Diagnosing and Staging of Osteosarcoma
All parts of the body are susceptible to cancer, including bones. There are multiple types of bone cancer, which, unfortunately, primarily affect children. The most common primary bone cancer is osteosarcoma, also known as osteogenic sarcoma.
Osteosarcoma is a malignant tumor typically found in children between the ages of 10 and 19, and it usually appears in the humerus, femur or tibia, which are the longest bones in the body.
Even though it’s the most common bone cancer, it’s still a rare disease overall, accounting for approximately 2.4% of all childhood cancers.
Osteosarcoma can be difficult to diagnose, not only because of its rarity, but also because all bone cancers may appear to be similar, especially in their early stages. However, specialized medical centers provide accurate and advanced diagnosis.
The following are common tests employed as part of the diagnostic process for osteosarcoma:
Imaging tests involve sending forms of energy, such as radioactive particles, X-rays, magnetic fields or sound waves, through the patient’s body to create an ‘image’ of the relevant tissues.
By examining these images, medical professionals can see if there are any irregularities inside your body.
Imaging tests are used for a variety of purposes, including:
- Early-stage cancer detection in asymptomatic patients
- Detecting metastasis
- Finding tumors in patients who have exhibited symptoms and determining their size
- Locating a tumor and determining whether it is cancerous
- Testing for cancer recurrence after treatment
It is very common to use a bone scan to detect bone disorders of any kind. Using this method, a medical professional can determine if there is a problem with one or more bones.
During the procedure, a small amount of radioactive material, known as a tracer, is injected into the patient’s body. As the tracer is being absorbed, a special camera can detect excessive or weak absorption, which indicates structural damage or an abnormality.
Often used as an initial examination when suspicions of cancer first arise, a bone X-ray can indicate osteosarcoma or any other bone tumor, but it isn't conclusive.
In some cases, osteosarcoma can spread to other body parts, most often the lungs. If a medical professional suspects that is the case, they will perform a chest X-ray to see if there are any lung abnormalities. However, a chest X-ray can only detect a tumor when it has spread and is relatively large in size.
Computed Tomography (CT) Scan
A CT scan is similar to an X-ray but provides a more precise image. During a CT scan, the machine will take cross-sectional X-ray images of multiple body parts to see if a tumor has spread to fat and muscle cells or tendons.
Magnetic Resonance Imaging (MRI)
Even though X-rays and CT scans can be of great help when diagnosing osteosarcoma and other cancers, they aren't always enough. When a more detailed image is required, an MRI, which operates by utilizing a magnetic field, is often used.
Positron Emission Tomography (PET) Scan
Another way a medical professional can detect whether or not osteosarcoma has spread is by performing a positron emission tomography scan. A PET scan is performed by injecting a radiotracer into the patient’s blood and then scanning for its absorption into tissue. As cancer cells grow quickly and absorb the radiotracer faster, they can be detected by the PET machine.
Following an imaging test that indicates a possible osteosarcoma, a biopsy is usually performed.
A biopsy is the process of removing a part of the tumor from the patient’s bone and viewing it under a microscope.
There are two types of biopsy:
- Core needle biopsy: During a core needle biopsy, the doctor removes a small cylinder of tissue from the tumor under local or general anesthesia. They do this by inserting a needle and guiding it to the tumor using imaging technology.
- Surgical biopsy: During a surgical biopsy, also known as an open biopsy, a surgeon cuts through the patient’s skin to expose the tumor and removes a piece of it. This is usually done under general anesthesia.
A medical professional can diagnose osteosarcoma without a blood test. However, one is likely to be ordered to determine the stage of the osteosarcoma based on the levels of certain chemicals in the blood.
Staging refers to determining the extent to which cancer has advanced in terms of size and location. Staging is important because when a doctor knows how far the cancer has progressed, it will be easier for them to choose the best possible treatment.
- 1A: The tumor is low grade, meaning it is likely to grow more slowly, is less likely to spread, and is localized within the bone.
- 1B: The tumor is low grade but has spread to nearby tissues outside the bone.
In both cases, the cancer has not spread to lymph nodes or distant body parts. Surgery and chemotherapy are common treatment options.
- 2A: The tumor is high grade, indicating a more aggressive, faster-growing cancer, but remains localized within the bone.
- 2B: The tumor is high grade and has spread to nearby tissues, but not to distant sites or lymph nodes.
As high grade tumors are more aggressive and have a greater tendency to spread, treatment often involves a combination of surgery, chemotherapy, and sometimes radiation therapy.
In this stage, the tumor may be either high grade or low grade, but multiple areas in the same bone are affected. The cancer has not spread to distant sites or lymph nodes. Similar to Stage 2, treatment often involves surgery and chemotherapy.
- 4A: The tumor has spread to the lung(s).
- 4B: The tumor has spread to other distant sites or lymph nodes, which may include the lung(s).
This is the most advanced stage, and treatment is often more complicated. A multimodal approach, including surgery to remove accessible tumors, chemotherapy, and possibly targeted or novel therapies, may be used.
Osteosarcoma Center at Sheba
Dealing with any kind of cancer can be a harrowing experience, especially in cases of rare cancer such as osteosarcoma. Choosing an advanced, expert center is critical for timely, accurate diagnosis and proper treatment.
At Sheba, which serves as a global osteosarcoma referral center, our multidisciplinary specialists employ the latest diagnostic and therapeutic modalities to ensure patients receive the prompt, advanced care they require.
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Sheba Medical Center provides innovative, personalized medical care to patients from around the world. We are the largest, most comprehensive hospital in the Middle East and dedicated to providing advanced and compassionate medicine for everyone. We welcome all cases, including the rarest and the most challenging. Our medical teams collaborate to provide the best possible health outcomes. From your initial inquiry through the long-term follow-up care, we are here for you.
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