Supplementary AppendicesTable of Contents

Supplementary methods for generation of Dose Surface Maps

Supplementary methods for delineation of the anorectum

Supplementary methods for construction of Atlases of Complication Indices

Table S1: Dose constraints used in the CHHiP trial

Table S2: Thresholds for defining moderate or severe toxicity for CRO and PRO-based endpoints

Figure S1: DVH for the anorectum of all patients evaluated.

Figure S2. Anorectum DVH separated according to CHHiP dose schedule, and including relevant dose constraints used in CHHiP

Table S3: Univariate logistic regression to assess the relationship between dose to the anorectum and bowel CRO

Table S4: Univariate logistic regression to assess the relationship between dose to the anorectum and bowel PRO

Table S5. Univariate logistic regression to assess the relationship between dose to the anal canal and bowel CRO

Table S6. Univariate logistic regression to assess the relationship between dose to the anal canal and bowel PRO

Figure S3. ROC analysis with 1000 bootstraps to derive anorectal dose constraints for rectal bleeding and increased bowel frequency (EQD2 correction applied to all DVH).

Figure S4: ROC analysis with 1000 bootstraps to derive anorectal dose constraints for faecal incontinence and rectal pain (note EQD2 correction applied to all DVH).

Figure S5. New anorectal dose constraints for 74Gy schedule applied to DVH of patients treated in CHHiP.

Table S7. Comparison of baseline characteristics according to whether CHHiP patients were missing versus present in the dosimetric analysis.

Supplementary methods for generation of Dose Surface Maps

The DSM were generated by virtual unfolding of the relevant structure. For all anal or rectal structures, this involved unzipping the structure at the posterior-most location for each CT slice or contour. The dose was calculated at 180 points around each contour and the 180 points were then down-sampled to 21 equally-spaced points. In order to facilitate inter-patient comparisons, these maps were then normalized in the longitudinal direction by interpolation. The outermost pixels only were used for this analysis. Each DSM was then described by a set of binary images; for these a systematic range of threshold doses were

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used. The entire set corresponded to the range of doses used in the CHHiP trial, and subsequent images increased in 2Gy intervals. Feature extraction was conducted from the binary images; for this pixels with the same value (either 0 or 1) were combined into a single cluster. In the occasional situations where more than one cluster was present, the largest cluster was used in the subsequent analysis.

Supplementary methods for delineation of the anorectum

The superior extent of the anorectum was defined as the recto-sigmoid junction, and the inferior extent was defined as the anal verge which is consistent with the CHHiP trial protocol, the rectal QUANTEC report, and the RTOG pelvic atlas. The inferior aspect of the anorectum was re-defined as the anal verge which matches the QUANTEC definition and the RTOG atlas, but differs to the CHHiP protocol. The main reason for this revision was that the anal verge corresponded with a more consistent point in the anorectum than the bottom of the ischial tuberosities (as defined in the CHHiP protocol). As per the RTOG pelvic analysis and the published literature, the anorectum was then split into the anal canal, consisting of the lower 3cm, and the rectum, which consisted of the remaining upper portion.

Supplementary methods for construction of Atlases of Complication Indices (ACI)

To construct the ACI, DVH data were exported into a pre-defined Excel template (Excel 2013, Microsoft, CA, USA) for each cohort of cases and controls selected for each CRO or PRO.

Within the excel spreadsheet, percentage volume was shown on the y-axis and dose (Gy) on the x-axis. Every box within the atlas described a specific range of dose and volume, and within each box was both a fraction and a colour. For the fraction, the denominator represented the total number of patients (i.e. cases and controls) with a DVH in the range of volume of the specific box. The numerator represented the total number of cases with moderate or severe toxicity, whose DVH is within the range of the specific box. A colour scale was assigned to indicate the fractional incidence of toxicity for each box, ranging from violet (no toxicity) to red (100% toxicity). The colour scale was normalised according to the incidence of each symptom. Consequently, the overall spread of colour across the atlas gives a good visual impression of how dose and irradiated volume relate to toxicity.

