Braun et al. BMC Cancer 2011, 11:353 http://www.biomedcentral.com/1471-2407/11/353 Table 4 Univariate Cox regression analysis for overall survival QoL Domain Global Physical Role Emotional Cognitive Social Fatigue Nausea/vomiting Pain Dyspnea Insomnia Appetite Loss Constipation Diarrhea Age at presentation Gender (male as reference) Stage at diagnosis (locoregional disease as reference) Prior treatment history (previously treated as reference) The findings described above were confirmed using the forward stepwise method. It was interesting to see that most of the function and symptom scales that were pre- dictive of survival upon univariate analysis lost their sta- tistical significance upon multivariate analysis. This is not an uncommon observation in QoL analyses, because many of the individual QoL scales are highly correlated with each other, and therefore lose their statistical sig- nificance when analyzed together. Table 6 describes the results of multivariate Cox regression analyses using the block entry method for global QoL after controlling for the effects of gender, tumor stage and prior treatment history. Every 10-point increase in global QoL was associated with a 9% increase in survival (95% CI = 6% to 11%, p < 0.001). Gender, stage of disease and prior treatment history were also found to be significant predictors in the final multivariate model (p < 0.01 for all). Discussion Even though the QoL of patients is considered a critical endpoint in oncology that can also provide useful prog- nostic information to patients and clinicians, QoL con- tinues to be evaluated infrequently in most clinic oncology practices apart from research studies. The bar- rier is not a lack of valid tools but rather the challenges Table 5 Multivariate Cox regression analysis for QoL function and symptom scales (Block Entry Method) QoL Domain Physical Role Emotional Cognitive Social Fatigue Nausea/vomiting Pain Dyspnea Appetite Loss Constipation Diarrhea Gender (male as reference) Stage at diagnosis (locoregional disease as reference) Prior treatment history (previously treated as reference) HR 0.991 0.988 0.993 0.997 0.996 0.994 1.009 1.005 1.006 1.005 1.000 1.006 1.004 1.004 0.998 0.77 1.57 0.55 HR 0.990 0.999 1.001 1.000 1.000 0.996 0.997 1.002 1.001 1.003 1.000 1.003 0.78 1.67 0.55 95% CI 0.989 to 0.994 0.985 to 0.990 0.991 to 0.995 0.994 to 1.00 0.993 to 0.999 0.992 to 0.996 1.006 to 1.011 1.002 to 1.008 1.004 to 1.009 1.003 to 1.008 0.998 to 1.003 1.004 to 1.008 1.002 to 1.006 1.001 to 1.008 0.991 to 1.006 0.67 to 0.89 1.4 to 1.8 0.48 to 0.64 95% CI 0.986 to 0.994 0.995 to 1.002 0.997 to 1.005 0.996 to 1.003 0.996 to 1.003 0.992 to 1.001 0.993 to 1.001 0.999 to 1.005 0.999 to 1.004 1.000 to 1.005 0.998 to 1.003 0.999 to 1.006 0.67 to 0.90 1.4 to 1.9 0.47 to 0.64 Page 5 of 9 P-value < 0.001 < 0.001 < 0.001 0.04 0.003 < 0.001 < 0.001 0.001 < 0.001 < 0.001 0.66 < 0.001 0.001 0.02 0.65 < 0.001 < 0.001 < 0.001 P-value < 0.001 0.50 0.58 0.80 0.85 0.16 0.20 0.16 0.34 0.07 0.73 0.16 0.001 < 0.001 < 0.001