Metastatic Spine Tumors Recommendations

Incidence, epidemiology, radiology, and classification of metastatic spine tumors:

1- Metastatic spinal neoplasms are the most commonly encountered tumors of the spine with Incidence 6.68 cases per 100,000. They can be found on autopsy in more than 30% patients died from cancer diseases, having mean clinical cumulative incidence is 16%.

2- Approximately two thirds of spinal metastases arise from breast (16.5%), prostate (20.7%) and lung carcinoma (24.6%).

3- Roughly 1 in 10 patients with SM will develop metastatic epidural spinal cord compression (9.5%) or pathological vertebral fracture (12.6%).

4- Spinal metastases are most commonly seen in individuals aged between 40 and 70 years and comparatively higher in males.

5- In 75% cases the metastatic spine lesion can be detected on the thoracic spine most likely proportional to bone volume, followed by lumbar, cervical and sacral area.

6- The median time interval from initial diagnosis to SM is 9 months for lung cancer, 14.9 m. for breast and 17.4 months for prostate carcinoma respectively. This is most likely related to overall survival of patients with specific histological tumors type.

7: MRI is the gold standard of imaging for spine metastasis, due to its proven ability of identified pathologic tissue and compression of surrounding nervous tissue.

8: CT scan is the study of choice to characterize changes of the bone architecture related to spinal metastasis.

9: Nuclear medicine technologies (PET/CT or MRI, SPECT) may have a role in diagnosis when standard MR or CT study findings are inconclusive. They are also highly useful in assessing the extent of systemic metastatic disease.

10: The Neurologic, Oncologic, Mechanical and Systemic (NOMS) framework is a commonly used tool to determine the appropriate treatment of patients with metastatic spinal tumors.

Clinical evaluation, diagnosis and decision-making for metastatic spine tumors:

1- A high index of suspicion for early detection and diagnosis of spinal metastasis in cancer patients and adult patients more than 60 years presenting with new onset fractures / neurological deficits is
recommended.

2- Pain is the most common symptom in patients with spinal metastasis closely followed by motor radiculopathy. Origin of pain can be multifactorial, owing to local tumor related pain, nerve root irritation or pain due to spinal instability.

3- Bladder and bowel symptoms are present in more than half of the patients at the time of diagnosis.

4- An effective treatment for spinal metastases should be able to achieve pain, tumor control, prevention of neurological compromise and treat instability.

5- Separation surgery combined with SRS is an effective treatment for spinal metastases.

Radiation therapy, radiosurgery, chemotherapy, and targeted therapy for metastatic spine tumors:

1- Multidisciplinary team consisting of spine surgeons, radiation oncologists, radiologists and oncologists should be involved in the management of patients of metastatic spine tumors. SRS (Stereotactic Radiosurgery) / EBRT (External Beam Radiotherapy) should be delivered after consideration by surgeons who can potentially help achieve cytoreduction/ separation surgery.

2- Choices for treatment of recurrence include re-irradiation with SBRT vs EBRT, surgical debulking, additional chemotherapy or palliative care.

3- There is a lack of current clinical evidence to support the routine use of targeted therapies in the management of metastatic spinal tumors.

Surgical options for metastatic spine tumors:

     a) Instability criteria of metastatic vertebral tumors:

1- The Spinal Instability Neoplastic Score (SINS) is an effective tool for evaluating spinal instability and has resulted in improved uniform reporting of spinal instability criteria in metastatic tumor patients.

2- The SINS score has good reliability across multiple specialties, particularly in experienced spine surgeons, and may improve referrals of unstable spine patients to surgeons. However, it's utility for non-spine practitioners is less clear.

3- The decision to operate should not be based solely on SINS, as there are multiple other factors, including number of levels of disease, tumor type, prior treatment history, patient frailty, and life expectancy. All these factors should be incorporated in treatment recommendation and plan.
         

      b) Surgical options for cervical and CVJ metastatic vertebral tumors:

4- Surgical planning for cervical and CVJ metastatic vertebral tumors should be done using prognostic scoring systems.

5- Metastatic disease of the junctional areas of the cervical spine (occipitocervical and cervicothoracic) will need robust and more frequent surgical stabilization.

6- In craniocervical junction metastatic tumors, posterior instrumentation including occiput may be sufficient for stabilization, pain control and neurologic preservation.

7- Complications of surgery of cervical and CVJ metastatic tumors are approximately 25%. Anterior surgeries tend to have more complications than posterior surgeries.

8- Prognostic factors for postoperative overall survival are tumor histology, preoperative disease progression status, postoperative RT and chemotherapy.

    c) Surgical options for thoracic, lumbar and sacral metastatic vertebral tumors:

1- Asymptomatic patients with metastatic lesion in the thoracic, lumbar spine and sacrum generally do not need surgery. Patients with high risk of vertebral compression fracture after radiation or chemotherapy may be considered for pre-treatment vertebral augmentation.

