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Chemotherapy-free intervals (CFI) in patients with metastatic colorectal cancer (MRC).

3581 Background: Median survival in patients (pts) with MRC can reach 20 months with chemotherapy and should further improve with combined targeted therapies. CFI should be considered in order to improve quality of life of long survivors.


METHODS
197 pts responders or stable with chemotherapy in a single institution benefited from CFI of at least 3 months, for any reason, in a 12 year period (1992-2005). Therapy was rechallenged in case of disease progression. Duration of CFI and overall survival (OS) were analyzed according to therapy and prognostic factors.


RESULTS
In 146 pts who had a CFI after a first-line, chemotherapy was 5FU-based in 32 pts, oxaliplatin-based in 103 pts (FOLFOX alone in 64 pts, FOLFOX followed by 5FU in 39 pts), irinotecan-based in 11 pts. In 51 pts who had a CFI after a second-line, chemotherapy was 5FU-based in 6 pts, oxaliplatin-based in 30 pts, irinotecan-based in 15 pts. There was no correlation between therapy duration before CFI and CFI duration, p=.66. Median CFI duration was 29 weeks (wks) in first line and 21 wks in second line, p=.0005. Median therapy duration and CFI were 42 and 26 wks after 5FU-based chemotherapy, 12 and 27 wks after FOLFOX and 36 and 37 wks after FOLFOX followed by 5FU, p=.001 and p=.12, respectively. In first-line, CFI lasted a median of 39 wks in 15 pts in complete response, 29 wks in 61 partial responders and 27 wks in 70 stable pts, p=.33. Among patients who had a CFI after a first-line therapy, those with good prognostic factors (PS 0, normal LDH and alkaline phosphatases <3UNV) experienced a longer CFI and a longer OS than others, median 27 vs 25 wks (p=.025) and 139 vs 108 wks (p=.007), respectively.


CONCLUSIONS
CFI should be considered especially in good prognosis patients and in first-line therapy. The Optimox 2 study which compares 5FU maintenance therapy and CFI after FOLFOX should further evaluate CFI. [Table: see text].