Just read this interesting article from the New York Times about wrong diagnosis of ductal carcinoma in situ, the earliest form of breast cancer. What I found most haunting - besides women being told they had cancer when they didn't, and the need for a second opinion - is that the abnormal cells in ductal carcinoma, which is diagnosed in more than 50 000 women a year in the US alone, are "removed before they develop into invasive cancer. There are estimates that if left untreated, it will turn into invasive cancer 30 percent of the time, though it could take decades in some cases."
So one wonders about that too. About the need for surgery in such cases.