Table 2.
Pathological outcomes of dMMR/MSI-H LACRC patients treated with nIT and surgery.
| nIT with PD-1 inhibitor group (n=29) | First-line nIT with PD-1 inhibitor group (n=22) | Second-line nIT with PD-1 inhibitor group (n=7) | |
|---|---|---|---|
| ORR | 29/29 (100% ) | 22/22 (100% ) | 7/7 (100% ) |
| Pathological response rate | 29/29 (100% ) | 22/22 (100% ) | 7/7 (100% ) |
| MPR rate | 25/29 (86.2%) | 20/22 (90.9%) | 5/7 (71.4%) |
| pCR rate | 22/29 (75.9%) | 17/22 (77.3%) | 5/7 (71.4%) |
| TRG | |||
| 0 | 22/29 (75.9%) | 17/22 (77.3%) | 5/7 (71.4%) |
| 1 | 3/29 (10.3%) | 3/22 (13.6%) | 0 |
| 2 | 4/29 (13.8%) | 2/22 (9.1) | 2/7 (28.6%) |
| 3 | 0 | 0 | 0 |
| Pathological T stage | |||
| ypT0 | 22/29 (75.9%) | 17/22 (77.3%) | 5/7 (71.4%) |
| ypT1 | 3/29 (10.3%) | 3/22 (13.6%) | 0 |
| ypT2 | 3/29 (10.3%) | 2/22 (9.1%) | 1/7 (14.3%) |
| ypT3 | 1/29 (3.5%) | 0 | 1/7 (14.3%) |
| Pathological N stage | |||
| ypN0 | 29/29 (100% ) | 22/22 (100% ) | 7/7 (100% ) |
| ypN1 | 0 | 0 | 0 |
| Pathological TNM stage | |||
| ypT0N0M0 | 22/29 (75.9%) | 17/22 (77.3%) | 5/7 (71.4%) |
| ypT1N0M0-I | 3/29 (10.3%) | 3/22 (13.6%) | 0 |
| ypT2N0M0-I | 3/29 (10.3%) | 2/22 (9.1%) | 1/7 (14.3%) |
| ypT3N0M0-IIA | 1/29 (3.5%) | 0 | 1/7 (14.3%) |
LACRC, Locally advanced colorectal cancer; dMMR, Mismatch repair-deficient; MSI-H, Microsatellite instability-high; nIT, Neoadjuvant immunotherapy; ORR, Objective response rate; MPR, Major pathological response; pCR, Pathological complete response; TRG, Tumor regression grade; TNM, Tumor Node Metastasis.
In our study, one LARC patient who received nIT was both dMMR and MSS, so the patient was not included in the pathological evaluation. Three patients with dMMR/MSI-H low LARC achieved cCR after nIT and adopted the WW strategy, so these three patients were also excluded from pathological evaluation.