Dr. Harry Bear, surgical oncologist at the Virginia Commonwealth University's Massey Cancer Center in Richmond, agreed. "Some of our [breast cancer] treatments delay recurrence rather than eradicating the last remaining cancer cell," he said.
For any breast cancer survivor, the notion of recurrence plays an important role in treatment decisions.
The typical treatment for breast cancer patients can be divided into four categories: surgery to remove the cancer, radiation therapy to kill remaining cancer cells in the breast tissue, chemotherapy to stop the growth of cancer cells and hormone therapy to cease the production of hormones that fuel cancer cell growth.
Each of these treatment options reduces a woman's risk for breast cancer recurrence by a certain percentage. But the breast cancer patient is the ultimate decider of which of these treatments to take on, and whether the small reduction in recurrence risk is worth the side effects of treatment.
But the study, Shockney said, does not delve into the individual risk factors that could increase one woman's risk for recurrence over another's. For example, she noted, women who are genetically predisposed for developing breast cancer are at higher risk for disease recurrence, yet these women were grouped together with those who do not carry this genetic risk.
Moreover, she said, the study did not account for the different kinds of breast cancer recurrence -- some of which are small and localized, and some of which are aggressive and spread rapidly to other parts of the body -- or the methods by which women choose to treat their disease.
"Someone with [early stage] breast cancer who did bilateral mastectomies would have a small risk of distant or local recurrence [compared to] someone with [advanced stage] disease doing a lumpectomy [who] would have a higher risk," Shockney said.
Generally, women who have hormone-responsive breast cancer are at higher risk for disease recurrence after five years of survival. Brewster hopes that this study will influence more of these patients to consider remaining on adjuvant therapy even after five years of survival.
"I would like the take-home message of this study to be if you do have a [hormone-responsive] tumor and received Tamoxifen for five years and are post-menopausal, you probably want to speak with [an] oncologist about whether or not there's a rule for taking extended adjuvant therapy by reviewing the risks and benefits of such treatment," Brewster said.
But for women who have survived breast cancer, a silver lining -- the longer you survive without disease recurrence, the less chance for recurrence you have.
"What women need to know from this is that there is a long-term recurrence, but the longer you live the smaller it is," said Dr. Susan Love, president and medical director of the Dr. Susan Love Research Foundation in Santa Monica, Calif. "If you are 10 years out, you are less likely [to have a recurrence] than if you are five [years out]."