Charles L. Shapiro MD, FASCO
The New England Journal of Medicine published an article November 9 about the long-term risks of breast cancer recurrence after stopping endocrine therapy at five years.
Here are some answers to patient questions from Charles L. Shapiro MD, FASCO, Professor of Medicine (Hematology and Oncology) at the Icahn School of Medicine at Mount Sinai and Director of Translational Breast Cancer Research and Director of Cancer Survivorship at The Tisch Cancer Institute.
Q: What is important about this study?
A: The idea that breast cancer can reoccur late is not new information. There were always a small minority of women who experience a recurrence 10, 15, 20 years and even more after the diagnosis and treatment of the original primary breast cancers.
Q: What is new in the study?
A: What is new in this study is the magnitude of late-appearing recurrences, and that breast cancer-specific mortality is higher than one would expect. However, there are several caveats. Although more than 60,000 women participated in more than 80 clinical trials cited by the study, these trials were designed many years ago and included all estrogen receptor-positive cancers. So much has changed in the last 25 years.
Q: Can you give an example?
A: One change is our recognition that there are at least two types of estrogen receptor-positive breast cancers, Luminal A (that have a lower chance of recurrence) and Luminal B (that have a higher chance of recurrence), with very different biological behaviors and different clinical outcomes. This study does not distinguish between these two types of estrogen receptor-positive breast cancers. Also, there was no information in this study on patients who received adjuvant chemotherapy, and the studies didn’t use trastuzumab (Herceptin). Adjuvant chemotherapy and trastuzumab are frequently used to treat Luminal B cancers.
Q: What group of patients are affected by this study?
A: Women with estrogen receptor-positive breast cancers, which represent about 75 percent of all breast cancers.
Q: Who is most at risk?
A: Those most at risk of a recurrence are those treated decades earlier when treatment options and our knowledge of science were more limited.
Q: Should doctors immediately extend tamoxifen treatment to 10 years instead of five? If women have already gone off tamoxifen after five years, should they go back on?
A: No, not on the basis of this study. These trials were performed decades ago and do not reflect modern approaches to treatment in women with early stage estrogen receptor-positive breast cancers. For example, now we have tests based on genes expressed by the breast cancer that predict who is likely to recur five or more years after the original primary diagnosis. And more of these are coming.
Q: Should breast cancer patients be worried?
A: Women now undergoing treatment do not need to be extra worried. These study results are from old clinical trials, and so they are just not as relevant to women diagnosed today. There are improvements in breast imaging that leads to diagnosis of breast cancer at an earlier, more curable stage. That coupled with advances in treatments and supportive care (such as improved drugs for nausea or growth factors that boost the white blood cell count and aid recovery from chemotherapy) has led to a steady decline in breast cancer mortality during the last 30-plus years. Also, our deepening knowledge of the biology of breast cancer has led and will lead to new therapies for estrogen receptor-positive breast cancers. The future is full of hope.
Q: What should I do if I have questions?
A: Call your health care provider.