Prostate external beam radiotherapy combined with high-dose-rate brachytherapy: dose-volume parameters from deformably-registered plans correlate with late gastrointestinal complications

Table 2 Influence of the applied alpha-beta ratio on the findings for odds ratios, V_X and D_X%

Toxicity type	Findings for α/β = 5.4 Gy compared to α/β = 3 Gy^a
Rectal bleeding	Similar trends
Stool frequency	Similar trends
Diarrhoea	Odds ratios not significant for α/β = 5.4 Gy
Completeness of evacuation	No significance for α/β = 3 Gy or α/β = 5.4 Gy
Anorectal pain	Similar trends
Urgency/tenesmus	Similar trends
Proctitis	Similar trends

Abbreviations: V _X percentage of the rectal volume receiving at least X EQD2 Gy after applying an α/β = 3 or 5.4 Gy, D _X% minimum EQD2 Gy dose to the most irradiated X percentage of rectal volume after applying an α/β = 3 or 5.4 Gy, EQD2 Gy equivalent dose in 2-Gy fractions using α/β = 3 or 5.4 Gy, α/β alpha-beta ratio
^aIndication of whether significance still exists when an α/β of 5.4 Gy is used instead of 3 Gy

ISSN: 1748-717X