As the Median Size of Invasive Breast Cancers at Time of Diagnosis Continues to Fall, How Does the Oncologist Guard Against Over-Treatment?

Because of mammographic screening, the most common presentation of breast cancer is now as Stage 1 disease. These patients have on average a low risk of recurrence and death due to their primary cancer of about 10% on average. Most of these patients will never relapse and, therefore, to treat all these patients is clearly less than ideal. Unfortunately, current clinical and pathologic information cannot reliably identify who is destined to relapse. For most of these patients, therefore, a decision needs to be made about whether and what type of adjuvant therapy should be given. For many of these low-risk patients, it is often not obvious what the balance is between the benefit of adjuvant therapy (which on average will be small) versus its risks and costs. There are various approaches to making these decisions, but present day guidelines are not entirely satisfactory, because although they are evidence based, they often lack quantitative information. This leaves the patient and her physician unable to reweigh the evidence for themselves, and this is not informed decision making. Decision tools are playing ever greater roles in medicine. Even more so than guidelines, they can give individualized estimates. Furthermore, they also can provide individualized quantitative information. Decision tools, like guidelines, have limitations in that they are only as strong as the data on which they are based, and it is important that they acknowledge areas of controversy and conflicted views about the interpretation of the data. Some of the issues involved in the use of decision tools are illustrated in a discussion of the tool Adjuvant!. These tools now are using classical clinical and pathologic parameters, but have the potential to incorporate parameters from the new multigene molecular tests.