We examine the effects of two important types of medical innovation—diagnostic imaging innovation and pharmaceutical innovation—and cancer incidence rates on U.S. cancer mortality rates during the period 1996–2006. The outcome measure we use is not subject to lead-time bias, and our measures of medical innovation are based on extensive data on treatments given to large numbers of patients with different types of cancer.
We estimate difference-in-difference models of the age-adjusted cancer mortality rate using longitudinal, annual, cancer-site-level data on over 60 cancer sites. There is a significant inverse relationship between the cancer mortality rate and both lagged imaging innovation and contemporaneous drug innovation, and a significant positive relationship between the cancer mortality rate and the lagged incidence rate. Imaging innovation, drug innovation, and declining incidence jointly explain about three-fourths of the decline in cancer mortality.
Only 7% of the mortality decline is attributable to the decline in (lagged) incidence. About one-fourth of the mortality decline is attributable to drug innovation, and 40% of the decline is attributable to (lagged) imaging innovation. Life expectancy at birth may have been increased by almost three months between 1996 and 2006 by the combined effects of cancer imaging and cancer drug innovation.