Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
Clinical Trial
. 1996 Feb 1;34(3):555-64.
doi: 10.1016/0360-3016(95)02103-5.

Conventional vs. conformal radiotherapy for prostate cancer: preliminary results of dosimetry and acute toxicity

Affiliations
Clinical Trial

Conventional vs. conformal radiotherapy for prostate cancer: preliminary results of dosimetry and acute toxicity

A Pollack et al. Int J Radiat Oncol Biol Phys. .

Abstract

Purpose: To compare conformal radiotherapy using three dimensional treatment planning (3D-CRT) to conventional radiotherapy (Conven-RT) for patients with Stages T2-T4 adenocarcinoma of the prostate.

Methods and materials: A Phase III randomized study was activated in May 1993, to compare treatment toxicity and patient outcome after 78 Gy in 39 fractions using 3D-CRT to that after 70 Gy in 35 fractions using Conven-RT. The first 46 Gy were administered using the same nonconformal field arrangement (four field) in both arms. The boost was given nonconformally using four fields in the Conven-RT arm and conformally using six fields in the 3D-CRT arm. The dose was specific to the isocenter. The first 60 patients, 29 in the 3D-CRT arm and 31 in the Conven-RT arm, are the subject of this preliminary analysis.

Results: The two treatment arms were first compared in terms of dosimetry by dose-volume histogram analysis. Using a subgroup of patients in the 3D-CRT arm (n=15), both Conven-RT and 3D-CRT plans were generated and the dose-volume histogram data compared. The mean volumes treated to doses above 60 Gy for the bladder and rectum were 28 and 36% for the 3D-CRT plans, and 43 and 38% for the Conven-RT plans, respectively (p < 0.05 for the bladder volumes). The mean clinical target volume (prostate and seminal vesicles) treated to 95% of the prescribed dose was 97.5% for the 3D-CRT arm, and 95.6% for the Conven-RT arm (p < 0.05). There were no significant differences in the acute reactions between the two arms, with the majority experiencing Grade 2 or less toxicity (92%). Moreover, no relationship was seen between acute toxicity and the volume of bladder and rectum receiving in excess of 60 Gy for those in the 3D-CRT arm. There was also no difference between the groups in terms of early biochemical response. Prostate-specific antigen levels at 3 and 6 months after completion of radiotherapy were similar in the two treatment arms. There was only one biochemical failure in the study population at the time of the analysis.

Conclusions: Comparison of the Conven-RT and 3D-RT treatment plans revealed that significantly less bladder was in the high dose volume in the 3D-CRT plans, while the volume of rectum receiving doses over 60 Gy was equivalent. There were no differences between the two treatment arms in terms of acute toxicity or early biochemical response. Longer follow-up is needed to determine the impact of 3D-CRT on long-term patient outcome and late reactions.

PubMed Disclaimer

Publication types

Substances