Re: Median survival of cancer patients has risen from one to 10 years over past 40 years
Many would be flabbergasted to learn that the number of people dying of cancer has not fallen significantly since the 1960s.. Given the mind-boggling advances in molecular biology and biomedical technology over the past 5 decades, many would have expected the cancer death rates to have fallen significantly in UK and other western countries.
By contrast, many would not have been surprised by the recent news from Cancer Research UK that ‘Half of patients who are given a diagnosis of cancer today will survive at least 10 years, whereas only a quarter would have done so 40 years ago’..
In marked contrast to survival statistics showing a dramatic increase in survival, a plot of cancer deaths in UK since 1960s shows an unimpressive flat line. (Figure 1).
Why are the survival statistics and death rates discordant? With survival statistics, as with a magician’s sleight of hand, what is seen on one hand is impressive, but what is not seen on the other hand provides the clue.
It is too much of a coincidence for the spectacular rise in cancer survival to be accompanied by an equally remarkable increase in cancer incidence over the last four decades with number of cancer deaths remaining virtually stable. There is a probable unifying explanation for these interrelated facts..
The stable death rates indicate that incurable cancers have largely remained incurable over the last 4 decades in spite of advances in medical technology and early diagnosis. The improving survival rates indicate that paradoxically, the drive for early diagnosis has resulted in over-diagnosis of indolent cancers in an ageing population. (eg PSA testing for prostate cancer, mammography for breast cancer).. Physicians are curing cancers that don’t need to be diagnosed in the first place. Over-diagnosis is masking the lack of substantial progress in curing cancer.
1 OECD Health Statistics 2013. http://www.oecd.org/health/health-systems/oecdhealthdata.htm (accessed 29 Apr2014).
2 Torjesen I. Median survival of cancer patients has risen from one to 10 years over past 40 years. BMJ 2014;348:g3011.
3 Welch HG, Black WC. Overdiagnosis in cancer. J Natl Cancer Inst 2010;102:605–13. doi:10.1093/jnci/djq099
4 Ilic D, Neuberger MM, Djulbegovic M, et al. Screening for prostate cancer. Cochrane Database Syst Rev 2013;1:CD004720. doi:10.1002/14651858.CD004720.pub3
5 Gøtzsche PC, Jørgensen KJ. Screening for breast cancer with mammography. Cochrane Database Syst Rev 2013;6:CD001877. doi:10.1002/14651858.CD001877.pub5
Competing interests: No competing interests