Is Cancer Being Overdiagnosed?

April 23, 2010— -- Doctors have known that some cancer patients receive treatment for disease that may have disappeared on its own. But whether cancer screenings should be reduced before science has found a way to distinguish harmless tumors from bad ones has been a hotly contested issue.

So on Thursday, when a provocative journal article suggested that the medical community should try to learn how to reduce cancer screenings, it sparked a fierce debate.

The article, published in the Journal of the National Cancer Institute, argued that a sizable percentage of certain cancers are "over-diagnosed," and an accompanying editorial suggests that some slow-growing cancers should be renamed "IDLE Tumors. "

The article set off a firestorm of debate within the cancer research community.

On one side are those who doubt the motives of the article's authors. More doctors say it is too soon to bring up the concept of "over-diagnosed" cancers, since doctors have no way to distinguish which tumors will be deadly, and which ones would never grow enough to do harm.

"Be very cautious about this. Until we have better ways of predicting future behavior of these 'indolent' tumors, we are better off removing them," said Dr. Bruce Chabner, clinical director for the Massachusetts General Hospital in Boston. "Cancer is cancer until proven otherwise, and unfortunately we have no way of making accurate predictions in individual cases at this point in time."

On the other side are those who say doctors should do more research into tumors, and hopefully, one day save people from unnecessary treatment.

Doctors cannot always foresee the course for an individual's tumor, but by looking at populations that were -- and were not -- screened for cancer over time, the study's authors argued that doctors are detecting and sometimes treating too many harmless tumors. They estimated 25 percent of breast cancers detected with mammograms and about 60 percent of prostate cancers are "over-diagnosed."

"I think part of the problem is you see the words 'breast cancer' and everyone thinks we need to be aggressive and treat it," said Dr. Laura Esserman, a co-author of the accompanying editorial and director of the University of California San Francisco Carol Franc Buck Breast Care Center. Esserman and co-author Dr. Ian Thompson make the case that doctors should start calling low-risk cancer something other than cancer, such as IDLE tumors -- InDolent Lesions of Epithelial origin.