Metastatic Spine Cancer

　　1. Metastatic lesions can invade the spine through various mechanisms, including hematogenous, direct spread, and cerebrospinal fluid dissemination. The mechanism of tumor spread is closely related to the biological behavior of the primary tumor. Hematogenous spread through veins or arteries is considered the most common route for primary tumors to metastasize to the spine. Due to the rich arterial blood supply to the vertebrae, tumor cells can metastasize from distant primary sites to the spine and form metastatic lesions. The venous dissemination route usually occurs through the Batson plexus, which is a longitudinal venous network without venous valves, connecting the vertebral veins and numerous other venous return pathways, including the systemic venous, portal venous, azygos venous, intercostal venous, pulmonary venous, and renal venous systems. Changes in pressure in the main body cavities (such as the thoracic, abdominal, and pelvic cavities) cause blood to flow through the Batson plexus, resulting in the retention of tumor cells in the spine through retrograde or antegrade venous flow. Regardless of the arterial or venous route, hematogenous spread of tumors usually causes multiple spinal lesions. Direct spread of the primary tumor can also form metastatic lesions in the spine. Lesions in the chest, abdomen, or pelvis can locally invade the spine, causing symptomatic spinal metastatic cancer.

　　2. Lung cancer can invade the thoracic vertebrae posteriorly or the cervical-thoracic junction superiorly. In addition, prostate, bladder, and colorectal cancers can infiltrate the lumbar or sacral vertebrae. Tumor cells in cerebrospinal fluid can form spinal or spinal cord metastases through shedding or implantation, which often occurs after surgery for metastatic or primary tumors in the brain or cerebellum, similar to hematogenous dissemination, causing multiple lesions. Spinal tumors are classified into three types based on anatomical distribution: extradural, extramedullary-intradural, and intramedullary. The vast majority of spinal metastatic cancers occur in the extradural space, that is, the bony part of the spine and surrounding tissues. Most extradural metastases occur in the vertebral bodies, with or without posterior infiltration into the vertebral bodies, followed by the paravertebral region and the extradural space. Intradural and intramedullary metastases are rare and generally spread through cerebrospinal fluid. Metastatic tumors can occur in all spinal segments, but the thoracic vertebrae are the most common site, followed by the lumbar, cervical, and sacral vertebrae.

　　Spinal metastatic cancer can cause a group of symptoms, including pain, active or autonomous dysfunction, and sensory disorders. Spinal metastatic cancer may also be accompanied by orthostatic hypotension, drowsiness, dizziness, and other conditions.

　　Spinal metastatic cancer can cause a group of symptoms, including pain, active or autonomous dysfunction, sensory disturbances, which mainly depend on the growth rate of the tumor, the extent of bone involvement and destruction, the degree of nerve compression, and the severity of the systemic disease. Rapid tumor growth can lead to rapid progression of symptoms. Dissolving tumors due to bone destruction can lead to pathological fractures or deformities. Metastases can also cause involvement of nerve roots and compression of the spinal cord, resulting in radiculopathy and myelopathy. In addition, systemic disease signs may also be present, including weight loss, decreased appetite, or organ failure. In cases of large sacral metastases, significant paravertebral or rectal masses may be found during physical examination.

