Purpose: After radiation therapy for prostate cancer, approximately 50% of the patients experience acute genitourinary symptoms, mostly nocturia. This may be highly bothersome with a major impact on the patient's quality of life. In the past, nocturia is seldom reported as a single, physiologically distinct endpoint, and little is known about its etiology. It is assumed that in addition to dose-volume parameters and patient- and therapy-related factors, a genetic component contributes to the development of radiation-induced damage. In this study, we investigated the association among dosimetric, clinical, and TGFβ1 polymorphisms and the development of acute radiation-induced nocturia in prostate cancer patients.
Methods and materials: Data were available for 322 prostate cancer patients treated with primary or postoperative intensity modulated radiation therapy (IMRT). Five genetic markers in the TGFβ1 gene (-800 G>A, -509 C>T, codon 10 T>C, codon 25 G>C, g.10780 T>G), and a high number of clinical and dosimetric parameters were considered. Toxicity was scored using an symptom scale developed in-house.
Results: Radical prostatectomy (P<.001) and the presence of pretreatment nocturia (P<.001) are significantly associated with the occurrence of radiation-induced acute toxicity. The -509 CT/TT (P=.010) and codon 10 TC/CC (P=.005) genotypes are significantly associated with an increased risk for radiation-induced acute nocturia.
Conclusions: Radical prostatectomy, the presence of pretreatment nocturia symptoms, and the variant alleles of TGFβ1 -509 C>T and codon 10 T>C are identified as factors involved in the development of acute radiation-induced nocturia. These findings may contribute to the research on prediction of late nocturia after IMRT for prostate cancer.
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