Massively expensive new cancer drugs do extend the lives of patients significantly, a new study finds.

Critics of the new anticancer medications, whose prices have been rising by as much as 10 percent per year, have questioned whether their benefits justify the costs. But after assessing the price of the drugs and their effectiveness, researchers found that patients with breast cancer, lung cancer, kidney cancer and chronic myeloid leukemia had big gains in life expectancy when treated with such drugs.