Slow adoption and limited results
Between 1930 and 1950, Dr. Warren, Jacob Gershon-Cohen, MD (1899-1971) of Philadelphia, and radiologist Raul Leborgne of Uruguay “spread the gospel of mammography as an adjunct to physical examination for the diagnosis of breast cancer.”4 The latter also developed the breast compression technique to produce better quality images and lower the radiation exposure needed, and described the differences that could be visualized between benign and malign microcalcifications.
But despite the introduction of improvements such as double-emulsion film and breast compression to produce higher-quality images, “mammographic films often remained dark and hazy. Moreover, the new techniques, while improving the images, were not easily reproduced by other investigators and clinicians,” and therefore were still not widely adopted.4
Little noticeable effect of mammography
Although the technology existed and had its popularizers, mammography had little impact on an epidemiological level.
There was no major change in the mean maximum breast cancer tumor diameter and node positivity rate detected over the 20 years from 1929 to 1948.10 However, starting in the late 1940s, the American Cancer Society began public education campaigns and early detection education, and thereafter, there was a 3% decline in mean maximum diameter of tumor size seen every 10 years until 1968.
“We have interpreted this as the effect of public education and professional education about early detection through television, print media, and professional publications that began in 1947 because no other event was known to occur that would affect cancer detection beginning in the late 1940s.”10
However, the early detection methods at the time were self-examination and clinical examination for lumps, with mammography remaining a relatively limited tool until its general acceptance broadened a few decades later.
Robert Egan, “Father of Mammography,” et al.
United States. Public Health Service
Robert L. Egan, MD, discusses his mammography technique in a 1965 United States. Public Health Service film.
The broad acceptance of mammography as a screening tool and its impacts on a broad population level resulted in large part from the work of Robert L. Egan, MD (1921-2001) in the late 1950s and 1960s.
Dr. Egan’s work was inspired in 1956 by a presentation by a visiting fellow, Jean Pierre Batiani, who brought a mammogram clearly showing a breast cancer from his institution, the Curie Foundation in Paris. The image had been made using very low kilowattage, high tube currents, and fine-grain film.
Dr. Egan, then a resident in radiology, was given the task by the head of his department of reproducing the results.
In 1959, Dr. Egan, then at the University of Texas MD Anderson Cancer Center, Houston, published a combined technique that used a high-milliamperage–low-voltage technique, a fine-grain intensifying screen, and single-emulsion films for mammography, thereby decreasing the radiation exposure significantly from previous x-ray techniques and improving the visualization and reproducibility of screening.
By 1960, Dr. Egan reported on 1,000 mammography cases at MD Anderson, demonstrating the ability of proper screening to detect unsuspected cancers and to limit mastectomies on benign masses. Of 245 breast cancers ultimately confirmed by biopsy, 238 were discovered by mammography, 19 of which were in women whose physical examinations had revealed no breast pathology. One of the cancers was only 8 mm in diameter when sectioned at biopsy.
Dr. Egan’s findings prompted an investigation by the Cancer Control Program (CCP) of the U.S. Public Health Service and led to a study jointly conducted by the National Cancer Institute and MD Anderson Hospital and the CCP, which involved 24 institutions and 1,500 patients.
“The results showed a 21% false-negative rate and a 79% true-positive rate for screening studies using Egan’s technique. This was a milestone for women’s imaging in the United States. Screening mammography was off to a tentative start.”5
“Egan was the man who developed a smooth-riding automobile compared to a Model T. He put mammography on the map and made it an intelligible, reproducible study. In short, he was the father of modern mammography,” according to his professor, mentor, and fellow mammography pioneer Gerald Dodd, MD (Emory School of Medicine website biography).
In 1964 Dr. Egan published his definitive book, “Mammography,” and in 1965 he hosted a 30-minute audiovisual presentation describing in detail his technique.11
The use of mammography was further powered by improved methods of preoperative needle localization, pioneered by Richard H. Gold, MD, in 1963 at Jefferson Medical College, Philadelphia, which eased obtaining a tissue diagnosis for any suspicious lesions detected in the mammogram. Dr. Gold performed needle localization of nonpalpable, mammographically visible lesions before biopsy, which allowed surgical resection of a smaller volume of breast tissue than was possible before.
Throughout the era, there were also incremental improvements in mammography machines and an increase in the number of commercial manufacturers.
Xeroradiography, an imaging technique adapted from xerographic photocopying, was seen as a major improvement over direct film imaging, and the technology became popular throughout the 1970s based on the research of John N. Wolfe, MD (1923-1993), who worked closely with the Xerox Corporation to improve the breast imaging process.6 However, this technology had all the same problems associated with running an office copying machine, including paper jams and toner issues, and the worst aspect was the high dose of radiation required. For this reason, it would quickly be superseded by the use of screen-film mammography, which eventually completely replaced the use of both xeromammography and direct-exposure film mammography.