Osteosarcoma is a malignant tumor originating from bone tissue. It is characterized by a tendency to rapid flow and early metastasis. In the initial stages, it is manifested by local pain, similar to the pain of rheumatism. In the future, there is swelling, restriction of movements in the nearby joint. The pains become sharp, unbearable. Metastases occur. Pathology is diagnosed on the basis of anamnesis, examination results, radiography, CT, MRI and other studies. Treatment includes surgery to remove the tumor in combination with preoperative and postoperative chemotherapy.
ICD 10
C40 C41
Meaning
Osteosarcoma (from Lat. osteon bone, Greek. sarkos meat, flesh + oma tumor) is a malignant neoplasm arising from bone elements. This tumor is characterized by earlier metastasis and rapid course. Previously, the prognosis for this disease was very unfavorable. Five-year survival was observed in less than 10% of cases. Currently, due to the emergence of new methods of treatment, the chances of patients have increased significantly. Today, more than 70% of patients with localized osteosarcoma and 80-90% with a tumor sensitive to chemotherapy survive 5 years after diagnosis.
According to experts in the field of clinical oncology, osteosarcoma is more often observed in young patients. More than two thirds of all cases of the disease occur at the age of 10-40 years. At the same time, men suffer twice as often as women. The peak of morbidity occurs during a period of rapid growth: 10-14 years for girls and 15-19 years for boys. After 50 years, such a tumor is extremely rare.
Osteosarcoma causes
The causes of the disease have not yet been clarified. However, there are a number of circumstances in which the risk of its occurrence increases. These include radiation therapy and chemotherapy previously performed for another oncological disease. By itself, the injury (bruise or fracture) does not affect the likelihood of a tumor. Nevertheless, in some cases, it is a rather serious traumatic injury (pathological fracture) or unusual pain in the affected area that persists for a long time after a bruise that causes treatment to a traumatologist and subsequent detection of osteosarcoma. In some cases, osteosarcoma develops against the background of chronic osteomyelitis. The risk of tumor formation also increases with Paget’s disease (deforming osteitis).
Pathanatomy
Usually the disease affects long tubular bones. The proportion of short and flat bones is no more than 20% of the total number of all osteosarcomas. The lower extremities are affected 5-6 times more often than the upper ones. At the same time, about 80% of the total number of osteogenic sarcomas develops in the area of the distal end of the femur. Then, in descending order of frequency, the tibia, humerus, pelvic and fibula bones are located. Then – the bones of the shoulder girdle and the ulna. The bones of the skull are rarely affected, mainly in children or the elderly.
A typical localization of osteosarcoma is the metaphysis region (the part of the bone located between the articular end and the diaphysis). Nevertheless, about 10% of the total number of osteosarcomas of the hip are found in its diaphyseal part, while the metaphysus remains intact. In addition, osteosarcoma has “favorite” locations in each individual bone. Thus, the distal end is usually affected at the hip, the inner condyle at the tibia, and the area where the roughness of the deltoid muscle is located at the humerus.
Classification
When making a diagnosis of osteosarcoma, staging is carried out – an assessment of the prevalence of the process. Taking into account the prevalence , all osteosarcomas are divided into two large groups:
- Localized sarcomas. There are tumor cells only in the place of its initial localization or surrounding tissues.
- Metastatic sarcomas. Metastatic lesion of other organs is detected.
It is assumed that 80% of patients have micrometastases that are so small that they are not detected during additional studies. In addition, multifocal sarcoma is isolated, in which tumors occur simultaneously in several (two or more) bones.
Osteosarcoma, like other malignant tumors, in some cases returns after treatment. A new tumor can occur both at the location of the previous one and in another part of the body (in the area of metastases). This condition is called a relapse. Relapse in osteosarcoma most often develops 2-3 years after treatment and is found in the lungs. In the future, relapses are also possible, but the probability of their development decreases.
Osteosarcoma symptoms
The disease begins gradually, gradually. At first, the patient is concerned about dull vague pains that occur near the joint. By their nature, they may resemble pain syndrome in rheumatic myalgia, arthralgia, myositis or periarthritis. At the same time, there is no effusion (fluid) in the joint. The tumor is gradually growing, nearby tissues are involved in the process, and the pain increases. The affected part of the bone increases in volume, the soft tissues above it become swollen, phlebectasia occurs on the skin (a network of small dilated veins). Contracture is formed in a nearby joint. When osteosarcoma is localized on the bones of the lower limb, lameness develops. Palpation of the affected area is sharply painful.
