If this is not your name, click here.
| | If this is not your name, click here. | | |
| | Contact Us | Order Now | Journals | Bookstore | Register a colleague | | |
| |  DG DISPATCH - ASTRO: Higher-dose, 3D Radiotherapy Offers Low Toxicity For Prostate Cancer By Maria Bishop Special to DG News
BOSTON, MA -- October 26, 2000 -- Patients treated for early-stage prostate cancer using three-dimensional radiation therapy (3DCRT) show better-than-expected tolerance to the treatment despite dose escalation, researchers report. The research team described a dose-escalation trial of 3DCRT for localized prostate cancer at the 42nd Annual Meeting of the American Society for Therapeutic Radiology and Oncology (ASTRO) in Boston, Massachusetts. "We were concerned that, as the dose increased, complication rates would also increase-maybe not right after treatment, but several months and several years later," stated lead author Jeff M. Michalski, MD, Assistant Professor, Department of Radiology, Mallinckrodt Institute of Radiology, Washington University School of Medicine, St. Louis, Missouri. From August 1994 to September 1999, 424 patients were entered into this ongoing, cooperative-group trial conducted at 40 institutions across the United States as a Radiation Therapy Oncology Group (RTOG) trial. At the interim of this study, 396 patients were analysable for toxicity. Patients were stratified into three groups. The lower-risk patients in Group 1 had clinical stage T1-2 tumours, with a seminal-vesicle-invasion (SVI) risk of less than 15 percent. Group 2 had stage T1-2 tumours and an SVI risk of 15 percent or greater. Group 3 had more advanced, stage T3 tumours. The standard trial doses of 3DCRT comprised two levels. Level-one doses were 68.4 Gy (n=111); level-two doses were 73.8 Gy (n=274). Late toxicity effects were low, with the frequency of grade 3 or higher toxicity at less than 1 percent in Group 1, less than 3 percent in Group 2 and less than 10 percent in Group 3. In Group 3 (patients treated with 73.8 Gy, and no reduction in dose over the course), 7 percent of patients reported grade 3 toxicities and 3 percent reported grade 4 toxicities. Grade 1 and 2 acute and late toxicities were also low -- 16 -21 percent in groups 1 and 2; 25 -31 percent in group 3. "Tolerance to 3DCRT [in this study] remains better than expected, despite dose escalation," noted Dr. Michalski. While results on a 79.2-Gy dose arm are not yet available for analysis, Dr. Michalski said it is likely there will be no increase [compared to historical controls] in complication rates for that arm, either. A further benefit of this analysis, added Dr. Michalski, is that it proves that 3DCRT can be performed well at community hospitals and centers-not just at academic facilities. The RTOG is a cancer-study research group funded by the U.S. National Cancer Institute and headquartered in Philadelphia, Pennsylvania.
|
