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Stereotactic Radiosurgery Shows Promise as a Therapeutic Option for Patients With Primary Renal Cancer

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BOSTON, Oct. 31, 2012 (GLOBE NEWSWIRE) -- The first trial of safety and toxicity shows promise for stereotactic radiosurgery as a therapeutic option for patients with localized primary renal cancer who are considered poor surgical candidates and who do not have a prior history of pelvic or abdominal radiation, according to research presented today at the American Society for Radiation Oncology's (ASTRO's) 54th Annual Meeting.
    
This study of stereotactic radiosurgery presents results of patients from two to 41 months post-treatment using a four-part dose escalation schema. The response rate indicates that patients reacted well and had acceptable levels of treatment-related toxicity following stereotactic radiosurgery in all age groups from 58 to 92 years old. There were no reports of gastrointestinal or small bowel toxicity, or cancer-related deaths.  For 94 percent of patients across all four groups, their tumors remained stable or decreased on post-treatment imaging. For patients who underwent a post-treatment biopsy, incomplete or refractory treatment was found in 91 percent, which suggests the need for higher radiation doses for adequate tumor control. Acute toxicity was limited to Grade 1 fatigue in two patients in the highest dose treatment group, which was relieved by rest. Late toxicity was limited to worsening of preexisting chronic renal disease in two patients who had a mean epidermal growth factor receptor (EGFR) of 19.5. 
     
Twenty patients ranging from 58 to 92 years old received initial doses of 600 cGy per fraction, followed by increments of 200 cGy per fraction to total doses of 24 Gy, 32 Gy and 48 Gy. Doses were escalated after patients showed non-prohibitive levels of toxicity within 180 days from the date of treatment. Limiting levels of toxicity were defined as any Grade 3 or higher gastrointestinal/genitourinary acute radiation toxicity, according to the National Cancer Institute common toxicity criteria. Imaging and post-treatment biopsy results were evaluated for tumor response and treatment efficacy.
     
"Our first trial shows that low to moderate doses of stereotactic radiosurgery is a safe and viable option for renal cancer patients who typically do not have surgical options," said Rodney J. Ellis, MD, lead author of the study, clinical director and vice chair for clinical affairs of the department of radiation oncology at University Hospitals Case Medical Center Seidman Cancer Center, and an associate professor in radiation oncology and urology at Case Western Reserve University School of Medicine in Cleveland.  "Dr. Lee Ponsky, who is the principle investigator for this study from the department of urology, and I agree that further studies are needed to determine safe levels for the maximum dosage. By doing so, we hope to find increased response and cure rates with this method."
     
The abstract, "Stereotactic Radiosurgery for Renal Cancer: Phase I Safety and Toxicity," will be presented during a scientific session at ASTRO's 54th Annual Meeting at 11:00 a.m. Eastern time, on Wednesday, October 31, 2012. To speak with Dr. Ellis, call Michelle Kirkwood on October 28-31, 2012, in the ASTRO Press Office at the Boston Convention and Exhibition Center at 617-954-3461 or 617-954-3462, or email michellek@astro.org.
     
ASTRO's 54th Annual Meeting, held in Boston, October 28 – 31, 2012, is the premier scientific meeting in radiation oncology and brings together more than 11,000 attendees including oncologists from all disciplines, medical physicists, dosimetrists, radiation therapists, radiation oncology nurses and nurse practitioners, biologists, physician assistants, practice administrators, industry representatives and other health care professionals from around the world. The theme of the 2012 Annual Meeting is "Advancing Patient Care through Innovation" and examines how innovation in technology and patient care delivery can lead to improved patient outcomes. The four-day scientific meeting includes six plenary papers and 410 oral presentations in 63 oral scientific sessions, and 1,724 posters and 130 digital posters in 18 tracks/topic areas. 

ABOUT ASTRO











ASTRO is the largest radiation oncology society in the world, with more than 10,000 members who specialize in treating patients with radiation therapies. As the leading organization in radiation oncology, biology and physics, the Society is dedicated to improving patient care through education, clinical practice, advancement of science and advocacy. For more information on radiation therapy, visit www.rtanswers.org. To learn more about ASTRO, visit www.astro.org.

