Background: Impact of time to start first-line systemic chemotherapy following diagnosis of metastatic colorectal cancer (mCRC) needs to be studied.
Methods: This is a pooled analysis of the raw data of the comparator arms of two randomized studies (NCT00272051; NCT00305188). Univariate and multivariate analyses of predictors of overall and progression-free survival were conducted through Cox regression analysis. Factors with statistically significant P value (P < 0.05) in the univariate part of the analysis were included in the multivariate analysis.
Results: In univariate analysis, time to start systemic therapy did not affect overall or progression-free survival (P=0.694; P= 0.891 respectively). In multivariate analysis for overall survival, the following factors were predictive of worse overall survival: younger age (P = 0.019), higher ECOG performance score (P = 0.001), more than one site of metastatic disease (P = 0.002), colon site of the primary tumor (P = 0.004), and no oncologic surgery to the primary tumor (P < 0.001). Likewise, in multivariate analysis for progression-free survival, the following factors were predictive of worse progression-free survival: no oncologic surgery to the primary (P < 0.001), more than one organ of metastatic disease (P < 0.001), and no concurrent bevacizumab administration (P = 0.015).
Conclusion: Time to start systemic chemotherapy does not appear to impact overall or progression-free survival among mCRC patients.
Keywords: Colon cancer; prognosis; rectal cancer; survival; systemic treatment.