Abstract 21P
Background
Colorectal cancer (CRC) ranks among the most prevalent cancers globally. In Stage III colon cancer, high-risk patients (pT4 or pN2) receive 6 months of adjuvant chemotherapy, while low-risk patients (pT-3 and N1) are recommended either 3 or 6 months of CAPOX (capecitabine and oxaliplatin) or 6 months of FOLFOX therapy. Tumor deposits (TDs) are known to have a poor prognosis independent of lymph node (LN) involvement and are considered equivalent to LN metastases in the latest staging system. However, the optimal chemotherapy duration for patients classified as pN1c remains unknown. The aim of this study is to investigate the impact of adjuvant chemotherapy duration (3 months vs. 6 months) on survival in pN1a-b and pN1c patient groups.
Methods
We retrospectively analyzed patients with stage III colon cancer who underwent surgery between January 2014 and February 2024. Demographic and pathological data of patients were retrospectively collected. The primary outcome was progression-free survival (PFS).
Results
A total of 144 patients were included. 116 were pT1-3N1a-b and 28 were pT1-3N1c. Local (21.4% vs. 3.4%, P=0.001) and total recurrences (39.3% vs 14.6%, P=0.001) were significantly higher in the pN1c group. Univariate and multivariate analyses revealed no significant impact of adjuvant chemotherapy duration on PFS in the pN1a-b group (P=0.121), whereas in the pN1c group, 3-month chemotherapy resulted in significantly poorer PFS (HR: 2.13, 95% CI, 0.999-4.546, p=0.043). Table: 21P
Univariate and multivariate analysis of factors affecting progression-free survival
| pN1a-b, n (%) n=116 | pN1c, n (%) n=28 | |||||||
| Univariate analysis | Multivariate analysis | Univariate analysis | Multivariate analysis | |||||
| P value | HR | 95% CI | P value | P value | HR | 95% CI | P value | |
| Age ≤50 >50 | 0.243 | 0.488 | ||||||
| Sex Male Female | 0.836 | 0.938 | ||||||
| Tumor location Right sided Left sided | 0.044 | 3.31 1 | 1.240-8.947 | 0.017 | 0.819 | |||
| pT stage pT1-2 pT3 | 0.369 | 0.684 | ||||||
| Tumor grade Low grade High grade | 0.006 | 1 5.29 | 1.455-19.243 | 0.011 | NA | |||
| Lymphovascular invasion No Yes | 0.777 | 0.254 | ||||||
| Perineural invasion No Yes | 0.961 | 0.156 | ||||||
| Tumor budding No Yes | 0.271 | 0.095 | ||||||
| Microsatellite instability MSS MSI-H | 0.274 | 0.841 | ||||||
| Adjuvant chemotherapy regimen XELOX FOLFOX Capecitabine | 0.205 | 0.763 | ||||||
| Duration of adjuvant chemotherapy 3 months 6 months | 0.121 | 0.043 |
Abbreviations: CI: confidence interval, MSI-H: microsatellite instability high, MSS: microsatellite stable, PFS: progression-free survival.
Conclusions
In conclusion, our study suggests that 6-month chemotherapy is more suitable for patients with pT1-3N1c disease. Further research is needed for personalized treatment guidance.
Legal entity responsible for the study
The authors.
Funding
Has not received any funding.
Disclosure
All authors have declared no conflicts of interest.