Sarcoma Explained: Symptoms, Causes, & What Breast Cancer Survivors Need to Know

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If you’ve been through breast cancer, you already know how important it is to stay informed about your health, even after treatment ends.

But what if new symptoms like bone pain or swelling appear months or years later? Could it be a recurrence, or something entirely different, like sarcoma?

Sarcoma is a rare type of cancer that starts in the body’s connective tissues. These tissues include bone, muscle, fat, or cartilage. Though very uncommon, it can be aggressive and often goes unnoticed in its early stages.

While sarcoma is different from breast cancer, the two can overlap in key ways. Breast cancer often spreads, or metastasises, to the bones, and the symptoms of bone metastases can look very similar to bone sarcoma.

This article breaks down what sarcoma is, how to spot the symptoms, and what breast cancer patients and survivors should watch out for.

What is a Sarcoma?

Sarcoma is a rare form of cancer that develops in the body’s connective tissues. These are the structural and supportive components of the body, which include bone, muscle, fat, cartilage, blood vessels, and fibrous tissue.

Unlike more common cancers that begin in organs or glands, such as the breast, colon, or lungs, sarcomas arise from the tissues that hold the body together and help it move.

Sarcomas are quite uncommon, accounting for less than 1% of all adult cancers. However, they can be aggressive and difficult to detect early.

Because they often start deep in the body, sarcomas may grow unnoticed until they cause pain or swelling. The most common types include soft tissue sarcomas and bone sarcomas, each with several subtypes.

Understanding the Overlap Between Sarcoma and Breast Cancer

While sarcoma is a separate disease from breast cancer, it’s important to understand their potential overlap, especially when it comes to symptoms and sites of spread.

One of the most common places breast cancer spreads is the bones, where it can cause pain, swelling, or fractures. These symptoms are also common in primary bone sarcomas, which can sometimes lead to confusion during diagnosis.

For breast cancer survivors, especially those experiencing new or unexplained bone symptoms, understanding the difference between bone metastasis and primary sarcoma is important.

Both can affect the bones and present with similar symptoms, but they are distinct conditions that require different treatments.

Bone metastasis means the original breast cancer has spread. Bone sarcoma is a new, separate cancer that begins in the bone or surrounding tissue. A very small number of breast cancer patients may also develop radiation-associated sarcomas years after treatment.

Having awareness and being able to distinguish between the two through proper diagnosis is key to receiving the right care as early as possible.

Symptoms of Sarcoma

Sarcomas can develop in different parts of the body, and their symptoms often depend on the type and location of the tumour. Because sarcomas tend to develop quietly at first, they may go unnoticed until they begin to affect surrounding tissues or cause physical discomfort.

Here are some common signs to watch for:

A painless lump or swelling

This symptom of soft tissue sarcoma develops in areas like the thigh, arm, or abdomen. People are usually able to feel this lump under the skin before it becomes visible. Over time, the lump may grow or begin to cause discomfort as it presses against nerves or organs.

Persistent bone pain

Bone sarcomas often cause a deep, aching pain that worsens at night or during physical activity. The pain may start off mild but gradually increase in intensity.

Unexplained fractures

Weakened bones affected by sarcoma may fracture more easily, even with minor injuries or normal movement.

Fatigue and weight loss

Just like many cancers, sarcoma can cause symptoms such as low energy, unintended weight loss, or loss of appetite.

Limited range of motion

If the tumour presses on muscles, nerves, or joints, it can reduce mobility or make certain movements painful or difficult.

Why These Symptoms Can Be Confusing

Many of these symptoms can be similar to other less serious conditions, like joint strain, arthritis, muscle injury, or general ageing.

For breast cancer survivors, sarcoma symptoms may also resemble signs of bone metastasis. Both bone sarcomas and bone metastases can cause pain, swelling, or fractures, making it crucial to investigate any new or persistent symptoms promptly.

If you or a loved one is experiencing ongoing bone discomfort or an unusual lump that doesn’t go away, don’t ignore it.

Early consultation with a doctor and, if needed, a biopsy can help determine whether it’s a benign issue, a metastasis of breast cancer, or a primary sarcoma, each of which requires a different treatment approach.

Causes and Risk Factors of Sarcoma

Sarcomas are very rare, and in most cases, the exact cause is unknown. However, researchers have identified certain risk factors that may increase the chances of developing sarcoma.

