Table 2: Comparison between the present cohort and the historical control, Koizumi et al.’s combined cohort, in Japan.

Survival (years)012345678910
Present cohort
 Number at risk2018161411865553
Koizumi et al.’s combined cohort
 Number at risk (solitary, sternum + other, from Table of [19])28922215710675533819842
Difference of population ratio at each year
 Chi square test, =0.0030.0050.0190.0370.003<0.0001