Stage 4 Breast Cancer

Breast Cancer staging

stage 4 breast cancer is when a tumor of any size has spread to other organs of the body such as the brain, lungs, stomach, intestines, liver, and pancreas. When breast cancer cells are found growing in distant areas of the body, the tumor is said to have metastasized. At this stage, cancer becomes very challenging to cure completely.[4]

What are the subtypes of stage 4 Breast Cancer?

The breast tissue cells from which breast cancer cells originate determine the type of cancer it is. More commonly, cancer originates from the cells lining the ducts within breast tissue, while some begin in the cells of the lobules or milk glands and others more rarely in other tissues.

According to the extent of the tumor, breast cancer is divided into two major subtypes:

Non-Invasive Breast Cancer: Cancer that remains confined to the ducts or lobules of breast tissue are known as ductal and lobular carcinoma in situ and considered non-invasive cancer.

  • Lobular carcinoma in situ is less common and considered a factor for high-risk cancer.
  • Ductal carcinoma in situ accounts for 90% of cases of non-invasive breast cancer. [3]

Invasive Breast Cancer: It is considered invasive breast cancer once cancer breaks through the ducts or lobules of breast tissue and invades the surrounding fat and connective tissue of the breast.

  • Infiltrating or Invasive Lobular Carcinoma, or ILC, starts in the milk glands before spreading to other breast tissues or nearby lymph nodes, accounting for 10% to 15% of breast cancer cases.
  • Infiltrating or invasive Ductal Carcinoma, or IDC, starts in the milk ducts and spreads to nearby connective, fatty, or lymphatic tissues. This type of cancer accounts for 80% of diagnoses [3]

Rare Types of Breast Cancer: Other than lobular and ductal carcinoma, whether invasive or in situ, there are other much rarer types of breast cancer, each not accounting for more than 5% of cases

  • Medullary carcinoma
  • Mutinous carcinoma
  • Tubular carcinoma
  • Inflammatory breast cancer
  • Paget's disease of the nipple
  • Phyllodes tumor [3]

Stage 4 Breast Cancer staging and diagnosis

Breast Cancer Staging

In general, the TNM system is used to describe and classify cancers, including breast cancer, where:

T (tumor) describes the size and location of the tumor

N (nodes) indicates whether or not it has spread to nearby lymph nodes

M (metastasis) describes if and how far the cancer has spread from its origin

How common is stage 4 Breast Cancer?

Breast cancer is the most common cause of cancer affecting women.[3] 1 in 8 women who live until the age of 80 experience breast cancer in their lifetime. It is estimated that by the end of 2023, 297,790 new cases of breast cancer will be diagnosed in the U.S. alone.

While mostly affecting nearly half the population, breast cancer still accounts for 15% of all cancer diagnoses and 7% of cancer-related deaths per year. [1] It is also the leading cause of death related to cancer in women. [3] Breast cancer is more common among women older than 50 years old. [2]

Nearly 20% to 30% of easily stage breast cancer may reach stage for breast cancer. [13] 6% patients in the united states have already reached stage 4 breast cancer in the United States and in 2020, roughly 684,996 women around the world died of breast cancer. [4]

How is stage 4 Breast Cancer diagnosed?

Breast cancer is diagnosed in the following steps:

  • Breast Self-Examination: A monthly examination done by yourself to keep track of any changes or symptoms of breast cancer is the first line defense against untreated breast cancer. Move three fingers in circular motions across both breasts and under the armpits. This will help you check for any irregularities or lumps.
  • Mammography: Mammography uses low-energy x-rays to examine and screen the breast tissue for any lumps or irregularities. It can find any lumps or causes of concern but cannot confirm if it’s cancer.
  • Biopsy: A biopsy is the examination of suspicious breast tissue to know for a fact whether or not it is cancer

Once you have been diagnosed with breast cancer, the doctor must confirm what stage of cancer it is. For that they will recommend further imagine and screening to see how far it has spread. If your doctor suspects your cancer has metastasized or that you have stage 4 breast cancer, they will recommend getting a:

  • Chest x-ray
  • Bone scintigraphy (bone scan)
  • Ultrasound of the liver [14]

If any of these tests indicate there’s a chance the cancer has metastasized, doctors will put the patient through further scrutiny by performing a/an:

  • MRI
  • PET
  • CT
  • Biopsy [14]

Not all these tests are needed for all cases. Each breast cancer case is different and your doctor will discuss the options for the best individualized investigations of the disease.

Stage 4 Breast Cancer symptoms

While invasive breast cancer may progress without obvious symptoms for some patients, noticeable breast cancer symptoms include:

  • Swollen, red, inflamed breasts
  • Ulcerations on breasts
  • Inexplicable pain or itchiness in breasts
  • Change in breast or nipple size or shape
  • Nipple discoloration, inversion, secretion
  • Dimples on breast skin like an orange
  • Lumps in the breast [5], [6]

Once a patient reached stage 4 breast cancer, they experience more varied symptoms. The exact symptoms depend on where the cancer has migrated. If the cancer migrates to the brain, the patient will experience neurological symptoms and if the cancer spread to the liver, the patient will experience liver dysfunctional symptoms. Breast cancer commonly metastasizes to the liver, lungs, bones, and brain.

Physicians will be more alert to check patients who have already been treated for breast cancer once and the disease has recurred after a period of remission.

Once diagnosed with cancer, patients must remain vigilant of any symptoms they experience. While mostly they are other illnesses, it is possible the cancer metastasized. Here are some symptoms to look out for depending on the location of the metastasized tumor once you’ve been diagnosed with invasive breast cancer.

Stage 4 Breast Cancer Treatment

Stage 4 Breast Cancer Primary Treatment

In stage 4 breast cancer, the tumor has spread beyond the breast tissue or surrounding lymph nodes. The cancer may spread to the liver, lungs, brain, bones, or other rarer areas.

