As I scanned my E-mails this morning, several were from readers asking for my take on the latest breast cancer news showing that the risk of relapse after five years is much lower than a patient might expect. The study, published yesterday in the Journal of the National Cancer Institute, found that once patients make it to the five-year mark without a relapse, about 89 percent are disease free five years later at the 10-year mark and 80 percent at the 15-year mark. That’s certainly reassuring news for those patients paralyzed by a fear of relapse long after they finish their treatments.

Still, the statistics quoted in the news reports are meaningless for the individual woman diagnosed with breast cancer. Certainly, cancer can recur 15 years after treatment—or even 20 or 30 years out. One survivor wrote me: “All my doctors informed me that the two-year mark is important and then the six-year mark, but with breast cancer, you are never out of the woods.” Today’s conflicting news reports could only have added to her confusion. “Risk of Breast Cancer Relapse Can Linger” blares one headline. “Risk of Breast Cancer Relapse Is Low After Surviving 5 Years” declares another.

The real story lies in a complicated table that accompanied the study, which shows the various factors that predict recurrence. They include: whether cancer spread to the lymph nodes; tumor size; and whether the cancer is fueled by the hormone estrogen. A doctor needs to factor in these and other characteristics of the tumor before determining a particular patient’s risk of relapse and when she’s most likely to experience a recurrence.

For example, women whose tumors grow in the presence of estrogen (the most common type of breast cancer) tend to have fewer recurrences within the first five years but are more likely to relapse a decade later. What’s more, breast cancer expert Susan Love previously told me that the protective effects of antiestrogen drugs like tamoxifen can persist for 15 years after women stop taking them. So, it could be that recurrences in these women occur beyond the 15-year mark, which the study didn’t examine. The study also didn’t measure whether taking aromatase inhibitors (another class of antiestrogen drug now routinely given instead of or after tamoxifen) protects a woman even longer. That’s something a woman should also discuss with her doctor if she’s thinking about taking an aromatase inhibitor after finishing tamoxifen. For more details on this, click here. And if you’ve previously had breast cancer, you can employ these lifestyle measures to help lower your recurrence risk.

Deborah Kotz