Following the publication of the controversial article, the American Cancer Society (ACS) responded by confirming the value of mammography.

“The overwhelming weight of scientific evidence supports regular screening with mammography as the best strategy to detect breast cancer early and thus begin treatment early,” says Robert Smith, PhD, director of cancer screening for the ACS.

After studies in the 1960s and 1970s involving more than 300,000 US women showed mammography could detect breast tumors too small to be found any other way, widespread mammography screening began in the US in the mid-1980s.

Between 1988 and 1999, seven other large trials involving about 500,000 women solidified widespread agreement in the medical community of mammography’s value.

But Danish researchers Ole Olesen and Peter Gøtzsche first published an article in 2000 in The Lancet (Vol. 355, No. 9198: 129-134) saying none of the seven were very good, and the two that were adequate showed no benefit to mammography.

“There is no reliable evidence that screening decreases breast cancer mortality,” the researchers concluded then.

Olsen and Gøtzsche noted death rates from breast cancer hadn’t yet dropped in Sweden, even though mammography was being used there.

The researchers’ first report met with criticism from cancer experts and organizations.

Along with the 2000 article, Lancet published a critique (Vol. 355, No. 9198: 80-81) in which commentator Harry J. de Koning questioned the researchers’ reasoning, methods, and results.

De Koning noted Sweden’s mammography program might not have been going on long enough to produce a drop in breast cancer death rates by 1999, but United Kingdom and Finland breast cancer death rates were beginning to drop after older mammography programs there.

Cancer organizations such as the ACS and the National Cancer Institute and cancer doctors dismissed the 2000 report and confirmed the value of mammography in early detection of breast cancer.

And, as reported in an editorial accompanying the current article in The Lancet, the editors at the Nordic Cochrane Center, where both researchers work, distanced themselves from the report, saying it had not been through the rigorous review for which their institution is well known.

Gøtzsche and Olsen then re-did their earlier work. They reported the new analysis confirmed their earlier conclusions that mammography does not save lives.

And, they said, their review now also showed mammography may lead to more aggressive treatment than necessary for some women.

The researchers’ institution again disagreed with the report’s conclusions, refusing to publish it as written, resulting in one version published in The Lancet, and a different version by the institution’s library.

The 2001 Lancet article is meeting with much the same rejection from cancer experts as its predecessor.

Smith notes that in both reports the researchers labeled, based on dubious criteria, five of the seven studies as being of poor or flawed character, leaving them with two which they said together showed no benefit, even though one didn’t and one did.

Experts summarily dismissed that process after the original report, says Smith.

Smith notes that the reason more than 80% of US women have had a mammogram is because expert groups supported by leading medical organizations have also looked very carefully at the available evidence, and concluded that mammograms are an important part of women’s health care and reduce deaths from breast cancer.

Women should continue to be screened according to the appropriate ACS guidelines, Smith says.

Smith also noted, “Over the past 30 years, mammography has come under constant, aggressive scrutiny. The clinical trials of mammography have been analyzed, re-analyzed, and subjected to numerous overview and meta-analyses by many separate investigators and expert groups.

“It is highly unlikely that all of these carefully performed studies are wrong, and this one is right, especially given the numerous flaws that were identified in the previous analysis,” Smith says.

Smith also observes that the Swedish Board of Health has independently scrutinized the five studies of mammography performed in that country, and thoroughly reviewed all of the information regarding the women who were screened.

In May, Smith and his colleagues published a 29-year follow-up study of women in two counties in Sweden, which found a 63% decrease in deaths from breast cancer in women age 40 to 69 since the introduction of mammography in that area.

“The overwhelming weight of scientific opinion — based on the overwhelming weight of scientific evidence — is that early detection saves lives by providing an opportunity to treat tumors at a more favorable stage, resulting in better outcomes for women with breast cancer,” he says. “That’s the value of mammography, and from a scientific standpoint, the evidence is beyond dispute.”