Stereotactic radiosurgery may hold potential 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 data from a safety and toxicity study recently presented at the American Society for Radiation Oncology’s (ASTRO’s) 54th Annual Meeting.
This study of stereotactic radiosurgery presented results of patients from 2 to 41 months posttreatment using a four-part dose escalation schema. Across all four groups, tumors remained stable or decreased on post-treatment imaging in 94% of patients. For patients who underwent a posttreatment biopsy, incomplete or refractory treatment was found in 91%. Acute toxicity included grade 1 fatigue in two patients in the highest dose treatment group. Late toxicity included worsening of preexisting chronic renal disease in two patients.
Phase I Study Details
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 NCI common toxicity criteria. Imaging and post-treatment biopsy results were evaluated for tumor response and treatment efficacy.
Rodney J. Ellis, MD, lead author of the study, commented, “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.” Dr. Ellis is 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. Ellis added, “Further studies are needed to determine safe levels for the maximum dosage.” ■
1. Ellis RJ, Patel RB, Kunos C, et al: Stereotactic radiosurgery for renal cancer: Phase I safety and toxicity. 54th Annual Meeting of the American Society for Radiation Oncology. Abstract 294. Presented October 31, 2012.