Preliminary Report of Toxicity Following 3D Conformal Radiation Therapy (3DCRT) for Prostate Cancer on 3DOG/RTOG 9406, Level III (79.2 Gy)
Heather Jones, MD
University of Pennsylvania Cancer Center
Last Modified: November 7, 2001
Presenter: J. Ryu
Presenter's Affiliation: Rad Onc, UCD, Sacramento, CA
Type of Session: Scientific
The high rates of local relapse observed in prostate cancer patients with conventional radiation techniques have stimulated research to develop high precision radiation to decrease the risks of local recurrence. The three dimensional conformal approach applies sophisticated computer-driven techniques, programmed to deliver the prescribed radiation dose to the entire target volume, while conforming to the anatomical boundaries of the tumor in its entire three-dimensional configuration. This study is a prospective phase I dose escalation study conducted to determine the maximally tolerated radiation dose in men treated with 3D conformal RT for localized prostate cancer. This is a preliminary report of toxicity at level III (79.2 Gy) on 3DOG/RTOG 9406.
Group 2 (G2) T1,2 disease with risk of SV invasion >=15%;
Group 3(G3) clinical local extension of tumor beyond the prostate capsule (T3).
Based on excellent tolerance of 3D conformal RT for stage T1,2 prostate cancer, further biological dose escalation has been pursued to levels IV and V, 74 Gy and 78 Gy respectively, at 2 Gy per day, in an attempt to reduce the total treatment duration. RTOG is planning to evaluate whether this treatment approach improves efficacy.
3D-conformal RT has been developed, in part, to address the issue of tissue toxicity in the setting of dose escalation. This study demonstrates the ability of the 3D approach to reduce rectal and bladder toxicities. This approach permits an increase in the tumor dose to levels beyond those feasible with conventional two-dimensional radiation therapy, with a concomitant decrease in the risk of normal tissue complications. We await the studies that evaluate the impact on survival.
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