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Bile acid malabsorption after pelvic and prostate intensity modulated radiation therapy: an uncommon but treatable condition.
- Source :
-
International journal of radiation oncology, biology, physics [Int J Radiat Oncol Biol Phys] 2012 Dec 01; Vol. 84 (5), pp. e601-6. Date of Electronic Publication: 2012 Sep 18. - Publication Year :
- 2012
-
Abstract
- Purpose: Intensity modulated radiation therapy (IMRT) is a significant therapeutic advance in prostate cancer, allowing increased tumor dose delivery and increased sparing of normal tissues. IMRT planning uses strict dose constraints to nearby organs to limit toxicity. Bile acid malabsorption (BAM) is a treatable disorder of the terminal ileum (TI) that presents with symptoms similar to radiation therapy toxicity. It has not been described in patients receiving RT for prostate cancer in the contemporary era. We describe new-onset BAM in men after IMRT for prostate cancer.<br />Methods and Materials: Diagnosis of new-onset BAM was established after typical symptoms developed, selenium-75 homocholic acid taurine (SeHCAT) scanning showed 7-day retention of <15%, and patients' symptoms unequivocally responded to a bile acid sequestrant. The TI was identified on the original radiation therapy plan, and the radiation dose delivered was calculated and compared with accepted dose-volume constraints.<br />Results: Five of 423 men treated in a prospective series of high-dose prostate and pelvic IMRT were identified with new onset BAM (median age, 65 years old). All reported having normal bowel habits before RT. The volume of TI ranged from 26-141 cc. The radiation dose received by the TI varied between 11.4 Gy and 62.1 Gy (uncorrected). Three of 5 patients had TI treated in excess of 45 Gy (equivalent dose calculated in 2-Gy fractions, using an α/β ratio of 3) with volumes ranging from 1.6 cc-49.0 cc. One patient had mild BAM (SeHCAT retention, 10%-15%), 2 had moderate BAM (SeHCAT retention, 5%-10%), and 2 had severe BAM (SeHCAT retention, <5%). The 3 patients whose TI received ≥45 Gy developed moderate to severe BAM, whereas those whose TI received <45 Gy had only mild to moderate BAM.<br />Conclusions: Radiation delivered to the TI during IMRT may cause BAM. Identification of the TI from unenhanced RT planning computed tomography scans is difficult and may impede accurate dosimetric evaluation. Thorough toxicity assessment and close liaison between oncologist and gastroenterologist allow timely diagnosis and treatment.<br /> (Copyright © 2012 Elsevier Inc. All rights reserved.)
- Subjects :
- Aged
Humans
Ileum metabolism
Malabsorption Syndromes diagnostic imaging
Malabsorption Syndromes metabolism
Male
Middle Aged
Prospective Studies
Prostatic Neoplasms metabolism
Prostatic Neoplasms pathology
Radiation Injuries diagnostic imaging
Radiation Injuries metabolism
Radionuclide Imaging
Radiotherapy Dosage
Radiotherapy, Intensity-Modulated methods
Taurocholic Acid analogs & derivatives
Taurocholic Acid pharmacokinetics
Bile Acids and Salts metabolism
Ileum radiation effects
Malabsorption Syndromes etiology
Prostatic Neoplasms radiotherapy
Radiation Injuries complications
Radiotherapy, Intensity-Modulated adverse effects
Subjects
Details
- Language :
- English
- ISSN :
- 1879-355X
- Volume :
- 84
- Issue :
- 5
- Database :
- MEDLINE
- Journal :
- International journal of radiation oncology, biology, physics
- Publication Type :
- Academic Journal
- Accession number :
- 22995663
- Full Text :
- https://doi.org/10.1016/j.ijrobp.2012.07.2368