Breast Cancer Screening: Balancing Evidence With Culture, Politics, Money, and Media

History of the Breast

Over the years, well-intentioned individuals have reviewed the scientific evidence on breast cancer screening, yet come to surprisingly different conclusions. While many chapters in this textbook describe the scientific evidence surrounding breast cancer screening dating back decades, the interpretation of this evidence is influenced by complex factors. Individual interpretation of scientific medical information is colored by a heightened fear of breast cancer, mass media campaigns promoting screening, political involvement, and financial incentives all colliding with the complicated culture that surrounds women’s health in general, and breast health in particular. While a financial conflict of interest might be concrete and obvious, an emotional conflict of interest is subtle and can be deeply rooted. Just as a Rorschach ink blot might be interpreted quite differently by individuals, the interpretation of scientific evidence remains challenging in the area of breast cancer screening with multiple and variable interpretations.

To understand the complex nature of breast cancer screening scientific data, a reflection on the history of the breast is a helpful starting point. While thousands of pages have been written on this topic, a summary of key themes is briefly covered here.

The breast was depicted in ancient art as a symbol of motherhood, comfort, and nourishment. For example, this ancient Greek sculpture ( Fig. 1.1 ) depicts a mother feeding her twins, with the mother’s right hand gently playing with the foot of one of the infants. The mother seems relaxed in this nurturing context. Sculptor Jean-Jacques Caffieri’s marble statue titled Hope Nourishes Love shows a young woman who represents Hope nursing a winged Cupid, personifying love ( Fig. 1.2 ). Fig. 1.3 depicts Artemis, goddess of the hunt and wild animals, in her temple at Ephesus (in present-day Turkey) with striking rows of pendant objects on her torso. Most scholars have identified these pendant objects as breasts. The nourishing breast is tied to power and strength in this hunter-goddess’s statue. Just as scientists variably interpret medical data, the interpretation of art has varied over the years. While most assume that the repeated paired objects on this statue are breasts, a scientist in 1978 claimed that, as no nipples were depicted, the round objects represent bulls’ testicles, adding an example of variability in interpretation of visual data based on the viewer’s perspective.

While historic depictions have also sexualized the breast, over the centuries, artistic depictions of the breast became increasingly sensual. Representations of the breast moved from scenes of nourishment between Madonna and Child to increasingly sexualized images. In the last century, the slender flapper image of a woman was replaced with full-bodied women and the breast came to represent a key feature of a woman’s sexuality. Push-up bras and breast augmentation became commonplace and were openly discussed in conversations.

Breast cancer is one of the most feared afflictions in modern society because of its potential devastation of both the woman and her family, given the nurturing, comforting, and sexual attributes of breasts, in addition to the risk of death from the disease. Descriptions of breast cancer treatments date back thousands of years and include the cauterization of breast tumors and ulcers as described in Egyptian textbooks. In describing breast cancer, authors of the past bluntly stated: “There is no treatment.” Thankfully, this is no longer the case. However, early treatments included extensive surgical resections. As the surgical treatments for breast cancer were developed, images of mastectomy scars came to represent mutilation of the body and death. This new symbolism was evident in artist and former fashion model Matuschka’s stunning self-portrait, featured on the cover of The New York Times Magazine in 1993, in which she boldly exposed the remnants of her postmastectomy breast. The juxtaposition of the model’s lithe body and the taboo scar forced readers to confront breast cancer and its raw physical impact.

History of Medical Screening

Given the historical value society has placed on women and the breast, it is no surprise that breast cancer screening remains in the forefront of societal focus. With the development of successful treatment for early-stage breast cancer, early detection screening programs became a possible approach to consider.

Effective medical screening includes consideration of whether earlier treatment of disease improves prognosis and whether screening tests are accurate and able to detect disease at an early stage. Over time, the criteria for evaluating the usefulness and appropriateness of medical screening tests expanded to take into consideration characteristics of the specific disease, such as its severity and frequency in the target population, and characteristics of the screening test, such as cost and acceptability. Additionally, the impact of implementing screening exams in the target health care system became a requirement for consideration as well ( Table 1.1 ).

The success of mass screening programs, such as cervical cancer screening on reducing morbidity and mortality, has been impressive. These successes have increased enthusiasm for the general concept of screening to allow early-stage detection of disease while it is easier to treat. Screening for many diseases has now become a vital part of public health efforts to improve health and health outcomes.

