Predictors of survival during treatment of metastatic colorectal cancer with an intermittent chemotherapy regimen.

Abstract

e14063 Background: Patients with metastatic colorectal cancer (mCRC) undergo month to year-long therapy with different chemotherapy regimens and biological agents. We aimed to identify predictors of mortality during an intermittent treatment regimen in an unselected cohort of patients with mCRC. Methods: Consecutive patients, treated from August 2007 until June 2011, were included. Standard 1st line treatment was biweekly FLIRI plus Bevacizumab. Clinical information was obtained from patient files. The outcome was overall survival. Cox regression analysis was used to identify predictors of outcome. We analyzed reduction in chemotherapy dosage (no reduction, ≤75% or >75%), administration of Bevacizumab to ≤50% of chemotherapy treatments, best response during the first 6 months of treatment (NC, RD or PD), and local treatment of metastases (any type). We adjusted for following baseline variables: Gender, age, PS, primary tumor site, resection of primary tumor, metachronous metastases, more than two metastatic sites, liver-only metastases, and low albumin Results: We included 314 patients (median age 64.5 IQ (57-70) years, 194 (61.8%) male). Median follow-up for survival was 471 IQ (257-708) days. One-year survival was 79%, CI (74-84%). Median overall survival was 676 days, CI (577-750). Chemotherapy reduction did not influence outcome, ≤75%: HR 1.08 CI (0.64-1.83), p=0.77, >75%: HR 0.66 CI (0.29-1.5), p=0.32. Local treatment of metastases was borderline significant: HR 0.45 CI (0.20-1.00), p=0.051. Bevacizumab was administered in 262 patients and a reduction in bevacizumab treatments was associated with increased mortality: HR 1.90 CI (1.12-3.23), p=0.018. Regression vs. NC improved outcome HR 0.48 (0.30-0.78), p=0.003, whereas PD vs. NC increased mortality HR 3.84 (1.75-8.42), p=0.001. Conclusions: In an unselected cohort of mCRC patients, using an intermittent treatment regimen, administration of Bevacizumab to less than 50% of chemotherapy treatments and PD were associated with increased mortality. Regression improved outcome compared to stable disease. Local treatment of metastases was borderline significant. Reduction in chemotherapy dosage did not influence outcome.