Osteosarcoma is the primary form of malignant bone formation. Osteosarcoma is on the sixth place among all malignant pathologies and accounts for almost 70% of all skeletal sarcomas. The tumor originates in bone-forming mesenchyme, which can later pass into bone, cartilaginous or fibrous tissue.
Osteosarcoma is mostly sick in the second decade of life, from the age of ten to twenty years. In addition, among boys this malignant neoplasm occurs much more often than among girls in a proportion ratio of 1.3: 1. After thirty years, osteosarcoma acts as a secondary pathology against the backdrop of such tumor processes as Paget's disease, dyschondroplasia, giant cell tumor, fibrosarcoma.
When diagnosing a disease, an important condition is the formation of malignant bone tissue. Osteosarcoma can affect any part of the skeleton, but mostly it occurs in the tubular bones of the extremities. In 80-90% of the localization of the tumor occurs on the limbs that are in the lower part and 10% of the osteosarcoma affects the humerus. The new malignant etiology in these bones is located in the metaphysis, but the flat bones, the bones of the hands, the foot, the spine of the osteosarcoma are very rare.
Cause of osteosarcoma
Moments of etiological formation of osteosarcoma of bones have not yet been studied, although there are several factors that contribute to their occurrence.
Osteosarcoma can develop in bones that previously received irradiation of ionizing radiation during the treatment of malignant or benign tumors. Radio-induced bone disease, as a rule, manifests itself three years after the end of irradiation, in the form of osteosarcoma.
Some role in the causes of certain cases of a malignant tumor is assigned to carcinogenic ankylating agents and anthracyclines. In addition, since osteosarcoma develops in those bones which grow comparatively rapidly and undergo physical exertion, they do not exclude a certain role of these loads as an assumed factor in the formation of osteosarcoma.
Sometimes, in an anamnesis of patients with osteosarcoma, the existing traumas are clarified. However, they are not considered for today a direct cause in the development of this disease. Although there are suggestions of their provocation of an anomaly, the cells of which already exist in the body.
It is also believed that many pathologies, such as fibrotic dystrophy, chondromas, deforming osteosis, bone-cartilaginous exostoses can be transformed into osteosarcoma.
This disease refers to extremely malignant tumors that are prone to spread with the help of hematogenous metastasis. Most often, metastases penetrate into the lungs, but other regions, lymph nodes and somatic organs are not excluded. Metastases can generally appear from two months to three years, and on average it is up to nine months from the start of therapeutic treatment. In the majority of patients with osteosarcoma, multiple metastases in the lungs and only 11% with a solitary lesion are observed.
For osteosarcoma is characterized by a classic triad of symptoms, which include: impaired limb function, swelling and pain. That is why the mistaken diagnosis of this disease is explained, since such signs refer to many pathologies of the musculoskeletal system.
Clinically, two forms of osteosarcoma are distinguished. The first form is a rapidly developing tumor, which is characterized by an acute onset, severe pain, rapid lethal outcome. The second form is a slowly developing tumor, for which less vivid clinical manifestations are characteristic. Rapidly growing osteosarcoma can give pulmonary metastases, which are found even during the initial examination of patients. This kind of osteosarcoma, as a rule, is detected in children.
Also for osteosarcoma is characterized by aggressive course of the disease. In addition, the disease can begin completely spontaneously or in 50% of the history can be an indication of a previous injury.
Cardinal signs of the disease are painful symptoms. At the first stages of osteosarcoma, they can be mild, occur periodically, especially after physical exertion. These pains appear as a result of joining the pathological process of the periosteum, but gradually they become permanent. A particularly intense manifestation of these pains relates to lesions of the bone in the region of the shin, which is associated with its anatomical structure. Very often pains appear at night, although the overall somatic state of patients remains positive. Only in some patients the temperature reaches subfebrile parameters.
A characteristic feature of the disease is the appearance of a tumor in the form of a swelling. Rapid growth of osteosarcoma is considered the main diagnostic index. As the tumor continues to progress in growth, the soft tissue over it becomes strained, the skin acquires a peculiar luster, and enlarged subcutaneous veins appear. As a result, the patients limit the motor functions of the limbs in the form of flexion contracture and lameness. Thus, muscle atrophy develops.
The general symptomatology of osteosarcoma is observed in the late stages of the disease and is characterized by symptoms such as general malaise, weakness, weight loss, sleep disturbance.
In 10% there are fractures of a pathological nature that are characteristic of osteolytic sarcoma.
Very often, this disease is diagnosed as an inflammatory disease in the early stages of progression, and this, in turn, leads to erroneous treatment.
