Dose Constraint for Minimizing Grade 2 Rectal Bleeding Following Brachytherapy Combined With External Beam Radiotherapy for Localized Prostate Cancer: Rectal Dose-Volume Histogram Analysis of 457 Patients

Journal Article · Tue Nov 01 00:00:00 EDT 2011 · International Journal of Radiation Oncology, Biology and Physics

DOI:https://doi.org/10.1016/j.ijrobp.2011.01.012· OSTI ID:21590447

Shiraishi, Yutaka; Yorozu, Atsunori ^[1]; Ohashi, Toshio ^[2]; Toya, Kazuhito ^[1]; Seki, Satoshi ^[2]; Yoshida, Kayo; Kaneda, Tomoya ^[1]; Saito, Shiro; Nishiyama, Toru ^[3]; Hanada, Takashi; Shigematsu, Naoyuki ^[2]

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1. Department of Radiology, Tokyo Medical Center, Tokyo (Japan)
2. Department of Radiology, Keio University, School of Medicine, Tokyo (Japan)
3. Department of Urology, Tokyo Medical Center, Tokyo (Japan)

Purpose: To determine the rectal tolerance to Grade 2 rectal bleeding after I-125 seed brachytherapy combined with external beam radiotherapy (EBRT), based on the rectal dose-volume histogram. Methods and Materials: A total of 458 consecutive patients with stages T1 to T3 prostate cancer received combined modality treatment consisting of I-125 seed implantation followed by EBRT to the prostate and seminal vesicles. The prescribed doses of brachytherapy and EBRT were 100 Gy and 45 Gy in 25 fractions, respectively. The rectal dosimetric factors were analyzed for rectal volumes receiving >100 Gy and >150 Gy (R100 and R150) during brachytherapy and for rectal volumes receiving >30 Gy to 40 Gy (V30-V40) during EBRT therapy in 373 patients for whom datasets were available. The patients were followed from 21 to 72 months (median, 45 months) after the I-125 seed implantation. Results: Forty-four patients (9.7%) developed Grade 2 rectal bleeding. On multivariate analysis, age (p = 0.014), R100 (p = 0.002), and V30 (p = 0.001) were identified as risk factors for Grade 2 rectal bleeding. The rectal bleeding rate increased as the R100 increased: 5.0% (2/40 patients) for 0 ml; 7.5% (20/267 patients) for >0 to 0.5 ml; 11.0% (11/100 patients) for >0.5 to 1 ml; 17.9% (5/28 patients) for >1 to 1.5 ml; and 27.3% (6/22 patients) for >1.5 ml (p = 0.014). Grade 2 rectal bleeding developed in 6.4% (12/188) of patients with a V30 {<=}35% and in 14.1% (26/185) of patients with a V30 >35% (p = 0.02). When these dose-volume parameters were considered in combination, the Grade 2 rectal bleeding rate was 4.2% (5/120 patients) for a R100 {<=}0.5 ml and a V30 {<=}35%, whereas it was 22.4% (13/58 patients) for R100 of >0.5 ml and V30 of >35%. Conclusion: The risk of rectal bleeding was found to be significantly volume-dependent in patients with prostate cancer who received combined modality treatment. Rectal dose-volume analysis is a practical method for predicting the risk of development of Grade 2 rectal bleeding.

• OSTI ID: 21590447
• Journal Information: International Journal of Radiation Oncology, Biology and Physics, Vol. 81, Issue 3; Other Information: DOI: 10.1016/j.ijrobp.2011.01.012; PII: S0360-3016(11)00063-0; Copyright (c) 2011 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA); ISSN 0360-3016
• Country of Publication: United States
• Language: English

Related Subjects

62 RADIOLOGY AND NUCLEAR MEDICINE
BRACHYTHERAPY
HAZARDS
IODINE 125
MULTIVARIATE ANALYSIS
NEOPLASMS
PROSTATE
RADIATION DOSES
RECTUM
BETA DECAY RADIOISOTOPES
BODY
DAYS LIVING RADIOISOTOPES
DIGESTIVE SYSTEM
DISEASES
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ELECTRON CAPTURE RADIOISOTOPES
GASTROINTESTINAL TRACT
GLANDS
INTERMEDIATE MASS NUCLEI
INTERNAL CONVERSION RADIOISOTOPES
INTESTINES
IODINE ISOTOPES
ISOTOPES
LARGE INTESTINE
MALE GENITALS
MATHEMATICS
MEDICINE
NUCLEAR MEDICINE
NUCLEI
ODD-EVEN NUCLEI
ORGANS
RADIOISOTOPES
RADIOLOGY
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STATISTICS
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