Understanding the Difference Between Invasive and Metastatic Breast Cancer

Medically reviewed by Violet Hanft RN — By Ann Pietrangelo — Updated on May 29, 2020


Understanding Abnormal Cells

Abnormal cells aren’t cancerous, but they may increase your risk of developing cancer. When you have atypical cells that haven’t spread, the cells are considered noninvasive. This is sometimes referred to as pre-cancer or stage 0 cancer.

Ductal carcinoma in situ (DCIS) is an example of this. DCIS is a noninvasive breast cancer of the milk duct. It hasn’t spread beyond the duct where it started.

If abnormal cells move beyond the layer of tissue where they originated, the cells become invasive. When abnormal cells inside the milk ducts or lobules move out into nearby breast tissue, it’s considered a local invasion or invasive breast cancer.

Breast Cancer by the Numbers: Facts and Statistics

These cells can also break free from the primary site and migrate to other parts of the body. When this happens, the cancer isn’t just invasive, it’s also metastatic.

What Are the Symptoms of Metastatic Tumors?

Although metastatic tumors can cause symptoms, this isn’t always the case. Whether you have symptoms depends on how big the tumor gets and exactly where it’s located.

A metastatic tumor in the brain, for example, might cause headaches. A tumor in the lungs might cause shortness of breath.

What Causes Metastasis?

As cancer cells advance further, they make their way to the nearest blood vessels or lymph vessels. Once there, the cells can travel the bloodstream or lymphatic system to reach other parts of the body.

Eventually, the cancer cells find a place to land. The cancerous cells can remain dormant indefinitely. At any time, these cells can begin to grow into nearby tissue. When this happens, the cells first form small tumors called “micrometastases.” These small tumors trigger the growth of new blood vessels that are later used to fuel tumor growth. The new tumors are called metastatic tumors.

Even though these new tumors are growing in another part of the body, it’s the same type of cancer as the original tumor. For instance, kidney cancer that spreads to the bone is still considered kidney cancer, not bone cancer.


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How are Metatstatic and Invasive Cancers Diagnosed?

You should report persistent symptoms to your doctor, especially if you’ve previously been treated for cancer.

There’s no single test that can determine whether you have invasive cancer or metastatic cancer. Diagnosis usually requires a series of tests.

Tumors may be seen on imaging tests like:

  • ultrasounds
  • MRIs
  • X-rays
  • CT scans
  • bone scans
  • positron emission tomography (PET) scans

Blood tests can provide some information but can’t say for certain if you have cancer or what type it may be.

If a tumor is found, a biopsy must be done. Following a biopsy, a pathologist will analyze the cells to determine what type they are. This analysis will help explain whether it’s primary or metastatic cancer.

In some cases, even though a metastatic tumor is discovered, the primary cancer can’t be found. That may be because the original tumor is too small to visualize on diagnostic studies.

Whether it’s early-stage invasive cancer or metastatic disease, you’ll need to work closely with your doctor. Your oncology team will offer recommendations about potential treatments based on your test results.

Your doctor may also be able to give you information about clinical trials for people with metastatic cancer.

How are Invasive and Metastatic Cancers Treated?

Invasive cancer can spread to distant sites, so the goal is to get treatment before that happens. Your options will depend on the type of cancer you have and the cancer stage at diagnosis. Some types of cancer tend to grow and spread faster than others. If this applies to you, more aggressive treatment may be necessary.

Common treatments for cancer include surgery to remove the primary tumor and radiation to kill any cells that may have been left behind. Chemotherapy is a systemic treatment used to kill cancer cells that may have drifted elsewhere in the body. For some types of cancer, additional targeted treatments are available.

The same therapies can be used for metastatic cancer, but it’s more difficult to treat. The goal is to control growth, ease your symptoms, and improve your quality of life. Despite where the metastatic tumor is found, some of your treatment options will depend on where the cancer originated.

How Is Stage 4 Breast Cancer Treated?

Other determining factors include your age, overall health, and whatever cancer treatments you may have had in the past.

Research into treatment for metastatic cancer is ongoing.


It’s normal to wonder about the outlook. Although statistics can provide a general guide, your doctor knows the unique circumstances of your medical history. This means your doctor is in the best position to tell you what to expect.

Being diagnosed with any stage of cancer can have an enormous impact on your life. If you have cancer that’s in an advanced stage, your doctor may be able to recommend support groups or other resources that can provide assistance.

Posted in: Just Diagnosed, Medical/Science