A study just released in the Journal of the National Cancer Institute is getting a lot of media attention.
The research, from the
The goal of the study was to find out how many women had their breast cancer recur 5 years or more after they completed their adjuvant therapy. What it also pointed out, to me at least, was that some commonly held beliefs about the outlook for women with breast cancer aren’t always correct.
The women in the study represented the universe of women with primary breast cancer. There were younger and older women, women whose breast cancers were hormone sensitive or not, pre and post menopausal women, and women with various stages of primary breast cancer, among other factors.
Many of the women had received tamoxifen as their adjuvant therapy. Some of the women also received chemotherapy.
Since aromatase inhibitors (AIs)—which are now probably the treatment of choice for adjuvant therapy in post-menopausal breast cancer patients—had just become available during the time of the study, there were only a handful of women who received these medications.
For the overall group—and remember this was a large number of women covering all types of breast cancer at all stages and ages—the recurrence rate at 10 years after diagnosis was 11%, and at 15 years was 20%.
If you had a more advanced cancer at the time of diagnosis, your chance of recurrence 10 years after surgery was almost double that of someone with an earlier stage cancer (Stage 1: 7%; Stage 3: 13%).
But there was also something reported in the study that I would not have expected: the long term recurrence rate for women with hormone receptor-positive breast cancer was significantly higher than for women who were not hormone sensitive at the time of diagnosis.
The reason this finding is important is that most of us are of the opinion that women with hormone negative breast cancers fare worse than their hormone sensitive counterparts. However, the fact may be that (unfortunately) women with hormone negative cancers may have had very early relapses. Those that did not relapse within 5 years after diagnosis may have been “selected” to have a better long-term outlook, as seen in this study.
The study also showed that women diagnosed with lower grade breast cancers—which we would think would have a better long term outlook, since lower grade is supposed to be associated with a less aggressive cancer —actually had a higher rate of long term relapse. Again, the same reasoning noted above may apply to this circumstance as well, namely that women with higher grade cancers experienced relapse earlier in the course of their disease, and if they made it through the first 5 years they did better in the long term.
What are the practical implications of this study?
The primary one is that we need to be aware that adjuvant therapy does not completely remove the risk of breast cancer recurrence after 5 years. In fact, up to 20% of the women remain at risk of recurrence at 15 years, depending on the unique characteristics of their cancers and other factors such as age.
As the authors note in their report:
“The magnitudes of the residual risk of recurrence for pre- and postmenopausal patients were within the range (8%-20%) considered appropriate to recommend AST (adjuvant systemic therapy) at the time of (initial) diagnosis, indicating a need for the continued development of risk reduction strategies for these survivors.”
In other words, we need to revisit the question of whether we have to consider providing additional preventive therapies once women complete their initial primary adjuvant treatment.
But there are some important limitations to this study that must be pointed out.
This was a diverse group of women, with different ages, stages of breast cancers, different treatments, and so on. The drugs used in treating these women are different today than they were back at the time the study was done. We have newer techniques and diagnostic tests available today that help us better understand what treatment a women requires, and we have new approaches to the treatment of pre-menopausal women that may significantly improve their outlook with adjuvant hormonal therapy.
As to what this study means for you personally if you are a woman with breast cancer and are concerned by this report, I strongly urge you to speak to your oncologist.
We have made considerable progress in the early diagnosis of breast cancer, and what we can do to prevent it from returning. We already know that adjuvant therapies don’t completely eradicate breast cancer in some women, and this study reinforces that fact.
What we need to do now is take a careful look at what we do and how we do it to determine whether there is something else we can do better to improve the outlook for all women with primary breast cancer.