　　1. Pain

　　Pain is the most common chief complaint in patients with symptomatic spinal metastatic cancer, occurring in 83-95% of patients, and it may appear several weeks or months earlier than other neurological symptoms. The earliest symptom is pain in the thoracic or lumbar region at the level of the lesion, which is usually mild, intermittent, and often goes unnoticed. Symptomatic treatment may gradually lead to persistent severe pain. The initial symptom in 10% of cancer patients is pain related to spinal metastasis. Patients with spinal metastatic cancer have three typical types of pain, including local pain, mechanical pain, and radicular pain. The pain experienced by patients may be one type or a combination of several types. Differentiating the type of pain in individual patients is a key part of the diagnostic evaluation process. Local pain is caused by the stretching and inflammation of the periosteum due to tumor growth, described as deep 'gnawing' or 'aching' pain, which often occurs at night, improves after activity, and can be rapidly relieved by anti-inflammatory drugs or corticosteroids. Percussion or palpation of the spinous process may cause tenderness or pain in patients with this type of pain. Unlike local pain, mechanical back pain is usually ineffective with anti-inflammatory drugs and analgesics, and it varies with posture and activity. This type of pain is attributed to instability that is about to form or has already formed. Deformities caused by tumors or compression of affected vertebrae often lead to spinal instability, increasing the tension in the supporting and stabilizing structures of the spine, including muscles, tendons, ligaments, and joint capsules. This tension causes characteristic pain associated with spinal movement or axial loading, which can be induced in prone or supine positions but is usually relieved in lateral positions. Wearing a brace or undergoing surgical fixation can stabilize the spine and relieve mechanical pain. Spinal metastatic radicular pain may occur when the tumor compresses the nerve root at the exit of the spinal nerve root or when a compressive fracture blocks the nerve root canal, invades the nerve root, similar to radicular pain related to intervertebral disc protrusion, and is often described as severe, piercing-like sharp pain. In cases located in the cervical spine, such as compression of the upper cervical nerve root, it can cause pain in the occipital area. Compression of the C4 nerve root can cause pain resembling a neck band. Compression of the lower cervical nerve can cause arm and finger pain, which worsens with coughing and straining. Extramedullary-intradural metastases can cause irritation or invasion of nerve roots, leading to dull or radicular pain. Unlike typical radicular pain, this pain is described as a severe burning sensation.

　　2. Neurological dysfunction

　　Another common symptom in patients with spinal metastatic cancer is motor dysfunction. 60-85% of patients with metastatic epidural spinal cord compression (MESCC) have muscle weakness in one or more muscle groups. This muscle weakness may be related to spinal cord disease or radiculopathy, and can be caused by direct compression of neural structures by the tumor, or by pathological fractures causing bone fragments to protrude into the spinal canal or nerve root canal. MESCC patients may exhibit varying degrees of autonomic dysfunction, such as abnormal bowel, bladder, or sexual function, unless directly inquired by the doctor, these manifestations are often not discovered. The most common symptom in these patients is bladder dysfunction (usually urinary retention), which is clearly related to the degree of motor dysfunction. If not treated, patients with motor dysfunction may develop complete paralysis. Sensory disturbances include paresthesia, hyperesthesia, and sensory abnormalities, which usually occur simultaneously with motor dysfunction and corresponding pain in the dermatome. Patients with spinal cord disease may have sensory abnormalities distributed in a strip-like pattern across the chest and abdomen. MESCC patients with thoracic spinal cord involvement may describe a sense of discomfort in the chest, similar to the feeling of a too-tight shirt or brassiere. Essentially, this discomfort is similar to that described by patients with transverse myelitis of the thoracic spinal cord. When the diagnosis of spinal cord compression is clear, the patient's neurological function is closely related to the prognosis. Most patients have symptoms of pain before the occurrence of neurological dysfunction, but due to the common occurrence of back pain in the general population, diagnosis delay often occurs in patients with spinal metastatic cancer who initially present with new-onset back pain or neck pain. Therefore, clinicians should remain highly vigilant to back pain in patients with a tendency towards tumors. In addition, pain caused by non-tumor factors is not common in the thoracic and cervical spine compared to the lumbar spine, so pain in this region should be considered as a tumor.

　　Aggressive treatment of the primary cancer: If the primary cancer exists, or is untreated, or recurs after treatment, aggressive treatment of the primary cancer is required. Otherwise, the efficacy of the metastatic tumor will be affected, and new metastatic foci may appear. For those whose primary cancer has not been discovered, active search and treatment of the primary cancer should be carried out.

