What Makes Breast Cancer “Aggressive”?

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What Makes Breast Cancer “Aggressive”?

A breast cancer diagnosis comes with a lot of new terms that you need to learn. In planning your treatment, the doctor will determine if your cancer has spread beyond your breast and determine the tissue type where the cancer began. They may also discuss whether your cancer is “aggressive.” What does that mean?

Aggressive breast cancer tends to grow and/or spread quickly. In many cases that also means it has a poor prognosis (outcome), although it is survivable with treatment. The growth rate of aggressive cancer is impacted by the genetic makeup of the tumor and the rate the cells are dividing.

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Breast Cancer Proliferation Rate Indicates How Aggressive the Breast Cancer Is

Your oncologist may discuss the proliferation rate of your breast cancer. This is the percentage of cancer cells actively dividing. The higher the proliferation rate, the more aggressive the breast cancer is, and the more likely it is to spread to other parts of the body.

If the tumor has a high proliferation rate the patient usually has a lower chance of survival compared to patients with a low proliferation rate.

The proliferation rate is also a part of the treatment planning process. It gives the oncologist a sense of which treatments are more likely to work best and in which order they should be given. The Ki-67 test may be used to determine the proliferation rate of a breast tumor.

Is Invasive Cancer the Same as Aggressive Cancer?

The term “invasive” may also be used as you speak with the oncologist about your specific type of breast cancer. Not all invasive breast cancers are considered aggressive. Breast cancer usually develops first in the milk ducts or lobules of breast tissue. When it is invasive, it means cancer has spread within the breast, to surrounding breast tissue, or nearby lymph nodes. 

Which Types of Breast Cancer are Aggressive? 

Triple-negative breast cancer (TNBC)

This is known to be the most aggressive type of invasive breast cancer. It tests negative for three common types of receptors that are known to cause breast cancer to grow – estrogen (ER), progesterone (PR), and HER2.

About 10%-15% of all breast cancers are TNBC. They are more common in younger women (40 or younger) who are Black, or have the gene mutation BRCA1. 

TNBC grows and spreads very quickly, usually having spread by the time it’s diagnosed. Hormone therapy will not work because the cancer cells don’t have hormone receptors. Targeted therapy targeting the HER2 protein isn’t effective because TNBC cells either have no HER2 or too much. Other treatments are used to kill the cancer cells. However, even after successful treatment, triple-negative breast cancer is more likely to return than other types of breast cancers.

Inflammatory breast cancer (IBC) 

This is an aggressive type of invasive breast cancer that is rare (1% to 5% of all breast cancers). IBC is more common in younger women, Black women, and women who are obese. 

Although the cause is unknown, inflammatory breast cancer can develop when a breast cell’s DNA changes. IBC usually develops in milk ducts. DNA changes can cause cells to quickly grow and divide. Extra cancer cells clog the lymph system and cause swollen, red, and tender breasts. 

Is Metastatic Breast Cancer Aggressive?

Metastatic is not a type of breast cancer, but it is the most advanced stage of cancer – Stage 4. Metastatic cancer has spread to other areas of the body beyond the lymph nodes such as the chest wall, bones, brain, liver, and lungs. 

Metastatic cancers are considered aggressive.

How are Aggressive Breast Cancers Treated? 

The biopsy lets the oncologist know if the breast cancer is likely to respond to certain types of treatments and how quickly the cancer is going to grow. The right set of treatments for each patient depends on:

  • Hormone status
  • HER2 status
  • Stage
  • Grade
  • Proliferation Rate
  • The patient’s overall health condition
  • Previous breast cancer treatments that have been used.

For these patients, treatment will typically begin right away, often before surgery is scheduled. Your cancer care team will discuss your individual situation to create a treatment plan that uses several types of therapies including:

Radiation therapy 

Radiation therapy is often used before surgery to shrink the tumor. It’s also used after surgery to be sure all of the cancer cells were removed. If the cancer is metastatic, radiation can be used to shrink tumors in other areas of the body that have developed. 

Download Guide on Breast Cancer Radiation Facts & Tips


This treatment uses drugs to destroy the cells of aggressive breast cancer. Chemotherapy may be indicated before surgery for patients with large tumors to shrink the size of the tumor. The smaller the tumor, the more successfully it can be removed with surgery. 

Invasive tumors that have spread to other parts of the body are often treated with chemotherapy to help control them. Chemotherapy can also decrease painful cancer symptoms. 

Hormone-blocking therapy  

If the cancer tested positive for hormone receptors, this type of treatment can be used before and after surgery. Before surgery, it can be part of the process of shrinking the cancer to make surgery easier. It’s often used for years after surgery to keep the cancer from coming back.

Targeted therapy drugs

HER2-positive tumors or breast cancer that shows a specific genetic mutation can be treated with a targeted therapy that is known to work for the specific protein or mutation that is causing the cancer to grow. 


Immunotherapy uses the patient’s immune system to fight cancer. This is a category of therapy under extensive clinical research for triple-negative breast cancer and is currently used for some metastatic breast cancer patients often in combination with chemotherapy.

Is it Possible to Survive Aggressive Breast Cancer? 

Survival rates depend on many factors, and they vary for each patient. Survival rates for aggressive breast cancers are lower than other types of breast cancer. Curing aggressive breast cancer depends on numerous factors, including: 

  • If the cancer has spread
  • Its location
  • Its stage
  • Patient’s age
  • Overall health
  • If the initial cancer or a previously treated cancer has returned
  • How the cancer responds to treatment

What Are the Survival Rates for Breast Cancer? 

Survival rates give you an idea of what percentage of people with the same type and stage of cancer are still 5 years after they were diagnosed. A survival rate does not predict how long an individual patient will live. But rather, it gives you a sense of how others have fared compared to people without breast cancer. 

  • Localized - the cancer is contained within the breast
  • Regional -  the cancer has spread to lymph nodes nearby.
  • Distant - cancer has spread to distant areas of the body such as the brain, lungs, liver, bones

Invasive Breast Cancers (all types)


Breast Cancer (TNBC

Inflammatory Breast Cancer



91% NA


86% 66% 52%


30% 12% 39%


When Radiation Therapy is Part of Your Breast Cancer Treatment Plan

Breast cancer patients often receive radiation therapy as part of their treatment plan. Be sure you choose a location that’s convenient for you because treatments are usually five days a week for several weeks. Radiotherapy Clinics of Georgia (RCOG) offers radiation therapy treatment centers in the greater Atlanta area including Blairsville, Conyers, Covington, Decatur, and Snellville, Georgia. You get to choose where you receive your radiation treatments. Request an appointment with one of our radiation oncologists for a consultation and treatment plan. 

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