highly significantP < 0.0001
Analysis of their survival curves indicated that these decreases were highly significant (S‐Cairns: χ 2 = 175.8, df = 1, P < 0.0001; R‐TL: χ 2 = 60.61, df = 1, P < 0.0001; R‐BC: χ 2 = 85.02, df = 1, P < 0.0001; Fig. 1(a) ).