Sarcomas are a rare group of cancers that begin in the bones or soft tissues of the body. In other words, sarcoma is a term used to describe bone cancer and cancers that develop in the connective tissues. It accounts for about 1 per cent to 2 per cent of all cancers that affect children, adolescents, and even adults. Although bone cancer can develop anywhere in the body, it mostly develops in the arms and legs.

Since it develops deep in the body and becomes evident after the appearance of a lump, one might not be able to see any significant signs or symptoms. This makes, early diagnosis of sarcoma very crucial.

How bone sarcoma is diagnosed

Sarcoma of bone is a type of cancer that requires various tests for accurate diagnosis, although not all tests are necessary for every individual. When selecting diagnostic tests, doctors take into account several factors such as the suspected type of cancer, the patient’s signs and symptoms, age, general health, and the results of previous medical tests.

Here are the tests commonly used to diagnose and determine the stage of bone sarcoma:

Bone scan: A bone scan aids in determining the stage of bone sarcoma. A small amount of radioactive tracer is injected into a patient’s vein, which collects in areas of the bone. A special camera detects the radiation emitted by the tracer, creating images. Healthy bone appears lighter, while areas affected by cancer cells or fractures stand out.

Blood tests: Laboratory blood tests alone cannot diagnose sarcomas. However, in some cases of osteosarcoma or Ewing sarcoma, elevated levels of alkaline phosphatase and lactate dehydrogenase may be present. It’s important to note that these substances can also be elevated due to non-cancerous causes, such as normal growth in children or healing broken bones.

X-ray: X-rays use a small amount of radiation to create images of the body’s internal structures. They provide a visual representation of the bones and can help identify any abnormalities or tumors.

Computed tomography (CT or CAT) scan: CT scans utilise X-rays taken from different angles to create detailed 3-dimensional images of the body. They can measure tumor size and identify abnormalities or tumors. Contrast medium, a special dye, may be administered to enhance the image’s clarity.
Magnetic resonance imaging (MRI): MRI employs magnetic fields instead of X-rays to produce detailed body images. It can measure tumor size and detect the involvement of nearby soft tissues. A contrast medium may or may not be used to enhance the image’s quality.

Positron emission tomography (PET) or PET-CT scan: A PET scan is often combined with a CT scan to determine the stage of bone sarcoma. A radioactive sugar substance is injected into the body, which is absorbed by cells that actively use energy, including cancer cells. The scanner detects this substance, producing images of organs and tissues.

Biopsy: A biopsy involves the removal of a small tissue sample for microscopic examination. While other tests may suggest cancer, only a biopsy can provide a definitive diagnosis. A pathologist analyses the sample to confirm the presence of cancer. Biopsies can be performed through a needle or by making a small incision, depending on the tumor’s location. It is crucial to undergo the biopsy process in a specialised center, as the procedure is extremely important both in diagnosis and proper treatment outcome. Additionally, an expert pathologist should review the tissue sample to ensure an accurate diagnosis of sarcoma.

After conducting the necessary diagnostic tests, the doctor will discuss the results with the patient. In the case of a cancer diagnosis, these results assist in describing the cancer and determining its stage and grade. Staging and grading help guide the appropriate treatment approach. It is crucial for individuals with bone sarcoma to seek care at a sarcoma specialty center, where experts can ensure accurate diagnosis and provide appropriate treatment.

(Dr. Aakaar Kapoor is the CEO and Lead Medical Advisor, of City X-Ray & Scan Clinic and a partner, at City Imaging and Clinical Labs)