There is no single treatment for breast cancer. Treatment depends on the cancer's type, stage, lymph-node involvement, and biological characteristics such as hormone-receptor and HER2 status.
Treatment may include surgery, radiation, hormone therapy, chemotherapy, targeted therapy, or immunotherapy. Not every woman needs all—or even most—of these treatments.
An important trend is treatment de-escalation: avoiding treatments when evidence shows they are unlikely to provide meaningful additional benefit.
The goal is not necessarily the most treatment possible, but the treatment that provides the best balance of benefit, side effects, and quality of life.
For many women with early-stage breast cancer, lumpectomy followed by radiation and mastectomy provide similar long-term survival. Removing the entire breast does not necessarily improve the chance of surviving the cancer.
A lumpectomy removes the cancer along with a margin of surrounding tissue while preserving most of the breast. It is usually followed by radiation to reduce the chance of cancer returning in the breast.
A mastectomy removes most or all of the breast. It may be recommended when the cancer is large relative to the breast, occurs in several areas, cannot be completely removed with a lumpectomy, or when radiation is not appropriate. Some women also choose mastectomy because of genetic risk or personal preference.
For women who are good candidates for either approach, the decision can therefore involve more than survival. Appearance, radiation, recovery, reconstruction, risk of local recurrence, and personal comfort with keeping the breast can all matter.
A useful question to ask is: “Would mastectomy improve my survival compared with lumpectomy and radiation in my particular case?”
Radiation therapy is commonly given after a lumpectomy to destroy cancer cells that may remain in the breast and reduce the chance that the cancer will return there.
Radiation may also be recommended after a mastectomy when the risk of recurrence is higher—for example, because of a large tumor, involved lymph nodes, or certain other features of the cancer.
But radiation is not necessary for every woman after lumpectomy. Studies have found that some older women with small, early-stage, hormone-receptor-positive cancers can omit radiation if they receive hormone therapy.
Omitting radiation increases the chance that cancer will recur in the breast. However, two major randomized trials—CALGB 9343 and PRIME II—found that in carefully selected older women with small, hormone-receptor-positive early breast cancers who received hormone therapy, radiation substantially reduced local recurrence but did not improve overall survival.
This creates an important individual choice: How much reduction in the risk of a local recurrence is worth the inconvenience and possible side effects of radiation?
Chemotherapy can be very important for some breast cancers, but many women with early breast cancer do not benefit enough from chemotherapy to justify its side effects.
The decision depends on factors including the stage and grade of the cancer, lymph-node involvement, hormone-receptor and HER2 status, age, and overall health.
Chemotherapy is more likely to be recommended for cancers that are triple-negative, HER2-positive, higher-grade, larger, or involving lymph nodes, although treatment is individualized.
For many women with hormone-receptor-positive, HER2-negative early breast cancer, genomic tests such as Oncotype DX can help determine whether adding chemotherapy to hormone therapy is likely to provide meaningful benefit. Major studies have shown that chemotherapy can safely be avoided for many women in this group.
For some breast cancers, chemotherapy is given before surgery. This can shrink the tumor and, particularly with HER2-positive or triple-negative cancers, show how well the cancer responds to treatment.
The important question is not simply “Do I need chemotherapy?” but “How much additional benefit is chemotherapy expected to provide in my particular case?”
Ductal carcinoma in situ (DCIS) consists of abnormal cells confined within the breast ducts. It is commonly called Stage 0 breast cancer because the cells have not invaded surrounding breast tissue.
The usual treatment has been surgery, often followed by radiation and, for hormone-receptor-positive DCIS, sometimes hormone therapy. Treatment substantially reduces the risk of DCIS returning or developing into invasive breast cancer.
But DCIS creates a dilemma. Some lesions may grow very slowly—or never become dangerous during a woman's lifetime. Doctors currently cannot reliably determine which cases will progress. This raises the possibility that screening detects some DCIS that is overdiagnosed and overtreated.
Researchers are therefore studying active monitoring for carefully selected women with low-risk DCIS.
The COMET randomized trial compared active monitoring with standard treatment in women with certain low-risk, hormone-receptor-positive DCIS. Early results found that after two years, women assigned to active monitoring did not have a higher rate of invasive breast cancer than women assigned to standard treatment.
This is important evidence, but follow-up is still relatively short. Active monitoring is therefore an emerging approach rather than the established choice for all women with DCIS.
The larger question is important: Can doctors identify breast abnormalities that are unlikely to become dangerous and safely spare some women surgery and radiation?
Breast cancer treatment often involves more than one reasonable option, and a second opinion can sometimes provide useful reassurance—or change the treatment plan.
A second opinion may be particularly valuable when the diagnosis is unusual, the treatment choices are complicated, major surgery is being considered, or there is uncertainty about whether chemotherapy, radiation, or other treatment is necessary.
It can also be useful to have the pathology slides reviewed by another breast pathologist. Details such as the type and grade of the cancer and its ER, PR, and HER2 results can directly affect treatment.
Getting a second opinion does not mean distrusting the original doctor. It is a way to make sure the diagnosis is clear, the important alternatives have been considered, and the benefits and disadvantages of each option are understood before making a major decision.
What treatment do you recommend, and why?
How much will this treatment reduce my risk of the cancer returning?
Will it improve my chance of surviving breast cancer, or mainly reduce the risk of recurrence?
What are the likely short-term and long-term side effects?
What would happen if I chose not to have this treatment?
Is there a less intensive treatment that would give me nearly the same benefit?
Would a genomic test help determine whether I need chemotherapy?
If radiation is recommended, what is my risk of recurrence with and without it?
Are there clinical trials that I should consider?
Would you recommend a second opinion before I make my decision?
A comprehensive overview of surgery, radiation, chemotherapy, hormone therapy, targeted therapy, and treatment by stage.
A patient-friendly overview of breast cancer treatment choices and how treatment varies by type and stage.
Long-term randomized trial in women age 70 and older with selected early-stage, estrogen-receptor-positive breast cancer. Radiation reduced local recurrence but did not improve overall survival.
Ten-year randomized trial in women age 65 and older with selected hormone-receptor-positive early breast cancer. Radiation substantially reduced local recurrence, but overall survival was virtually identical.
Randomized trial comparing active monitoring with guideline-concordant treatment for selected women with low-risk DCIS. Early results provide important evidence about whether some women may safely avoid immediate surgery. Longer follow-up is needed.
An evidence-focused discussion of the COMET trial and whether some women with low-risk DCIS may be able to choose active monitoring rather than immediate surgery.
NBCC's perspective on evidence showing that many women with certain early-stage, hormone-receptor-positive breast cancers can avoid chemotherapy.