Radiosurgery Clinical Data for Otorhinolaryngologists

As a head and neck surgeon, you are likely familiar with radiosurgical treatment of tumors. For example, radiosurgery is often used by neurosurgeons working with head and neck surgeons to treat acoustic neuromas. In fact, neurosurgeons have been successfully treating intracranial tumors with radiosurgery since the 1960s.

At CyberKnife of Southern California at Vista, we’re innovating how you treat head and neck tumors by enabling you to effectively remove and shrink localized, solid-mass tumors with radiosurgery. CyberKnife® tracks a tumor’s true location during treatment and continually adjusts for movement. This makes a stereotactic frame unnecessary, enabling treatment anywhere on the head and neck (and the entire body) and giving you a proven, effective method for treating inoperable patients and unresectable and marginally resectable tumors.

While radiotherapy irradiates both normal and cancerous tissues, CyberKnife delivers an ablative dose to the tumor with submillimeter accuracy and minimal exposure of normal tissue. As a result, CyberKnife of Southern California at Vista can treat inoperable patients, shrink tumors for less radical resections, destroy radioresistant tumors and treat patients previously treated with radiation. In addition, patients experience short, painless treatments with far fewer side effects, limited (if any) downtime and an immediate return to activities.

CLINICAL INDICATIONS for CyberKnife.

With CyberKnife, the range of head and neck tumors treatable with stereotactic radiosurgical ablation is unprecedented. Which patients can benefit from this advanced method of tried-and-true radioablation? As the head and neck surgeon, that determination rests with you. Here are some of the clinical situations for which CyberKnife may serve as a viable and/or less risky alternative to surgery for head and neck tumors...

• Localized, solid-mass tumors – While conventional radiation therapy doesn’t do as well in the treatment of these kinds of lesions, CyberKnife’s ablative radiation dose is quite effective in destroying or shrinking them. Although CyberKnife is contraindicated for widespread metastatic disease, it is effective in nonsurgical treatment of certain metastatic tumors or tumors that need to be treated for palliative reasons.

• Medically inoperable patients – Because CyberKnife is noninvasive, it can treat patients who can’t endure surgery or who have a high risk for postoperative complications. With CyberKnife, treatment occurs in one to five short sessions, after which patients can immediately return to their lives. All with far less risk, side effects, recovery period, pain, scarring and hospital stay than surgery.

• Unresectable & marginally resectable tumors – Many localized solid-mass tumors that are not resectable may still be treatable – and effectively – by CyberKnife. The same is true for those that are marginally resectable. CyberKnife often is used alone to treat these lesions but can also be combined with surgery and other treatments to maximize treatment benefit. CyberKnife can also be used preoperatively to reduce tumor volume to make it more easily resected.

• Tumors adjacent to critical structures – CyberKnife’s submillimeter precision means we’re able to destroy or shrink tumors near to or involved with critical structures. In some cases, critical structures may be the reason a tumor is considered unresectable or only marginally resectable. Tumor proximity to critical structures also increases risk of surgical complication. With significantly less irradiation of surrounding tissues, CyberKnife can even treat tumors untreatable with convention radiotherapy because of nearby critical anatomy.

• Prior radiation treatment – With conventional radiation therapy, previous treatment often precludes future radiotherapy. With CyberKnife, however, highdose, short-course, focused treatment is so precise that cumulative exposure is significantly less. Therefore, previous radiation treatment is not a contraindication for CyberKnife.

• Tumors with high risk of recurrence – For tumor types known to have a high likelihood of recurrence, CyberKnife’s low cumulative exposure makes it an ideal treatment option. If the tumor recurs, the patient can be treated with CyberKnife again (and perhaps multiple times) or be treated with other forms of radiation.

• Radioresistant tumors – It’s true that some tumor types are resistant to the radiobiological effect of conventional radiation therapy. But they aren’t resistant to radiosurgical ablation, which destroys the tumor while preserving surrounding tissue.

• Palliation – CyberKnife can destroy or shrink tumors for reasons of pain relief even if cure is no longer an option.

Brain Tumors:

• Staged stereotactic irradiation for acoustic neuroma. Chang et al. 2005 . Stanford researchers show that fractionated treatment using the CyberKnife System for acoustic neuromas may improve hearing preservation.

• Visual field preservation after multisession CyberKnife radiosurgery for perioptic lesions. Adler, et al. 2006. Stanford University researchers used the CyberKnife System to obtain high rates of tumor control for tumors near (less than 2 mm from) the optic apparatus; over 90% of patients treated maintained or improved their vision.

• Stereotactic radiosurgery using CT cisternography and non-isocentric planning for the treatment of trigeminal neuralgia. Lim et al. 2006. Researchers from Stanford University used the CyberKnife System to treat trigeminal neuralgia.  Ninety percent of patients treated rated their pain control as excellent with limited facial numbness at 10 months follow-up.

• Stereotactic radiosurgery of the postoperative resection cavity for brain metastases. Soltys, et al. 2007. Researchers from Stanford University used the CyberKnife System for adjuvant treatment of brain metastases by targeting post-resection cavities. They obtained a 79% local control rate at 12 months, which compares favorably to historic whole brain radiation treatment results.

• A volumetric study of CyberKnife hypofractionated stereotactic radiotherapy as salvage for progressive malignant brain tumors: initial experience. Giller et al. 2007.  Researchers from Baylor University Medical Center used the CyberKnife System to perform fractionated stereotactic radiosurgery on lesions that are difficult to treat in a single fraction approach.

• Survival following CyberKnife radiosurgery and hypofractionated radiotherapy for newly diagnosed glioblastoma multiforme. Lipani et al. 2008. Researchers from Stanford University performed CyberKnife System treatment on 20 GBM patients after tumor resection. The overall median survival was 16 months, which compares favorably to post-surgical external beam radiation therapy.

Spine:

• CyberKnife stereotactic radiosurgical treatment of spinal tumors for pain control and quality of life. Degen, et al. 2005. Georgetown University Researchers performed CyberKnife System radiosurgery on patients with both benign and malignant spinal tumors. The results show pain relief and maintenance of quality of life after the treatment.

• CyberKnife radiosurgery for benign intradural extramedullary spinal tumors. Dodd et al. 2006. Stanford University researchers determined that benign lesions located on the spinal cord can be treated safely and effectively with the CyberKnife System.

• Multisession CyberKnife radiosurgery for intramedullary spinal cord arteriovenous malformations. Sinclair et al. 2006. Stanford University researchers used the CyberKnife System to treat spinal cord AVMs with fractionated stereotactic radiosurgery.

• CyberKnife radiosurgery for breast cancer spine metastases: a matched-pair analysis. Gagnon et al. 2007. Georgetown University researchers performed a comparison of external beam radiation therapy to CyberKnife System stereotactic radiosurgery for breast cancer metastasis to the spine.  Outcomes were statistically comparable, even though most of the patients treated with the CyberKnife System had previously undergone external beam radiation therapy.

• Radiosurgery for spinal metastases: clinical experience in 500 cases from a single institution. Gerszten et al. 2007. Researchers from the University of Pittsburgh Medical Center performed the largest published study on spinal radiosurgery. Their results show that single fraction CyberKnife System radiosurgery is safe and effective both as a primary treatment modality and as salvage treatment for spinal tumors.