1. Genetic Factors

Some individuals inherit mutations that make it more likely for them to develop certain types of cancer, including sarcomas. For example:

Li-Fraumeni syndrome, a rare inherited condition which significantly increases the risk of several cancers, including soft tissue sarcomas, bone sarcomas, and breast cancer.
Other syndromes, like Neurofibromatosis type 1 (NF1) and Retinoblastoma gene mutations, may also elevate sarcoma risk.

If you have a strong family history of cancer or were diagnosed with cancer at a young age, your doctor may recommend genetic counselling.

2. Radiation Exposure

Radiation therapy is highly effective in treating cancer. However, it may slightly increase the risk of developing a new, unrelated cancer in the years that follow.

This includes a rare form of sarcoma known as a radiation-induced sarcoma. These typically appear within five to ten or more years after radiation treatment, in or near the area that received radiation.

For breast cancer survivors, this is particularly relevant.

Radiation therapy to the chest, breast, or underarm area can, in rare cases, lead to sarcomas in nearby tissues, such as the skin, bone, or connective tissue.

It’s important to note that this risk is small, and the benefits of radiation in treating breast cancer far outweigh the potential long-term risks. Still, it’s wise to remain aware and report any unusual lumps, skin changes, or discomfort in previously treated areas.

3. Chemical Exposure

Long-term exposure to certain industrial chemicals, typically due to someone’s work environment, may increase the risk of certain types of sarcoma. Some of these chemicals include:

Vinyl chloride, which is used in plastic production.
Arsenic exposure for those working in mining, farming, or electronics manufacturing.
Polychlorophenols, which are present in some herbicides and disinfectants.

People in certain job areas may be more exposed, which highlights the need for extra care regarding chemical exposure in those professions.

Diagnosis and Treatment of Sarcoma

Diagnosing sarcoma begins with a thorough physical exam and review of symptoms, followed by imaging tests such as MRI, CT scans, X-rays, or PET scans to locate and assess the tumour. A biopsy is essential to confirm the diagnosis and identify the exact sarcoma subtype.

In breast cancer survivors, additional tests like bone scans may be used. Together, these tests can help doctors distinguish between bone metastases and primary sarcoma.

Treatment typically depends on the type, size, location, and stage of the sarcoma:

Surgery is often the primary treatment to remove the tumour while leaving the surrounding healthy tissue intact.
Radiation therapy may be used before surgery to shrink the tumour, or after surgery to eliminate any remaining cancer cells.
Chemotherapy may be given through oral medication or intravenously.
Targeted therapies and immunotherapy may be considered for certain subtypes of sarcoma. These cancers may be very advanced or respond poorly to chemotherapy.

Survival rates for sarcoma rely heavily on the type and location of the disease. Soft tissue sarcomas have survival rates of up to 83% if found and treated early. Meanwhile, there is a 76% to 91% survival rate for bone sarcoma that is treated before it has spread to other tissues.

These numbers show how important early detection is in the treatment of sarcoma.

Because sarcomas often grow quietly and can be mistaken for less serious conditions, breast cancer survivors and other high-risk individuals should stay alert to unusual symptoms and seek medical advice early if anything feels off.

Recognising unusual pain, swelling, or lumps early on gives patients the best chance for effective treatment and recovery.

Staying Alert and Proactive as Breast Cancer Survivors

As a breast cancer survivor, it’s important to be vigilant for any new or unusual symptoms that may develop.

While sarcoma is rare, being aware of its signs can help you catch potential problems early, whether it’s a recurrence, a metastasis, or something new.

Notice persistent bone pain, swelling, a painless lump somewhere on your body, or other changes? Trust your instincts and speak with your doctor as soon as possible.

At International Cancer Specialists (ICS), we’re here to support you with compassionate and accessible care in an environment that always prioritises your physical, emotional, and mental wellness.

You can consult our team of expert oncologists and obtain a full cancer-focused health screening to detect early signs of sarcoma, recurrence, or other concerns.

We also offer second opinion consultations to help you feel confident in your diagnosis and treatment options.

If you have difficulty travelling to our centre, you may take advantage of our teleconsultation services so that you can connect with our team anywhere, anytime.

References

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September 3, 2025