Table S1: Dose constraints used in the CHHiP trial. *optional constraints

Total dose 74Gy Total dose 60Gy Total dose 57Gy Volume (%)

Prescribed dose (Gy)

Prescribed dose (Gy)

Prescribed dose (Gy)

Maximum Volume (%)

30* 24.6 23.4 80

40* 32.4 30.8 70

50 40.8 38.8 60

60 48.6 46.2 50

65 52.3 50.2 30

70 56.7 54.2 15

74 60 57 3

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Table S2: Thresholds for defining moderate or severe toxicity for CRO and PRO-based endpoints (BL: baseline, RT: radiotherapy, G: grade, x: times, outpt: out-patient, mx: management, Tx: treatment, excl: excluding, prev: previous, hmds: haemorrhoids)

Clinician-reported outcomes    Criteria for moderate/severe Criteria for excluding at BL/pre-RTRMH Bowel    

Frequency G2: 3-4x (simple outpt mx) G1: 3-4 times

Rectal bleeding G2: Moderate (simple outpt mx) G1: Occasional no Tx (excl prev haemorrhoids)

RTOG Bowel  Diarrhoea

G3: Distressing symptoms altering performance status

G1 RMH bowel frequency

Proctitis G2 LENTSOM tenesmus, G1 RMH rectal bleeding plus no haemorrhoids, G2 LENTSOM mucosal loss, G1 RMH bowel frequency

Rectal ulcer G1 LENTSOM ulceration

LENT/SOM Rectum    Subjective: Tenesmus G2: Intermittent urgency G2: Intermittent urgency

Subjective: Stool frequency

G2: 5-8 per day G1: 2-4 per day

Subjective: Mucosal loss

G2: Intermittent G2: Intermittent

Subjective: Sphincter control

G2: intermittent use of pads G1: occasional

Subjective: Pain G2: intermittent & tolerable G1: occasional and minimal

Objective: Bleeding G2: occasional >2/week G1: occult (excl prev hmds)

Objective: Ulceration G1: superficial <1cm2 G1: superficial <1cm2

Patient-reported outcomes    Criteria for moderate/severe Criteria for excluding at BL/pre-RTOverall bowel bother G4 Moderate G3 Small

Rectal urgency G4 Daily G2 Weekly

Loose stools G4 Usually G3 About half the time

Crampy pain G4 Daily G2 Weekly

Bowel distress G3 Moderate G2 Little

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Figure S1: DVH for the anorectum of all patients evaluated.

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Figure S2. Anorectum DVH separated according to CHHiP dose schedule, and including relevant dose constraints used in CHHiP (note that the dose constraints at 30Gy and 40Gy were not mandatory

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Table S3: Univariate logistic regression to assess the relationship between dose to the anorectum and bowel CRO

Dose (Gy) Rectal bleeding Increased bowel frequency Tenesmus Increased mucosal loss

