Metastatic breast cancer in the lungs refers to cancer that originally developed inside the breast tissue but has spread to the lungs.

Breast cancer can spread to various parts of the body. This is called metastasis. The most common sites for breast cancer metastases include the bones, brain, lungs, and liver.

This article will discuss metastatic breast cancer in the lungs, including its symptoms, diagnosis, treatment options, and outlook or prognosis.

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Breast cancer is the most common form of cancer among women.

Metastatic is a term that refers to cancer that has spread outside of the original area to a different place in the body. Metastatic breast cancer in the lungs refers to cancer that originally developed inside the breast tissue but has spread to the lungs.

About 60% of all metastatic breast cancer patients progress to the lungs or the bones within the person’s lifetime. Of these, 21–32% of cases affect the lungs specifically.

This article explores the symptoms, outlook, causes, diagnosis, and treatment of metastatic breast cancer in the lungs.

People may not experience symptoms of metastatic breast cancer in the lungs immediately. If symptoms do appear, they can resemble those of a cold or flu.

Symptoms of metastatic breast cancer in the lungs include:

  • a constant cough
  • pain in the lung
  • difficulty breathing or shortness of breath
  • wheezing
  • fatigue
  • recurring infections in the chest
  • coughing up blood
  • loss of appetite
  • unintentional weight loss

Metastatic breast cancer is the most advanced form and is not curable, so treatment options focus on weakening the tumor and preventing further growth.

Experts calculate cancer prognoses using a 5-year survival rate, which is the percentage of people who survive for at least 5 years after diagnosis. These are estimates, and actual survival varies depending on a person’s characteristics.

What is the outlook when breast cancer spreads to the lungs?

The Surveillance, Epidemiology, and End Results (SEER) database from the National Cancer Institute (NCI) measures 5-year survival rates for women with breast cancer with a different stage classification system as follows:

localizedno metastasis99%
regionalmetastasis in nearby tissue or lymph nodes86%
distantmetastasis to distant structures such as the lungs30%

The long-term outlook for people with metastatic breast cancer in the lungs depends on many variables. These include:

  • age
  • overall health status
  • how the tumor responds to treatment
  • the size of the primary and secondary tumors
  • whether or not the primary cancer has metastasized to multiple sites within the body

Doctors consider metastatic breast cancer to be a stage 4 cancer. It is not curable, and treatments focus on weakening cancer to stop it from growing while working to improve the quality of life for the individual.

Treatments for metastatic breast cancer in the lungs usually involve systemic, or body-wide, medications that treat cancer throughout the body, such as the following:

  • Chemotherapy: This is a drug therapy that destroys fast-growing cells in the body, both cancerous and healthy.
  • Hormonal therapy: This is a cancer treatment that controls cancer cell growth by lowering the levels of certain hormones the cancer needs to grow. Hormone receptor-positive breast cancers respond well to this treatment.
  • Targeted therapy: This form of cancer treatment attempts to treat cancer with more precision than chemotherapy. These treatments target specific receptors, proteins, or molecules on cancer cells that either make it easier for the body’s immune system to identify and destroy cancerous cells or reduce their growth.
  • Radiation: In the case of metastatic breast cancer, doctors often use radiation therapy to reduce symptoms and control the cancer’s growth. Radiation therapy can help reduce pain and lower the risk of broken bones weakened due to cancer.

Surgery for metastatic breast cancer in the lungs

Surgery may be necessary to remove cancerous tissue from the lungs.

In some cases, breast cancer cells can form in the region between the outside of the lungs and the chest wall, also known as the pleural space. This can cause a buildup of excess fluid, a condition known as a malignant pleural effusion.

A doctor can treat this by performing procedures that help drain a person’s lungs and prevent more fluid from accumulating. Doctors may repeat these procedures as needed.

In addition, a person also has the option to undergo palliative care along with traditional treatment to help manage the symptoms of the disease and any complications.

As the cancer cells divide and multiply, the primary tumor grows larger. As the primary tumor grows, cancer cells can break off from the primary tumor. These rogue cancer cells can then enter the bloodstream or the lymph system. From there, the cancer cells can travel to distant areas of the body.

In some cases, small amounts of breast cancer cells can survive initial treatment and remain inactive in the body for some time before growing again in the primary site or spreading to another area of the body. Doctors call this recurrent, or recurring, breast cancer.

Breast cancer cells must undergo significant changes to survive and grow in the lungs. These cells must also change to withstand attacks from the body’s immune system. The treatment options for the newly formed cancer will depend on how it has altered during metastasis.

It is not unusual for cancer to metastasize to multiple sites at once.

The earlier doctors discover metastatic breast cancer in the lungs, the better. Research shows that lung metastases are more common within 5 years of a person’s initial breast cancer diagnosis.

Diagnosis begins with a physical examination and blood tests. If a healthcare professional suspects lung metastasis, they will likely order an imaging test, such as:

If a doctor does find a tumor in the lung, their next task involves confirming that the tumor is metastatic breast cancer and not primary lung cancer. This is especially important for people who have smoked or currently smoke.

Other diagnostic procedures that can help confirm a metastatic breast cancer diagnosis include:

  • testing a mucus sample
  • bronchoscopy, where a doctor threads a flexible camera through the nose or mouth into the lungs to examine the respiratory structures
  • needle biopsy of the lung, where a doctor removes a sample of lung tissue for further testing

Currently, the best way to help prevent breast cancer from metastasizing to the lungs is to receive an early diagnosis of the disease and start treatment immediately.

In addition, after someone has received initial treatment, breast cancer can lay dormant in the body before spreading to other areas. People who have received treatment in the past should monitor themselves for any signs or symptoms that could indicate cancer recurrence.

While there is no single way to avoid developing metastatic breast cancer, there are some lifestyle changes and other practices that can help reduce the chance of a person developing breast cancer. This includes:

  • having regular health screenings
  • having regular breast cancer screenings
  • eating a balanced diet
  • exercising regularly
  • not smoking or quitting smoking
  • avoiding excessive alcohol intake
  • maintaining a moderate body weight
  • monitoring vitamin D levels
  • reducing stress

In addition, there is some research suggesting that lung metastasis can occur not only due to the spreading cancer cells themselves but also due to a lung environment that is favorable to the spread of cancer. Targeting medications to change a person’s pulmonary environment during treatment may be able to reduce the chance of lung metastasis.

Metastatic breast cancer in the lungs can cause other health complications that affect a person’s overall health and well-being.

Toxicity due to treatment

Cancer treatments can cause significant side effects that affect a person’s health and quality of life. Chemotherapy and other systemic cancer treatments can cause a wide range of symptoms, such as:

  • lowered immune system function
  • infection
  • fatigue
  • loss of appetite
  • nausea
  • vomiting
  • constipation

Psychological impact

Receiving a diagnosis of stage 4 cancer can leave lasting psychological impacts. People can experience depression, anxiety, and stress as a result of their condition.

People who are experiencing negative psychological symptoms might want to consider joining a support group or seeking professional counseling to help them cope with their situation. Reaching out to friends or loved ones can make a significant difference.

According to the World Health Organization, 2.3 million women were diagnosed with breast cancer in 2020. In addition, about 0.5–1% of breast cancers occur in men.

The earlier doctors diagnose lung metastasis, the better. Around 6–10% of new breast cancer cases are metastatic.

If a person living with breast cancer experiences symptoms that may indicate lung metastasis, it is best to speak with their oncologist. They can confirm (or rule out) the presence of a tumor in the lungs.

A secondary tumor contains breast cancer cells. If there are no breast cancer cells present, the tumor could be a newly developed primary cancer.

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