Radiosurgery for spinal malignant tumors

Bone metastases in thyroid cancer

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Osseous metastases (OMs) occur in only 4% of all thyroid cancer patients but are associated with greatly increased morbidity and mortality.

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OMs are about twice as frequent in follicular, hurthle cell, and medullary thyroid cancers as compared to papillary thyroid cancers.

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OMs are often lytic, triggered via activation of osteoclasts by tumor cells in a “vicious cycle”.

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OMs are often initially asymptomatic, but associated with eventual skeletal related events in >75%.

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Early identification of OMs, preemptive treatment with antiresorptive agents, and aggressive treatment of focal lesions before crisis are key.

Whereas preemptive screening for the presence of lymph node and lung metastases is standard-of-care in thyroid cancer patients, bone metastases are less well studied and are often neglected in thyroid cancer patient surveillance. Bone metastases in thyroid cancer are, however, independently associated with poor/worse prognosis with a median overall survival from detection of only 4 years despite an otherwise excellent prognosis for the vast majority of thyroid cancer patients. In this review we summarize the state of current knowledge as pertinent to bony metastatic disease in thyroid cancer, including clinical implications, impacts on patient function and quality of life, pathogenesis, and therapeutic opportunities, proposing approaches to patient care accordingly. In particular, bone metastasis pathogenesis appears to reflect cooperatively between cancer and the bone microenvironment creating a “vicious cycle” of bone destruction rather than due exclusively to tumor invasion into bone. Additionally, bone metastases are more frequent in follicular and medullary thyroid cancers, requiring closer bone surveillance in patients with these histologies. Emerging data also suggest that treatments such as multikinase inhibitors (MKIs) can be less effective in controlling bone, as opposed to other (e.g. lung), metastases in thyroid cancers, making special attention to bone critical even in the setting of active MKI therapy. Although locoregional therapies including surgery, radiotherapy and ablation play important roles in palliation, antiresorptive agents including bisphosphonates and denosumab appear individually to delay and/or lessen skeletal morbidity and complications, with dosing frequency of every 3 months appearing optimal; their early application should therefore be strongly considered.

Evaluation of efficacy and safety of robotic stereotactic body radiosurgery and hypofractionated stereotactic radiotherapy for vertebral metastases

Aim of the study

The purpose of this study was to evaluate the efficacy and safety of applying CyberKnife (CK) radiosurgery in patients with spinal metastases.

Material and methods

Twenty-eight patients with vertebral metastases treated using the CK system were included in the study. Eleven patients suffered from pain, and in 1 case neurological symptoms were observed. The remaining patients were free from clinical symptoms of metastatic disease. The doses applied ranged between 8 and 40 Gy delivered in 4 fractions of 8–15 Gy.

Results

In the first follow-up evaluation (mean 4.5 months after the treatment), pain was stable in 5 of 8 evaluable cases and in 3 regression occurred. The last follow-up examination (mean 11 months after stereotactic radiosurgery) revealed stable ailments in 3 of 6 evaluable cases, improvement in 3 and new complaints in another 4 patients. In 17 patients imaging studies were conducted after a mean time of 11 months after CK treatment. Stabilization was confirmed in 11, regression in 4 and progression in 2 cases. Median overall survival was 20.6 months. Median progression-free survival was 12.6 months. No side effects attributable to the treatment were observed, but during follow-up transient or permanent deterioration in neurological status as a consequence of disease progression was diagnosed in 4 patients. Delivery time of a single fraction ranged between 0.5 and 1.5 hours.

Conclusions

Robotic stereotactic radiosurgery as part of multimodality therapy for metastatic spinal tumours is safe and effective. Because of long irradiation times, this kind of treatment is not suitable for patients in poor general condition.

