SABCS 2010: Clinical Science Forum Review
December 9, 2010
By Jane Zones, BCA Board Member
Controversies in screening for breast cancer
Eric Winer, Dana-Farber
Laura Esserman -- "Rethinking and improving screening in the context of breast cancer biology"
Chris Flowers MBBS Moffitt Cancer Center, Tampa BC Screening—The radiology perspective
Judy Garber, MD, MPH Dana-Farber Cancer Inst, Boston
Chris Tannous, PhD (Susan G. Komen for the Cure, Orange Co.)
BCA spent quite a bit of energy this past year responding to the US Preventive Services Task Force (USPSTF in what follows) recommended guidelines for breast cancer screening, and this July, using information provided in the Task Force report, we issued our revised policy perspective.
Therefore, we were looking forward to a one hour lunchtime special Clinical Science Forum “Controversies in Screening for Breast Cancer,” which was very well attended. Although it was to be a panel discussion with audience participation, the first two speakers went well over their six minute allotment, and by the time the other two panel members made their comments and the moderator asked them a question with follow-ups, it was time to go. Several people from the floor did get a chance to come to the three microphones, but statements were made rather than any real questions, and the overtime discussion was mostly focused on MRIs rather than the new recommended guidelines.
The first speaker, Chris Flowers, a British radiologist now practicing in Florida, gave “the radiologists’ perspective,” which adhered loyally to the viewpoint of the American College of Radiology. ACR has been heavily critical of the USPSTF proposed guidelines since they were issued. The radiologists insist that mammography saves lives, do not address the issues of radiation exposure or overtreatment, and cite anecdotes about patients of theirs who benefited from screening. Of all the medical specialties, radiology has the most to lose if the USPSTF guidelines were implemented—it would be a huge loss in this $7 to $10 billion a year industry.
At one point, Dr. Flowers said it was time to stop discussing numbers (this was in reference to the Task Force research that showed that about ten thousand women 40-49 would have to be screened annually for ten years to save one life). He referred to percentage reductions in mortality (rather than absolute numbers), which in these large populations with relatively small incidence, greatly exaggerate seeming benefit. If Dr. Flowers speaks for the radiologists, it seems the radiologists would like for us to stop discussing the data, accept the current guidelines, and move on, leaving them to their business.
Laura Esserman, UCSF’s prominent breast cancer surgeon, gave an excellent presentation that fully covered the significant issues related to population screening. Her talk came from an article she wrote with two others for the Journal of the American Medical Association (“Rethinking Screening for Breast Cancer and Prostate Cancer,” JAMA. 2009;302(15):1685-1692.) Esserman started off by stating that she’d like to see polarization end on this issue.
Esserman stated that “screening is complex because cancer is complex.” She then described the model that BCA also uses in its screening policy perspective, that population screening of people without known increased risk of breast cancer is most likely to benefit those with “medium growth” tumors, which are most responsive to treatment.
Those with what she calls “idle” cancers (very slow growing) are often subject to unnecessary treatment for something that would be unlikely to develop into a problematic condition. And early detection of rapidly growing, aggressive tumors does not appear to be an advantage to allay morbidity and mortality with current treatments.
Almost half of “interval cancers”—cancers detected between screenings either through clinical breast exam or by the women themselves—are found in women in their 40’s.
Further, population screening has greatly increased the detection and treatment of non-invasive disease. The incidence of ductal carcinoma in situ (DCIS) has increased 500 times since the advent of mammography screening.
Esserman noted that the difficulties with population screening are not limited to breast cancer, and that 25 to 70% of cancers may fall into the category of overdiagnosis. She said that it is estimated that about a third of the reduction in mortality is attributed to screening, and two-thirds to adjuvant treatment.
The next steps to improving screening include reduction of the negative effects by “appropriately reducing frequency.” During the comments period, Esserman said that there is a dearth of well-qualified radiologists, and that bi-annual screening would give women a likelihood of more accurate readings of their mammograms. An additional means of improving screening would be to initiate the screening process with risk assessment that can be managed by using patient-navigated decision trees, which can be completed on-line.
The first of the two commentators on the panel, Chris Tannous, an advocate representing Komen in Orange County, CA, gave a good overview of the USPSTF recommended guidelines, emphasizing that they were meant for healthy women with no known increased risk of breast cancer, and that women in their 40’s were urged to discuss screening with their physicians. She noted that the strong negative reaction to the guidelines was in part a function of miscommunication, and distortion of what the guidelines actually say by their detractors.
Tannous pointed out that the current and future budget deficits faced by the states are already cutting into financial support for diagnostic mammograms as well as screening mammograms, and that this situation will probably increase.
The last panelist, Judy Garber, a physician at Dana-Farber in Boston, focused her comments on MRI and screening of high-risk women.
One audience member who was able to get the floor stated that primary care physicians were often not capable of having a discussion with women about their risks and benefits of screening, and that it was a cop-out for experts to urge women to discuss the issues with their physician. In the current climate of managed care, physician visits could not be long enough to have a thoughtful discussion, even if the provider was well informed about the issues.