　　1. Imaging examination

　　1. X-ray radiography

　　For a long time, X-ray imaging has been the primary assessment method for newly diagnosed patients with symptoms related to the spine. This is mainly due to its simplicity, low cost, and widespread application. Therefore, X-ray radiography has become an effective screening tool for confirming lytic and sclerotic lesions, pathological fractures, spinal deformities, and large mass formations. Breast cancer and prostate cancer can produce sclerotic lesions, but the majority of spinal metastatic cancers are lytic. X-ray radiography cannot show related changes before more than half of the vertebral body is involved. Due to this relative insensitivity, a definitive diagnosis often requires the combination of other imaging techniques. Radionuclide scanning (bone scanning) is a sensitive method for identifying areas of increased metabolic activity in the skeletal system. Before the vertebral body is involved by 30-50%, changes related to the tumor cannot be shown by X-ray radiography, while bone scanning can detect metastatic tumors earlier, with a resolution of up to 2mm. Reports have shown that the sensitivity of radionuclide bone scanning for detecting spinal metastatic cancer is 62-89%. However, since radionuclide scanning detects enhanced metabolic activity, and inflammation or infection can also enhance metabolic activity, it does not have specificity for metastatic lesions. Low image resolution hinders the effect of scintigraphy, and CT or MRI imaging should be combined to exclude benign manifestations. If necessary, surgical exploration should be performed.

　　2. SPECT (Single Photon Emission Computed Tomography)

　　It is a more advanced method than nuclear bone scanning, providing 3D imaging of suspicious spinal metastatic cancer. This technology has more detailed imaging in detecting lesions than planar scanning and increases sensitivity and specificity. Moreover, unlike other imaging techniques, SPECT imaging can differentiate between metastatic lesions and benign lesions. In terms of detecting spinal metastatic cancer, when planar scanning cannot make a definitive diagnosis, SPECT is an effective and relatively inexpensive detection tool. Positron Emission Tomography (PET) using fluorodeoxyglucose (FDG) as a tracer is also a routine overall monitoring tool for detecting metastatic lesions and tumor staging. PET equipment has been proven to be superior to planar scintigraphy in detecting spinal metastatic cancer, as it directly measures the metabolic activity of the tumor rather than the indirect sign of bone transformation in metastatic tumors, thus enabling early detection of tumors. PET scanning is also used to distinguish between the cystic and necrotic areas of tumors, which can increase the diagnostic rate of biopsy sampling and help in formulating surgical intervention plans. However, the resolution of PET is limited and must be combined with CT or MRI imaging. In addition, PET scanning is time-consuming and expensive. The latest generation of multi-row CT scanning equipment provides highly detailed images of the spinal bone anatomy and the extent of tumor invasion. The increased sagittal and coronal digital reconstruction further enhances the detail of CT imaging. When myelography is combined with CT imaging, it can obtain a high-precision representation of the spaces occupied by neurons to identify compressed structures, which helps to clarify the cause of spinal cord compression, whether it is tumor invasion into the spinal canal or pathological fracture fragments posteriorly protruding into the spinal canal. Due to the thorough identification of regional anatomical structures, it can assist in guiding surgical approaches, determining surgical methods, and defining the range of internal fixation, making CT imaging highly valuable in formulating surgical intervention plans. In addition to CT scanning of the involved part of the spine, for patients suspected of having spinal metastatic cancer but unable to determine the primary site, CT scanning of the main body cavities should be performed to determine the primary tumor site. In addition, CT angiography can evaluate the blood supply and return of spinal metastatic cancer.

