Abstract 501P
Background
Some patients with mCRC have better outcomes regarding lines of chemotherapy that can receive, which impacts in terms of survival. However, it is not well known whether these patients may have a different clinical and molecular status that can be identified as a prognostic factor.
Methods
We performed a retrospective analysis of 555 mCRC patients, comparing the clinical characteristics and survival trends of those who received ≥3 lines of treatment (n = 256) versus those who received <3 lines of treatment. We applied the exact test of Fisher to identify significant association between categoric variables, while we used Mann-Whitney test to identify significant differences between quantitative variables. PFS and OS were compared using a long-rank test, and the estimate of hazard ratio (HRs) between studied groups was calculated by means of Cox proportional hazards model.
Results
Several characteristics were associated with receiving ≥3 lines of treatment: age <65 years (n = 141, OR 1.81, p < 0.001), primary tumor site at rectum (n = 80, OR = 1.52, p = 0.034), resection of primary tumor (n = 221, OR 1.96, p = 0.003), having an ECOG 0 (n = 87, OR 1.49, p = 0.048), presenting symptomatic improvement during treatment (n = 87, OR 1.67, p = 0.024) and undergoing metastases resection (n = 174, OR 1.79, p < 0.001). Patients receiving ≥3 lines of treatment also underwent more surgeries (mean 1.83 vs 1.02, p = 0,000). We did not found differences in terms of sex, BMI, tumor mutational status (KRAS, NRAS, BRAF, MSI, PI3K and HER2), tumor side (right colon vs left colon), synchronous or metachronous presentation of metastatic disease, or response rate in first line chemotherapy. In the survival analysis, we did not find differences in PFS in first line treatment, but we found differences in OS rates showing better outcomes in patients receiving ≥3 lines of treatment (median 87.5 months vs 36.6 months, HR for death 0.45, 95 % confidence interval (CI) 0.35 to 0.58; p < 0.001).
Conclusions
mCRC patients with rectal cancer, primary tumor resected, ECOG 0 and symptomatic improvement during treatment have a higher probability of receiving three or more lines of treatment, which may impact in terms of OS.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
The authors.
Funding
Has not received any funding.
Disclosure
All authors have declared no conflicts of interest.