In the recent hubbub about the use of PSA to screen for prostate cancer, the word overdiagnosis has appeared several times. In an online dictionary, it is defined as “the diagnosis of a disease more often than it is actually present.”
But the diagnosis of prostate cancer is pretty straightforward, with a biopsy determining whether cancerous cells are present. The diagnosis can be either correct or incorrect. But, there can be overtreatment, when low-risk prostate cancer is treated aggressively. So somehow, overtreatment has spilled over into diagnosis to produce the word overdiagnosis. That is, if a person has a biopsy confirmed prostate cancer, which is low risk and receives aggressive treatment – he has been over treated, not over diagnosed.