Objective  To evaluate the safety and preliminary efficacy of a modified FOLFOXIRI (mFOLFOXIRI) regimen as a salvage treat ment for patients with unresectable metastatic colorectal cancer (mCRC), after standard treatment failure.

  Methods  We systematically analyzed all patients with mCRC who were treated at the Hangzhou First People's Hospital and Hangzhou Cancer Hospitals, from January 2011 to December 2016. A total of 13 patients who received mFOLFOXIRI (combination of irinotecan, oxaliplatin, leucovorin, and 5-fluorouracil/capecitabine with reducing dosages) treatment were followed up.

  Results  The median patient age was 54 (ranged from 41 to 68) years. All 13 patients who received a median of 4 (ranged from 1 to 8) cycles of the mFOLFOXIRI regimen were evaluated for treatment efficacy and toxic effects. Of the 13 patients, 10 patients (76.9%) received more than 4 cycles of the regimen, and the median progression-free survival (PFS) was 4.5 (95% CI 2.5-6.5) months. Due to the short observation time, 4 patients did not reach the end point of observation. The median overall survival (OS) was 14 (95% CI 5.7-22.3) months, and across all data, the objective remission rate was 30% and the clinical benefit rate was 90%. The most frequent 3/4 grade adverse events were anemia, leukocyte reduction, thrombocytopenia, and peripheral neuropathy. No treatment-related deaths occurred.

  Conclusions  In this study, the mFOLFOXIRI regimen, which was applied after the failure of the standard treatment, was feasible in patients with good performance statuses and it demonstrated improvements in PFS and OS. The associated adverse reactions were controllable.