　　3. Magnetic Resonance Imaging

　　It is considered the gold standard imaging equipment for evaluating spinal metastatic cancer. In terms of detecting spinal lesions, MR imaging is more sensitive than standard X-ray films, CT, and radionuclide scans. This sensitivity is largely due to the excellent resolution of MR images of the soft tissue structures of the spine, including intervertebral discs, spinal cord, nerve roots, meninges, as well as the muscle groups and ligaments of the spine. MR images can show the boundary between bone and soft tissue, providing anatomical details of tumor invasion or compression of bone, nerves, and paravertebral structures. A set of MR images includes three standard axis images (axial, sagittal, and coronal) after the application of contrast agent, T1 and T2 weighted images. In addition, due to the high-intensity signal of bone marrow fat in T1 weighted images, fat suppression studies can further explain the principle of signal enhancement in the lesion of spinal bone tissue. Diffusion-weighted imaging, although not a routine application, can distinguish pathological and non-pathological compression fractures.

　　4. Conventional Digital Subtraction Angiography

　　It is an important tool for evaluating spinal metastatic cancer. For patients with metastatic tumors from primary tumors with abundant blood supply (such as renal cell tumors, thyroid tumors, angiosarcomas, leiomyosarcomas, hepatocellular tumors, and neuroendocrine tumors), understanding the blood supply of the metastatic tumor is of great significance if surgery is considered. Angiography can also be used for preoperative embolization of the metastatic tumor, which is an effective treatment for patients who cannot undergo surgery. After embolization, the amount of blood loss during surgery can be reduced, which helps in the complete resection of the lesion. In addition, controlling blood loss during surgery and reducing the blood supply of the metastatic tumor can potentially shorten the operation time and prevent postoperative hematoma from causing incisional dehiscence and neural tissue degeneration.

　　Second, percutaneous biopsy

　　The advancement of imaging technology has improved the detection of cancerous lesions, but confirmation usually still requires biopsy material from the spinal lesion. More than 10-20% of spinal metastatic cancer tissues have an unclear source. If the biopsy of surgical resection cannot obtain immediate results, percutaneous biopsy is required because most treatment decisions are based on the findings of tumor histopathology. The advancement of biopsy technology has brought the accuracy of diagnosis close to 90%, and many biopsies can now be performed in outpatients. When considering the possibility of primary tumors, surgeons should consult on the planned biopsy procedures because some primary tumors can spread and locally recur through biopsy needles, such as chordoma.

　　Provide patients with rich, easily digestible, light food that suits their taste, while ensuring that the food is colorful, fragrant, and delicious to enhance the appetite of patients, and to eat more vegetables and fruits. At the same time, create a good dining environment for patients, encourage them to eat more, and prefer to eat less and more often, or perform high-nutrition nasogastric feeding if necessary, and adopt intravenous hyperalimentation when necessary to supplement nutrition and maintain electrolyte balance in the body. Encourage patients to engage in bed activities, and those who can walk should do some qigong, Tai Chi, and other exercises to regulate the vital energy, regulate their mental and physical condition.

　　First, treatment principles

　　1. Active treatment of the primary cancer

　　If the primary cancer exists, or has not been treated, or has recurred after treatment, active treatment of the primary cancer is required. Otherwise, the efficacy of the metastatic tumor will be affected, and new metastatic foci may appear. For patients with undetected primary cancer, active search and treatment of the primary cancer should be carried out.

　　2. Comprehensive treatment for metastatic tumors

　　(1) Chemotherapy: Different types of tumors have their own sensitive chemotherapy drugs. The most common breast cancer metastasis responds well to hormonal therapy, and some single drugs such as 5-fluorouracil, doxorubicin, and cyclophosphamide have certain efficacy, but combined chemotherapy is preferred. Chemotherapy for spinal metastatic cancer can alleviate or relieve pain, but the effect is not durable.

　　(2) Radiotherapy: Local radiotherapy can be performed for both solitary and multiple metastatic foci, inhibiting tumor growth and alleviating symptoms.

　　(3) Hormonal therapy: Some cancers are related to endocrine function, such as breast cancer and prostate cancer in men and women are related to sex hormones, which can be treated with sex hormones.

