MUSCULOSKELETAL TUMORS

MUSCULOSKELETAL TUMORS

The body’s bones (the skeletal system), muscles (muscular system), cartilage, tendons, ligaments, joints, and other connective tissue that supports and binds tissues and organs together comprise the musculoskeletal system. Abnormal swellings may develop in the muscles, bones, nerves, cartilage, tendons, blood vessels and the fatty and fibrous tissues, and are called musculoskeletal tumours.

WHAT IS A BONE TUMOUR?

Bone tumours are abnormal swellings/lumps or masses that develop from bone or other body tissues, able to grow (sometimes fast) without control of the body and are of no benefit to the body.

Tumours start in body cells, which are tiny building blocks that make up the organs and tissues of the body. Usually, these cells divide to make new cells in a controlled way, when required. This is allows for normal growth, healing and repair of body tissues.

Sometimes, this orderly process goes wrong and the cell becomes abnormal, dividing and making more and more abnormal cells; to form a lump or tumour.

Some lumps can grow into nearby tissues and spread elsewhere in the body, and are termed cancers (malignant tumours).

Other lumps that may grow but cannot spread to other parts of the body are called benign tumours. These cause problems when they put pressure on nearby structures.

TYPES OF BONE CANCERS

• Primary
• Secondary

Bone cancers are called primary when they start within the skeletal system. On the other hand, cancer cells that form in other parts of the body sometimes break away from where the cancer first started (the primary cancer) and travel through the blood or lymphatic system to bones, where the new abnormal growth that develops is called a secondary cancer or metastasis.

BONE SARCOMA (SOMETIMES CALLED PRIMARY BONE CANCER) is rare. It can affect anyone at any age but is slightly more common in men. There are different types of bone cancer. The most common ones include:

Osteosarcoma – is the most common type of cancer that starts in bone and mostly affects the knee, thigh bone, shin bone or upper arm. They make up 30% of all bone sarcoma diagnoses and are mostly diagnosed in teenagers and young people (aged 11 to 30 years); however, it can also affect older adults. People may complain of pain followed by a palpable mass.

Ewing’s sarcoma – is more common in teenagers and young adults, but can occur at any age. It can start in any bone but is more frequent in the pelvis, shin and thigh bone. It makes up 14% of all bone sarcoma diagnoses. Ewing’s sarcoma may also start in the soft tissues of the body. Symptoms include pain, a mass, with or without fever or feeling ill.

Chordoma – is usually a slow-growing cancer that starts in the bones of the spine. It makes up only 6% of all bone sarcoma diagnoses and most commonly affects adults in their 40’s and 50’s.

Chondrosarcoma – is a slow-growing bone sarcoma that develops in the cartilage cells. It mostly affects adults aged 30 to 50 years and the most common sites are the upper arm, pelvis and thigh bone. Its symptoms are pain, an enlarging mass or both.

Spindle cell sarcoma – is similar to osteosarcoma but is more likely to affect people over 40years.

Angiosarcoma – develops from the cells that make up the walls of blood vessels. It can occur anywhere throughout the body. Usually affects the soft tissues but can sometimes develop in bone. It can develop in more than one bone at the same time.

Malignant Fibrous Histiocytoma – Is a rare (<5%) primary bone tumour that can occur in any age group but more common in adult males. It is most commonly found in the bones of the upper arm, leg and thigh, with pain and pathological fracture being the main symptoms.

Giant cell tumours (GCT) – are benign (non-cancerous) tumours that develop in the bone, and are capable of changing into cancer. They mostly occur in the long bones found in the arms and legs, between the ages of 21 to 30 years. They are always found at the end of the bone next to the joint and can grow to a large size.

SECONDARY CANCER IN THE BONE (sometimes called bone secondaries or bone metastases) are more common in people over 70 years of age. They may involve only one area of bone, or the cancer may spread to a number of areas.

