Desigualdades socioeconômicas na sobrevida de pacientes com câncer de mama, próstata e pulmão: um estudo de base populacional em Curitiba.

Abstract

Cancer incidence and mortality have increased considerably among low and middle-income countries. At the same time, improvements in the methods of detection and treatment have allowed significant gains in survival of cancer patients. However, this increase has been much more significant in the most socioeconomically privileged population groups. We aimed to analyze the effect of socioeconomic inequalities in the survival of patients diagnosed with breast, prostate and lung cancers, from 1998 to 2007, in the city of Curitiba, Paraná, Brazil. The source of information for the present population-based study was the Population-based Cancer Registry (PBCR) of Curitiba. Socioeconomic inequalities were measured by quintiles of the Municipal Human Development Index (MHDI) calculated for areas of residence called Human Development Units (HDU). HDUs are socioeconomically homogeneous census sector clusters. All cancer patients were allocated to a HDU according to home address. In total, we analyzed the information of 9,639 cancer patients: 3,063 with prostate cancer, 5,033 with breast cancer and 1,543 with lung cancer, 929 male and 614 female. We estimated the one-year and five-year net survival by sex and MHDI quintiles. Net survival is defined as the estimated survival of a group of patients in the hypothetical situation in which the cancer of interest is the only possible cause of death. Sensitivity analysis was performed using the English mortality pattern by deprivation to simulate socioeconomic-specific life tables in Curitiba. The effect of socioeconomic inequalities, represented by the survival gap between the fifth and first quintiles, in the five-year net survival was larger than for one-year, for the three types of cancer. Five-year net survival of prostate and breast cancer patients living in more affluent areas was, 24.2% and 30.2%, respectively, higher than the figures for patients from more deprived areas. These gaps increased significantly in lung cancer: 83.7% among men and 103.8% for women. Although using specific life tables by MHDI quintiles mitigated the effect of inequality, the gap still remained significant. Cancer survival information is essential in the development of health policies aimed at increasing not only life expectancy, but also the quality of life of cancer patients. Surveillance of population-based survival should therefore become an essential ongoing process in Brazil.