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Table 5 Predicted late rectal toxicity rates using spatial NTCP models

From: Dosimetric feasibility of moderately hypofractionated/dose escalated radiation therapy for localised prostate cancer with intensity-modulated proton beam therapy using simultaneous integrated boost (SIB-IMPT) and impact of hydrogel prostate-rectum spacer

End point *

Whole group

(23 patients)

Non-spacer group

(8 patients)

Spacer group

(15 patients)

P value

Necrosis/stenosis

Mean ± SD

3.9 ± 2.37%

5.87 ± 2.17%

2.87 ± 1.77%

0.005

Range

(0–8%)

(2–8%)

(0–6%)

Late rectal bleeding ≥ 3

Mean ± SD

1.56 ± 1.24%

2.5 ± 1.51%

1.067 ± 0.7%

0.016

Range

(0–5%)

(0–5%)

(0–2%)

Late toxicity ≥ 3

Mean ± SD

9.43 ± 4.15%

12.75 ± 2.87%

7.67 ± 3.66%

0.002

Range

(1–15%)

(7–15%)

(1–13%)

  1. *Poisson-LQ model for Necrosis/stenosis [25], LKB model for late rectal bleeding ≥ 3 [26], and LKB model for late effects ≥ 3[27]
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Radiation Oncology

ISSN: 1748-717X

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