3.2 The effect of body composition parameters on survival
outcomes
The measured median PFS and OS times of all 108 patients with metastatic
RCC were 11 (95% CI: 8-14) months and 46 (95% CI: 42.9-49.1) months,
respectively. Among the obese
(BMI≥30 kg/m2)
and non-obese (BMI<30 kg/m2) patients,
Kaplan–Meier analysis revealed a significant difference in the PFS
(median 14 and 8 months, respectively, P= 0,039) while
no significant difference was found in OS (median, 46 and 47 months,
respectively, P=0,921) . The median PFS times for each IMDC risk
groups were 21 months (favorable-risk group; 95% CI: 16.8–25.2),
14.0 months (intermediate-risk group; 95% CI: 11.9-16.1) and 6 months
(poor-risk group; 95% CI 4.9-7.1). The median OS times for each risk
group were 48 months (favorable-risk group; 95% CI: 46-50), and
46 months (intermediate-risk group; 95% CI: 43-49) and 28 months (poor
risk; 95% CI: 25-32).
Using univariate Cox regression
analyses as presented in Table 3, none of the body composition variables
and their changes after 3-4 months of treatment initiation were
associated with OS while SMI (HR: 0.979, 95% CI: 0.961–0.997, P=0.021)
and psoas index (HR: 0.871, 95% CI: 0.776–0.978, P=0.020) were
identified as the factors predicting better PFS. Multivariate Cox
regression models have identified the independent prognostic factors for
PFS and OS (Table 4). When adjusted by significant and potential
variables in univariate analyses, only SMI was determined as an
independent prognostic factor for PFS (HR: 0.975; 95% CI: 0.955–0.995,
P=0.015). However, SMI was not found as a significant factor for OS.
Although we found no association between VBC parameters or change in
their values and OS according to univariate analyses; applying
multivariate analyses, VATI (HR: 1.005; 95% CI: 1.001-1.009, P=0.024),
SATI (HR: 0.976, 95% CI: 0.957-0.996, P=0.019) and TATI (HR: 0.982,
95% CI: 0.966-0.999, P=0.035) were determined as independent predictors
for OS in addition to IMDC scoring system.