Relationship between tumor bulk and survival. Association of the estimated PFS (A) and OS (B) HR (with 95% CI, dashed line) with the maximum diameter. The nonlinear effect of maximum diameter on risk of relapse/death (A) and death (B) was modeled with a penalized spline expansion. Corresponding Kaplan-Meier survival curves show that larger tumor diameter (≥5 vs <5cm) had no effect on PFS (C) but was associated with better OS (D).