Speaking the language is the first step in learning to read reports and studies. Many basic DCIS terms can be found on this breastcancer.org website: http://www.breastcancer.org/symptoms/types/dcis/diagnosis
A description of the different kinds of imaging available, plus an explanation of the BI-RADS categories used to estimate a patient’s risk of developing cancer are also explained at: http://en.wikipedia.org/wiki/BI-RADS and http://www.uptodate.com/contents/diagnostic-evaluation-of-women-with-suspected-breast-cancer#H4.
Understanding your pathology report can be challenging. This John Hopkins FAQ sheet is designed to help you understand pathology terminology:
Undoubtedly you will also hear about the results of various cancer studies. These are reported using relative risk percentages and do not give an accurate picture of the actual (absolute) risk incurred.
The National Surgical Adjuvant Breast and Bowel Project B-24 study illustrates this well. In this study, half of the DCIS patients received tamoxifen for five years and half did not. At five years, the group that took tamoxifen had 43% fewer invasive breast cancers. When presented this way, the decreases in risk to women who take tamoxifen seem quite substantial. However, when these same results are presented as actual risks rather than relative risks, the study found that only 4% of the women who did not take tamoxifen developed invasive breast cancer, compared to 2% who took tamoxifen. The 43% reduction is actually a difference of only 2%.
The study also reported a 52% relative reduction in risk to the opposite breast for women with DCIS who took tamoxifen. Again, the actual absolute risks were much smaller, 3.4% for the group not taking tamoxifen and 2% for the group that did take tamoxifen. This is a difference of just 1.4%.
Cancer study results always need to be examined carefully to see what the real risk to an individual might be.
DCIS Redefined 