Orthopedic oncology is a sub-specialty in orthopedics and orthopedic oncologists specialize in diagnosing and treating different tumors of bones, soft tissues and nerves of the musculoskeletal system. Tumors are abnormal tissue masses formed by uncontrolled multiplication of cells or impaired normal cell death process.
Types of tumors
Tumors can be classified as benign and malignant based on the ability to spread to distant tissues, and primary and secondary on the basis of site of origin. A benign tumor is a non-cancerous growth that does not intrude nearby tissues or spread to other parts of the body. A malignant tumor is cancerous, destroying nearby tissues and spread to other parts of the body.
Primary tumors develop in muscles and bone whereas secondary tumors have their site of origin in other organs of the body.
Benign bone tumors
Benign bone tumors are more common in people below 30 years of age. They can develop in any bone, but most commonly the femur, tibia, humerus and pelvis bones are involved. A lump or swelling that can be felt by touch is usually the first sign of a benign tumor. A benign mass causes pain that persists for a longer duration. In some cases, the tumor remains undiscovered until it weakens the bone and causes fracture. Various benign tumors affecting the bones include:
- Enchondroma: Enchondroma is a benign bone tumor developing around the bone and affects people of all ages but is more common in people between the ages of 10 to 40 years old. It arises inside the bone. Patients remain symptom free in the initial days and as the tumor enlarges in size, causes severe pain.
- Osteochondroma: Osteochondroma, the most common type of benign bone tumor, may develop in any bone but commonly occurs at the ends of the long bones. This tumor is commonly seen in people between the ages of 10 to 20 years old.
- Chondroblastoma: Chondroblastoma is a rare tumor and is common in people of between the ages of 10 to 20 years old. It develops at the epiphyseal region of the bone and spreads across the bone destroying the entire bone and joint.
- Osteoid osteoma: Osteoid osteoma is more common in long bones. It is often seen in young people between the ages of 10 to 35 years old. It causes pain which worsens in night. If it occurs in children of growing age, the inflammatory response and increased circulation of blood near the open growth plates may result in overgrowth and limb length discrepancy.
- Giant cell tumors: Giant cell tumors commonly occur in the second or third decade of life and arise in the epiphysis gradually eroding away the remaining bone to extend into the soft tissues. They have a tendency to recur.
Malignant bone tumors are rare compared to benign tumors but are very dangerous as they spread from the site of origin. The tumor cells enter the blood stream or travel through lymph vessels and spread to other sites. Lungs are the most common site where malignant tumors spread.
- Osteosarcoma: Osteosarcoma is the most common bone cancer and commonly affects people between the ages of 10 to 30 years old. It often develops in the arm and leg bones, and pelvis. It metastasizes to the lungs and other bones.
- Chondrosarcoma: Chondrosarcoma is the second most common type of malignant bone tumor. It involves the cartilage cells and is commonly seen in older adults. It is rare in people below 20 year of age and in the elderly above 75 years of age. It affects the arm bones, legs, pelvis and the ribs. Usually, this cancer arises in the normal cartilage, but may also form within a benign cartilage tumor called osteochondroma.
- Ewing’s sarcoma: Ewing’s sarcoma develops in the bone cavity, often in the mid portion of the long bones of the legs and arms. This type is common in childhood and is very rarely seen in adults over 30 years of age. The most common symptoms include pain and swelling.
Secondary or metastatic bone tumors may develop from the spread of carcinoma of the breast, lung, prostate, kidney, thyroid and colon. Breast cancer is the most common cancer that has a tendency to metastasize to the bone.
Benign muscle tumors consist of two types called leiomyomas and rhabdomyomas. Leiomyomas arise in the smooth muscles and develop in the walls of blood vessels. Most commonly, they are found in the uterine wall and are called fibroids. Rhabdomyomas are benign tumors of the skeletal muscles and are rare.
Malignant muscle tumors include leiomyosarcomas and rhabdomyosarcomas. Leiomyosarcomas are malignancies arising in the smooth muscles and often occur in internal organs, blood vessels and at the back of the abdominal cavity. They typically occur in elderly adults.Rhabdomyosarcoma cancers comprise cells that would normally develop into skeletal muscles. This tumor commonly affects children rather than adults. The arms, legs, head and neck region, urinary and reproductive organs such as vagina, bladder and prostate gland are the common sites of occurrence.
The two main subtypes of rhabdomyosarcomas include embryonic rhabdomyosarcomas and alveolar rhabdomyosarcomas. Embryonal rhabdomyosarcoma affects infants and young children. It occurs in the head and neck region, bladder, vagina or prostate. Alveolar rhabdomyosarcoma affects teenagers and older children. Often, large muscles of the arms, legs and abdomen are affected.
Treatment options depend on the type, stage and extent of spread of cancer and other general health factors. Treatment options include surgery, radiation therapy, and chemotherapy. Chemotherapy is the use of drugs to destroy the cancer cells. It is used before surgery to kill the tumor cells and shrink the tumor. It is also used after surgery to kill the remaining cancer cells and prevent recurrence. Radiation therapy destroys the tumor by exposing the cancerous region to cells using high-energy radiations. Surgical treatment involves removing the cancerous tissue and different techniques can include amputation or limb-salvage surgery. Limb-sparing surgery removes the bone and the affected muscle. The bone that is removed is replaced by filling the gap with a bone graft (normally bone taken from a bone bank) or a specially designed metal prosthesis. Amputation, removal of a part or whole of the affected limb, may also be needed if the cancer has spread from the bone into the surrounding blood vessels. In some cases, surgical resection can be combined with chemotherapy or radiation therapy.
Adverse effects of cancer therapy
Chemotherapy causes various adverse effects,the most common effects include nausea, hair loss, mouth sores and fever. Oncologists prescribe appropriate medication to counteract the adverse effects.
Common side effects of radiation therapy include skin problems, muscle scarring, injury to surrounding organs, delayed wound healing, reduction in bone growth, risk of developing a new cancer, and chronic swelling. The risks and complications associated with the surgery include infection at the site of surgery; complications related to prosthesis and wound healing.
After surgery, patients should limit the amount of weight imparted on the reconstructed limb. Rehabilitation, including physical therapy, provides strength to muscles and increases the range of motion. Avoid strenuous or athletic activities that impart more stress on the reconstructed limb.