Mature bones are composed of a variety of tissues including bone, cartilage, bone marrow, nerves, blood vessels, and fibers, any of which can develop tumors. Although the overall incidence of primary bone tumors is very low.
There are benign, malignant and neoplastic bone tumors. Benign bone tumors, such as osteochondroma and chondrosarcoma, can be radically treated with good prognosis. Malignant bone tumors can be primary, such as osteosarcoma, chondrosarcoma, fibrosarcoma, etc., or secondary, which are caused by malignant tumors of other tissues or organs in the body (such as lung cancer, thyroid cancer, breast cancer, prostate cancer, etc.) metastasizing to the bone through blood circulation or directly invading the bone, malignant bone tumors often develop rapidly and are difficult to diagnose and treat, which has been a difficult area in orthopedic science and oncology, and there is no satisfactory treatment method yet. There is no satisfactory treatment method and poor prognosis.
Etiology of bone tumor
Bone tumors, like other tumors, have complex pathogenesis factors, generally speaking, the endogenous conditions exist first, and the exogenous factors occur through the endogenous ones. The endogenous factors include quality theory, genetic theory, endocrine theory, etc. The exogenous factors include chemical element substance and chronic stimulation by internal and external irradiation, viral infection theory, etc. Both osteochondroma multiforme and fibrous proliferative disorder are related to family Tumors are caused by abnormal proliferation of a cell. Tumor cells are derived from normal cells, but differ from them in structure, function and metabolism. In recent years, as the basic research of tumor has been intensified, a lot of new contents have been added to the concept of tumor. Current research results indicate that tumors are the result of accumulation of multiple genetic mutations in cells, which are concentrated in three types of genes: oncogenes, tumor suppressor genes and DNA repair genes. The occurrence of cancer is a multifactorial, multi-stage and complex progressive process, which not only has external factors, but also genetic factors, immune status and other self factors.
1.Genetic: The genome of tumor cells contains genetic information that determines the tumor phenotype. With the division of tumor cells, daughter cells maintain the characteristics of abnormal cell phenotype. The process of transformation of cells with normal differentiated phenotype to tumor cell phenotype has multi-step molecular alterations, which affect the protein functions of many normal cells. The process of malignancy development can be viewed as a series of molecular alterations encoded within the cellular genome. Some molecular alterations can be vertically inherited, causing tumors to develop in susceptible offspring. In addition, some genetic mutations do not immediately cause adverse effects and can be replicated in daughter cells, and these mutations may cause tumors only late in life.
2.Viral infection: The etiological relationship between viral infection and malignant tumors is still not fully understood, but experimental studies have shown that viral infection is indeed related to certain malignant tumors in humans.
3.Chemical carcinogens: Chemical carcinogens are chemicals that can cause tumor formation in humans or animals.
4.Physical carcinogens: Ionizing radiation is the main physical carcinogenic factor, mainly including the radiation of electromagnetic waves characterized by short wave and high frequency as well as the radiation of electrons, protons and neutrons. Long-term exposure to radium, uranium, radon, cobalt and strontium and other radionuclides can cause malignant tumors. Survivors of atomic bombings have an increased incidence of leukemia and osteosarcoma.
The main symptoms and signs of bone tumor are
1. pain and pressure pain: pain is the most significant symptom of rapidly growing tumor. Benign tumors are mostly painless, but some benign bone tumors, such as osteoid osteoma, can produce severe pain in response to the growth of bone; malignant bone tumors almost always have local pain, which starts as intermittent and mild pain, and later develops into persistent severe pain, nocturnal pain, and may have pressure pain. When benign bone tumor becomes malignant or tumor destroys bone causing pathological fracture, the pain may suddenly increase.
2.Local swelling and lump: benign tumors are hard masses with slow growth and no obvious pressure pain, which are usually discovered by chance, such as osteochondroma in children’s limbs, which is often discovered by parents when bathing. Localized swelling and rapid development of the mass are most often seen in malignant tumors. The appearance of thickened blood vessels on the local skin reflects the rich blood flow of the tumor, which is mostly malignant.
3.Dysfunction and neurological compression symptoms: Tumor near the joints may restrict joint activities due to pain and swelling, and tumor on the spine may compress the spinal cord, resulting in numbness, pain, weakness and even limb paralysis.
4.Pathological fracture: Pathological fracture caused by minor trauma is the first symptom of some bone tumors, and is also a common complication of malignant bone tumors and bone metastatic cancer. Trauma causes early detection of tumor, but does not lead to tumor. Advanced malignant bone tumors may present with systemic symptoms such as anemia, emaciation, loss of appetite, weight loss, and hypothermia. Early detection of bone tumor has a great impact on the diagnosis and treatment of doctors and the prognosis of patients, so it is very important to be familiar with the common symptoms of bone tumor for early detection and timely consultation. Pain in bone or joint (including pain in spine), bony mass, and limb dysfunction are considered as the three main signs of bone tumor, especially malignant bone tumor. Also noteworthy are skin and local vascular signs. Malignant tumors often have abundant blood vessels, skin color may change significantly, skin may become warm, and superficial veins may become angry. Benign bone tumors, in general, have slow development, no obvious early symptoms, pain and swelling are not very obvious, and only when they grow to a certain extent near the joints, they can cause mild limb or movement limitation or deformity.
