Sometimes, when it comes to science, it seems like we can’t make up our minds—which is true. This is because of how science works: We make observations and, on the basis of what we see, come up with an hypothesis. We move forward with that hypothesis until more observations or new information makes it clear we need to question our current hypothesis. That leads to the next hypothesis, and so on.
In a viewpoint published online yesterday in the Journal of the American Medical Association three cancer experts, who led a National Cancer Institute working group, recommended changing the definition of cancer and giving new names to categories like ductal carcinoma in situ (DCIS), which include the word “cancer” but are actually precancers.
Their recommendations stem from a shift in our understanding of the biology of the disease. We used to think that all cancers were the same and that they started in a bad cell and then grew until they got out of the organ where they started and spread to other parts of the body, resulting in death. What we now know is that there are many different kinds of cancers and that there can be a variety of cancer cells that make up the tumor that can be categorized according to the types of mutations in their genes. Even in a particular organ there may be several different kinds of cancers that grow at different rates. Some of these cancers may remain precancers throughout a person’s lifetime. Others may grow so rapidly that they have already spread to other parts of the body before they are found. The problem is that we currently treat all cancers the same. This leads to overtreatment of some and undertreatment of others.
The cancer experts are proposing that we take a more nuanced view of the disease, acknowledging that it is more complicated than the campaigns that promote early cancer detection suggest. As they say in their piece, “The ideal screening intervention focuses on detection of disease that will ultimately cause harm, that is more likely to be cured if detected early and for which curative treatments are more effective in early-stage disease.” They also note that, “physicians, patients, and the general public must recognize that overdiagnosis is common and occurs more frequently with cancer screening.” As a result, they are recommending that, “the term cancer should be reserved for describing lesions with a reasonable likelihood of lethal progression if left untreated.”
They are proposing that precancers be called IDLE (indolent lesions of epithelial origin). It’s not yet clear if this specific term will catch on, but I hope the larger idea of giving precancers a new name does. Once we have given new names to these lesions, which in the breast include DCIS and LCIS, we could go on to address their second proposal: Creating observational registries that would follow women with DCIS and LCIS over time so that we could determine which precancers do progress and, if so, over what time frame. We could also identify the local environments that egg precancers on to become a cancer that could result in death and that which will not–which would keep many women from worrying and being overtreated. Or, even better, we could figure out what causes precancerous and cancerous to arise in the first place so we can prevent them all together!