Plasma citrulline concentration: a surrogate end point for radiation-induced mucosal atrophy of the small bowel. A feasibility study in 23 patients.

L.C.H.W. Lutgens*, N. Deutz, M. Granzier-Peeters, R.G.H. Beets-Tan, D.K.M. de Ruysscher, J. Gueulette, J.P.M. Cleutjens, M.P.F. Berger, B.G. Wouters, M.F. von Meyenfeldt, P. Lambin

*Corresponding author for this work

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PURPOSE: Plasma citrulline, a nitrogen end product of glutamine metabolism in small-bowel enterocytes, was suggested as a marker of radiation-induced small-bowel epithelial cell loss in mice after single-dose whole-body irradiation. Our objective was to evaluate the feasibility of citrulline as a marker for radiation-induced small-intestinal mucosal atrophy in patients during and after abdominal fractionated radiotherapy. METHODS AND MATERIALS: Twenty-three patients were studied weekly during treatment and at intervals of 2 weeks and 3 and 6 months after treatment by postabsorptive plasma citrulline concentration and clinical toxicity grading. The interrelationship between these variables and the correlation with small-bowel dose and volume parameters were investigated. RESULTS: During fractionated radiotherapy, citrulline concentration significantly decreased as a function of the radiation dose (p < 0.001) and the volume of small bowel treated (p = 0.001). The plasma citrulline concentration correlated with clinical toxicity during the last 3 weeks of treatment. As a whole, citrulline concentration correlated better with radiation dose and volume parameters than clinical toxicity grading. CONCLUSIONS: In patients treated with fractionated radiation therapy for abdominal or pelvic cancer sites, plasma citrulline concentration may be a simple objective marker for monitoring epithelial cell loss, a major event in acute radiation-induced small-bowel toxicity.
Original languageEnglish
Pages (from-to)275-85
JournalInternational Journal of Radiation Oncology Biology Physics
Issue number1
Publication statusPublished - 1 Jan 2004

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