The UK data suggest potential overdiagnosis of uterine, prostate, oral and thyroid cancers, according to a new analysis published in Scientific Reports.
Researchers from the Nuffield Department of Primary Care Health Sciences at the University of Oxford used Cancer Research UK incidence and mortality data to estimate the percentage change in incidence and mortality rates and the incidence-mortality ratio (IMR) for cancers in which incidence had increased by more than 50%.
Incidence increases of more than 50% were seen for 10 of the 20 most common cancers in the United Kingdom since the 1980s - breast, cervical, kidney, liver, melanoma, oral, prostate, thyroid and uterine cancers and non-Hodgkin lymphoma. Increases ranged from 67% for uterine cancer to 375% for melanoma.
Change in mortality rates ranged from a decrease of 69% for cervical to 239% increase in mortality for liver. The greatest divergences between incidence and mortality rates occurred in uterine (IMR=132), prostate (IMR=9.6), oral (IMR=9.8) and thyroid (IMR=5.3) cancer.
Only in liver cancer did the change in mortality reflect changes in incidence (IMR=1.1).
The authors suggest overdiagnosis could be a significant contributor to these trends. They say uterine, prostate, oral and thyroid cancer incidence and mortality trends “are suggestive of overdiagnosis”.
Trends in melanoma and kidney cancer suggest potential overdiagnosis and an underlying increase in true risk, whereas for cervical and breast cancer, trends may also reflect improvements in treatments or earlier diagnosis, they add.
Whilst the risks for harm may be small, they say there are many more people at risk for overdiagnosis than people with aggressive cancer. They recommend more detailed analysis to fully understand the patterns.
