Women's Expectations for Breast Cancer Prevention and Early Detection: High Expectations Can Be Achieved.

Inhis commentary titled “BreastCancerPrevention:CanWomen’s Expectations Be Met?” [1], Dr. Ponzone raises an important and timely question. Dr. Ponzone asks whether breast “cancer prevention”and“earlydetection”areattainablegoalsandwhether these phrases have the samemeaning to women at risk of breast canceras tohealthprofessionals.This is a critically important issue, because researchers andhealth careproviders strive to reduce the incidence andmortality frombreast cancer byworking to develop safe and effective methods to prevent breast cancer. As Dr. Ponzone points out, mammography “is not without its drawbacks” [1]. Mammography, although associated with reduced breast cancer-specific mortality in some studies [2, 3], has not been found to reducebreast cancer-specificmortality in others [4]. In addition, mammograms can detect noninvasive cancers, some of which might not evolve to invasive breast cancer (theproblemofoverdiagnosis) [5].However, Ibelieve it is misguided to conclude that “preventive measures for a given individual might have only modest impact” and that “efforts of cancer specialists should focus more on improving the length and quality of life of patients through therapeutic advances.” Although cancer specialists should work to develop more effective therapies for women with all stages of breast cancer, the greatest impact on breast cancer incidence and mortality will come from appropriately applying risk-based cancer preventive and early detection strategies. Theword “prevention” is often interpreted differently by the general population and health care providers. For health care experts, interventions that reduce the incidence of disease (in this case, cancer), even if incompletely, are considered to have prevented the disease in some individuals. However, for most of the general population, interventions that “prevent” disease are considered to be 100% effective (i.e., to reduce the incidence to zero)andtohaveminimal toxicity.Thecommonperception isthat an individual receiving preventive treatment will have no side effects and will never develop the disease to be prevented (cancer, in this case).The commonexample of such a “preventive intervention” is that of the polio vaccine given in childhood with minimal toxicity and almost 100% efficacy [6]. Other acceptable “preventiveinterventions” includetreatmentwithstatinstoreduce cholesterol levels to prevent heart disease [7], antihypertensive drugs to prevent strokes [8], andbisphosphonate drugs to prevent bonefractures[9].However, ineachofthesecases,theintervention is neither 100% effective nor risk-free. It is remarkable that the general population accepts medical intervention to prevent heart disease, strokes, and bone fractures but often does not accept “preventive interventions” to prevent cancer. There are currently available interventions that clearly prevent many breast cancers in high-risk women. These include bilateral prophylactic mastectomy, which prevents up to 90% of breast cancers in very high-risk women [10, 11]; antiestrogen preventive therapy (with anti-estrogen selective estrogen receptor modulators, such as tamoxifen or raloxifene), which prevents approximately 50% of breast cancers [12]; and aromatase inhibitors, which prevent up to 70% of breast cancers in moderately high-risk women [13]). These interventions prevent breastcancer inmanywomenbutareoftennotacceptedbecause of the possible side effects.The behavioral interventions that Dr. Ponzonementions (avoidanceofenvironmental carcinogens and lifestyle factors suchasdietandexercise) likely alsoprevent some cancers; however, these highly tolerable interventions are less effective thanthesurgicalormedical interventionsmentioned. In clinical practice, these various preventive interventions are being used in a tiered fashion according to risk. Thus, for women at extremelyhighriskofbreastcancer (suchasthosecarryingBRCA1 or BRCA2 mutations), bilateral prophylactic mastectomies are consideredand frequentlyperformed. Forwomenatmoderately high risk (e.g., those with precancerous lesions such as atypical ductal hyperplasia), preventive therapy with tamoxifen, raloxifene, or an aromatase inhibitor is being prescribed and accepted by many women. The remaining women (those at low to moderate risk of breast cancer) might benefit from behavioral interventions such as exercise, diet, and alcohol avoidance alone. Thecurrent interest inhealthylifestyleshasledDr.GrahamColditz to suggest that by avoiding exposure to carcinogens, receiving vaccination for oncogenic viruses, and implementing lifestyle measures to minimize tobacco use and obesity, it is possible to reduce cancer incidence by 50% or more [14]. Although it is currentlydifficult todeterminewhetheran individualwomanwill benefit from these behavioral interventions, such measures are generally healthful and thus should be recommended. Dr. Ponzone also cites the recent report by Tomasetti and Vogelstein as evidence that cancer prevention interventions