　　(4) Immunotherapy: Interferon is effective for some cancers. When combined with chemotherapy and radiotherapy, the effect is even better. Even some hollow areas can be locally injected.

　　(5) Surgical treatment: The purpose is to improve the quality of life for patients with effective survival period, such as alleviating symptoms, stabilizing the spine, improving paralysis, and extending life.

　　3. Symptomatic supportive treatment: Regardless of the effectiveness of comprehensive treatment, some symptoms may exist for a period of time, requiring symptomatic treatment, such as administration of sedatives and appetite stimulants, intravenous and blood transfusions, nutritional and vitamin supplementation, maintenance of electrolyte balance, and improvement of organ function, etc.

　　4. Selection of Surgical Treatment and Patients

　　The progress in drug research and development has improved the treatment of many tumors and prolonged the survival of many patients. Treatment decisions for such patients need to refer to the most valuable literature, the clinical expertise and experience of physicians, and consider the patient's wishes, among which the latter two are crucial, especially since it is palliative treatment, the patient's wishes are particularly important. In fact, when making treatment decisions, clinicians should mainly consider three aspects: patient factors, spinal stability, and neurological function.

　　Over the past 20 years, surgical techniques have continuously developed, and anterior and posterior spinal stabilization procedures have improved decompression and tumor resection scope under acceptable complication rates. Some cases can achieve long-term disease-free survival, especially in patients with single renal cell malignant tumors, but for most patients, the purpose of surgical treatment is to preserve neurological function, alleviate pain, and ensure spinal mechanical stability. Most clinicians usually expect the patient's survival period to exceed 3 months before considering surgical treatment for spinal metastatic cancer.

　　2. Surgical Treatment

　　1. Surgical Indications

　　(1) Single metastatic tumors with unknown primary lesion are operated on simultaneously with frozen biopsy; (2) Recurrence or continued worsening after chemotherapy or radiotherapy; (3) Known to be radioresistant; (4) Patients with paraplegia or spinal instability.

　　Selecting patients with surgical indications is a challenging task. Tokuhashi et al. formulated a scoring system based on primary tumor type, number of spinal metastases, extraspinal and visceral metastasis manifestations, general condition, and neurological status. The better the prognostic indicators (low-invasive tumor, single spinal lesion, no metastases in other sites, good overall condition, no neurological dysfunction), the higher the value of surgical treatment. When the patient's score is greater than 9, it is recommended to surgically resect the lesion. When the patient's score is less than 5 and the prognostic indicators are poor, palliative therapy, i.e., restrictive decompression and fixation, is recommended. The advancement of surgical techniques and the expansion of treatment options have prompted Tomita et al. to develop a similar scoring system based on the grading of the primary cancer, the manifestation of visceral metastases, and the number of bone metastases. In this system, the better the prognostic indicators, the lower the score. For patients with a score of 2-3, the goal is to achieve long-term local control through extensive or marginal resection. For patients with a score of 4-5, it indicates that intermediate control should be achieved through marginal or intralesional resection. Patients with a score of 6-7 are recommended for palliative surgical treatment, and supportive therapy is only applicable to those with a score over 8. The principle of formulating this scoring system is to assist surgeons in selecting patients who can benefit from surgical treatment and to determine the reasonable scope of surgical resection. In fact, calculating the scores of the Tomita and Tokuhashi systems does not limit the choice of treatment methods, especially for other treatment modalities such as the recently developed SRS. However, the basic principles of these prognostic scoring systems still apply. Moreover, once a patient is considered suitable for surgical treatment, a comprehensive understanding of the anatomical and histopathological characteristics of the metastatic tumor and its adjacent structures, spinal biomechanics, and changes induced by the metastatic tumor is required when deciding on the surgical approach and fixation method.

