Estimating the impact of new clinical trial proven cancer therapy and cancer chemoprevention on population mortality: the Karnofsky Memorial lecture.

Purpose: The 31-year "war on cancer" has focused largely on therapeutic (as opposed to preventative) cancer research, which, in both the public and private sector, has received the majority of funding. Meanwhile the prevention of cancer has received less attention.

Patients And Methods: We analyzed eight positive phase III therapeutic trials of the Southwest Oncology Group, and estimated how the observed improvements in survival from the new therapies would impact mortality at the population level (utilizing Surveillance, Epidemiology, and End Results-data). We compared these results with the impact of the Prostate Cancer Prevention Trial. The measure of impact was person-years saved in the first 5 years.

Results: Estimates of person-years saved in the first 5 years included 28,534 from improved treatment of localized bladder cancer and 26,241 from improved treatment of advanced lung cancer, representing, respectively, 31.4% and 2.8% of the person-years which could have been saved for these diseases (the "relative impact of new treatment on survival"). The new therapies from all eight positive phase III trials would have saved 114,641 person-years over the first 5 years. The estimate from the Prostate Cancer Prevention Trial was 99,441 person-years over the first 5 years.

Conclusion: New cancer therapies have a proven and quantifiable impact on population mortality. Successful cancer prevention has a similarly large impact. However, federal funding for cancer prevention is less than half that of cancer treatment. As a result of its enormous potential for extending life, cancer prevention warrants increased funding and support from federal funding agencies.