August 21, 2008 – Tumor control and survival outcomes in the first year following lung cancer treatment with the CyberKnife System were positive, according to the study "Fractionated Stereotactic Body Radiation Therapy in the Treatment of Primary, Recurrent, and Metastatic Lung Tumors," conducted at the University of Pittsburgh Medical Center (UPMC).
Control of tumor growth was achieved in 85 percent of primary cancer patients, 92 percent of recurrent lung cancer patients, and 62 percent of metastatic cancer patients during the first year of follow-up. This is drastically different from response rates for radiation therapy in this patient population, which are typically associated with poor local control and survival rates ranging from 10 to 30 percent at five-year follow-up, as noted within the study.
The study followed three patient populations over an average 12 month period: 1) patients with primary stage I non-small cell lung cancer, 2) patients whose cancer recurred after it was surgically removed, and 3) patients with metastatic tumors in the lung. All patients were treated with CyberKnife radiosurgery over a three-day period as outpatients. These patients had limited treatment options because they were medically inoperable (unable to undergo surgery due to pre-existing medical conditions or prior surgery) or refused surgery.
Additionally the study reported few of the complications or side effects that are typical with radiation or other more invasive treatments within the first 12 months of follow-up. Both invasive surgery and conventional radiation therapy can be associated with post-treatment complications that can negatively impact a patient's quality of life. In addition, unlike conventional radiation therapy that is typically delivered over four to six weeks, patients completed CyberKnife treatment in three short outpatient visits. This is extremely significant for patients with a potentially life-threatening disease because it allows them to preserve their lifestyle and spend their time with family instead of taking trips to and from the hospital and spending months in treatment.
"The CyberKnife System's ability to non-invasively treat lung cancer with favorable local control rates and minimal toxicities make it an important tool in the fight against lung cancer," said Dwight Heron, M.D., chairman of the radiation oncology department at UPMC Shadyside. "As demonstrated by our study, this is particularly important for patients who previously had few or no other options because it gives them a chance for a positive outcome while maintaining their quality of life."
UPMC treated all the study participants using the Synchrony Respiratory Tracking System, which can deliver beams that physically move in real-time with 3D tumor motion. The technology allows patients to breath normally throughout the treatment, while still achieving pinpoint precision and minimizing damage to surrounding healthy tissue. According to the study, Synchrony "can allow for reductions in planning target volume margins because of less movement uncertainty while maintaining the desired level of accuracy."
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