Management and outcome in adult intramedullary spinal cord tumours: a 20-year single institution experience

Background

Several uncertainties remain concerning the management of intramedullary spinal cord tumours (IMSCTs). These include the timing and extent of resection, its interrelated functional outcome, and the adequate use and timing of radiation therapy and/or chemotherapy. In this retrospective study we report on all adult cases involving IMSCTs treated from 1987 to 2007 in our institution to validate our treatment strategy for IMSCTs. Pre- and post-operative functional performance was classified according to the McCormick scale.

Results

A total of 70 adult cases with IMSCTs consisting of ependymoma (39), astrocytoma (11), carcinoma metastasis (8), haemangioblastoma (5), cavernoma (3) and others (4) were reviewed. Mean age was 46.8 years (range, 18-79 years), and mean follow-up was 4.5 years (range, 1-195 months). The proportion of localisation in descending order was thoracic (36%), cervical (33%), cervicothoracic (19%) and conus region (13%), with 45 gross total resections, 22 partial resections and three biopsies. Surgery-related morbidity with worsening postoperative symptoms occurred immediately in 13 patients (18.6%). The preoperative McCormick grade correlated significantly with the early postoperative grade and the grade at follow-up (χ²-test; p = 0.001). None of the patients with preserved intraoperative evoked potentials exhibited significant postoperative deterioration. The degree of resection was correlated with progression-free survival (Duncan test; p = 0.05). Most patients with malignant tumours, namely anaplastic ependymoma (3), astrocytoma (2) or metastatic lesions (5), underwent postoperative radiation therapy. Six patients (one anaplastic ependymoma, two anaplastic astrocytomas and three metastatic lesions) received postoperative chemotherapy.

Conclusions

IMSCTs should be operated on when symptoms are mild. We recommend evoked potential-guided microsurgical total resection of ependymomas and other benign lesions; partial resection or biopsy followed by adjuvant therapy should be confined to patients with high-grade astrocytomas, whereas resection or biopsy with adjuvant therapy is the best option for metastatic lesions.

Spinal radiosurgery--efficacy and safety after prior conventional radiotherapy

Background

Conventional external beam radiotherapy is a standard procedure for treatment of spinal metastases. In case of progression spinal cord tolerance limits further radiotherapy in pre-irradiated areas. Spinal stereotactic radiotherapy is a non-invasive option to re-treat pre-irradiated patients. Nevertheless, spinal radiosurgery results in relevant dose deposition within the myelon with potential toxicity. Aim of the study was to retrospectively analyse the efficacy and feasibility for salvage radiosurgery of spinal metastases.

Methods

During a period of 4 years (2005-2009) 70 lesions in 54 patients were treated in 60 radiosurgery sessions and retrospectively analysed. Clinical (pain, sensory and motor deficit) and radiological (CT/MRI) follow-up data were collected prospectively after radiosurgery. Pain - as main symptom - was classified by the Visual Analogue Scale (VAS) score. Every patient received single session radiosurgery after having been treated first-line with conventionally fractionated radiotherapy. Kaplan-Meier method and life tables were used to analyse freedom from local failure and overall survival.

Results

At a median follow-up of 14.5 months the actuarial rates of freedom from local failure at 6/12/18 months were 93%, 88% and 85%, respectively. The median radiosurgery dose was 1 × 18 Gy (range 10-28 Gy) to the median 70% isodose. The VAS score of patients with pain (median 6) dropped significantly (median 4, p = 0.002). In 6 out of 7 patients worse sensory or motor deficit after SRS was caused by local or distant failures (diagnosed by CT/MRI). One patient with metastatic renal cell carcinoma developed a progressive complete paraparesis one year after the last treatment at lumbar level L3. Due to multiple surgery and radiosurgery treatments at the lumbar region and further local progression, the exact reason remained unclear. Apart from that, no CTC grade III or higher toxicity has been observed.

Conclusions

By applying spinal radiosurgery relevant radiation doses can be limited to small parts of the myelon. This prevents myelopathic side effects and makes it an effective and safe treatment option for well-suited patients. Especially for previously irradiated patients with local failure or pain salvage SRS represents a valuable treatment option with high local control rates, low toxicity and significant pain reduction.