After a while, the pain becomes unbearable, sleep-deprived. They appear both under load and at rest and are not removed by conventional analgesics. Osteosarcoma continues to grow rapidly, spreading to neighboring tissues, sprouting muscles and filling the bone marrow canal. Tumor cells spread with the blood flow, “settling” in various organs and forming metastases. In this case, the brain and lungs are most often affected.
Diagnostics
The diagnosis of osteosarcoma is made on the basis of clinical data, the results of instrumental and laboratory studies. The oncologist asks the patient, paying attention to the gradual onset and unclear pain near the joint, as well as to the intensification of these pains over time. Swelling in the affected area at the initial stages is determined in only 25% of patients. Phlebectasia occurs in the late stages and is also not observed in all patients. Therefore, the absence of these symptoms cannot be a reason to exclude a malignant neoplasm.
The final diagnosis is established based on the results of additional studies: radiography, bone scanning and biopsy of tissue taken from the affected area. To detect metastases in other organs, computed tomography and radiography are performed.
In the initial stage, osteoporosis and blurred contours of the tumor are determined on radiographs. Subsequently, a bone tissue defect is detected. Often there is a characteristic pattern of detachment of the periosteum with the formation of a “visor”. In children, needle periostitis is often found – thin bone formations (spicules) located perpendicular to the bone. On an X-ray image, such formations create a typical picture of “sun rays”.
When examining the biopsy, sarocomatous connective tissue cells are detected, some of which form osteoid and atypical bone cells. Serious violations of the bone structure are detected. In many cases, osteogenesis (bone formation) is poorly expressed and is observed only on the periphery of osteosarcoma. Osteosarcoma is differentiated with osteoblastoclastoma, cartilaginous exostoses, eosinophilic granuloma and chondrosarcoma.
Osteosarcoma treatment
The treatment tactics are chosen taking into account the location of the osteosarcoma, the stage of the disease, the age of the patient, his general condition, the presence of relapses, etc. Treatment of osteosarcoma is carried out in the oncology department and includes three stages:
- Preoperative chemotherapy to reduce the primary tumor and suppress small metastases. Ifosfamide, methotrexate, etoposide, as well as platinum preparations (cisplatin, carboplatin) are used.
- Surgical treatment to remove the tumor. In the past, amputations and exarticulations were performed for osteosarcomas. Currently, in most cases, a gentle organ–preserving operation is performed – segmental resection of the affected area with its replacement with an implant made of metal, plastic, the patient’s own bone or cadaver bone. Amputation is necessary only with a large osteosarcoma, a pathological fracture, germination of soft tissues or a neurovascular bundle. Surgically, not only the primary tumor can be removed, but also large metastases in the lungs. If the lymph nodes are affected, their surgical removal (lymphadenectomy) is also performed.
- Postoperative chemotherapy for the final suppression of malignant cells that could remain in the area of metastases or the location of the primary tumor.
Radiation therapy for osteosarcoma is ineffective and is carried out only if there are absolute contraindications to surgery.
Prognosis and prevention
The prognosis for osteosarcoma depends on certain factors both before and after treatment. Factors affecting the prognosis before the start of osteosarcoma treatment:
- The size and location of the tumor.
- The stage of osteosarcoma (localized tumor, the presence of metastases in other organs).
- Age and general health of the patient.
After treatment, the prognosis is determined by the effectiveness of chemotherapy and the result of surgery. A more optimistic prognosis is with a significant decrease in metastases and primary focus after chemotherapy, as well as with complete removal of the tumor.
In the past, osteosarcoma was one of the malignant tumors with the most unfavorable prognosis. Even though severe crippling operations were performed during treatment – amputations and exarticulations of limbs, the five-year survival rate did not exceed 5-10%. Currently, due to the emergence of new methods of treatment and the use of effective organ-preserving operations, the chances of patients for a successful outcome have significantly increased even in the presence of lung metastases. The five–year survival rate for localized osteosarcoma today is more than 70%, and in the group with osteogenic sarcomas sensitive to chemotherapy, this figure is even higher – 80-90%.