Acknowledging the uncertainties of mammography
The radiology community should disclose all of the uncertainties and certainties associated with mammography screening to the public in order to provide the whole truth, according to an article published online May 1 by the Journal of the American College of Radiology.
While the existence of overdiagnosis in breast cancer screening is undeniable, its frequency of occurrence is unknown. Overdiagnosis most commonly happens in patients with ductal carcinoma in situ (DCIS) and even though the likelihood that DCIS will evolve into an invasive cancer is less than 50 percent, all cases are aggressively treated nonetheless, according to the article’s author, Leonard Berlin, MD, of the University of Illinois in Chicago. "[A]s many as 70,000 women every year in the United States may be ‘overdiagnosed’ and therefore harmed by being overtreated for a ‘disease’ that in fact needs no treatment,” he wrote.
Berlin notes that guidelines and recommendations about mammography screening from prominent organizations such as the American College of Radiology (ACR) and American Cancer Society (ACS) fail to mention the issue of overdiagnosis.
“Notwithstanding the fact that since 2002 screening mammography has been greatly enhanced by extraordinary technical advances such as digital mammography, computer-aided detection, and tomosynthesis, the mindset of many in the radiologic community in 2002—that women would be ‘confused’ if they were informed about the controversies and debates regarding both benefits and harms of mammography such as overdiagnosis—apparently remains unchanged in 2014,” wrote Berlin.
Although both the ACR and ACS have made attempts at clearly delineating the benefits and harms of mammography, respective efforts failed to mention overdiagnosis. Berlin contends that an apparent perception of gender difference could be the culprit for this omission, as the two organizations address the possibility for overdiagnosis in shared decision making about prostate cancer quite differently.
Moreover, those who have tried to focus on overdiagnosis in the past have often been harshly criticized, with critics pointing to data that demonstrate a decrease in breast cancer mortality due to mammography in an attempt to make the original statement null.
“It is indeed truth when radiologists state that breast cancer mortality has dropped more than 30 percent due to screening mammography; however, the inference is clearly that mammography screening is the exclusive reason for the decrease. Does stating a ‘truth’ but at the same time omitting the fact that similar of even greater mortality rate reductions have occurred with other types of cancers in addition to breast cancer-all due to both early detection and improved treatment- qualify as representing the whole truth, and nothing but the truth? I suggest it does not,” wrote the article’s author.
Efforts to promote mammography for early detection and treatment of breast cancer by the radiology community have overlooked the entire truth about the screening method, argues Berlin. “For us to ignore or deny that overdiagnosis occurs, and that there is debate as to whether it is a major harm of screening mammography, is to lose credibility," he wrote.