During the 3 decades, the proportion of survivors treated with chemotherapy alone increased from 18% in 1970-1979 to 54% in 1990-1999, and the life expectancy gap in this chemotherapy-alone group decreased from 11.0 years (95% UI, 9.0-13.1 years) to 6.0 years (95% UI, 4.5-7.6 years).