2- Palliative radiotherapy alone may stabilize or improve neurologic deficits of patients with spinal cord compression.

3- SCORE 2 and SCORAD III randomized trials, both SFRT and MFRT improved ambulatory status at eight weeks in patients with metastatic spine disease.

4-Thoracic and lumbar metastatic lesions causing severe mechanical pain or instability (as measured by SINS) require stabilization. Anterior column reconstruction should be considered in patients with long-term survival.

5-Construct length and extent of surgery should be balanced with patient frailty.

6-Thoracic and lumbar metastatic lesions with significant epidural cord compression (Bilsky 2 and 3) from tumors resistant to cEBR should undergo decompression with / without instrumentation prior to radiation therapy.

7-Sacral metastatic lesions with cortical erosion or destruction of the posterior superior SI joint should be evaluated for sacroplasty or transiliac-transacral fixation to prevent fracture.

8-Lesions involving the sacral ala and lumbosacral junction require lumbopelvic fixation if there is evidence of instability.

     d) Minimally invasive surgery and percutaneous techniques for metastatic vertebral tumors: 

9-MISS may be considered in the treatment of patients with spinal metastatic disease. (7/7 agreement) MISS in patients with spinal metastasis has potential to achieve the goals of standard surgery, while reducing hospital stay, providing faster recovery, reducing the complications.

10-The MISS may provide an alternative surgical option which may be applied in frail patients with spinal metastasis.

Complication avoidance, rehabilitation, pain therapy, and palliative care for patients with metastatic spine tumors:

     a) Pain therapy and palliative care for metastatic vertebral tumors: 

1-Pain management and palliation in spinal metastasis should be performed as indicated by the WHO analgesic ladder appropriate for the severity of pain starting with non-opioids, weak opioids followed by strong opioids.

2-The opioid of first choice for moderate to severe cancer pain is oral morphine [1, A], with a different opioid to be considered in the absence of adequate pain control (despite opioid dose escalation) or in the presence of unacceptable opioid side effects.

3-IV-PCA may provide timely, safe, and useful analgesia for patient with severe breakthrough pain, however need to closely monitor delirium and toxicity in advanced cancer patients.

4-Bisphosphonates may be considered for the treatment of patients with bone metastases with a good prognosis, especially when pain is not localized, or RT is not readily accessible.

     b) Complication avoidance and rehabilitation of geriatric patients with metastatic vertebral tumors:

5-Preoperative assessment for complications following surgery in patients with metastatic spine tumors should include estimation of Karnofsky score, primary tumor, number of spinal and visceral metastasis, ASA score, and preoperative Hb (Hemoglobin) value.

6-There is evidence that advanced age (>65 years) is a significant risk factor for complications in treatment of patients with spinal metastases.

7-Preoperative ASA score of 3 and 4 increases the risk of medical and surgical complications in patients with spinal metastasis. Surgical treatment planning in these patients needs additional consideration in respect of duration and invasiveness of surgery and estimated blood loss.

8-Patients who underwent surgery for spine metastasis with greater blood loss have increased likelihood for cardiovascular events, pulmonary insufficiency and cerebral events, therefore these patients need careful monitoring of these potential postoperative complications.

9-Early postoperative mobilization and multimodal pain management are encouraged for high-risk patients with spinal metastasis.

Outcome prediction, life expectancy and quality of life of metastatic vertebral tumors:

1-Irrespective of the primary tumor, surgical decompression increases the life expectancy in patients with vertebral metastases.

2-Preoperative ambulatory status, overall performance and age are independent predictors of outcome and overall survival in patients with spine metastases.

3-Amongst principle-based decision-making systems NOMS is the most widely used, but other frameworks LMNOP and MNOP are now frequently utilized due to their incorporation of additive patient factors, like systemic therapy to primary disease and previous treatment taken.

4-Independent disease factors like primary tumor histology and the presence of visceral metastasis are significant prognostic indicators for spine metastases.

5-Principle-based decision-making system eg (NOMS, LNMOP, MNOP) provide more specific treatment suggestions for each patient with spinal metastasis based on their oncologic, systemic and functional status in contract to prognostic models (Tokouhashi, Baur's & SORG) which only predict patients' life expectancy.

6-Amongst tools to measure quality of life (QOL) in patients with metastatic spine disease, EUQOL5-D and SOSGOQ is being widely useful and validated. Data is scarce to prefer one over the other but SOSGOQ is more sensitive to interpatient differences.

7-Amongst the prognosis scoring system, SORG-ML algorithms in spinal metastatic disease, score well for 90 day and 1 year mortality and survival. However, multicenter cross-population studies are required for further validation.