Bone Cancer: Symptoms, Causes, Types & PET CT as a Diagnostic Tool

Bone cancer is a relatively uncommon form of cancer that starts in the bone structure. It affects various bones at various ages, depending on the type of cancer. Metastatic (secondary) bone cancer develops when cancer cells in the body break free, travel to the bone, and activate there. Primary bone cancers develop in the bone or bones. The majority of cancer that spreads to the bones in adults is not primary bone cancer, but rather a type of secondary cancer.

Persistent bone symptoms need to be assessed early, as symptoms of bone pain, swelling, and changes have many causes, most of which are not cancer. Based on suspicion of the condition, doctors use physical exam, blood tests, X-rays, Computed Tomography (CT), Magnetic Resonance (MR), PET or PET-CT, and biopsy. A bone cancer PET-CT is more useful for evaluating the extent of disease, the identification of other areas of involvement, and assessing treatment response in selected patients to give both anatomical and metabolic information.

What Is Bone Cancer?

Bone cancer affects abnormal cells in bones that become cancerous and start to grow out of control to form a cancerous tumor. Primary bone cancers are a kind of cancer that is known as sarcomas. Major types of primary bone cancers are osteosarcoma, Ewing sarcoma, chondrosarcoma, and chordoma. They have different patterns of growth and treatment and develop from different types of cells or tissues. People should also not confuse primary bone cancer with bone metastases. Cancer that spreads into bone is referred to as secondary or metastatic bone cancer. Cancer can spread to the bones, including breast, prostate, and lung cancers.

Bone Cancer Types

Osteosarcoma

Primary bone cancer is a type of cancer that occurs in cells that normally make new bone (osteosarcoma). Usually it happens in children, teenagers, and young adults, but can happen at any age. It often occurs in the long bones, especially in the area around the knee.

Ewing Sarcoma

A second kind of bone cancer, more commonly encountered in kids and youngsters, is known as Ewing sarcoma. It occurs in the bones or within the surrounding soft tissues and develops in the pelvis, legs, chest wall, and elsewhere.

Chondrosarcoma

In chondrosarcoma, the cartilage-producing cells turn into those that make cancer. It is more common in adults and is found in the pelvis, thigh bone, upper arm, or ribs.

Chordoma

Chordoma is one of many rare forms of bone tumor that usually occur in the spinal column around the base of the skull or in the sacrum region.

Bone Cancer Causes

In most instances, the exact cause of primary bone cancer is not identified. But some factors have been recognized as contributing to the development of bone cancer. Some bone cancers are more common in people who have been previously treated with high radiation doses or some of the chemotherapy drugs. Some inherited diseases and genetic syndromes also make a person more susceptible to certain types of bone tumors. Other diseases that are linked to a higher risk of osteosarcoma include Paget disease of bone, especially in the elderly. If a person has a risk factor, this does not imply that he/she will inevitably develop bone cancer. A large number of people with risk factors do not go on to contract the disease.

Bone Cancer Symptoms

Bone symptoms are different based on the site of the tumor, its size, and type. Pain is a very common symptom, and it also isn't always present at the onset of bone cancer. If pain persists or there is pain in or around a bone that is not typical for an injury, it is important. But some also have swelling or a lump close to the involved bone. If a bone breaks for no apparent reason, then it also needs medical evaluation. You may experience other symptoms, such as unexplained fever or other non-specific symptoms. These symptoms are caused by injury, infection, arthritis, benign bone growth, and other ailments. So, if someone does have bone pain, it is not necessarily related to cancer.

How Is Bone Cancer Diagnosed?

A series of steps is typically required to make a diagnosis of bone cancer. A doctor starts by asking about a patient's symptoms and health history, as well as a physical exam, followed by imaging tests based on the symptoms and findings. When a bone tumour is suspected, one of the first imaging tests performed is usually an X-ray. It reveals alterations in the shape, form, and size of a bone. 

Further imaging such as a computed tomography [CT] scan, magnetic resonance [MRI] scan, a bone scan, and/or positron emission tomography [PET] scan are advised if an abnormality is found. A biopsy is very important because sometimes images are ambiguous and do not make it easy to determine if a suspicious bone lesion is cancer. A biopsy is when tissue is removed to look for cancer cells by a pathologist.

Role of PET-CT in Bone Cancer

PET-CT combines two imaging techniques. PET provides information about metabolic activity, while CT provides detailed anatomical information. The most commonly used PET tracer is FDG, a radioactive form of glucose. Many cancer cells use glucose at higher rates than normal cells, which can make areas of increased metabolic activity visible on PET. CT helps show the exact anatomical location of these abnormalities. A bone cancer PET CT may therefore provide useful information when doctors need to evaluate the extent of disease or look for additional areas of involvement.

PET-CT for Staging Bone Cancer

Staging determines how extensively cancer has developed or spread and helps doctors plan appropriate treatment. PET-CT may help identify metabolically active disease in different parts of the body. This can be particularly useful when doctors need to assess whether disease is present beyond the original tumor. CT provides anatomical information, while PET can highlight areas with increased metabolic activity. The exact role of PET-CT varies according to the type of bone cancer and the individual patient's clinical situation. Other imaging tests, particularly MRI, may also be important for evaluating the local extent of a bone tumor.

Conclusion

There are very small number of cases of bone cancer, and it refers to several types of the disease, including osteosarcoma, Ewing's sarcoma, chondrosarcoma, and chordoma. Persistent pain, swelling, a lump, unexplained fracture, and unexplained fever are among the bone cancer symptoms, but none of them are exclusive to cancer and can be caused by other conditions. It is beneficial for patients to know the bone cancer causes and bone cancer types so that they are aware of why sometimes they need further evaluation. X-rays, other imaging procedures like CT scans, MRI scans, or PET-CT scans, and at times biopsy give important information.

A PET-CT is used to get a metabolic response to the cancer in addition to the anatomical information and can sometimes be used to diagnose disease distribution, to gauge response to therapy, or to monitor for future disease recurrence, if clinically appropriate. Molecular Diagnostics and Therapy has advanced services available in PET-CT and diagnostic imaging to assist cancer evaluation and monitoring of treatment based on individual clinical needs and physician's recommendations.