Who Needs Chemotherapy for Breast Cancer?

If you’re diagnosed with breast cancer, one of the first questions on your mind may be: Do I need chemo?

Many people assume the answer is yes. After all, chemotherapy is almost synonymous with cancer treatment in a lot of people’s minds.

But it’s not the right route for everyone.

Breast cancer treatment is highly personalized. Your team will carefully analyze the specific characteristics of your cancer and your risk of the cancer returning (recurrence) to understand whether you’d benefit from chemotherapy and other treatments.

Breast oncologist Azka Ali, MD, shares some of the factors your team will consider when deciding whether to recommend chemo.

Determining whether breast cancer needs chemotherapy

Doctors tailor their recommendation for breast cancer treatments, including chemotherapy, to your needs.

The goal is to balance the benefits of treatment with the risks. They’ll recommend chemo if they expect it to be helpful in treating your cancer and keep it from coming back.

That can mean that two people with similarly sized tumors can have two very different treatment plans.

“No two breast cancers are the same,” Dr. Ali emphasizes. “Your treatment plan can look very different from others’ with a similar size of cancer.”

To make decisions about chemo and other treatments, your team will look at a few key factors.

“I tell all my patients that we look primarily at two things: stage and biology,” Dr. Ali explains. “These features help us understand the risk of cancer recurrence and whether chemotherapy will provide benefit.”

Stage

One major factor doctors consider is the stage of the cancer. Cancer stage is a measure of whether the cancer has spread and how far.

Breast cancer stage is determined using what doctors call the TNM system:

• T (tumor): The size of the tumor in the breast
• N (nodes): Whether cancer has spread to nearby lymph nodes
• M (metastasis): Whether cancer has spread to other parts of your body

Together, these factors help determine how advanced the cancer is, on a scale of 0 to IV (4):

• Stage 0: Cancerous cells have remained within the milk ducts or lobules in your breast.
• Stage I: Cancerous cells have spread to nearby breast tissue.
• Stage II: A small tumor has either remained in the breast or is very small and has spread to the lymph nodes in your armpit (axillary lymph nodes).
• Stage III (locally advanced breast cancer): The tumor is larger in size and/or has spread to even more lymph nodes
• Stage IV (metastatic cancer): Cancer has spread to other organs.

Higher-stage cancers are typically more likely to benefit from chemotherapy than earlier stages.

Tumor biology

In addition to the stage, your providers will consider the biological features of the cancer — meaning how the cancer cells look under a microscope.

Why? Because those microscopic differences in cancer cells can say a lot about how aggressive the cancer may be and how likely it is to respond to chemo and other treatments.

Breast cancer grade

“Breast cancer cells are graded from 1 to 3,” Dr. Ali further explains. “The more ‘funky’ they look, the higher the grade.”

Higher-grade cancers are often considered higher risk and may be more likely to warrant chemotherapy.

Hormone and protein receptors

Doctors also analyze certain proteins called “receptors” on breast cancer cells. If these receptors are present, they can act like switches that help fuel cancer growth.

The main ones include:

• Estrogen receptor (ER)
• Progesterone receptor (PR)
• HER2

Your team may be more likely to recommend chemotherapy as part of your treatment plan if your cancer is negative for all three markers (triple-negative breast cancer) or if you have HER2-positive breast cancer.

Additional tumor testing

For some breast cancers (ER positive, HER2 negative), doctors may also recommend additional testing on the tumor tissue, like Oncotype DX or MammaPrint. 

The results of these tests will also be considered as your care team plans treatment.

“These tests look at genes within the tumor and generate a risk score,” Dr. Ali says. “The results help us understand the likelihood of recurrence and whether chemotherapy will provide benefit.”

It’s different from genetic testing, which your team may recommend depending on your individual risk, age at diagnosis, family history and type of cancer.

Genetic tests determine if you inherited high-risk genes from your biological parents that you could pass on. Oncotype DX or MammaPrint tests predict the risk of cancer recurrence.

Other factors to consider

Beyond stage and biology, several additional factors can influence chemotherapy recommendations, including:

• Your overall health
• Whether your lymph nodes are affected
• How the tumor appears to behave clinically (for example, if you had a healthy mammogram and then a large tumor was found a few months later)

Pre-menopausal women, for example, are statistically more likely to develop aggressive breast cancers and may be more likely to receive chemotherapy recommendations.

Bottom line: Your team will make recommendations personalized to you

Chemotherapy is an important part of treatment for many breast cancers — but it isn’t automatic. Your treatment plan will be tailored to your needs. It may include chemotherapy, as well as other treatments, like

• Surgery to remove the tumor
• Radiation therapy to destroy remaining cancer cells
• Hormone therapy to block estrogen or progesterone that fuels some cancers
• Targeted therapy that attacks specific proteins, such as HER2, that help cancer grow

Your team will carefully evaluate multiple factors to arrive at a plan for you. And they’ll talk with you about their reasoning, including why chemo is, or isn’t, appropriate for you.

The goal is to create a treatment plan tailored to your specific cancer and your overall health. And reaching that conclusion is a complex process.

“Those recommendations are based on your specific cancer and what will give you the best outcome long term,” Dr. Ali encourages. “Ask your team any questions you have about your treatment. You deserve to be knowledgeable about what your team is advising and why.”