Quality of life as a predictor of overall survival after breast cancer treatment

Abstract

Purpose: To describe quality of life (QoL) in a cohort of surviving women 4 years after breast cancer treatment and to analyze its role as a predictor of mortality within 2 years.

Methods: This is a prospective cohort study of 544 women who have undergone surgical treatment, from 2001 to 2002 and who answered a questionnaire about QoL in 2006. After, we conducted a survival study to evaluate the association between QoL and mortality within 2 years with the same population. We conducted factor analysis between the variables of the scales of function and symptoms. Survival analysis was conducted by Kaplan-Meier, and differences in survival curves were assessed with the log-rank test, assuming significant statistical level of 5 %. The Cox proportional hazards regression model was used to explore the relationship between QoL variables (functional scales) and prognostic value for survival.

Results: The mean age of the women was 59.1 years (SD 11.66). The mean of overall QoL score was 75.16 (SD 20.93). Using factor analysis, we identified three conditions that made up the construct of QoL in this group of patients: social, psycho-emotional, and physical. Social condition was the most important factor. After assessment of QoL, the mean survival was 23 months (SD 3.90). Women who reported worse future perspective had higher chance of death compared with women better prospect of future (HR = 3.46; 95 % CI 1.36-8.79; p value = 0.009).

Conclusion: Future perspectives were predictors of mortality, which reinforce the relevance of social support and psychological aspects for these women.