Impact of the Pre-radiotherapy Volume of the Urinary Bladder on its Filling Status During Hypo-fractionated Treatment for Prostate Cancer.

[BACKGROUND/AIM] Many patients with prostate cancer receive moderately hypo-fractionated radiotherapy (mHF-RT). Inappropriate bladder filling during the mHF-RT course increases urinary toxicity. This study investigated the impact of pre-RT bladder volumes on the subsequent filling status.

[PATIENTS AND METHODS] One-hundred-and-nineteen prostate cancer patients irradiated with mHF-RT (60 Gy in 20 fractions) were included in this retrospective study from three European countries. The impact of pre-RT bladder volumes on the number of fractions with a volume <200 ml was examined.

[RESULTS] In case of a pre-RT bladder volume <200, <250, and <300 ml, the corresponding mean number of fractions with a bladder volume <200 ml during mHF-RT was 16.6 (±5.0), 15.9 (±5.6), and 15.1 (±5.9), respectively. The impact of the pre-RT volume (<200 ≥200 ml, <250 ≥250, <300 ≥300 ml) on the number of fractions with a volume <200 ml was always highly significant (<0.0001).

[CONCLUSION] Pre-RT bladder volumes <200 ml, <250 ml, and <300 ml were significantly associated with higher numbers of bladder volumes <200 ml during mHF-RT. These findings will lead to an amendment to a prospective trial.