　　2. Surgical methods

　　Surgical anatomical and histopathological tumor typing: The method of surgical resection and decompression for patients with spinal metastases is mainly determined by the involved spinal segments, the location of the tumor in the spine, the histological characteristics of the tumor, and the type of spinal reconstruction required. The vertebral body is the most commonly involved part in spinal metastases, so anterior surgery can most effectively resect the lesion and decompress the spinal canal. However, this approach increases the incidence and mortality rate of surgical complications. Therefore, the frequently used posterior or posterolateral approach through the pedicle has become the preferred approach. Through this approach, three-column decompression and internal fixation can be performed, and this technique is increasingly used in the thoracolumbar spine, especially when performing circumferential resection and/or multi-segment resection.

　　Treatment of secondary spinal instability due to spinal metastases

　　Secondary spinal instability due to spinal metastases has not been clearly defined in the past. A review shows that there is no clear treatment guideline for impending or existing instability of the cervical or thoracolumbar spine. Currently, diagnosis depends on a set of clinical and imaging parameters, all of which have not been validated. Spinal biomechanical research shows that more than 80% of the support of the vertebrae comes from the axial load of the spine. Therefore, when the vertebral body, the most common site of metastatic tumors, develops destructive lesions, it has a significant impact on the load-bearing capacity of the spine. The extent of the impact depends on the volume of the lesion, the cross-sectional area of the intact vertebral body, and the total bone mineral density. As the volume of the destructive lesion continues to increase, the integrity of the vertebral body is destroyed, leading to compressive or burst fractures. These fracture fragments or tumor fragments enter the spinal canal or intervertebral foramen, causing compression of neural structures, leading to pain or motor/autonomic dysfunction. Studies have shown that 50-60% of thoracic vertebral and 35-45% of lower thoracic/thoracolumbar vertebral destructive lesions predict vertebral collapse. Segments with high activity or high pressure, such as the cervical-thoracic segment and the thoracolumbar segment, can fracture under a small tumor load. Metastatic tumors in the posterior aspect of the spine, especially the zygapophyseal joints, are considered to be the cause of pathological dislocation, spondylolisthesis, and horizontal instability in patients. Since the incidence of posterior spinal metastases is much lower than that of the vertebral body, such lesions are not common.

　　了解不稳的表现程度和特征能够协助选择手术方式和确定重建范围。由于损伤机制的不同，对在肿瘤形成过程中导致的脊柱不稳行内固定和减压的指征尚不清楚。Cybulski对评估肿瘤导致脊柱不稳的影像学标准建议如下：1.前中柱破坏（椎体高度塌陷>50％）；2.2个或以上相邻椎体塌陷；3.肿瘤累及中后柱（后方形成剪切畸形的可能）；4.既往行椎板切除术，未发现前中柱病变。这些研究建议，当这些不稳标准中一项存在时，或预期寿命>5-6个月的患者出现神经压迫症状、免疫或营养状态良好、不完全性神经功能障碍、肿瘤对化疗不敏感、肿瘤既往治疗失败时，可行手术建议内固定。

　　（2）脊髓压迫症的治疗

　　(2) Treatment of spinal cord compression. Understanding the degree and characteristics of instability can assist in selecting the surgical method and determining the scope of reconstruction. Due to different injury mechanisms, the indications for internal fixation and decompression of spinal instability caused by tumor formation are unclear. Cybulski's suggestions for imaging criteria for evaluating the instability of the spine caused by tumors are as follows: 1. Anteroposterior column destruction (vertebral height collapse > 50%); 2. Two or more adjacent vertebral bodies collapse; 3. Tumor involvement of the middle and posterior columns (possible formation of posterior shear deformity); 4. Previous laminectomy, no anterior and middle column lesions found. These studies suggest that when one of these instability criteria exists, or when patients with an expected lifespan of >5-6 months have neurological compression symptoms, good immune or nutritional status, incomplete neurological dysfunction, tumors insensitive to chemotherapy, or previous treatment failure, surgical recommendations for internal fixation can be made.