In laboratory studies, the increase in ESR, the level of alkaline phosphatase and leukocytosis in almost half of patients is determined in the blood test. For advanced stages of osteosarcoma, a characteristic feature of the disease is anemia of a progressive nature.
X-ray examination provides an extremely diverse picture of the lesion, localization and growth rates of the tumor, as well as a structural change in the elements of the bones. Important signs of osteosarcoma are a visor or triangular spur, long threadlike spicules and amorphous cloud-shaped calcifications.
As a result of the destructive process and osteoplastic, osteosarcoma is divided into osteolytic type, osteoblastic and mixed.
Osteosarcoma of the frontal bone
It is a malignant disease that has an osteogenic origin and affects the flat bones of the skull. Osteosarcoma of the frontal bone develops rapidly, therefore very soon it becomes visible visually. It forms on the skull peculiar protrusions and tumor processes of the bones. Such pathological neoplasm is extremely rare, which distinguishes it from other lesions of the skeleton.
Osteosarcoma can affect the vault and the base of the skull. In the arch most often changes in the tumor are: temporal, parietal and occipital. But sometimes osteosarcoma affects the frontal bone. This disease can be found in patients of different ages, but more frequent newly formed pathologies are observed at a young age. As a rule, the tumor is located on the frontal bone, but then it can germinate outside and into the cranial cavity. Osteosarcoma of the frontal bone is characterized by round-celled forms and spindle-cell forms.
Clinically, this malignant disease is manifested by the painlessness of a flat and dense exaltation, on the skin of which the enlarged veins are visible. Osteosarcoma of the frontal bone begins to grow rapidly, increase and sometimes reach considerable dimensions in comparison with the size of the skull. Subsequently, the tumor spreads outward and causes ulceration. When sprouting osteosarcoma into the skull, characteristic symptoms appear in the form of headaches, increased pressure inside the skull and other phenomena in the outbreak, which depend on the location of the tumor. Sometimes the osteosarcoma of the frontal bone pulsates with palpation, but the lymph nodes on the neck are very rarely affected.
In general, the prognosis for this disease is extremely unfavorable, even after a surgical operation. The best results can be achieved in combined treatment with radiation exposure. With inoperable osteosarcoma of the frontal bone, radiotherapy is prescribed as an independent treatment.
Osteosarcoma of the jaw
There are three forms of the disease: osteoblastic, osteolytic and mixed.
The first clinical manifestations of the jaw osteosarcoma are pain in the intact tooth, unpleasant itching in the marginal area of the gums, loosening of separate groups of teeth.
Painful symptoms with maxillary sarcoma of the upper jaw appear much later than with the disease of the lower jaw. They are late signs of malignant neoplasm. In some cases, before the appearance of these pains, there is a characteristic paresthesia at the site of the branching of the chin or infraorbital nerve. In addition, the disturbed sensitivity proceeds in the form of unstable and rapidly transient paresthesia.
At the site of the localization of the osteosarcoma of the jaw, a swelling is formed with different density, size and moderate soreness during palpation. With significant neoplasms, the edematous state of soft tissues is revealed, the widening of stagnant veins under the skin and mucous membrane with thinned skin above the surface of the tumor process.
With the localization of osteosarcoma next to the chewing muscles of the temporomandibular joint, early reduction of both jaws occurs. Very rarely, with the development of the osteosarcoma of the jaw, one can find a fracture of a pathological character and then in the late stages of the disease.
The overall clinical state of patients at the onset of malignant disease remains unchanged. But when osteosarcoma reaches a large size and disintegrates, then the temperature rises to 39-40˚С and an accelerated increase in ESR. The osteosarcoma of the jaw begins to metastasize and, as a rule, affects the lungs, and then penetrates into other organs, parts of the skeleton and promotes the development, for example, of the rib ostesarkoma.
The osteosarcoma of the osteolytic jaw manifests itself in the form of a significant destruction of the bone, and the roentgenogram shows the characteristic destruction of a particular part of the bone, which has no structural form. This defect is an uneven, jagged, eroded contour. And the outer edges are completely absent, so these changes merge with the nearby soft tissues.
Osteoblastic osteosarcoma of the jaw are characterized by prevalence of bone formation pathology. At the beginning of its development, the tumor on the radiograph resembles a small, indistinctly delineated, compacted focus of the bone, which is characterized by pronounced changes in the periosteum with needle periostitis. With the progression of the tumor, the affected jawbone continues to increase, to be sclerized, and then becomes almost opaque to the rays of the X-ray.
Diagnosis of the jaw osteosarcoma is performed on the basis of symptoms, x-ray examination and biopsy analyzes. Mandatory resort to differentiation of malignant disease with such sarcomas as fibrosarcoma, chondrosarcoma, from which you can expect periosteal reactions.