  OR (95% CI) P-value OR (95% CI) P-value OR (95% CI) P-value OR (95% CI) P-value

20 Gy 1.02 (1.00-1.03) 0.014 1.03 (1.01-1.05) 0.002 1.02 (1.00-1.04) 0.07 1.01 (0.98-1.03) 0.53

30 Gy 1.03 (1.01-1.04) <0.001 1.04 (1.02-1.05) <0.001 1.02 (1.00-1.04) 0.015 1.01 (0.99-1.04) 0.24

40 Gy 1.04 (1.02-1.05) <0.001 1.03 (1.02-1.05) <0.001 1.03 (1.00-1.05) 0.016 1.02 (0.99-1.05) 0.21

50 Gy 1.05 (1.03-1.07) <0.001 1.04 (1.02-1.06) 0.001 1.03 (1.01-1.06) 0.017 1.02 (0.99-1.05) 0.18

60 Gy 1.07 (1.04-1.09) <0.001 1.04 (1.01-1.07) 0.014 1.04 (1.00-1.07) 0.025 1.04 (1.00-1.09) 0.054

65 Gy 1.07 (1.04-1.11) <0.001 1.03 (0.99-1.07) 0.16 1.04 (1.00-1.09) 0.053 1.07 (1.01-1.13) 0.024

70 Gy 1.09 (1.03-1.15) <0.001 1.05 (0.98-1.11) 0.16 1.07 (1.00-1.14) 0.062 1.06 (0.98-1.16) 0.16

Dose (Gy) Faecal incontinence Rectal pain Rectal ulceration   

  OR (95% CI) P-value OR (95% CI) P-value OR (95% CI) P-value    20 Gy 1.02 (1.00-1.03) 0.045 1.04 (1.00-1.08) 0.053 1.03 (0.99-1.06) 0.112    30 Gy 1.02 (1.01-1.04) 0.001 1.04 (1.00-1.07) 0.034 1.04 (1.01-1.07) 0.004    40 Gy 1.02 (1.00-1.04) 0.014 1.03 (0.99-1.07) 0.221 1.05 (0.01-1.09) 0.006    50 Gy 1.02 (1.00-1.04) 0.034 1.03 (0.98-1.07) 0.247 1.05 (1.01-1.09) 0.008    60 Gy 1.02 (0.99-1.05) 0.162 1.03 (0.97-1.10) 0.33 1.05 (1.00-1.11) 0.044    65 Gy 1.02 (0.98-1.06) 0.291 1.00 (0.91-1.09) 0.957 1.07 (1.01-1.14) 0.03    70 Gy 1.02 (0.96-1.08) 0.57 0.99 (0.85-1.16) 0.905 1.11 (1.01-1.21) 0.022    

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Table S4: Univariate logistic regression to assess the relationship between dose to the anorectum and bowel PRO

Dose (Gy) Overall bowel bother Rectal urgency Loose stools

  OR (95% CI) P-value OR (95% CI) P-value OR (95% CI) P-value

20 Gy 1.02 (1.00-1.03) 0.045 1.01 (1.00-1.02) 0.12 1.00 (0.99-1.02) 0.76

30 Gy 1.02 (1.00-1.03) 0.02 1.02 (1.00-1.03) 0.003 1.01 (0.99-1.02) 0.38

40 Gy 1.01 (1.00-1.03) 0.09 1.02 (1.00-1.03) 0.04 1.00 (0.98-1.01) 0.71

50 Gy 1.01 (1.00-1.03) 0.13 1.01 (0.99-1.03) 0.21 0.99 (0.97-1.01) 0.23

60 Gy 1.01 (0.98-1.03) 0.56 1.01 (0.99-1.04) 0.22 0.97 (0.94-1.00) 0.08

65 Gy 1.02 (0.98-1.06) 0.39 1.02 (0.99-1.06) 0.22 0.97 (0.92-1.02) 0.21

70 Gy 1.02 (0.95-1.09) 0.55 0.99 (0.93-1.06) 0.73 0.95 (0.87-1.04) 0.3

Dose (Gy) Crampy pain Bowel distress   

  OR (95% CI) P-value OR (95% CI) P-value    20 Gy 1.01 (0.99-1.03) 0.39 1.00 (0.98-1.02) 0.99    30 Gy 1.01 (0.99-1.03) 0.18 1.01 (0.99-1.02) 0.51    40 Gy 1.00 (0.98-1.02) 0.72 1.00 (0.98-1.02) 0.7    50 Gy 1.00 (0.98-1.02) 0.96 1.00 (0.98-1.03) 0.87    60 Gy 0.99 (0.96-1.03) 0.67 1.00 (0.97-1.03) 1    65 Gy 0.99 (0.95-1.04) 0.79 1.02 (0.97-1.07) 0.48    70 Gy 0.99 (0.92-1.09) 0.97 1.02 (0.95-1.09) 0.62    

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Table S5. Univariate logistic regression to assess the relationship between dose to the anal canal and bowel CRO

Dose (Gy) Rectal bleeding Increased bowel frequency Tenesmus Increased mucosal loss

