Table 1.
Patients’ characteristics
| Pre-op CRT (n = 550) | Post-op CRT (n = 322) | P‡ | |
|---|---|---|---|
| Age (mean, yr) |
57.0 ± 10.9 |
57.8 ± 10.5 |
0.272 |
| Gender |
|
|
|
| Male |
370 (67.3) |
202 (62.7) |
0.173 |
| Female |
180 (32.7) |
120 (37.3) |
|
| Histological grade* |
|
|
|
| Low |
516 (94.9) |
278 (94.9) |
0.986 |
| High |
28 (5.1) |
15 (5.1) |
|
| CEA (ng/mL) |
|
|
|
| ≤ 5.0 |
370 (67.3) |
178 (65.0) |
0.508 |
| > 5.0 |
180 (32.7) |
96 (35.0) |
|
| Tumor location (cm) † |
|
|
|
| Low (< 5.0) |
203 (36.9) |
45 (14.9) |
< 0.001 |
| Middle (5.0–9.0) |
347 (63.1) |
143 (47.2) |
|
| Upper (> 9.0–12.0) |
|
115 (38.0) |
|
| Clinical stage |
|
|
|
| II |
111 (20.2) |
77 (23.9) |
0.196 |
| III |
439 (79.8) |
245 (76.1) |
|
| Pathological stage |
|
|
|
| 0 |
84 (15.3) |
|
< 0.001 |
| I |
145 (26.4) |
|
|
| II |
154 (28.0) |
88 (27.3) |
|
| III |
167 (30.4) |
234 (72.7) |
|
| CRM |
|
|
|
| Negative |
506 (92.0) |
290 (90.1) |
0.328 |
| Positive | 44 (8.0) | 32 (9.9) |
Abbreviations: CRT = chemoradiotherapy; CEA = carcinoembryonic antigen; CRM = circumferential resection margin.
*Evaluated with pretreatment diagnostic biopsy specimen. Low = well or moderately differentiated; high = poorly differentiated, mucinous, or signet ring cell carcinoma.
†Distance of distal end of tumor from anal verge.
‡t-test, Chi-square test, or Fisher’s exact test.