TABLE 5.
Subgroup analysis of the impact of NCRT by resectability status at diagnosis
| Variables | NCRT | NAC | p value (UVA) | ATE | p value (ATE) |
|---|---|---|---|---|---|
| Resectable/borderline tumors | n = 69 | n = 294 | |||
| CA19-9 reduction | 71% (56%) | 69% (64%) | 0.532 | < 1% (−25%, 26%) | 0.973 |
| CT T-size reduction | 14% (29%) | 12% (35%) | 0.612 | −5% (−20%, 9%) | 0.481 |
| T size, cm | 2.50 (1.00) | 2.50 (1.20) | 0.352 | −0.09 (−0.44, 0.27) | 0.640 |
| Lymph node ratio | 0.03 (0.12) | 0.05 (0.14) | 0.123 | −0.02 (−0.08, 0.04) | 0.466 |
| LN positive | 37 (53.6%) | 206 (70.1%) | 0.010 | −0.26 (−0.46, −0.07) | 0.009 |
| Margin (R1: 1 mm) | 25 (36.2%) | 148 (50.3%) | 0.034 | −0.09 (−0.28, 0.11) | 0.380 |
| Lymphovascular invasion | 39 (60.9%) | 213 (75.8%) | 0.019 | −0.14 (−0.32, 0.04) | 0.138 |
| Perineural invasion | 51 (73.9%) | 247 (85.2%) | 0.032 | −0.08 (−0.25, 0.09) | 0.357 |
| Near/complete response | 5 (8.8%) | 10 (3.5%) | 0.104 | 0.03 (−0.04, 0.10) | 0.347 |
| Disease-free survival, months | 16.07 (14.69–19.52) | 16.03 (14.62–17.94) | 0.539 | 6.44 (0.27, 12.61) | 0.041 |
| Overall survival, months | 29.63 (20.90–41.00) | 30.72 (28.16–37.03) | 0.362 | 7.19 (−4.59, 18.96) | 0.232 |
| Locally advanced tumors | n = 22 | n = 33 | |||
| CA19-9 reduction | 77% (69%) | 84% (33%) | 0.792 | 36% (−18%, 90%) | 0.189 |
| CT T-size reduction | 35% (38%) | 22% (34%) | 0.339 | −16% (−40%, 8%) | 0.194 |
| T size, cm | 2.05 (3.00) | 2.50 (1.20) | 0.249 | −0.84 (−1.86, 0.18) | 0.105 |
| Lymph node ratio | 0.00 (0.18) | 0.05 (0.10) | 0.137 | −0.02 (−0.10, 0.05) | 0.534 |
| LN positive | 10 (45.5%) | 24 (72.7%) | 0.042 | −0.20 (−0.51, 0.11) | 0.211 |
| Margin (R1: 1 mm) | 9 (40.9%) | 25 (75.8%) | 0.009 | −0.25 (−0.56, 0.07) | 0.126 |
| Lymphovascular invasion | 10 (45.5%) | 27 (84.4%) | 0.002 | −0.45 (−0.72, −0.17) | 0.002 |
| Perineural invasion | 13 (59.1%) | 27 (84.4%) | 0.038 | −0.06 (−0.37, 0.25) | 0.698 |
| Near/complete response | 6 (28.6%) | 2 (6.5%) | 0.030 | 0.19 (−0.05, 0.42) | 0.120 |
| Disease-free survival, months | 18.46 (10.58–31.21) | 18.14 (12.19–20.37) | 0.983 | 6.27 (−8.70, 21.23) | 0.412 |
| Overall survival, months | 36.63 (13.9–56.15) | 47.67 (19.78–91.27) | 0.279 | 0.40 (−19.43, 20.23) | 0.969 |
Bold value denotes staistical significance p < 0.05
NAC neoadjuvant chemotherapy, NCRT neoadjuvant chemoradiotherapy, ATE average treatment effect, CA19-9 carbohydrate antigen 19-9, CT computed tomography, T size tumor size, LN lymph node
All values depicted as median (IQR) or n (%). Survival depicted as median (95% confidence interval); p value < 0.05 considered significant