What are Bones?

The human body is made up of over 200 bones of different shapes and sizes, and categorized into “long bones” and “flat bones.” While we tend to think of bones as dry and brittle, they actually have living cells called osteocytes that are bound together by a hard, calcium-like material that makes bones strong and rigid. These living cells are constantly rebuilding the bone. Osteoclasts are the cells that dissolve the bone, and osteoblasts form the new bone.

Periosteum is the name of the layer of fibrous tissue that covers the outside of bones. Their insides are hollow and filled with a spongy material called bone marrow. Bone marrow produces the body’s blood cells.

In addition to making blood, bones support body structure, store essential minerals like calcium, and work together with muscles to facilitate movement. Flat bones protect organs in the body; for example, the ribcage protects the heart and lungs, and the skull gives protection to the brain. As a group, the bones of the body are known as the skeleton.

The majority of bones are long bones, tubular in structure with yellow marrow filling the middle. The round portions found at the end of long bones are called epiphysis, and are composed of red marrow and a spongy material known as cancellous. Muscles that move the arms and legs are attached to these bones.

A tough, flexible material called cartilage covers the joints of the bones. Its flexibility allows free movement at the joints and provides a cushion to prevent the bones from rubbing against each other.

What is Cancer?

Cancer consists of over 100 diseases characterized by abnormal blood cells. The basic process for cell regeneration is immature blood cells develop into mature blood cells, divide, and die off after their appointed number of days. As long as this process runs smoothly, there is a clean bill of health.

Cancer arises when these healthy cells mutate and reproduce in a disorderly manner. As they reproduce and spread, their abnormalities are passed on to the generation that sprouts from them and the abnormal cells will crowd out the healthy ones by living longer than they should. Often the abnormal cells do not mature, therefore the function they should be providing does not take place. For instance, without the proper number of mature white blood cells (WHCs) the immune system is unable to perform properly and the person becomes susceptible to infection and illness.

When the mutated cells begin reproducing rapidly and without any order, they form too much tissue. The extra tissue builds up and forms what is known as a tumor. A tumor in itself does not constitute cancer as they can be benign (non-cancerous) as well as malignant (cancerous).

Benign tumors are rarely a threat to life and do not spread to other parts of the body. Benign tumors that come from bone cells are called osteomas. Malignant tumors can invade nearby healthy organs as well as travel through the body via the bloodstream and locate another place to grow. This spreading out is called metastasis.

Bone Cancer

Cancers that begin in the bone are rather rare, but it is not uncommon for cancer to start somewhere else and metastasize to the bone. This is known as secondary (or metastatic) bone cancer, but will be labeled and treated as the cancer type of its origin.

Cancer that starts off in the bone is known as primary bone cancer. Bone cancer can begin in any bone, but is found most often in arms and legs. The most common types of primary bone cancer are chondrosarcomas, osteosarcomas, and the Ewing’s family of tumors.

Chondrosarcoma

Chondrosarcoma begins in the cartilage cells on the surface of a bone or with it. The most common tumor sites are the pelvic bones, shoulder blades, and the upper part of the arms and legs. It can occur at any age but seems to favor middle-aged adults. It is found a little more often in males than females.

Osteosarcoma

Osteosarcoma is also called osteogenic sarcoma is the most common primary bone cancer. This cancer tends to show up in young adults (but can occur at any age), and like chondrosarcoma, it appears slightly more often in males than females. Osteosarcoma develops most commonly at the end of long bones. About 80% of the osteosarcomas are found in the bones around and near the knee, but can develop in any bone.

Ewing’s family of tumors

This cancer family is named after Dr. James Ewing, the doctor who discovered the first of them in 1921. This bone cancer, called Ewing tumor, is more common in young people than adults and was different from its predecessors in that it could be treated with radiation therapy. In the beginning, this tumor was seen only inside bones, but was later found in the soft tissues outside the bone. Those are called extraosseous (outside the bone) Ewing (EOE).

Primitive neuroectodermal tumor (PNET) is another child hood cancer that shares similar features with the Ewing tumor. They have similar proteins rarely found in other cancers and same DNA abnormalities, and are believed to develop from the same type of cells in the body.

These 3 cancers are considered the Ewing family of tumors (EFT). These tumors occur most often in the early teen years, but can occur at any age. About 50% of Ewing family tumors begin in the middle of the long bones of the legs; the next common sites are the spine, ribs, and pelvis.

Symptoms

Pain is the most frequent reported symptom of bone cancer. In the beginning, the pain is periodical or only there when the bone is in use. As the cancer grows, the pain appears more often, until at last it is constant. Sometimes bone cancer will cause bones to fracture or break

Swelling may or may not occur, and depending on the location of the tumor, a firm, slightly tender lump or mass might be felt through the skin.

If the cancer has spread to other areas, there may be symptoms common to all types of cancer such as loss of appetite or fatigue.

