Although the contribution of health care to survival from cancer has been studied extensively, much less is known about its contribution to population health. We examine how medical innovations have influenced trends in cause-specific mortality at the national level. Based on literature reviews, we selected six innovations with proven effectiveness against cervical cancer, Hodgkin's disease, breast cancer, testicular cancer, and leukaemia. With data on the timing of innovations and cause-specific mortality (1970-2005) from seven European countries we identified associations between innovations and favourable changes in mortality. For none of the five specific cancers, sufficient evidence for an association between introduction of innovations and a positive change in mortality could be found. The highest association was found between the introduction of Tamoxifen and breast cancer mortality. The lack of evidence of health care effectiveness may be due to gradual improvements in treatment, to effects limited to certain age groups or cancer subtypes, and to contemporaneous changes in cancer incidence. Research on the impact of health care innovations on population health is limited by unreliable data on their introduction.