Any type of cancer can spread to the bone. But the most common types that do are:

• Breast cancer
• Prostate cancer
• Lung cancer
• Thyroid cancer
• Kidney cancer
• Myeloma: This is a cancer of plasma cells in the bone marrow – which is a spongy material inside bones; mainly the hip bones, breastbone, arm bones, leg bones, ribs and spine. It is rare before the age of 40years and found more in males.

Plasma cells are a type of white blood cell that makes immunoglobulins, which are also known as antibodies that circulate in the blood and attack any viruses and bacteria in the body.

Normally, new plasma cells replace old, worn-out cells in a controlled way. But in people with myeloma, the process gets out of control and large numbers of abnormal plasma cells (myeloma cells) are produced.

The myeloma cells fill up the bone marrow and interfere with the production of normal white blood cells, red blood cells and platelets. They can also damage the bone and cause bone thinning, pain and sometimes fractures. An area of damaged bone is often called a lytic lesion.

Myeloma cells can develop wherever there are plasma cells, and can spread throughout the bone marrow to several different parts of the body; in which case they are called multiple myeloma.

Myeloma may not cause any symptoms in the beginning. While some people may develop:

• Bone damage, which can cause pain, fractures, high calcium levels, pressure on the spine (spinal cord compression) or nerve problems.
• A reduced number of normal blood cells, which may lead to anaemia, tiredness and infections
• Abnormal proteins (Paraproteins) in the blood or urine, which can cause kidney problems, hyperviscosity or blood clots.

Other symptoms may include a poor appetite, or changes in bowel habits.

A secondary cancer may be noticed following a known primary cancer somewhere else in the body. However, occasionally, a secondary bone cancer is found before the primary cancer is diagnosed. At other times, the primary cancer may not be found, and such a secondary cancer is called a cancer of unknown primary.

Cancer cells migrating from primary site in to bloodstream

• WHAT ARE MUSCULOSKELETAL SOFT TISSUE SARCOMAS?

Soft tissue sarcomas are cancers that develop from cells in the soft, connective tissues of the body. They can occur in soft tissues such as fat, muscle, nerves, fibrous tissues, blood vessels or in any of the other tissues that support, surround and protect the organs of the body.

Soft tissue sarcomas can develop in any part of the body, but most of them develop in the arms and legs.

There are many different types, named after the type of cell it started from, rather than the part of the body where it started to grow. Knowing the type helps decide on the best treatment.

Some types of soft tissue sarcoma include:

• Fat tissue tumours (e.g. Liposarcoma – develops from the fat cells found all over the body. It can occur anywhere throughout the body but most commonly on the limbs of adult males aged between 52 and 56 years.)
• Muscle tissue tumours (e.g. Rhabdomyosarcoma – develops in the skeletal or voluntary muscles of the body – the muscles we can control ourselves. It is most commonly found in the head and neck but it also occurs in the abdomen. This is a rare type of sarcoma that affects more children than adults.)
• Peripheral nerve tumours (Malignant peripheral nerve sheath tumour – also known as neurofibrosarcomas, develop in the cells that cover nerves. They can occur anywhere throughout the body, mainly in adults, with the sciatic nerve most commonly affected.)
• Fibrous tissue tumours (e.g. Fibroblastic sarcoma develops in the fibrous tissues within the body. It is may be found in the limbs of middle-aged and older adults.)
• Blood and lymph vessel tumours (Angiosarcoma – May occur at any age but seen mostly in adults in their 70’s. Commonly found in subcutaneous tissue, but deep angiosarcomas occur mainly in the thigh).

Others include:

• Soft tissue Ewing’s sarcoma – Ewing’s sarcoma usually affects the bone; however, this type develops in the soft tissue around the bone. It is sometimes called extra osseoussarcoma – extra means outside, osseous means bone. They may occur in the limbs.
• Synovial sarcoma – develops in cells around joints and tendons. Synovial sarcoma can occur anywhere throughout the body but often near the knee. Synovial sarcoma is most commonly associated with young adults.

