Kaplan-Meier curves for RS survival from diagnosis according to clonal relationship. Clonally unrelated RS showed a significantly longer survival (Events/N, 4/12; median, 62.5 months; 95% CI, 34.0-91.0 months) compared with clonally related RS (Events/N, 35/49; median, 14.2 months; 95% CI, 7.7-20.6 months; P = .017).