Putting the “Informed” in Informed Consent About Mammography

Few health care topics have generated as much controversy as the appropriate age for screening women by mammography. In March 1993, the report of the International Workshop on Breast Cancer Screening (7) concluded that, for women aged 4049 years, randomized clinical trials of breast cancer screening showed no mortality benefit 5-7 years after entry. The report further stated that at 10-12 years after entry, the benefits of screening for women aged 40-49 years were marginal and uncertain. The controversy became dramatically more heated in 1993 when the National Cancer Institute (NCI) issued a statement of evidence about the benefits of mammography for women of different ages that replaced the previous screening guideline. Women and their physicians were encouraged to make informed decisions about mammography. Although routine mammograms were not proscribed, the NCI no longer specifically endorsed mammograms for all women aged 40-49 years. Some recent reports have corroborated the conclusions of the workshop (2), while others have raised concerns (3). The NCI statement of evidence was released in December 1993. In the months that have followed, the general press and the medical press have been filled with commentaries, controversy, and information. Yet, this plethora of information has not necessarily led to clarification, and the challenge of informed decision making remains. Few studies have attempted to explain how women and health professionals view the screening controversy or how this controversy will affect their decisions about breast cancer screening. In one of the few reports, Sutton et al. (4) found that women wanted more information before they would be comfortable with the new evidence. Focus groups conducted among women in North Carolina confirmed that many women feel uninformed. As one woman said, "They keep saying they want women to make informed decisions, but I am still uninformed. The information I need is still lacking" (Bloom D, Tessaro I, Rimer B: Focus Group Report About the Screening Controversy, March, 1994, unpublished). The article in this issue of the Journal by Black et al. (5) demonstrates that the ideal of informed decision making will be difficult to achieve in the face of faulty assumptions about breast cancer risk and overestimates of the benefits of mammography. The authors show that women overestimate the probability of developing and dying of breast cancer, as well as the benefits of mammography. In fact, respondents "overestimated their probability of dying of breast cancer within 10 years by more than 20-fold." Equally disturbing, they overestimated the benefits of mammography as well—by about sixfold. There were some important subgroup differences. Women who were classified as not numerate were more likely to overestimate their risks, as were women with less than a high school education. The study has some important limitations. Although the sample size is adequate for the analyses undertaken, it is a relatively small base from which to generalize. Moreover, as the authors themselves cautioned, there were no minority women and the sample was largely one of educated women. Previous studies have shown that many women, especially older women, underestimate the risk of breast cancer (6). Yet, Black et al. have performed a major service by providing insight into the challenges associated with informed decision making about mammography screening. One side of the decision-making equation—women—have been shown to overestimate the risks associated with breast cancer and the benefits of mammography. It would be useful to know if physicians and other health providers have similar biases. There cannot be informed decisions if the foundations of decisions are based on faulty assumptions. If women overestimate their risks, they may be more likely to seek mammograms because they view breast cancer as a greater risk than it really is. Since the harm associated with mammography often remains unclear, there also may be a bias toward mammography because the benefits of early detection are easier to understand. This bias is consistent with the belief that a test is considered effective until proven ineffective. The preference for continued use of mammography will be more pronounced, given the parallel overestimate of the benefits of mammography. An informed decision should be one that is based on a realistic appraisal of the risks and benefits of a proposed intervention, and it should be autonomous. Mammography may be the right decision for some women but not for others. As Penman et al.