CAUSES OF TUMOURS IN THE BONE

We (doctors) don’t know exactly what causes many tumours or cancers (including primary bone tumours), and research to find these out is being carried out all the time. But there are several things that can increase a person’s chance of getting cancer. These include: some external factors such as chemicals (including previous chemotherapy with certain drugs), exposure to ionizing radiation (including previous radiotherapy), viruses and bacteria, exogenous hormones, alcohol, tobacco, environmental pollutants, poor diet and lack of exercise; And some internal factors such as age related changes that happen when bones are growing (as many bone cancers occur in teenagers and young people), family history of certain cancers (thought to indicate likely inheritance of faulty genes), certain non-cancerous bone conditions (e.g. Paget’s disease, etc.), endogenous hormones, etc. Although an injury to bone has not been shown to cause cancers, attention is drawn to most already existing bone tumours by injuries.

In the case of secondary cancer in the bone, the cause is always a primary cancer somewhere else in the body.

SYMPTOMS OF BONE TUMOURS

Some changes might be noticed in the body when a bone tumour develops, so it’s important to know what to look out for, as the earlier a tumour is diagnosed the better the chances of successful treatment. Some of these changes that necessitate seeing a bone specialist (orthopaedic surgeon) include:

Pain or tenderness in the area of the tumour: This may start as an ache that doesn’t go away. It may be made worse by exercise or feel worse at night. Anyone with bone pain that lasts longer than a few weeks with no obvious cause should be referred to a bone specialist (orthopaedic surgeon).

Swelling around the affected area of bone: Swelling may be seen or felt at an earlier stage in bones close to the surface than in bones deep within the body tissues; in which the swelling may not show up until the tumour is quite large.

Reduced movement: The movement of joints close to a cancer or the whole limb may become difficult. Limping may be caused by a tumour in the leg; and weakness or numbness and tingling in the limbs may be caused by a tumour in the spine, pressing on nerves.

Broken bone: Cancer may weaken bones sufficiently to break spontaneously or after minor falls, causing pathological fractures.

General symptoms: General symptoms such as tiredness, a high temperature or sweats and weight loss (which can be caused by other conditions) are uncommon, but sometimes occur in people with Ewing’s sarcoma.

DIAGNOSIS

This is aimed at answering the questions:

• Is there a bone tumour?
• If yes, what type of tumour is it?

On presentation to a Bone specialist (Orthopaedic Surgeon), He/She will first listen to your description of your complaints, then ask specific questions to find out if you are likely to have a bone tumour and what type of tumour it likely is.

A person’s age is particularly important, as some tumours are found more in certain age groups. In Nigeria, half of primary bone tumours are found in persons under 30years. On the other hand, secondary bone tumours are more common in persons over 70 years.

The Bone specialist (Orthopaedic Surgeon) will then examine you (looking at and feeling any lumps), and arrange for some tests if a bone tumour is suspected.

Tests may include:

• Blood tests – These include tests to exclude:
  • infection (full blood count and erythrocyte sedimentation rate, C- reactive protein)
  • metabolic bone disorders like hyperthyroidism (Serum calcium and alkaline phosphatise)
  • anaemia (packed cell volume)
  • multiple myeloma (serum electrophoresis)
  • Prostate cancer (prostate specific antigen)
• Bone x-rays– use x-radiation to take images of dense tissues inside the body. They will show the part of the bone affected; the number of lumps (tumours); margins of the tumour; presence of bony reaction or destruction; nature and extent of surrounding tissue involvement.
• MRI scans– use magnetism to produce a detailed picture of the affected area, which would demonstrate tumour spread locally if present.
• Bone biopsy– a sample of bone is always needed to definitively diagnose bone cancer. There are several types of bone biopsies: core needle biopsy, fine needle aspiration cytology and open surgical biopsy. The samples are then sent to a pathologist who will examine them under a microscope and will be able to confirm the diagnosis (type of tumour).