None of these symptoms are specific to bone cancer and can be caused by any number of other conditions and/or illnesses. It is important to let the doctor make the diagnosis, not you.

Diagnosis

To make a diagnosis, the doctor will perform blood tests and any or all of the following procedures:

• Bone Scan—A radioactive material is injected into the blood stream and collects in the bones. It is then detected by an instrument called a scanner which outlines abnormal areas of the bone, bringing out the size, shape and location of tumors. Malignant tumors tend to be odd shapes with jagged edges, as opposed to the smooth, round appearance of benign tumors.
• CT (CAT scan)—Pictures of cross-sections of the body are taken by an x-ray machine and created by a computer.
• Magnetic Resonance Imaging (MRI)—This procedure also creates detailed pictures of cross-sections of the body, using a strong magnet linked to a computer.
• Chest X-ray—High energy beams are used to take pictures of the chest bones to see if bone cancer has spread to the lungs.
• Angiograms—An x-ray procedure used to get a detailed look at blood vessels. A dye is injected into the bloodstream to highlight the blood vessels.
• Positron Emission Tomography (PET scan)—This scan uses glucose (a sugar) that contains a radioactive atom. Because of their high metabolism rate cancer cells absorb the sugar and then a special camera is used to look for the cancer. It is being combined with CT scans to pinpoint some cancer types.
• Fine Needle Biopsy or Fine Needle Aspiration (FNA)—A very thin needle and syringe are used to withdraw a small amount of tissue and fluid from the mass. Local anesthesia is used on the area.
• Core Needle Biopsy—A small cylinder of tissue about 1/2 inch long and 1/16 inch in diameter is removed from the tumor mass using a slightly larger needle than the FNA.
• Surgical Bone Biopsy—A small part of a tumor mass is removed through the skin. This is usually done with local anesthesia, but for children or large tumors general anesthesia is often used.

A biopsy is necessary for a confirmation of any cancer found with any other method. The sample tissues that are taken from the bone tumor are observed under microscope. If cancer is present, the doctor will be able to determine if it is primary or secondary.

Grading and Staging

The previous test results will also be used in grading and staging the cancer. The grade refers to how aggressive (likely to spread quickly) the cancer appears. Staging refers to the size of the cancerous area and whether or not it has spread out. Grading and staging help the doctors to choose the treatment most appropriate to each individual.

According to the American Cancer Society, the most common system used for staging most, but not all, bone cancer is the TNM system of the American Joint Committee on Cancer.

T stands for tumor, regardless of where it is located on the bone.

N signifies that it has spread to lymph nodes (pockets immune system cells found throughout the body.

M means that it has metastasized.

• T1—The tumor is no bigger than 8cm.
• T2— The tumor is larger than 8 cm.
• T3—The tumor has skipped to other areas in the bone.
• T4—The tumor has directly invaded a surrounding organ.

• N0—The lymph nodes show no sign of cancerous cells.
• N1—Lymph nodes have cancer cells in them (Very rare with bone cancer)

• M0—No bone cancer has spread to other parts of the body.
• M1a—The cancer has spread to the lung.
• M2b—The cancer has spread to sites other than the lung.

An additional factor called the histological grade is used in staging bone cancer. While there technically 4 grades, it is common in the medical field for doctors to refer to just 2—high grade and low grade.

• G1—low grade, well differentiated (cells appear the least aggressive)
• G2—low grade, moderately differentiated (intermediate between G1 and G3)
• G3—high grade, poorly differentiated (cells appear more aggressive)
• G4—high grade, not differentiated (cells appear extremely aggressive)

A stage is assigned based on the all the information about the tumor and its behavior. This process is called stage grouping and the stages are as follow:

• Stage IA (G1, 2; T1; N0; M0): The cancer is low grade, smaller than 8 cm, and has not spread.
• Stage IB (G1, 2; T2; N0; M0): The cancer is low grade, larger than 8 cm, and has not spread.
• Stage IIA (G3, 4; T1; N0; M0): This high grade cancer is smaller than 8 cm and has not spread.
• Stage IIB (G3, 4; T2; N0, M0): This high grade cancer is larger than 8 cm and has not spread.
• Stage III (Any G, T3; N0; M0): This any-grade tumor has spread within the bone, but not out.
• Stage IVA (Any G, Any T; N0; M1a): The cancer has spread to only the lungs.
• Stage IVB (Any G; Any T; N1; Any M) or (Any G; Any T; Any N; M1b): The cancer has spread to lymph nodes and/or sites other than the lungs.

Bone cancer that returns after an initial treatment is called recurrent bone cancer.

Survival Rates

Staging helps the doctors select the treatment with the best prognosis (most likely outcome). Five-year survival rates are used as a standard for “survival” of cancer. Many, many people live longer than five years, and a 5-year survival is not a guarantee that there will be no recurrent cancer.

