This post is written by ASK Cancer Commons Scientist and Product Team Member Amanda Nottke, PhD. Dr. Nottke regularly provides guidance to patients through our ASK Cancer Commons service.
After a diagnosis of early stage, hormone-positive breast cancer, you may find yourself facing several daunting decisions, such as choosing between the extensive surgery of mastectomy versus a more minor lumpectomy procedure paired with radiation (with all its challenging side effects). And once surgery is complete, what next? Hormone therapy is clearly indicated for many women, but which drug, and how long to take it? And what about chemo—how to know if the tough side effects are worth the possible reduction in risk of recurrence?
Fortunately, there are a wealth of quality datasets available to inform these decisions. Below are some of the questions we get most frequently from patients using our ASK Cancer Commons service, answered according to the latest thinking from scientific literature and our expert physician network. If you are facing your own cancer treatment decisions and would like free one-one-one expert support, please submit your case here.
1. If my doctor has said either mastectomy or lumpectomy plus radiation are appropriate for me, how do I choose?
Many studies have looked at this, and overall the outcomes for mastectomy versus lumpectomy plus radiation are extremely similar (both are effective treatments, so you can instead weigh the side effects of radiation versus the more intensive surgery of the mastectomy). This webpage provides a helpful summary of the pros and cons of mastectomy compared to lumpectomy.
2. What are the rates of recurrence and overall survival rates for mastectomy versus lumpectomy plus radiation?
Barring other risk factors, first keep in mind that the rate of recurrence is likely very low, and also probably not significantly different between mastectomy or lumpectomy plus radiation.
Regarding the specifics of lumpectomy plus radiation versus mastectomy efficacy, the survival outcomes have been looked at in numerous studies and are quite similar. While there is mixed data supporting a slightly higher risk of local recurrence with lumpectomy, the risk of distant recurrence (metastasis) is quite consistently the same, as are the overall survival rates. According to this discussion of some recent-ish data exploring outcomes for mastectomy vs lumpectomy plus radiation, it is not completely clear-cut, but reasonable to say that lumpectomy is as safe, or even possibly even a little safer, than mastectomy.
In terms of long-term outcomes, there is an older dataset where hundreds of women were followed for 20 years. This study shows that while there was a slightly higher risk of local recurrence with mastectomy (presumably due to the lack of radiation), there was NO difference in the rates of cancer in the other breast, metastases, other primary cancers, or death from cancer. Note that these women were diagnosed and treated in the 1970s, so we would expect outcomes to be even better now.
3. Which hormone therapy should I take? What are the risks of each?
Per doctor and patient guidelines from the National Comprehensive Cancer Network (NCCN), a premenopausal woman would go one of two routes after surgery (plus or minus chemo first, depending on risk of recurrence):
- Estrogen inhibitor (tamoxifen) for 5 years plus ovarian suppression if higher risk of recurrence (younger age, lymph node involvement, high grade tumor); then consider 5 additional years of tamoxifen
- Aromatase inhibitor (anastrozole, letrozole, exemestane) plus ovarian suppression, regardless of risk status
A postmenopausal woman could go one of the above routes (minus the ovarian suppression, as that is no longer necessary post menopause)
Endocrine therapy is essentially mimicking menopause, so it can cause similar symptoms—hot flashes, vaginal discharge or dryness, sleep problems, weight gain, hair thinning, fatigue, and / or change in mood. Different women respond differently, and you can talk with your doctor about modifying the dose or even switching drugs if the side effects are too much. Tamoxifen also can have the rare side effects of uterine cancer and / or blood clots. However because these associated cancers are so rare, the overall benefit-risk ratio for the treated population is considered favorable, meaning the benefit of reducing breast cancer recurrence risk is greater than the increased risk of uterine cancer. In comparison, aromatase inhibitors can be associated with osteoporosis, which while not life-threatening can certainly impact quality of life.
4. What will happen if I don’t take hormonal therapy, and how much risk is there of recurrence or mortality?
It is clear that even in low-risk populations, outcomes for certain subsets of untreated women are worse than for the average population (specifically, younger women and those with larger tumors). In 2011, researchers reviewed outcomes for over 3,000 women who were considered low risk and did NOT receive any systemic (hormonal) treatment after surgery; all were node-negative and ER/PR-positive. By comparing rates of mortality over time for these women versus the general population of women, they identified sub-groups that were more or less at risk. They found that women with either of the following characteristics had a higher mortality over time than the general population:
- Tumor size larger than 10 mm
- Age younger than 60 at diagnosis or treatment
For example, after a median follow-up of 15 years, they found the risk of mortality for untreated women aged 40 to 45 was about 2.5 to 3 times higher than it was for the general population. This refers to relative risk, and an important caveat is that the absolute risk is still quite low. For women aged 40 to 54 with tumors less than 10 mm across, they found risk of recurrence was about 8% (about 5.5% had a local recurrence and 2.5% had a distant recurrence). Of course, a woman in this age range can expect to live many more years beyond the 10-year window, and we do not have good data about what happens 20, 30, or more years down the line.
5. Should I take chemo as well as hormonal therapy?
Chemotherapy is not always necessary for early stage breast cancer patients. Chemo is used when there is a relatively higher risk of recurrence, in order to minimize that risk. So, for tumors that have characteristics of being more aggressive (they have already spread to the lymph nodes, they are larger, or they display a particular gene signature), then chemo is recommended. The gene signature is assessed through a test like OncotypeDx. This gene test is included in the NCCN guidelines and is recommended to help inform decisions on how aggressively to treat (i.e., whether to include chemo as well as tamoxifen). For example, depending on the Oncotype risk score, the risk of recurrence after 10 years of tamoxifen can range from about 7% (if low risk, as measured by Oncotype) up to about 30% (if high risk by Oncotype). For that high risk population, the risk is reduced from about 30% down to about 10% if chemo is added to the tamoxifen.