History of Screening With Breast Self-Exam and Clinical Breast Exam

As improved treatment options became available to women with early-stage breast cancers and following the hypothesis that earlier detection saves lives, scientists and health care practitioners set out to identify the best strategies for finding breast cancer early via screening. Initially, a three-pronged approach was formulated involving screening mammography, clinical breast exam, and breast self-exam. The idea behind this comprehensive tactic was that: (1) breast self-exams would keep breast screening at the forefront of a woman’s health care practice and remind her to screen; (2) clinician breast exam would provide a good opportunity for the physician and woman to discuss breast health and screening; and (3) all three tactics would provide a thorough screening that improved the woman’s chance of finding a cancerous lesion early.

From the 1960s through 2000s, clinicians were encouraged to perform screening breast exams on their patients in the clinic, and clinicians instructed their patients in how to perform monthly breast self-examinations. As scientific evidence was collected, however, it became apparent that breast self-examination is not associated with a reduction in breast cancer mortality, though it does increase the risk of having a biopsy with benign results.

Studies of screening clinical breast examination performed by clinicians have been limited. The Canadian National Breast Screening Study found the 25-year cumulative mortality from breast cancer to be similar between women screened with mammography and clinical breast examinations and women screened with clinical breast examinations alone. However, the quality of these exams may have exceeded that of the standard community practice: the clinicians providing clinical breast examinations in the study were well-trained, spent 5–10 minutes examining each breast, and were periodically evaluated for examination quality. In general, clinical breast exams performed in the community setting were noted to have lower sensitivity compared with mammography. A US study found examination sensitivity to be only 21.6% in asymptomatic women who received a clinical breast examination within 1 year of breast cancer diagnosis but died of breast cancer within 15 years of diagnosis.

While the evidence on screening for breast cancer by breast self-examination and clinician breast examination is not covered in this textbook, and less research has been done on these topics, in general they are no longer recommended as part of most breast cancer screening programs in developed countries.

History of Mammography Screening

For many diseases, detection is best achieved through visualization. Initial advances in breast imaging occurred in the early 1900s when Dr Albert Salomon, a German surgeon, began using X-rays to image the breasts of symptomatic women. Mammography exams were initially evaluated as a diagnostic tool and not considered as a screening tool. With technological advances, the first dedicated mammography systems were in place the mid-1960s. As with any new, unproven device these mammography units were initially met with cautious regard by many practicing physicians, including breast surgeons, until their worth as a diagnostic aid was demonstrated.

The use of mammography as a screening tool took shape in the later part of the 1900s. In 1969, R.L. Egan published an article in Cancer describing screening mammography as having a “certain magic appeal” and saying that the patient “feels something special is being done for her.” The availability of a tool to identify early-stage breast cancer in order to improve treatment and survival helped to establish breast cancer screening as a common practice. Women wanted to do anything possible to reduce their risk of dying of breast cancer, and breast cancer screening with mammography was seen as promising.

In the 1960s, breast imaging became a radiology subspecialty in medical schools in the United States, and the Health Improvement Program (HIP) in New York—the first randomized controlled trial (RCT) of screening mammography—began in 1963. In 1972, the results of this HIP trial were published with much fanfare. This study reported a statistically significant reduction in breast cancer mortality among women randomized to the screening mammography arm of the study. This promising result was followed by additional studies including more RCTs (see chapter: Estimates of Screening Benefit: The Randomized Trials of Breast Cancer Screening ), observational studies (see chapter: The Importance of Observational Evidence to Estimate and Monitor Mortality Reduction From Current Breast Cancer Screening ), statistical modeling (see chapter: The Role of Microsimulation Modeling in Evaluating the Outcomes and Effect of Screening ), and even studies designed to identify best ways to promote mammography in different communities. Research on mammography and breast cancer screening in community settings became a primary focus in the early 1990s as the National Cancer Institute (NCI) initiated funding for the Breast Cancer Surveillance Consortium (BCSC). The consortium is a collaborative network of multiple, nationwide mammography registries with linkage to cancer registries for the sole purpose of research on breast cancer detection and identification. The BCSC has been in operation since 1994 and has been the source of more than 550 research articles about breast cancer.