Background
Materials and methods
Population and questionnaire
Patients characteristics | Total population (n = 613) | Hypermetabolism (n = 318) | Basal metabolism (n = 295) | p value |
---|---|---|---|---|
Age (years) | ||||
Mean ± SD | 61 ± 14 | 62 ± 13 | 61 ± 15 | 0.518 |
BMI (kg/m2) | ||||
Mean ± SD | 25.9 ± 5.4 | 27.7 ± 5.5 | 24.0 ± 4.4 | < 0.0001 |
Gender (n, %) | ||||
Females | 305 (49.8) | 146 (45.9) | 159 (53.9) | 0.048 |
Males | 308 (50.2) | 172 (54.1) | 136 (46.1) |
PET/CT-acquisition and reconstruction
PET/CT analysis
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Visual analysis of the hypermetabolism of the anal canal using a 3-point scale (0, no hypermetabolism; 1, moderate hypermetabolism; 2, intense hypermetabolism).
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Anal canal maximum standardized uptake values (SUVmax_EARL). VOI was determined using 50% of SUVpeak with adaptation to local tumor-to-background contrast, so called adapted 50% of SUVpeak (A50P) [12].
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Visual assessment of rectal content using a 4-point scale (empty; 0, air; 1, feces; 2, air and feces).
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Largest rectal diameter (mm).
Statistical analysis
Results
Population characteristics
Questionnaire analysis
Questions | Total population | Hypermetabolism (n= 318) | Basal metabolism (n= 295) | p value |
---|---|---|---|---|
1. Number of stools per day (n, %) | ||||
Number of answers | 605 | 314 | 291 | |
0 | 117 (19.3) | 63 (20.1) | 54 (18.6) | 0.869 |
1 | 309 (51.1) | 157 (50.0) | 152 (52.2) | |
2 | 131 (21.7) | 67 (21.3) | 64 (22.0) | |
3 | 48 (7.9) | 27 (8.6) | 21 (7.2) | |
2. Delay between last stool and FDG injection (hours) | ||||
Number of answers | 590 | 306 | 84 | |
Mean (SD) | 14.9 (16.7) | 14.5 (16.6) | 15.3 (16.8) | 0.238 |
3. Bristol classification (n, %) | ||||
Number of answers | 586 | 306 | 280 | |
0, constipation (1–2) | 114 (19.5) | 58 (18.9) | 56 (20.0) | 0.949 |
1, normal (3–4) | 346 (59.0) | 182 (59.5) | 164 (58.6) | |
2, diarrhea (5–7) | 126 (21.5) | 66 (21.6) | 60 (21.4) | |
4. Ongoing treatments | ||||
Laxative treatment (n, %) | ||||
Number of answers | 603 | 312 | 291 | |
Yes | 57 (9.5) | 27 (8.7) | 30 (10.3) | 0.487 |
No | 546 (90.5) | 285 (91.3) | 261 (89.7) | |
Anti-diarrhetic treatment (n, %) | ||||
Number of answers | 601 | 311 | 290 | |
Yes | 27 (4.5) | 17 (5.5) | 10 (3.4) | 0.233 |
No | 574 (95.5) | 294 (94.5) | 280 (96.6) | |
5. Anal, rectal, and pelvic history | ||||
Hemorrhoid history (n, %) | ||||
Number of answers | 598 | 309 | 289 | |
Yes | 155 (25.9) | 93 (30.1) | 62 (21.5) | 0.016 |
No | 443 (74.1) | 216 (69.9) | 227 (78.5) | |
Anal fissure history (n, %) | ||||
Number of answers | 600 | 310 | 290 | |
Yes | 20 (3.3) | 12 (3.9) | 8 (2.8) | 0.448 |
No | 580 (96.7) | 298 (96.1) | 282 (97.2) | |
Anal abscess history (n, %) | ||||
Number of answers | 599 | 310 | 289 | |
Yes | 4 (0.7) | 2 (0.6) | 2 (0.7) | 0.944 |
No | 595 (99.3) | 308 (99.4) | 287 (99.3) | |
Anal, rectal, or pelvic surgery history (n, %) | ||||
Number of answers | 602 | 312 | 290 | |
Yes | 131 (21.8) | 67 (21.5) | 64 (22.1) | 0.860 |
No | 471 (78.2) | 245 (78.5) | 226 (77.9) | |
Anal, rectal, or pelvic irradiation history (n, %) | ||||
Number of answers | 602 | 311 | 291 | |
Yes | 49 (8.1) | 27 (8.7) | 22 (7.6) | 0.615 |
No | 553 (91.9) | 284 (91.3) | 269 (92.4) | |
6. Inflammatory bowel disease history (n, %) | ||||
Number of answers | 603 | 312 | 291 | |
Yes | 12 (2.0) | 8 (2.6) | 4 (1.4) | 0.296 |
No | 591 (98.0) | 304 (97.4) | 287 (98.6) | |
7. Anal invasive act history* (n, %) | ||||
Number of answers | 603 | 312 | 291 | |
Yes | 55 (9.1) | 30 (9.6) | 25 (8.6) | 0.662 |
No | 548 (90.9) | 282 (90.4) | 266 (91.4) |
PET/CT characteristics
PET/CT characteristics | Total population (n = 613) | Hypermetabolism (n = 318) | Basal metabolism (n = 295) | p value |
---|---|---|---|---|
Mean injected dose (MBq/kg) | ||||
Mean ± SD | 3.47 ± 0.56 | 3.44 ± 0.56 | 3.50 ± 0.57 | 0.454 |
Mean blood glucose level (g/L) | ||||
Mean ± SD | 1.02 ± 0.21 | 1.03 ± 0.22 | 1.02 ± 0.21 | 0.996 |
Mean18F-FDG uptake time (min) | ||||
Mean ± SD | 59 ± 4 | 59 ± 5 | 59 ± 4 | 0.697 |
Rectal diameter (cm) | ||||
Mean ± SD | 41 ± 15 | 42 ± 14 | 40 ± 15 | 0.202 |
Rectal content (n, %) | ||||
Empty | 84 (13.7) | 37 (11.6) | 47 (15.9) | 0.019 |
0, air | 270 (44.0) | 134 (42.1) | 136 (46.1) | |
1, feces | 101 (16.5) | 66 (20.8) | 35 (11.9) | |
2, air and feces | 158 (25.8) | 81 (25.5) | 77 (26.1) |
Logistic regression
Parameter | Value | Standard error | Wald chi-square | Pr > chi2 |
---|---|---|---|---|
Intercept | − 4.340 | 0.544 | 63.547 | < 0.0001 |
BMI (kg/m2) | 0.155 | 0.020 | 60.051 | < 0.0001 |
Gender—male | 0.392 | 0.181 | 4.688 | 0.030 |
Hemorrhoid history | 0.493 | 0.205 | 5.790 | 0.016 |
Rectal content --1 (feces) | 0.666 | 0.259 | 6.587 | 0.010 |
Rectal content— 2 (air and feces) | − 0.043 | 0.220 | 0.038 | 0.846 |
Rectal content— empty | 0.039 | 0.278 | 0.020 | 0.888 |