-85); 59 males (63%) and 34 females (37%); small cleaved cell type in 33 (35%) , mixed cell type in 41 (44%) and large cell type in 19 (20%); stage I /II in 41 (44%) and stage III/IV in 50 (54%). Overall survival was 71% at 5 years, 58% at 10 years, and 43% at 15 years with a median surviv al of 13.3 years. Multivariate analysis revealed that two variables, a ge (>60) (P=0.001) and the serum LDH level (>1xnormal value) (P=0.026) , were unfavorably significant prognostic factors influencing survival . The predictive model using these two variables identified three risk groups with estimated five-year survival rates of 88.5%, 56.8%, and 3 1.5%. Age and serum LDH were significant predictors of survival in Jap anese patients with follicular lymphoma. Our predictive model may prov ide a basis for future therapeutic trials against follicular lymphoma in Japan.