Physiotherapy in the management of osteosarcoma
Osteosarcoma is a cancerous tumor in a bone. Specifically, an aggressive malignant neoplasm that arises from primitive transformed cells of mesenchymal origin (and thus a sarcoma) and that exhibits osteoblastic differentiation and produces malignant osteoid. It is the most common histological form of primary bone cancer. It is most prevalent in children and young adults.
Osteosarcoma is a deadly form of musculoskeletal cancer that most commonly causes patients to die of pulmonary metastatic disease. Most osteosarcomas arise as solitary lesions within the fastest growing areas of the long bones of children. Teenagers are the most commonly affected age group, but osteosarcoma can develop at any age. In children and young adults, osteosarcoma usually starts in areas where the bone is growing quickly, such as near the ends of the leg or arm bones:
• Most tumors develop in the bones around the knee, either in the distal femur (the lower part of the thigh bone) or the proximal tibia (the upper part of the shinbone).
• The upper arm bone close to the shoulder (proximal humerus) is the next most common site.
However, osteosarcoma can develop in any bone, including the bones of the pelvis (hips), shoulder, and jaw. This is especially true in older adults.
Causes and risk factors
Several research groups are investigating cancer stem cells and their potential to cause tumors. Radiotherapy for unrelated conditions may be a rare cause.
Familial cases where the deletion of chromosome inactivates the retinoblastoma gene is associated with a high risk of osteosarcoma development.
Bone dysplasias, including Paget’s disease, fibrous dysplasia, enchondromatosis, and hereditary multiple exostoses, increase the risk of osteosarcoma.
Li–Fraumeni syndrome (germline TP53 mutation) is a predisposing factor for osteosarcoma development.
Rothmund–Thomson syndrome (i.e. autosomal recessive association of congenital bone defects, hair and skin dysplasias, hypogonadism, and cataracts) is associated with increased risk of this disease.
Signs and symptoms
Many patients first complain of pain that may be worse at night, and may have been occurring for some time. Also, teenagers who are active in sports tend to complain about pain in their lower femur, right below the knee or shoulder region.
If the tumor is large, it can appear as a swelling. Sometimes a sudden fracture of bone is the first symptom because affected bone is not as strong as normal bones and may fracture with minor trauma (a pathological fracture). According to Bone Cancer Research Trust, the pain may come and go and vary in intensity. The swelling will not be visible if it is not near body surface.
Family physicians and orthopedists rarely see a malignant bone tumor (most bone tumors are benign). The route to osteosarcoma diagnosis usually begins with an X-ray, continues with a combination of scans (CT scan, PET scan, bone scan, MRI) and ends with a surgical biopsy.
A characteristic often seen in an X-ray is Codman’s triangle, which is basically a subperiosteal lesion formed when the periosteum is raised due to the tumor. Films are suggestive, but bone biopsy is the only definitive method to determine whether a tumor is malignant or benign.
A complete radical, surgical, resection of the cancer, is the treatment of choice in osteosarcoma. Although about 90% of patients are able to have limb-salvage surgery, complications, particularly infection, prosthetic loosening and non-union, or local tumor recurrence may cause the need for further surgery or amputation. Mifamurtide is used after a patient has had surgery to remove the tumor and together with chemotherapy to kill remaining cancer cells to reduce the risk of cancer recurrence.
Patients with osteosarcoma are best managed by a medical oncologist and an orthopedic oncologist experienced in managing sarcomas.
Osteosarcoma should be treated at large medical centers where a multi-disciplinary team including physiotherapists, occupational therapists, pediatricians, surgeons, psychologists and nursing staff will help manage the patient care. In an oncology setting, physiotherapists manage the patient’s musculoskeletal, neuromuscular, integumentary and cardiopulmonary rehabilitation needs.
Physiotherapy interventions will consist of early postsurgical mobility training, strength and endurance restoration, pain control, and education and training of family members in helping patients with limited mobility. Physiotherapists will help to correct balance and coordination impairments, make recommendations for home modifications that will enhance the patient’s independence, and educate and train the family members to assist and enable the patient to function independently. In addition, physiotherapists will train the patient in stump management and training with the prostheses for those patients who undergo amputation.
Rehabilitation following limb sparing procedures or amputations focuses on retraining muscles, increasing strength and endurance, balance and range of motion as well as helping the patient return to school or work activities.
It is of vital importance for the physiotherapist to educate the patient and the adolescent’s family in appropriate strength training protocols and precautions of overuse post discharge with a limb-sparing procedure. It is also not uncommon to have a total knee replacement if the tumor is located near the distal femur and proximal tibia. These patients are frequently young adolescent eager to return to full activities and may place their salvaged limbs at risk if they proceed too aggressively at discharge.
For further information and enquiry, contact PCA