Systematic treatments are the primary treatment for patients with metastasized cancer. These treatments effect the entire body. One or any combination of the following will be the primary treatment for most patients:

  • Hormone therapy
  • Chemotherapy (chemo)
  • Targeted drugs
  • Immunotherapy [18]

Chemotherapy: Chemotherapy is a systematic treatment using a drug injected intravenously to destroy cancer cells. Treatment is usually done in cycles involving treatment periods and recovery periods. Normally treatment is commenced after surgery, but sometimes it can be done prior to surgery to shrink the tumor. [3]

Radical mastectomy is no longer as prevalent as before with the rise of more options available to patients, like lumpectomies. While integral to cancer treatment success, radiation is often with-held from patients over 65 inappropriately. [7]

Hormone Therapy

Hormone therapy slows or stops the growth of hormone sensitive tumors in the body by interfering with the body’s ability to produce hormones. [19]

Targeted Drugs

Targeted drug therapy involved medicines that kill or stop the growth of breast cancer cells by targeting a specific protein present on them, not present on normal cells. This treatment utilizes knowledge of the differentiation of breast cancer cells from normal cells. [20]


Immunotherapy is a type of biological therapy utilizing the body’s own resources against cancer. It allows the body’s immune system to better recognize and kill cancer cells through different medications. [21]

Other Types of Treatment for stage 4 Breast Cancer

Most patients with stage 4 breast cancer may have already had surgery or radiation treatments. However, for the percentage that gets diagnosed with direct stage 4 breast cancer or aggressive recurring breast cancer, surgery and radiation may be useful.

Surgery: The surgical removal of the breast tissue is the most effective way to prevent the cancer from spreading further. If the cancer has already spread to a great extent, removing breast tissue aids in debulking the tumor to make other treatments work more effectively. The name of the surgery depends on the amount of breast tissue that is removed.

Lumpectomy: The removal of a small lump with a bit of surrounding normal tissue is known as a lumpectomy. It is the least invasive surgery.

Quadrantectomy: Removal of a quarter of breast tissue.

Mastectomy: The removal of the entire breast is known as a mastectomy. This is the most invasive surgical option.

Radiation: The bombardment of high-energy x-rays on the affected body area is known as radiation treatment. It kills cells in a specific area instead of systematically treating the entire body.

Can Stage 4 Breast Cancer be cured?

Unlike stage three breast cancer which can still be cured with aggressive treatment, stage 4 breast cancer is incurable. It can be treated systematically to extend life expectancy and locally to alleviate symptoms and improve the patient’s quality of life. There are many individuals living with metastatic breast cancer.

Prognosis: Stage 4 Breast Cancer survival rate

Stage 4 Breast Cancer Survival Rate

Over the years, breast cancer's survival rate has risen significantly. This is due to new treatments, better detection, and earlier diagnoses. However, at stage four the cancer has metastasized to distant locations of the body and becomes incurable

The sooner you are diagnosed, the better your survival rate for breast cancer. While the average 5-year survival rate for breast cancer is 91%, the 5-year survival rate for women diagnosed at stage 4 is 25% [9],[22] In 2017, only 17% women previously diagnosed with metastatic breast cancer 10 years ago remained alive. [23]

The survival rate for cancer also depends on the age at which the patient was diagnosed. There’s no connection between age and the severity of cancer. Younger patients are able to withstand more aggressive treatments to wipe out cancer. Younger patients can continuously withstand aggressive systematic treatments.

Stage 4 Breast Cancer Recurrence Rate

Since the cancer has spread far beyond the breast in stage 4 breast cancer, treatment is difficult and the disease incurable. Even once the entire tumor has been treated completely, and the tumor goes into remission, there’s still a chance the cancer will regrow in the same places or somewhere else in the body. This is called recurrence.

There is a 25% chance that the cancer will recur once again if it is discovered in the auxiliary lymph nodes. While radiation therapy after surgery reduces the risk by 6%, the recurrence rate for confirmed stage 4 breast cancer is up to 50%[10],[24]

Stage 4 Breast Cancer growth rate

The speed at which the cancer spreads depends on the grade of the cancer cells. The more differentiated the cancer cells are from normal breast cancers, the higher their grade is.

Low-grade cancer cells are very close to normal breast tissue cells and grow slowly. High-grade breast cancer cells are much different from normal breast tissue cells and grow much faster.[10]

Lifestyle Changes for Preventing and Managing Breast Cancer

Certain factors increase your risk for developing breast cancer. You can be significantly high risk and still not develop breast cancer or develop it while being low risk. However, here are some things you can do to reduce your chances of getting breast cancer:

  • Exercise and eat healthy to maintain a healthy weight.
  • Speak to your doctor and understand all the risks before using hormonal contraceptives or hormone therapy after menopause. Both these treatments increase the risk of breast cancer, and there are alternatives available that could be better for you.
  • Breastfeed your children if possible.
  • Have an active conversation about reducing your risks if you have a family history of breast cancer.
  • Either drink in moderation or stop drinking alcohol altogether.



stage 4 breast cancer is when the tumor has spread to distant areas of the body, commonly the lungs, liver, bones, and brain. This stage is difficult to treat since the cancer has spread considerably and impossible to cure. However, symptoms can be treated to improve patient’s quality of life.

Breast cancer is treated through systematic treatments like chemotherapy or hormone therapy, some combination of several systematic therapies and other treatments like surgery and radiology as needed.

You can reduce the risk of breast cancer by maintaining a healthy lifestyle, drinking less alcohol, avoiding hormonal birth control, and regularly taking self-examinations. The risk for women over 40 is greatly reduced with yearly mammograms. [12]