To treat osteosarcoma of the jaw, radiation exposure is used in the preoperative period. And then they perform a radical operation to remove the tumor, followed by the use of polychemotherapy Andriyamitsin.
Treatment of osteosarcoma
Previously, for primary treatment of extremities with osteosarcoma that did not have distant metastasis, tumor removal was used as an amputation or a large irradiation of the main lesion zone. Also, the first chemotherapy methods for osteosarcoma gave disappointing results, so the malignant pathology was chemoresistant.
And only since the 80-ies, there have appeared effective schemes of polychemotherapy in which Adriamycin has been successfully used, large doses of Methotrexate with the support of Leucovorin, preparations of platinum and Ifosfamide. It was found that these chemotherapeutic drugs can eliminate latent metastases, as well as microscopically small tumor spreads and improve survival.
The proposed polychemotherapy in the preoperative period, performs the main function, which is characterized by suppression of micrometastases and restriction in the spread of primary osteosarcoma. The reaction of a malignant tumor to polychemotherapy before surgery is assessed by clinical, laboratory, radiologic and pathomorphological characteristics.
The effectiveness of osteosarcoma therapy is manifested by such clinical signs as reduction of pain symptoms and puffiness. And laboratory diagnostics testifies to positive results of treatment of osteosarcoma in the form of a reduced level of alkaline phosphatase. After MRI, OSG is used to determine the reduced soft-tissue components of the tumor process or their absolute disappearance, recovering intermuscular gaps, healing pathological fractures and calcified periosteum.
Angiography is presented in the form of a subjective way of evaluating the expressed reaction of osteosarcoma to polychemotherapy. The gold standard for evaluating and detecting the response to the therapy included histological indicators that were detected in a distant tumor after chemotherapy before surgery. The pronounced drug pathomorphism in osteosarcoma is recognized as the main factor in predicting the disease.
Until recently, without effective chemotherapy drugs, radiation therapy was considered necessary in the treatment of primary pathology in order to avoid, for example, amputation of extremities affected by osteosarcoma with initially undetectable metastases. Although after five or six months in these patients, after the end of radiation exposure, distant metastases were detected. Therefore, many oncology clinics refuse this method of treatment, since osteosarcoma refers to highly radio-resistant pathology.
As a rule, radiation exposure is prescribed as a symptomatic treatment for pain relief, as well as for inoperable osteosarcomas that are localized in the bones of the pelvis or spine. In addition, the issue of radiation exposure is resolved if the pathological neoplasm is localized in the unresectable part, despite the fact that osteosarcoma is sensitive to the effects of radiation therapy. When a tumor is solitary, radiotherapy controls the size of the lesion.
The most important condition for successful resection of primary osteosarcoma is careful selection of patients and proper planning of surgical intervention. Mainly from the localization of the tumor process will depend on the technique of surgical intervention. To date, many leading centers that deal with the treatment of osteosarcoma have proven that the preservation of organs in children during surgery is considered an adequate and appropriate method of therapy in some patients who have passed all the conditions for proper selection.
The most important decision of oncologist surgeon is to determine the specific boundaries of tumor removal and the desire to conduct an economical operation that will ensure maximum rehabilitation of the patient. Studies prove that patients who have undergone amputation are physiologically adapted in the same way as patients who underwent an organ-preserving operation.
A central role is played by two factors in determining the level of osteosarcoma removal. The first refers to the length of the component of the soft tissues, which are associated with vessels and nerves. The second factor relates to the extent of the affected bone and the intramedullary degree of spread of osteosarcoma. This spread of intramedullary nature manifests itself in vastness, which distinguishes it from the soft-tissue component. Classically, amputation is performed approximately seven to eight centimeters above the soft tissue boundaries and the intramedullary component of the tumor. With good results on polychemotherapy before surgery, the resection margin can be reduced to three to five centimeters.
At present, existing lung metastases can not be a contraindication to organ-preserving surgical interventions. This method of surgical treatment is preferred for many patients with osteosarcoma.
Amputation is prescribed in cases where the disease in its primary form is inoperable. The main factor that leads to such an operation is the attachment to the pathological process of the bundle from the vessels and nerves. And auxiliary factors may include significant spread of osteosarcoma elements as a result of poorly performed biopsy or pathological fracture analysis.
Recently, significant advances have been made in the treatment of generalized osteosarcoma. Especially it concerns those pathologies in which there are metastatic lung lesions. As a rule, a positive trend in the treatment of such patients is associated with the appearance of chemotherapeutic active protocols, as well as the ability to determine the histological response of tumor metastases to therapy.
It was the use of radical surgical treatment in the removal of single and solitary metastases, and polychemotherapy, which resulted in a five-year survival rate in 35% of patients with lung metastases.