If a diagnosis of a bone cancer is made, your Bone specialist (Orthopaedic Surgeon) may ask you to have some more tests. These will help find out more about the cancer, and show whether the cancer has spread outside the bone. This helps doctors decide on the most appropriate treatment. Possible tests include:

• CT scan– this takes a series of x-rays to create a three-dimensional image of the affected part of the body.
• Bone scan– this will show all the bones in the body as well as any abnormal areas. An injection of radioactive chemicals (called radionuclides) will make any affected area shine on the scan.
• Bone marrow sample– During this test, a sample of bone marrow will be collected from the hip bone, after making the area numb or making the person sleep.
• PET – this measures the activity of cells in a specific area. May be combined with CT.
• Chest x-ray– to see if the cancer has spread to the lungs.
• Abdominal Ultrasound scan – Uses sound waves to create images from within the body, to see if the cancer has spread to abdominal organs (e.g. the liver).
• Kidney function tests may also be run, if chemotherapy is to be considered.

TREATMENT OPTIONS

For every normal person, being told one has cancer is a huge shock, that may cause anxiety and uncertainty about what will happen next.

Nonetheless, your doctor will explain the type of cancer you have, what tests you need to do, and the different treatment options available and their possible side effects.

Treatment options available include surgery, chemotherapy and radiotherapy. And most people will need a combination of different treatments.

Surgery is usually the main treatment for bone cancers in a lot of cases. It involves an operation to remove all of the cancer from the bone along with an area of normal tissue around it too; known as taking a margin. It allows any cancer cells that are not visible to the naked eye to be removed along with the tumour which can reduce the risk of the cancer coming back.

It is sometimes possible to spare/preserve a limb with bone cancer. Custom-made metal fitting implants (endoprosthesis), or bone from another part of the body (bone graft) can be used to replace the affected part of the bone that is removed, when necessary. At other times, the surgeons need to remove (amputate) a whole limb, to make sure the cancer has been completely removed.

The type of surgery you have will depend on a number of factors that will be discussed with the patient by the Bone specialist (Orthopaedic surgeon).

• Chemotherapyinvolves giving anti-cancer (cytotoxic) drugs to destroy the cancer cells. People with certain tumours, such as Ewing’s sarcoma, osteosarcomas and spindle cell sarcomas, will benefit from chemotherapy. Chemotherapy can be given before surgery (called neoadjuvant chemotherapy), to make a tumour smaller and easier to remove. It can also be given after surgery (called adjuvant chemotherapy), to destroy any remaining cancer cells. There are many different chemotherapy drugs, which are commonly given as injections into a large vein or as tablets or capsules, depending on the type of cancer.

Radiotherapy treats cancer by using high-energy rays that destroy the cancer cells while doing as little harm as possible to normal cells.

Radiotherapy works well for certain cancers (like Ewing’s sarcoma), but not so well with some others (like osteosarcoma, spindle cell sarcoma or chondrosarcoma). It is often given together with chemotherapy and/or surgery. If it’s not possible to have surgery to remove the tumour, radiotherapy may be used as the main treatment.

Other treatment options, mainly in secondary cancers include:

Hormonal therapies; these reduce the level of hormones in the body or block the hormones from reaching cancer cells. This can stop the cancer growing.

Targeted therapies; these destroy cancer cells, usually by interfering with the cancer’s ability to grow or survive.

Most commonly, these treatments are combined.

WHO TREATS BONE TUMOURS

Care is provided by a multidisciplinary team involving: Orthopaedic surgeons, Radiologist, Histopathologist/Cytologist, Medical Oncologist/Radiotherapist, Prosthetic designers, Rehabilitation specialists, Medical Social Workers.

TREATMENT OUTCOMES

For many people with early-stage bone cancer, it will never come back after appropriate treatment. However, some cancers can reappear in the same area after the treatment of a previous tumour; this is called a recurrence.

If the cancer comes back, it is important to get treated as quickly as possible. This could involve further surgery, radiotherapy and/or chemotherapy, based of the type of cancer.

If it isn’t possible to completely remove the cancer, chemotherapy and radiotherapy may be given to control the cancer and to help relieve any symptoms for as long as possible.

It is important to check for recurrences yourself through self-examination, and to see your doctor periodically for follow up.