Breast Cancer Screening: The Way Forward Worldwide
Breast cancer screening can be improved in the US and worldwide by training the hands of women and their practitioners to perform skilled, standardized exams.
The Canadian National Breast Screening Study
The breasts of 89,000 Canadian women were examined either by mammograms (x-ray) or by nurses trained to perform skilled clinical (manual) breast exams and self-exams. The women were randomly assigned to one of these two breast cancer screening procedures and followed for 25 years. The surprising result disrupted current beliefs because the number of breast cancers detected by the nurses were the same as those detected by radiologists using mammograms. The study also reported that mammograms “overdiagnosed” benign findings as cancer 22% of the time. Although the final report was challenged by radiologists who use mammograms, the results were validated. An update in 2016 found that the rate of false positives, (overdiagnosed) was significantly higher than first observed.
The finding, that skilled clinical breast exams coupled with self-exam training are as effective in detecting breast cancer as mammograms, is disruptive because it contradicts common beliefs, current recommendations and practices. The evidence from this landmark study challenges the advice of two associated US agencies that regularly issue “press releases” seeking to advise women and their practitioners not to perform clinical exams or self exams. Respected medical organizations don’t agree
The American College of Obstetricians and Gynecologists (ACOG), reports that self-exams are effective in detecting breast cancer
In their current Practice Bulletin, ACOG states “Although breast-self examination is no longer recommended, evidence of the frequency of self-detection of breast cancer provides strong rationale for breast self -awareness in the detection of breast cancer. Approximately 50% of cases of breast cancer in women 50 years and older and 71% of cases of breast cancer in women younger than 50 years are detected by women themselves. (40, 41). For example, 43% of the 361 breast cancer survivors who participated in the 2003 National Health Interview Survey reported detecting their cancer themselves (42). Additional evidence of the important role of breast cancer self-detection comes from a study of low-income women who received breast cancer care through California’s Breast and Cervical Cancer Treatment Program. Of the 921 women in the cohort, 64% detected their breast cancer (43) ”
Evidence also documents that the accuracy of both mammograms and clinical (manual) breast exams depend primarily on the quality of the examiner’s skills
Well designed studies also find that breast cancer detection accuracy depends on the competencies of the examiner as well as the method used. Mammograms are read (viewed) by clinicians whose accuracy depends on their training and development of visual discrimination skills whereas the accuracy of clinical breast exams depends on training the sense of touch and development of palpation skills.
Research studies also document wide variations in the accuracy among interpretations of mammograms. Training and experience are found to improve radiologists’ diagnostic accuracy although the rates of false positive and false negative readings remain considerable. Similarly, studies of clinicians (and women) trained to perform manual breast exams demonstrate significantly greater accuracy in detecting small suspicious breast tumors and fewer false positive “detections” than those who are untrained.
Why evidence is ignored
In science and medicine a period of resistance typically results when evidence contradicts established doctrines and beliefs even when the practices are inaccurate, ineffective or worse. This was dramatically demonstrated when an effective new treatment for stomach ulcers was rejected for nearly a decade by experts and by US health officials. In the present, far more potentially deadly case of breast cancer screening.
Resistance to the discovery that mammograms are not superior to trained hands in Canada can be expected from practitioners who are invested in their approach. One notion advanced by radiologists to explain the absence of discrepancy between the value of mammograms and manual exams in detecting breast cancer is that Canadian mammography machines are older than those in the US. But this argument lacks credibility because the image quality and resolution of x-ray mammography has not changed in more than 50 years. Moreover, images produced by newer digital mammograms do not improve the resolution or clarity of film x-ray.
So what should nurses and doctors and women and health agencies that screen women for breast cancer do?
Begin training the hands of women and their practitioners to perform skilled breast exams using valid performance standards that produce reliable detection of small suspicious breast lesions while eliminating or reducing false positives and insuring thorough coverage of all breast tissue.*
*Does This Patient Have Breast Cancer? The Screening Clinical Breast Examination: Should It Be Done? How? “Our recommendation incorporates practices from the Mammacare method, because its components have been validated in independent investigations of CBE technique” JAMA 283(13), (p. 1276), Barton, M.B., Harris, & Fletcher, S.W.