Radiosurgery Clinical Data for General Surgeons

Excising tumors is part of a surgeon’s routine, even though there’s nothing “routine” about it. To add to the challenges, some patients are inoperable, and some tumors are marginally resectable or unresectable.

At CyberKnife of Southern California at Vista, we make it possible for you to treat these patients. We ablate localized, solid-mass tumors using the same medical science that has been successfully treating tumors since the 1960s. Yet, we do it with unprecedented precision and flexibility.

Radiosurgical ablation has been a primary treatment for intracranial tumors for decades. But it required a stereotactic frame. Today, CyberKnife® tracks the tumor’s true location during treatment and continually adjusts for movement, making the frame unnecessary and permitting treatmentanywhere in the body (including areas that move with respiration). In addition, at CyberKnife of Southern California at Vista, we provide the area’s best radiosurgery expertise, its highest volume of radiosurgical experience and the world’s first next-generation CyberKnife platform and most advanced hardware and software.

CyberKnife delivers an ablative dose to the tumor with submillimeter accuracy and, therefore, minimal exposure of normal tissue. As a result, we cantreat inoperable patients, shrink tumors for less radical resections, destroy radioresistant tumors, 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 tumors treatable with stereotactic radiosurgical ablation is unprecedented. Which patients can benefit from this advanced method of tried-and-true radioablation? As the 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...

• 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, previoustreatment 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 – While it isn’t indicated for cases of obstructive viscera, CyberKnife can destroy or shrink tumors for reasons of pain relief even if cure is no longer an option.

• Tumors that move – For tumors in the abdomen, respiratory motion can complicate radiation treatment. CyberKnife tracks the tumor’s location and movement, and its ablative beam moves in synchrony with the patient’s respiratory pattern or any shifts in the tumor’s position, maintaining precision throughout treatment.

Pancreas:

• Phase I study of stereotactic radiosurgery in patients with locally advanced pancreatic cancer.  Koong et al. 2004. Stanford University researchers treated patients with locally advanced pancreatic cancer using the CyberKnife System.  They found it was feasible to achieve local control without significant acute gastrointestinal toxicity using a dose of 25 Gy.

• Phase II study to assess the efficacy of conventionally fractionated radiotherapy followed by a stereotactic radiosurgery boost in patients with locally advanced pancreatic cancer. Koong et al. 2005. Stanford University researchers found that concurrent IMRT and 5-FU followed by treatment with the CyberKnife System on patients with locally advanced pancreatic cancer results in excellent local control. Overall survival was not affected, and the combined treatment caused more toxicity than radiosurgery alone.

Liver: 

• BOOK CHAPTER:  Stereotactic Radiosurgery for Liver Malignancies Using the CyberKnife. Goodman 2008. Researchers from Stanford University treated 20 patients with liver malignancies using the CyberKnife System.  At a median of 7 months they observed limited toxicity and 76% of the treated lesions showed a decrease in size.  The researchers concluded that CyberKnife System treatment to the liver for primary or metastatic malignancies is feasible and safe.

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.