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Lateral rectal shielding reduces late rectal morbidity after high dose three-dimensional conformal radiation therapy for clinically localized prostate cancer: further evidence for a dose effect

Abstract

Purpose: Using conventional treatment methods for the treatment of clinically localized prostate cancer central axis doses must be limited to 65-70 Gy to prevent significant damage to nearby normal tissues. A fundamental hypothesis of three-dimensional conformal radiation therapy (3DCRT) is that, by defining the target organ(s) accurately in three dimensions, it is possible to deliver higher doses to the target without a significant increase in normal tissue complications. This study examines whether this hypothesis holds true and whether a simple modification of treatment technique can reduce the incidence of late rectal morbidity in patients with prostate cancer treated with 3DCRT to minimum planning target volume (PTV) doses of 71-75 Gy. Materials and Methods: 257 patients with clinically localized prostate cancer completed 3DCRT by December 31, 1993 and received a minimum PTV dose of 71-75 Gy. The median follow-up time was 22 months (range 4-67 months) and 98% of patients had followup of longer than 12 months. The calculated dose at the center of the prostate was <74 Gy in 19 patients, 74-76 Gy in 206 patients and >76 Gy in 32 patients. Late rectal morbidity was graded according to the LENT scoring system. Eighty-eight consecutive patients were treated with a  More>>
Publication Date:
Jul 01, 1995
Product Type:
Journal Article
Resource Relation:
Journal Name: International Journal of Radiation Oncology, Biology and Physics; Journal Volume: 32; Journal Issue: 971; Other Information: Copyright (c) 1995 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved; Country of input: International Atomic Energy Agency (IAEA); PBD: 1995
Subject:
63 RADIATION, THERMAL, AND OTHER ENVIRONMENTAL POLLUTANT EFFECTS ON LIVING ORGANISMS AND BIOLOGICAL MATERIALS; DELAYED RADIATION EFFECTS; DISEASE INCIDENCE; DOSE-RESPONSE RELATIONSHIPS; NEOPLASMS; PROSTATE; RADIATION INJURIES; RADIATION PROTECTION; RADIOTHERAPY; RECTUM; SHIELDING
OSTI ID:
20391347
Country of Origin:
United States
Language:
English
Other Identifying Numbers:
Journal ID: ISSN 0360-3016; IOBPD3; TRN: US03R1758059394
Submitting Site:
INIS
Size:
page(s) 142
Announcement Date:

Citation Formats

Lee, W Robert, Hanks, Gerald E, Hanlon, Alexandra, and Schultheiss, Timothy E. Lateral rectal shielding reduces late rectal morbidity after high dose three-dimensional conformal radiation therapy for clinically localized prostate cancer: further evidence for a dose effect. United States: N. p., 1995. Web. doi:10.1016/0360-3016(95)97668-Q.
Lee, W Robert, Hanks, Gerald E, Hanlon, Alexandra, & Schultheiss, Timothy E. Lateral rectal shielding reduces late rectal morbidity after high dose three-dimensional conformal radiation therapy for clinically localized prostate cancer: further evidence for a dose effect. United States. doi:10.1016/0360-3016(95)97668-Q.
Lee, W Robert, Hanks, Gerald E, Hanlon, Alexandra, and Schultheiss, Timothy E. 1995. "Lateral rectal shielding reduces late rectal morbidity after high dose three-dimensional conformal radiation therapy for clinically localized prostate cancer: further evidence for a dose effect." United States. doi:10.1016/0360-3016(95)97668-Q. https://www.osti.gov/servlets/purl/10.1016/0360-3016(95)97668-Q.
@misc{etde_20391347,
title = {Lateral rectal shielding reduces late rectal morbidity after high dose three-dimensional conformal radiation therapy for clinically localized prostate cancer: further evidence for a dose effect}
author = {Lee, W Robert, Hanks, Gerald E, Hanlon, Alexandra, and Schultheiss, Timothy E}
abstractNote = {Purpose: Using conventional treatment methods for the treatment of clinically localized prostate cancer central axis doses must be limited to 65-70 Gy to prevent significant damage to nearby normal tissues. A fundamental hypothesis of three-dimensional conformal radiation therapy (3DCRT) is that, by defining the target organ(s) accurately in three dimensions, it is possible to deliver higher doses to the target without a significant increase in normal tissue complications. This study examines whether this hypothesis holds true and whether a simple modification of treatment technique can reduce the incidence of late rectal morbidity in patients with prostate cancer treated with 3DCRT to minimum planning target volume (PTV) doses of 71-75 Gy. Materials and Methods: 257 patients with clinically localized prostate cancer completed 3DCRT by December 31, 1993 and received a minimum PTV dose of 71-75 Gy. The median follow-up time was 22 months (range 4-67 months) and 98% of patients had followup of longer than 12 months. The calculated dose at the center of the prostate was <74 Gy in 19 patients, 74-76 Gy in 206 patients and >76 Gy in 32 patients. Late rectal morbidity was graded according to the LENT scoring system. Eighty-eight consecutive patients were treated with a rectal block added to the lateral fields. In these patients the posterior margin from the prostate to the block edge was reduced from the standard 15 mm to 7.5 mm for the final 10 Gy which reduced the dose to portions of the anterior rectal wall by approximately 4-5 Gy. Estimates of rates for rectal morbidity were determined by Kaplan-Meier actuarial analyses. Differences in morbidity percentages were evaluated by the Pearson chi square test. Results: Grade 2-3 rectal morbidity developed in 46 of 257 patients (18%) and in the majority of cases consisted of rectal bleeding. No patient has developed grade 4 or 5 rectal morbidity. The actuarial rate of grade 2-3 morbidity is 22% at 24 months and the median time to the development of grade 2-3 complications is 15 months. A statistically significant dose effect is evident. The incidence of grade 2-3 rectal morbidity increased as the dose at the center of the prostate increased (Table 1, p=.05). The use of a rectal block significantly reduced the incidence of grade 2-3 toxicity (Table 2); 6 of 88 (7%) with block vs. 30 of 137 (22%) without block, (p=.003). Conclusion: The incidence of late rectal morbidity with 3DCRT to minimum PTV doses 71-75 Gy is acceptable and to date no grade 4-5 rectal morbidities have been observed. In our experience, higher doses to the center of the prostate are associated with an increased likelihood of developing grade 2-3 rectal morbidity but treatment techniques that reduce the total dose to the anterior rectal wall have reduced the incidence of late rectal morbidity. If clinical studies indicate improved tumor control with minimum PTV doses above 70 Gy, then dose escalation above 76 Gy to the center of the prostate should be pursued cautiously with treatment techniques that limit the total dose to the anterior rectal wall.}
doi = {10.1016/0360-3016(95)97668-Q}
journal = {International Journal of Radiation Oncology, Biology and Physics}
issue = {971}
volume = {32}
journal type = {AC}
place = {United States}
year = {1995}
month = {Jul}
}