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Worth Attention Prostate

Overfilling the bladder made prostate radiotherapy longer and more frustrating

Bladder diameter >10 cm at simulation was associated with longer fractions, more interruptions and greater patient frustration during prostate RT.

RadOncToday · ·1 min read

KEY POINTS

  • The retrospective study included 211 consecutive prostate cancer patients treated with 20–44 fractions of VMAT across three centres. Patients receiving prostate, prostate-bed and pelvic-node RT were included; SBRT was excluded.
  • Bladder filling was measured simply as sagittal dome-to-trigone diameter on the simulation CT. 39 patients (18.5%) had a diameter >10 cm, while 172 had ≤10 cm; the cutoff was pragmatic rather than previously validated.
  • Patients simulated with bladders >10 cm spent significantly longer on treatment: 498.5 versus 444.0 seconds per fraction (p=0.01). The difference persisted after adjustment for the number of VMAT arcs (456.4 vs 412.7 seconds; p=0.02).
  • Excessive filling also made daily setup harder. Patients in the >10-cm group had to leave the treatment table for bladder correction 0.14 versus 0.04 times per week (p<0.01), approximately a threefold difference.
  • By the final treatment week, patients with large simulation bladders reported more concern about reproducing their bladder filling (1.58 vs 0.90; p<0.01) and more frustration (1.06 vs 0.65; p=0.01) on a 0–4 Likert scale.
  • A separate cohort of 20 patients presenting with >10-cm bladders underwent a simple correction protocol: patients voided a small amount and were rescanned until diameter was ≤10 cm. All succeeded, reaching a median 7.53 cm, and subsequent treatment time averaged 425.2 seconds, significantly shorter than the uncorrected >10-cm group (p=0.03).
  • The study did not establish that 10 cm is a universal optimal bladder size, and patient questionnaires were unavailable in the corrected cohort. The more general message is that forcing an unusually full simulation bladder may create a geometry patients cannot reliably reproduce.

CLINICAL TAKEAWAY

A “comfortably full” bladder may be more useful than a maximally full one in fractionated prostate RT. A rapid bladder-size check at simulation could prevent weeks of avoidable delays and patient frustration, although individual centres would need to validate their own practical threshold.

SOURCE

Practical Radiation Oncology

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