National Breast Cancer Coalition

National Breast Cancer Coalition Statement on The Canadian National Breast Screening Study

NBCC President Fran Visco calls results of study helpful to women’s health

A Canadian screening study published Tuesday in the British Medical Journal confirms NBCC’s long-held position that an enormous amount of resources and attention have been spent on mammography, despite the lack of strong evidence that screening significantly reduces mortality from breast cancer. The Canadian study found that 22% of women whose cancers were detected by mammograms were overdiagnosed and subjected to unnecessary treatment.

“NBCC has taken the position for many years that the benefits of screening mammography in reducing mortality are modest and that there are harms associated with screening,” said NBCC President Fran Visco. “No individual woman can be assured that screening mammography will be effective for her, and from a public health perspective, the harms and public health costs of screening mammography may outweigh the modest benefits of the intervention.”

In 2009 when the U.S. Preventive Services Task Force released their recommendations on mammography screening, the National Breast Cancer Coalition commented in its statement, “We hope that policy makers, the public and the health care community will take time to carefully analyze the basis of the revised recommendations. Women have been given different messages for years, but unfortunately, those messages were not based on strong evidence. Women deserve the truth, even when it is complicated.”

Visco calls the Canadian study “of the highest quality science” and warns that “we cannot ignore the results because we may not like them.”

“We invest in science and research, so things change for the better. So while mammograms may have been beneficial before the advent of effective treatment and significant public education, we have progressed beyond mammograms and now better recognize its harms and limitations,” Visco said.

Women Have Been Told for Years That Early Detection Saves Lives. The Reality Is Otherwise. Since 2010, NBCC has issued an annual Progress Report on the state of breast cancer. And each year it has addressed the issue of early detection. In the latest report, issued October 2013, NBCC noted that several studies have been published that describe the harms that outweigh the benefits of screening.

The report went on to say that “…while the incidence of early-stage breast cancer increased significantly in the period between 1976 and 2008, the incidence of late-stage disease decreased only slightly and the incidence of metastatic breast cancer did not change at all.1 More data continues to be collected regarding the magnitude of overdiagnosis due to mammography screening and the resulting harms. One study estimates the rate of overdiagnosis from screening to be between 15% and 25%.2 The harms from overdiagnosis are not insignificant.”

NBCC continues to believe that a woman's decision to undergo a screening mammogram must be made on an individual level, based on quality information about her specific risk factors, and her personal preferences. Women who have symptoms of breast cancer such as a lump, pain or nipple discharge should seek a diagnostic mammogram. Ultimately, resources must be devoted to finding effective preventions and treatments for breast cancer and tools that detect breast cancer truly early.

A Way Forward
Breast cancer continues to take lives, and decades of screening have not changed that fact significantly. This year, more than 522,000 (GloboCan 2012) women worldwide will die of breast cancer. In the United States alone, 39,620 women and 410 men will die of breast cancer (ACS 2013-2014). To renew the sense of urgency to its mission and refocus global efforts on ending breast cancer and saving lives, the National Breast Cancer Coalition set a deadline. Breast Cancer Deadline 2020®: We will know how to end breast cancer by January 1, 2020.

Many women in non-western countries, present with large palpable tumors that have been untreated for some time. The efforts would be better spent educating women and reducing the barriers that lead women to delay seeking care and timely treatment than spending resources on population-based mammography screening programs for asymptomatic women that have questionable results at best. For example, a Malasian program that trained health staff in skills associated with earlier detection of breast tumors and raised public awareness resulted in a decrease in stage III–IV tumors from 60% to 35% in four years.3  

In light of the evidence from this latest study, NBCC urges the public, the health care community, policy makers and the scientific community to focus resources on knowing how to end breast cancer and to reassess the push to increase screening worldwide. 

1Welch, H.G., and Bleyer, A. Effect of Three Decades of Screening Mammography on Breast-Cancer Incidence. N Engl J Med2012;367:1998-2005. 

2Kaleger, M., et al. Overdiagnosis of Invasive Breast Cancer Due to Mammography Screening: Results From the Norwegian Screening Program. Ann In Med April 2012; 156 (57): 491-499. 

3Harford, J. Breast-cancer early detection in low-income and middle-income countries: do what you can versus one size fits all. Lancet Oncol 2011; 12: 306–12