The following numbers are a generalization of all types of Primary bone cancer combined. Also consider that these survival rates are based survivors, people who received their treatments anywhere from 5-20 years ago and have lived to tell the tale. Modern medicine continues to improve treatments, which increases the chances of survival as well as extends the length of it.

Stage of Bone Cancer / Survival Rate (5+ years)

• Stage IA----------88%
• Stage IB----------71%
• Stage IIA---------70%
• Stage IIB---------57%
• Stage III----------Unavailable
• Stage IVA--------49%
• Stage IVB--------19%

(Statistics from the American Cancer Society at www.cancer.org)

Treatments

Primary bone cancer is treated with one or more of the following: surgery, radiation, and chemotherapy. The doctor must consider a number of factors when creating a treatment plan for an individual, included the patient’s age and general health, and the location, type, and size of the tumor. While all treatments are composed of the same treatments, doses and methods will vary with different people.

Secondary bone cancer is treated according to what type of cancer it has originated from, prior treatment, and other factors. For many cases of secondary bone cancer there may be no cure and treatment may be focused on pain relief and quality of life issues. The physician will assist the patient in choosing what is right for that individual.

Nearly all bone cancer treatment plans require surgery (an operation to remove a tumor by cutting it out). The tumor is removed, along with several centimeters of tissue surrounding it. Sometimes the surgery is followed up with radiation and/or chemotherapy. At other times radiation and/or chemotherapy are used before the operation to shrink the tumor.

Chemotherapy is a series of anti-cancer drugs that can be taken through the mouth, through the vein, through subcutaneous (through the skin) injection, and directly through the spine. Chemotherapy combined with surgery is very often used to treat bone cancer.

Chemotherapy is taken as an inpatient or outpatient at the hospital, a clinic, the doctor’s office, or even at home. It all depends on the drugs being given and the individual’s reaction to the treatment.

Radiation therapy is the use of high-energy radiation to treat cancer. Radiation destroys the cells’ reproductive abilities and the body gets rid of the damaged cells. External radiation therapy involves a machine directing beams of radiation into the cancerous area. Internal radiation involves placing radioactive material inside the patient, near the tumor.

Radiation is administered in a clinic or hospital on a daily basis. A standard treatment plan includes 5 days a week for 5 to 8 weeks.

In the past, amputation (removal of the cancerous limb) was usually necessary. It is still required sometimes, but there are also alternatives for many people. Often it is possible to remove the cancerous part of the bone and replace it with bone from another part of the body. This is called a bone graft.

Another option is to remove the affected part of the bone and replace it with an endoprosthesis, a specially designed metal fitting. Whole joints can also be replaced with artificial ones. Artificial limbs such as arm, hands, feet, and legs can also be made to replace the natural ones if an amputation is absolutely necessary. An artificial limb is called a prosthesis.

Side Effects

Chemotherapy has a wide range of medications, depending on what is prescribed the patient may experience nausea, vomiting, mouth sores, loss of appetite, compromised immune system, hair loss, and fatigue. These are temporary and will stop after the treatment is complete.

The side effects of chemo will vary from person to person, and even vary from treatment to treatment with the same individual. Medication is available to help with many side effects and attempts are made to keep side effects to a minimum.

Radiation causes fatigue and some people experience skin reactions such as dryness or redness. It is best to keep your skin protected from the sun, but only use lotion or cream if it is recommended by the doctor. Cover your skin with clothing when you must be exposed. Long sleeve shirts, hats, pants, covered shoes, sunglasses, etc.

Surgery is a major stress on the body and requires proper time to heal and watching for infections. In the case of amputations, the side effects will be after-effects in regards to physical therapy and the practical matters of learning how to use the artificial limb, and the psychological effects of the natural one no longer being there. Therapy may be recommended.

Amputees (along with all cancer survivors) are encouraged to meet other patients through self-help and support groups. Many people have found it very encouraging and therapeutic to talk to others who are experiencing the same difficulties, or have faced the same challenges and overcome them.

Any cancer survivor, of any type of cancer, needs a support system when they are done with treatments and trying to integrate back into a “normal” life. Some people are surrounded with family and friends who are willing and able to do what is necessary. Some people aren’t. Those without that framework should speak to the doctors and nurses about that need, they may be able to make suggestions. Also, hospitals and clinics usually have a social worker on site who can suggest national and local groups that may be able to assist with transportation, home care, financial aid, emotional support, rehabilitation, and other unseen matters that might arise.

Prevention

The exact cause of primary bone cancer is still unknown so there are no recommendations on avoiding it. Changes in lifestyle may prevent many types of cancer, helping to avoid secondary bone cancer. The best things to do are live healthy, see your doctor regularly, and report anything unusual to your health care provider.

Yes, I know, nobody wants to be a hypochondriac, but as a leukemia survivor who should have gone to the doctor long before I did, I have decided it is better to be a hypochondriac than a corpse. Good luck and best wishes for a healthy future.