Low socioeconomic status is a strong independent predictor of relapse in childhood acute lymphoblastic leukemia

The results of the treatment of acute lymphoblastic leukemia (ALL) in child ren depend not only on the biologic diversity of the leukemia cell, the mul ti-drug treatment schedule and the individual variability of drug metabolis m, but also on the socioeconomic and cultural background of the leukemic ch ild. Social and cultural disparity is very marked in underdeveloped countri es and has been increasing in industrialized nations. The prognostic influe nces of these factors are poorly documented and sometimes mistakenly attrib uted to differences in ethnic origin. We have investigated in Brazil the re lative impact of malnutrition and socioeconomic status on the outcome of AL L, adjusting for the known influence of biologic factors. Children with ALL (n = 167) treated with a Berlin-Frankfurt-Munster-based protocol were stud ied prospectively. At a median follow-up of 1623 days, the estimated probab ility of disease-free survival was 43 +/- 4%, The main cause for interrupti on of remission was bone-marrow relapse. Socioeconomic indicators of povert y (poor housing conditions, low per capita income and energy consumption) w ere significantly associated with a greater risk of relapse in univariate a nalysis, They were consolidated in a single index, socioeconomic status (SE S), defined by the product of monthly per capita income times mean familial daily energy consumption. Other unfavorable findings included age, z score for the height for age at diagnosis (HAZ) below - 1.28 and the z score for weight for age below -1.28, After adjustment in Cox's multivariate model, only HAZ and poor SES remained as predictive factors for relapse. Poor prog nosis for leukemic children of low SES is just another indicator of social inequality. (C) 1998 Wiley-Liss, Inc.