Osteosarcoma is the most common primary bone tumour. It is characterized by the presence of the fusiform cells producing a malignant extracellular osteoid. Both, the malignancy and the ability to create metastasis depend on the histological type. Osteosarcoma is an eighth most common tumour in infants with a peak of incidence between 10 and 14 years. Nevertheless, we should not forget that osteosarcoma is also an adult cancer. In this case it can occur either as an idiopathic or as a secondary disease (e.g. to Paget disease).
Osteosarcoma is often considered an infant tumour. No wonder that it is the most common primary bone tumour in patients between 10-20 years. Osteosarcoma in 75% concerns people below 19 years. It does not occur in children younger than 5 years, then the morbidity increases and the peak is achieved between 10-14 years. It is considered that osteosarcoma can be related to a growth spurt in pubescence. The incidence of the disease in people below 19 years is approximately 5 per 1 million.
Nevertheless, osteosarcoma is also a tumour of the adults and it is the most common primary bone tumour in this age group. We can distinguish two peaks of incidence: the first one in the third decade of life (about 60%), the second one between sixth and seventh decade (20%). Annually among adults the incidence of osteosarcoma is about 1-2 person per million (in Poland about 60-100 cases per year). In the following part of the article the symptoms, diagnosis and treatment of the adult patients with the disease will be presented.
In the research of the adult osteosarcoma patients(365 people), whose average age was 63 years, demographic and environmental impact on the tumour formation were examined. The results show that 49% of patients were women and 80% of all were white. The most common histological subtype of the disease was not classified otherwise osteosarcoma (67%) and chondroblastic osteosarcoma (12%). Osteosarcoma occurs more frequently in the vicinity of the knee (29%) and in the pelvis and sacrum region (17%). In adults, more often than in children, it is located in the pelvic region or in the jaw. Risk factors are: previous occurrence of another cancer (27%), radiotherapy (20%), previous trauma or infection in the osteosarcoma region (20%), as well as Paget’s disease (6%). Another characteristic of the adults osteosarcoma is its occurrence against other diseases: 5-10% in the older age group of all patients. In this case the prognosis is extremely poor (5-year of survival in approximately 8%) and the location is often different than in typical case.
Symptoms of the disease are nonspecific. Due to the fact that osteosarcoma is the most common in the knee region, swelling, pain (escalating at night), and even palpable tumour can occur. At this stage all metabolic diseases, namely benign tumours, fibrous dysplasia and aneurysmal bone cyst, should be excluded. The next step is to make a radiograph of the tumour area. To obtain more accurate results scintigraphy and CT scan can be ordered (sometimes also MRI ). Nevertheless, the “gold standard” still remains an open biopsy of the tumour. Only the histological examination is able to give an exact answer to the question of osteosarcoma type and the kind of treatment that should be applied. Before the initiation of therapy RT of the lungs is also done in order to check if there are any metastases since it is the most common place where they can be found.
In the treatment of osteosarcoma chemotherapy and tumour resection are used. The removal of osteosarcoma itself gives unsatisfactory results (5-year survival rate in approximately 20%). Before surgery preoperative chemotherapy is administered (doxorubicin and cisplatin) in at least three doses every 3 weeks. In adults methotrexate is not applied. At the time of the fourth dose a surgery should be performed.
The next step is a surgical excision. Tumours located axially (e.g. around the spine or in the skull) have worse prognosis because the radical resection is impossible. If the tumour is located peripherally, two types of excision can be done: amputation or limb-salvage surgery. In recent years, owing to improvement of diagnostic techniques and chemotherapy usage (which removes micrometastases), the number of limb-saving surgeries with a prosthesis reconstruction has increased.
After surgical excision, 2-12 courses of chemotherapy with doxorubicin and cisplatin are applied. In case of insufficient clinical response therapy with isofosfamide, etoposide and carboplatin should be started and doxorubicin with cisplatin should not be administered anymore.
Osteosarcoma in Poland can be treated only in specialized centres to which patients should be directed. 5-year survival with the use of proper treatment and fast diagnosis is about 70%. The acceleration of diagnosis and the use of chemotherapy has contributed to the improvement of survival rates in the recent years.
Written by: Magdalena Mroczek
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