Chemotherapy efficacy in metastatic colorectal cancer (mCRC) patients treated with adjuvant or first-line FOLFOX-based chemotherapy.

e15048 Background: Efficacy results of Folfox or Folfiri chemotherapies (CT) are not different as 1st line in mCRC patients, alone or with targeted therapies. No data reported on progression-free survival (PFS) of 1st line Folfiri after Folfox-based adjuvant CT and of 2nd line Folfiri-based CT after a Folfox-based 1st line. The objective was to evaluate the efficacy of a Folfiri-based CT after adjuvant or 1stline Folfox-based treatment. Methods: 210 of 568 pts from a mCRC database were retrospectively selected and divided in 2 cohorts: pts who received adjuvant Folfox then Folfiri as 1st line treatment (n = 76, AdjF) and those treated with Folfox as 1st line treatment then Folfiri 2nd line (n = 134, FFox). PFS1 was the time from beginning of Folfox to 1st progression and PFS2 the time from the Irinotecan-based CT to 2ndprogression. Results: Median age was 62 (22-80). 49.3% pts had synchronous liver (72%) metastases. Primary tumour was right and left colon in 22% and 70% patients. Primary tumour was resected in 91% pts (98.7% and 86.6% in the AdjF and FFox groups, p= 0.003). KRASand BRAF-mutated status were found in 21.8% and 4.7% pts. In the AdjF group, pts received Folfiri as 1st line combined with Bevacizumab (Beva) or anti-EGFR therapy (Cetuximab or Panitumumab) in 70% and 13% cases. In the FFox group, 1st line Folfox-based CT was associated with Beva and anti-EGFRs in 7 and 6% pts, and 2ndline Folfiri-based CT with Beva or Aflibercept in 51 and 4% pts, and with anti-EGFRs in 7.5%. Median duration of a therapeutic line was 5 months (0-29.8). Grade 3-4 toxicities were for the AdjF and FFox groups respectively, diarrhea 13/15%, neutropenia (febrile) 16(7)/37%(1%) and neuropathy 24/18%. Response rates were 55.3% and 68.7% in the AdjF and FFox groups. Median PFS1 were 14 (95%CI:10-16) and 10 (95%CI:8-11) months in the AdjF and FFox groups, and PFS2 10 (95%CI:8-11) and 7 (95%CI:6-9) months, respectively. Median overall survival was 43 (95%CI:39-50) and 33 months (95%CI:26-36) respectively. Conclusions: Results in terms of survival are in favor of the AdjFFox group. It would be interesting to identify a subgroup of pts rapidly progressing after adjuvant Folfox, who might show the same profile than pts in the FFox group.