Impact of treatment planning and delivery factors on gastrointestinal toxicity: an analysis of data from the RADAR prostate radiotherapy trial

Table 2 Distributions of investigated factors

Participants
Age	69 ± 7(49–85) years
BMI	27.98 ± 4.12(17.17-45.77) kg/m²
Year commenced EBRT	2004(125); 2005(200); 2006(234); 2007(181); 2008(12)
Risk category	Intermediate (464); High (290)
Planning & Delivery factors
Dose calculation algorithm [2]	Type-a (401); Type-b (350)
Patient orientation at set-up	Prone (66); Supine (687)
Prescription dose	66Gy (99); 70Gy (423); 74Gy (229)
Treatment beam definition	Block/collimator (259); MLC (484)
Beam energy	6MV (96); 10MV (158); 15MV(5); 18MV (493)
Number of beams	3 (89); 4 (396); 5 (155); 6 (110);7 (2)
Rectal dietary intervention	No intervention (280); laxatives (77); bulking agent (394)
Anatomical/Dosimetric parameters
PTV1 volume	192 ± 65 (30–704) cm³
95% isodose volume	257 ± 104 (60–1425) cm³
Conformity index [18]	1.34 ± 0.26 (0.72 – 2.94)
Rectal cranio-caudal length	9.6 ± 1.3 (5.4 – 13.5) cm
Mean rectal CSA	7.9 ± 3.4 (0.1 – 26.7) cm²
PTV-rectum separation	0.12 ± 0.32 (−2.6 – 3.39) cm

Continuous factors are specified as mean ± standard deviation (range), categorical factors are specified as category (number of patients). Not all patients available for all assessments due to missing data, exclusions etc. Abbreviations: BMI Body mass index, EBRT External beam radiotherapy, PTV1 Phase 1 planning target volume (PTV), CSA Cross sectional area.

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