  OR (95% CI) P-value OR (95% CI) P-value OR (95% CI) P-value OR (95% CI) P-value

20 Gy 1.02 (1.01-1.03) <0.001 1.01 (1.00-1.02) 0.007 1.00 (0.99-1.01) 0.427 1.01 (0.99-1.02) 0.331

30 Gy 1.02 (1.01-1.03) <0.001 1.01 (1.00-1.02) 0.004 1.00 (0.99-1.02) 0.499 1.01 (1.00-1.03) 0.14

40 Gy 1.03 (1.02-1.04) <0.001 1.01 (1.00-1.03) 0.041 1.01 (0.99-1.02) 0.503 1.01 (0.99-1.03) 0.195

50 Gy 1.03 (1.02-1.05) <0.001 1.02 (1.00-1.04) 0.042 1.01 (0.99-1.03) 0.333 1.02 (0.99-1.04) 0.128

60 Gy 1.05 (1.02-1.07) <0.001 1.03 (1.01-1.06) 0.017 1.02 (0.99-1.05) 0.178 1.03 (1.00-1.07) 0.073

65 Gy 1.06 (1.03-1.09) <0.001 1.05 (1.01-1.09) 0.011 1.03 (0.99-1.07) 0.118 1.04 (0.99-1.10) 0.109

70 Gy 1.10 (1.03-1.16) 0.002 1.10 (1.02-1.18) 0.011 1.06 (0.98-1.15) 0.173 1.05 (0.94-1.16) 0.414

Dose (Gy) Faecal incontinence Rectal pain Rectal ulceration   

  OR (95% CI) P-value OR (95% CI) P-value OR (95% CI) P-value    20 Gy 1.01 (1.00-1.02) 0.019 1.01 (0.99-1.02) 0.485 1.01 (0.99-1.03) 0.122    30 Gy 1.01 (1.00-1.02) 0.031 1.01 (0.99-1.03) 0.28 1.01 (0.99-1.03) 0.366    40 Gy 1.01 (1.00-1.02) 0.118 1.00 (0.97-1.03) 0.929 1.01 (0.98-1.03) 0.549    50 Gy 1.01 (1.00-1.03) 0.142 0.99 (0.96-1.03) 0.77 1.01 (0.98-1.04) 0.57    60 Gy 1.02 (0.99-1.04) 0.159 0.99 (0.93-1.05) 0.634 1.01 (0.97-1.06) 0.577    65 Gy 1.02 (0.98-1.05) 0.324 0.97 (0.88-1.07) 0.542 1.02 (0.96-1.09) 0.556    70 Gy 0.98 (0.90-1.06) 0.595 0.91 (0.70-1.17) 0.48 1.06 (0.94-1.20) 0.363    

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Table S6. Univariate logistic regression to assess the relationship between dose to the anal canal and bowel PRO