2012 American Society for Radiation Oncology (ASTRO) 54th Annual Meeting
News Briefing, Wednesday, October 31, 7:00 – 7:45 a.m. Eastern time

Scientific Session: Wednesday, October 31, 2012, 11:00 a.m. – 12:30 p.m. Eastern time, Boston Convention & Exhibition Center

294   Stereotactic Radiosurgery for Renal Cancer: Phase I Safety and Toxicity

R. J. Ellis1,2, R. B. Patel12, C. Kunos1,2, Y. Zhang1, J. Brindle1, V. Kudithipudi1,3, D. A. Kaminsky1, L. Ponsky4, 1University Hospitals Seidman Cancer Center, Department of Radiation Oncology, Cleveland, OH, 2Case Western Reserve University Medical School, Cleveland, OH, 3Northeastern Ohio University College of Medicine, Rootstown, OH, 4University Hospitals Seidman Cancer Center, Department of Urology, Cleveland, OH

Purpose/Objective(s): Poor-surgical candidates with localized primary renal cancer have limited treatment options. Stereotactic radiosurgery represents a promising therapeutic option. This trial is, to our knowledge, the first prospective report of safety and toxicity using stereotactic radiosurgery for primary renal cancer. We present 2-41 month outcomes after stereotactic radiosurgery treatments using a 4-part dose escalation (DE) schema.

Materials/Methods: As defined by an institutional review board approved protocol; eligibility criteria for the study required biopsy or radiologically determined diagnosis of localized primary renal cancer, considered a poor surgical candidate, without history of prior pelvic or abdominal radiation. Mean age was 80, range 58-92 years (15 men and 5 women). Qualifying patients were assigned to treatment groups according to the DE schema. An initial dose of 600 cGy per fraction was delivered, followed by DE of 200 cGy increments per fraction to total doses of 24 Gy, 32 Gy and 48 Gy maximum dose. DE was initiated in the absence of a dose limiting toxicity within 180 days from the date of treatment. Dose limiting toxicity was defined as any Grade 3 or higher gastrointestinal/genitourinary acute radiation toxicity, according to the National Cancer Institute common toxicity criteria (v4.0). Imaging and post treatment biopsy results were evaluated for tumor response and treatment efficacy.

Results: For the 20 patients enrolled (DE total dose: 4 to 24 Gy, 6 to 32 Gy, 4 to 40 Gy, and 6 to 48 Gy), we found acceptable levels of treatment related toxicity following SR. Acute toxicity was limited to Grade 1 fatigue (relieved by rest) in 2 patients, both in the 48 Gy treatment group. Late toxicity was limited to worsening of preexisting chronic renal disease (an expected consequence of treatment in the 2 patients having a mean eGFR of 19.5) 1 each in the 24 Gy and 40 Gy treatment groups. No gastrointestinal or small bowel toxicity was reported. Tumor response rate, defined by stable or reduced tumor volume on post treatment imaging, was observed in 94% across all treatment groups: 4/4 (24 Gy), 6/6 (32 Gy), 2/3 (40 Gy), and 5/5 (48 Gy). For the subset having undergone a post treatment biopsy, incomplete or refractory treatment was found in 91%: 2/2 (24 Gy), 3/4 (32 Gy), 4/4 (40 Gy), and 1/1 (48 Gy); suggesting the need for higher radiation doses for adequate tumor control. No cancer related deaths were reported.

Conclusions: Stereotactic radiosurgery was well tolerated across all treatment groups. Based on these findings of limited toxicity using low to moderate stereotactic radiosurgery doses for primary renal cancer, we recommend initiation of a follow-on stereotactic radiosurgery trial for renal cancer, utilizing a 3-part DE schema defined as 3 fractions in 200 cGy increments to 48 Gy, 54 Gy, and 60 Gy maximum total dose.

Author Disclosure Block:


















R.J. Ellis: None. R.B. Patel: None. C. Kunos: None. Y. Zhang: None. J. Brindle: None. V. Kudithipudi: None. D.A. Kaminsky: None. L. Ponsky: G. Consultant; Accuray Inc., Sunnyvale, CA, Tengion Inc., Winston-Salem, NC, US Endoscopy, Mentor, OH, Varian Medical System, Palo Alto, CA.

CONTACT: Michelle Kirkwood, 703-286-1600, michellek@astro.org
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