Abstract 42P
Background
Neoadjuvant chemotherapy has the encouraging potential to shrink tumors and reduces the risk of incomplete resection. Preoperative immunotherapy has proved effective in rectal cancer, but not in colon cancer. This study aims to explore the efficacy and safety of neoadjuvant tislelizumab combined with CAPOX in pts with MSS/pMMR high-risk locally advanced colon cancer.
Methods
MSS/pMMR pts aged 18-75 years, with high-risk locally advanced (T3N+ or T4N+) colon cancer was enrolled and received neoadjuvant tislelizumab (200 mg) combined with CAPOX every 3 weeks. After two cycles of treatment, pts underwent CME, followed by six cycles; or continued another two cycles, then CME, followed by four cycles therapy. The primary endpoint was pCR. Safety was analyzed in all pts.
Results
Between Nov 2022 and Nov 2023, 27 pts were enrolled and received at least one cycles of tislelizumab with CAPOX therapy. The median age was 49 years and 18 pts were male. 15 (55.6%) pts had a downgrade in T stage (p<0.0001) and 21 (77.8%) in N stage (p<0.0001) based on enhanced CT. Of the 15 pts with high CEA levels, 9(60%) pts showed a reduction in CEA levels (p=0.004). The median duration from the first dose of therapy to surgery was 15 weeks. Treatment was well tolerated and of the resections 100% were radical under laparoscopy. A pCR was achieved in 14 (51.85%) of 27 pts. 1 (3.7%) pt was TRG1, 9 (33.3%) pts were TRG2, and 3 pts (11.1%) were TRG3. The most common adverse events (AEs) were peripheral sensory neurotoxicity (33.3%, 9/27). The incidence of grade 3 AEs was 5.2%, and no grade 4 or 5 treatment-related AEs occurred. Postoperative complications were mild intestinal obstruction and mild pneumonia in 2 pts. After a median follow-up of 6.5 months, none had disease recurrence or metastasis. Table: 42P
| (n=27) | p | ||
| Before NET | After NET | ||
| Male/Female | 18/9 | ||
| Median age, years | 49（23-70） | ||
| T stage | <0.0001 | ||
| T0 | 0 | 5 | |
| T1-2 | 0 | 10 | |
| T3 | 14 | 11 | |
| T4 | 13 | 1 | |
| N stage | <0.0001 | ||
| N0 | 0 | 21 | |
| N1 | 9 | 4 | |
| N2 | 18 | 2 | |
| CEA | 0.004 | ||
| CEA＜5ng/ml | 12 | 23 | |
| CEA ≥ 5ng/ml | 15 | 4 |
NET: Neoadjuvant therapy
Conclusions
In pts with MSS/pMMR high-risk locally advanced colon cancer, neoadjuvant tislelizumab combined with CAPOX is effective and tolerable, and significantly increases pCR rate.
Clinical trial identification
NCT06124378.
Legal entity responsible for the study
The authors.
Funding
National Natural Science Foundation of China (82003072).
Disclosure
All authors have declared no conflicts of interest.