Dose (Gy) Overall bowel bother Rectal urgency Loose stools

  OR (95% CI) P-value OR (95% CI) P-value OR (95% CI) P-value

20 Gy 1.01 (1.00-1.01) 0.16 1.00 (1.00-1.01) 0.268 1.00 (0.99-1.00) 0.343

30 Gy 1.01 (1.00-1.02) 0.126 1.01 (1.00-1.02) 0.011 1.00 (0.99-1.01) 0.483

40 Gy 1.00 (0.99-1.02) 0.408 1.01 (1.00-1.02) 0.065 0.99 (0.98-1.00) 0.178

50 Gy 1.00 (0.99-1.02) 0.58 1.01 (1.00-1.02) 0.128 0.98 (0.96-1.00) 0.092

60 Gy 1.01 (0.99-1.03) 0.415 1.02 (1.00-1.04) 0.107 0.98 (0.95-1.01) 0.129

65 Gy 1.02 (0.98-1.05) 0.314 1.02 (0.99-1.05) 0.241 0.97 (0.92-1.02) 0.194

70 Gy 1.02 (0.95-1.10) 0.503 1.00 (0.94-1.07) 0.929 0.94 (0.84-1.05) 0.246

Dose (Gy) Crampy pain Bowel distress   

  OR (95% CI) P-value OR (95% CI) P-value    20 Gy 1.00 (0.99-1.01) 0.678 1.00 (0.99-1.01) 0.984    30 Gy 1.01 (1.00-1.02) 0.236 1.00 (0.99-1.01) 0.892    40 Gy 1.01 (0.99-1.02) 0.407 1.00 (0.98-1.01) 0.79    50 Gy 1.00 (0.99-1.02) 0.591 1.00 (0.98-1.02) 0.639    60 Gy 1.01 (0.98-1.03) 0.65 0.99 (0.96-1.02) 0.623    65 Gy 1.01 (0.97-1.05) 0.766 1.00 (0.95-1.04) 0.891    70 Gy 1.01 (0.93-1.11) 0.763 1.00 (0.92-1.10) 0.96    

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Figure S3. ROC analysis with 1000 bootstraps to derive anorectal dose constraints for rectal bleeding and increased bowel frequency (EQD2 correction applied to all DVH).

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Figure S4: ROC analysis with 1000 bootstraps to derive anorectal dose constraints for faecal incontinence and rectal pain (note EQD2 correction applied to all DVH).

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Figure S5. New anorectal dose constraints for 74Gy schedule applied to DVH of patients treated in CHHiP

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Table S7. Comparison of baseline characteristics according to whether CHHiP patients were missing versus present in the dosimetric analysis.

N % N % N %Treatment arm74Gy/37f 376 32.7% 688 33.3% 1064 33.1%

60Gy/20f 389 33.8% 684 33.1% 1073 33.4%

57Gy/19f 385 33.5% 691 33.4% 1076 33.5%

Tumour stageT1a/1b/1c/1x 459 39.9% 712 34.5% 1171 36.4%

T2a/b/c/x 608 52.9% 1156 56.0% 1764 54.9%

T3a/x 83 7.2% 194 9.4% 277 8.6%

Unknown 0 0.0% 4 0.2% 4 0.1%

Calculated Gleason score6 415 36.1% 707 34.2% 1122 34.9%

7 704 61.2% 1290 62.4% 1994 62.0%

8 31 2.7% 68 3.3% 99 3.1%

Unknown 0 0.0% 1 0.0% 1 0.0%

Categorised PSA at baseline0-4.99 77 6.7% 161 7.8% 238 7.4%

5-9.99 453 39.4% 874 42.3% 1327 41.3%

10-19.9 538 46.8% 906 43.9% 1444 44.9%

20-49.99 81 7.0% 123 6.0% 204 6.3%

Unknown 1 0.1% 2 0.1% 3 0.1%

NCCN Risk Group1 188 16.3% 296 14.3% 484 15.0%

2 854 74.3% 1493 72.3% 2347 73.0%

3 108 9.4% 277 13.4% 385 12.0%

DiabetesYes 127 11.0% 215 10.4% 342 10.6%

No 1018 88.5% 1816 87.9% 2834 88.1%

Unknown 5 0.4% 35 1.7% 40 1.2%

HypertensionYes 460 40.0% 816 39.5% 1276 39.7%

No 683 59.4% 1215 58.8% 1898 59.0%

Unknown 7 0.6% 35 1.7% 42 1.3%

Inflammatory Bowel or Diverticular diseaseYes 46 4.0% 77 3.7% 123 3.8%

No 1100 95.7% 1942 94.0% 3042 94.6%

Unknown 4 0.3% 47 2.3% 51 1.6%

Previous pelvic surgeryYes 81 7.0% 171 8.3% 252 7.8%

No 1063 92.4% 1850 89.5% 2913 90.6%

Unknown 6 0.5% 45 2.2% 51 1.6%

Symptomatic haemorrhoids in past 12 monthsYes 87 7.6% 122 5.9% 209 6.5%

No 1028 89.4% 1844 89.3% 2872 89.3%

Unknown 35 3.0% 100 4.8% 135 4.2%

Any previous TURPYes 114 9.9% 145 7.0% 259 8.1%

No 1020 88.7% 1843 89.2% 2863 89.0%

Unknown 16 1.4% 78 3.8% 94 2.9%

(n=1150) (n=2066) (n=3216)Included patients Missing patients All CHHiP patients

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