Imaging examination
1.Plain X-ray examination: X-ray examination is the most basic and primary imaging examination to diagnose bone tumor, which can not only detect bone tumor, but also play an important role in judging the benignity and malignancy of bone tumor and its pathological type, and help doctors to decide whether to use further imaging examination. It can also help doctors to decide whether to use any further imaging examination.
2.CT examination: CT scan and enhancement can accurately show the scope and degree of bone destruction of bone tumor and the size of soft tissue masses. For irregular bone parts such as pelvis and vertebrae, it can make up for the overlap and poor image on X-ray film and detect the lesion at an early stage. CT of the chest can detect metastatic lesions in the lungs earlier and more accurately than X-rays.
3.MRI: MRI has the characteristics of high tissue resolution and multi-planar urban and rural, which can accurately show the extent of bone tumor in bone and soft tissue, whether the tumor is substantial or cystic, and can detect jumping lesions in adjacent parts at an early stage. At present, MRI has become an indispensable preoperative examination for malignant bone tumor surgery, especially limb preservation surgery. For discovering early lesions in vertebrae, pelvis and other parts, MRI has more advantages than X-ray and CT.
4.Radionuclide bone imaging (also called bone scan): It is used to check whether there are tumor lesions in the whole body bones and can detect bone metastases at an early stage. The false positive rate of bone scan is higher.
5.PET-CT: PET-CT is a functional examination of malignant tumor and is used for whole body examination. Its examination scope includes bone, soft tissue and internal organs, which is helpful to detect tumor, determine whether there is recurrence and metastasis after surgery, and identify bone and soft tissue tumor, etc. Its false positive rate is lower than that of bone scan.
Treatment of bone tumor
1.Follow-up observation
Some benign bone tumors and tumor-like lesions, such as osteochondroma, bone hemangioma, simple bone cyst, non-ossifying fibroma, etc., can be followed up and observed if the lesions are small in scope, without obvious pain and nerve and vascular compression. If symptoms appear, such as pain, dysfunction, compression of blood vessels or nerves, pathological fracture, etc., or if there is a tendency of malignant transformation, surgery should be taken promptly.
2.Surgical treatment
Surgery is the basic treatment method for most bone tumors at present.
3.Chemotherapy
Before 1980s, the treatment of primary malignant bone tumors was mainly amputation, and for osteosarcoma, despite amputation, the 5-year survival rate of patients was only about 20%. For osteosarcoma, Ewing sarcoma, malignant fibrous histiocytoma, myeloma, malignant lymphoma, etc., chemotherapy is no longer an adjuvant treatment, but a major life-saving measure. At present, the drugs commonly used in chemotherapy for malignant bone tumors are: methotrexate, adriamycin, cisplatin, carboplatin, cyclophosphamide, isocyclophosphamide, vincristine, actinomycin, etc.
Neoadjuvant chemotherapy: After the diagnosis of malignant bone tumor, preoperative chemotherapy for 6-8 weeks, followed by tumor resection, and then chemotherapy for 4-6 months after surgery, this treatment mode is called neoadjuvant chemotherapy, which has become the standard treatment mode for osteosarcoma, Ewing sarcoma and malignant fibrous histiocytoma.
4.Radiotherapy
Radiotherapy is effective for certain malignant bone tumors, such as Ewing sarcoma, myeloma and malignant lymphoma, but radiotherapy is only effective for tumors within the radiotherapy area, so it can only be used as a local treatment measure in combination with chemotherapy. In most other malignant bone tumors, radiotherapy is not sensitive and cannot be used as a conventional treatment, but only as palliative treatment or postoperative adjuvant treatment when surgery is not possible.
5.Interventional treatment
Selective arterial infusion chemotherapy and embolization can be used for larger, vascular malignant bone tumors, which can be used alone as a palliative treatment for inoperable malignant bone tumors or in combination with surgical treatment. The commonly used drug for arterial infusion chemotherapy is cisplatin.
6.Drug therapy
Most bone tumors have bone destruction, and the bone destruction of some benign bone tumors and aneurysmal lesions is mainly caused by the enhanced activity of osteoclasts. Diphosphonates can inhibit the activity of osteoclasts to stop or slow down the bone destruction.
7.Other treatment methods
Immunotherapy has now become an adjuvant treatment for malignant bone tumors, such as the application of various cytokines and tumor necrosis factors, as well as the application of drugs that enhance the immunity of the body (interferon). Recombinant human vascular endothelial inhibitor Endo has been clinically used for the adjuvant treatment of osteosarcoma.