　　When tumor tissue or bone fragments protrude into the spinal canal, metastatic epidural spinal cord compression (MESCC) occurs. When this lesion causes neurological damage, it is usually an emergency. This situation occurs in 5-10% of cancer patients and over 40% of patients with bone metastases from other sites. Corticosteroids and X-ray radiotherapy are the main treatment methods. In the past, the choice of surgical methods was limited to laminectomy, but this technique cannot decompress the anterior aspect of the vertebrae and causes instability of the posterior structures, leading to spinal instability, deterioration of neurological function, and pain. Therefore, the active surgical technique of circumferential decompression of the spinal cord is more commonly used.

　　(3) Adjunctive therapy. There are reviews showing that the improvement of clinical results over time is related to the progress of increasingly aggressive surgical treatment strategies. Although there is a relatively higher postoperative mortality rate (average 10%), the best reported improvement in motor function comes from studies on patients undergoing anterior decompression and internal fixation (average 75%). There are also studies showing that surgery combined with XRT is superior to XRT alone in the treatment of MESCC. Although the results of this study are impressive, it is important to consider the selection criteria of the study. It is noteworthy that patients with highly sensitive tumors to radiotherapy, such as lymphoma, myeloma, and small cell lung cancer, were excluded from both groups. In these patients, XRT alone is suitable for MESCC without spinal instability. In addition, XRT alone is also suitable for patients with rapid progression of neurological dysfunction, no obvious bone block protrusion into the spinal canal, or expected survival time

　　① Drug therapy

　　The application of drug therapy in the treatment of spinal metastatic cancer can be divided into two categories: drugs directly acting on the tumor and drugs that minimize secondary symptoms of the tumor. Many spinal metastatic cancers are not very sensitive to cytotoxic agents, and the antitumor drugs used to treat these lesions are limited. Conversely, the use of drugs to prevent and improve symptoms of spinal tumors, including pain, inflammation, and bone destruction, is widespread.

　　② Chemotherapy: Although the progress of chemotherapy regimens in the past few decades has improved the effectiveness of cancer treatment, these therapies are usually limited in the treatment of spinal metastatic cancer because spinal metastatic cancer is a late complication of cancer. However, the application of neoadjuvant therapy after surgery has improved the effectiveness of treatment for some metastatic tumors, including germ cell tumors, high-risk neuroblastoma, Ewing's sarcoma, osteosarcoma. In addition, tumors that were previously considered inoperable can now be surgically removed after receiving neoadjuvant therapy. For example, due to the high incidence of surgical complications and limited postoperative improvement, it was previously considered that the spinal metastasis of non-small cell lung cancer above the scalene muscle was inoperable. However, after receiving neoadjuvant therapy (依托铂甙 and cisplatin) and XRT, two-thirds of such tumor patients found that the tumor volume had decreased and the possibility of negative resection margins had increased during surgery. Other drug therapies for the treatment of spinal metastatic cancer are also effective.

　　③ Hormonal Therapy: Some spinal metastatic cancers, especially those originating from breast cancer and prostate cancer, may have hormone receptors, and treatment directly targeting these receptors is effective. Selective estrogen receptor modulators, such as tamoxifen, aromatase inhibitors, such as letrozole, anastrozole, and exemestane, have shown effectiveness in the treatment of breast cancer. For prostate cancer, the use of estrogen inhibitors combined with gonadotropin-releasing hormone agonists and/or flutamide is an effective therapy. Even if the primary tumor is sensitive to hormonal therapy, the metastatic tumors may not have the same hormone receptors and may not be sensitive to hormonal therapy.

　　④ Bisphosphonate Therapy: Such drugs inhibit bone destruction and bone resorption associated with spinal metastatic cancer, can reduce the risk of pathological fractures, alleviate local pain caused by destructive lesions, and reduce hypercalcemia associated with malignant tumors. The treatment of metastatic breast cancer, multiple myeloma, and other osteolytic metastatic tumors has been proven to be effective.