Many people in the US are being over-diagnosed and over-treated for cancer and better definitions of cancer and new molecular diagnostic technologies could help solve the problem, according to a working group of the National Cancer Institute.
In a new viewpoint article in the Journal of the American Medical Association, the working group says that many people have lesions or other abnormalities that are officially called cancer, but which may not prove harmful during their lifetimes.
This broad definition of cancer is leading to overtreatment — too many biopsies, operations, and radiation and chemotherapy treatments bring their own risks and psychological pain, the group argues.
What is needed is a new way of classifying some of these non-lethal cancers that are detected in screenings, the working group says. It proposes that the term "indolent lesions of epithelial origin", or IDLE conditions, would better express what these pathologies actually are.
“We need a 21st-century definition of cancer instead of a 19th-century definition of cancer, which is what we’ve been using,” says Otis Brawley, the chief medical officer of the American Cancer Society, according to the New York Times.
The effort to look closely at the link between cancer diagnoses, indolent lesions, and the lexical questions of where the lines defining cancer should be drawn came about due to an increasing concern "among doctors, scientists, and patient advocates that hundreds of thousands of men and women are undergoing needless and sometimes disfiguring and harmful treatments" for such lesions, the Times reports.
NCI Director Harold Varmus tells the Times that it can be difficult to get patients to understand that unusual things that are found in screening and testing "are not always malignancies in the classical sense that will kill you."
The working group says that an ideal screening intervention focuses on detecting diseases that will cause harm, that are more likely to be cured if caught early on, and that have early-stage treatments. It will be necessary to be able to better characterize the biology of cancers and IDLE conditions in order to reach that ideal, the group says, and it offered several recommendations on how to get there.
Foremost, doctors, patients, and the public need to recognize that overdiagnosis is common and happens more often as more people are screened earlier.
But there also will need to be a change in the terminology used — change that will in part be based on companion diagnostics — and premalignant conditions like ductal carcinoma should not be labeled as cancer.
The group also says that molecular diagnostic tools that can identify indolent or low-risk lesions need to be adopted and validated, and some of these cancers need to be reclassified at IDLE conditions.
It also would be a big help if there were a registry of lesions that are unlikely to be malignant, the working group says.