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.
"I would hope in the future that we would be able to tailor our screening strategies as we have our treatment strategies," she said.
The study's authors also argued for a change in research focus, rather than immediate action to curb cancer screenings.
"It means we have to change our paradigm. Our paradigm for the last 50 years is look hard for early cancer," said Dr. H. Gilbert Welch, a co-author of the paper published Thursday in the Journal of the National Cancer Institute.
Yet not everybody is convinced by Welch's choice of data, and the implication that improved screening is catching a greater proportion of mild tumors that would ultimately never hurt the patient.
"The authors went back only 30 years in SEER [Surveillance, Epidemiology and End Results] data in their selective effort to make it appear as if breast cancer screening was a major cause of over-diagnosis," said Dr. Daniel B. Kopans, a professor of radiology at Harvard Medical School and the director of the Breast Imaging Division at Massachusetts General Hospital in Boston.
Kopans admits that with his specialty, he would obviously be a proponent of better imaging.
But, he adds, "There is no question, that there are cancers that are indolent, and may not kill the individual. This has been known for decades."
"The death rate from breast cancer has decreased in the United States by 30 percent, predominantly, due to mammography screening. This is 15-20,000 lives saved each year. The effort to reduce screening will mean that women will die unnecessarily," Kopans said.
Kopans and other doctors interviewed by ABC News pointed out that Welch has published similar arguments before, and wrote a book in 2004 titled "Should I Be Tested for Cancer?: Maybe Not and Here's Why."
Even the journal in which the article was published has drawn critiques. Despite its name, the Journal of the National Cancer Institute is not affiliated with the National Cancer Institute. Since the 1990s, it has been owned and operated by Oxford University Press.
Still, Dr. Otis W. Brawley, chief medical officer of the American Cancer Society, and other high-profile cancer researchers say Welch has a compelling argument.
Dr. Susan Love, president of the Dr. Susan Love Research Foundation, agreed.
"This is not only true but is in sync with all the recent science suggesting that it is not just the mutated cell that leads to cancer, but it also needs to be in a micro- and probably macro-environment that will egg it [the tumor] on," said Love.
Welch agrees that he's not the first to recognize that statistics prove some portion of cancers would be non-lethal and slow-growing. But he argues medicine in the United States is so focused on screening that now some people are suffering needless harm with chemotherapy and other treatments.
"People have been aware of this theoretical problem for many years," said Welch. "But what's happened recently is that all of a sudden what was a theoretical concern has become a very real problem."