KEY POINTS
- Multicenter planned-dose analysis of 37 prostate radiotherapy plans from four centers, with an additional 8-case institutional cohort used only to assess workflow applicability.
- All final analytic cases were treated with five-fraction volumetric modulated arc therapy; explicit target prescription-dose information was available in 33 of 37 plans, with a median prescribed dose of 36.25 Gy.
- Bladder volume was strongly inversely associated with planned bladder dose: bladder D95 r = -0.78, p < 0.001 and bladder mean dose r = -0.76, p < 0.001.
- Bladder longitudinal extent was also inversely associated with bladder D95 r = -0.72, p = 0.002; prescription-normalized sensitivity analyses preserved the main bladder-related pattern.
- No toxicity or clinical outcome endpoints were reported. Near-zero bladder D2cc values in 8 of 35 cases were interpreted as geometric separation from the high-dose region rather than dose-reconstruction failure.
CLINICAL TAKEAWAY
This study suggests that simple planning computed tomography-derived geometry may help flag prostate radiotherapy cases requiring closer organ-at-risk review. The evidence is technical and hypothesis-generating: the analysis was small, static, based on planned dose only, and did not include delivered-dose reconstruction or toxicity validation.