Experience with S-1 in older Caucasian patients with metastatic colorectal cancer (mCRC): Findings from an observational chart review.

BACKGROUND: An aging population will increase the number of older patients with metastatic colorectal cancer (mCRC). However, there is limited knowledge about treatment in older patients as they are under-represented in clinical trials. The oral fluoropyrimidine S-1 is associated with a lower rate of adverse events than capecitabine and may therefore be a suitable drug for elderly. However, data on the use of S-1 in Caucasian mCRC patients are lacking/scarce.

MATERIAL AND METHODS: In the present study we evaluated safety and the efficacy of S-1 alone or in combination with oxaliplatin (SOx) or irinotecan (IRIS) in older mCRC patients. Patients who received at least one cycle of S-1 (first-line therapy), SOx (mainly first-line therapy) or IRIS (second-line therapy) were included.

RESULTS: From June 2012 to December 2014, 71 older patients received ≥1 cycle of either S-1 (n = 9), SOx (n = 44) or IRIS (n = 18) for mCRC. Median age was 76 years and most patients had a WHO performance status of 0 (32%) or 1 (56%). All patients were evaluable for response and safety. In the SOx group, 18 (41%) and 20 patients (45%) had partial response (PR) and stable disease (SD), respectively (disease control rate 86%). Median progression-free survival (PFS) was 8.5 months and median overall survival (OS) was 18.5 months. In the S-1 group (median age 82 years), PR was 22%, median PFS 6.4 months and median OS 15.8 months. In the IRIS group, PR was 28%, median PFS 7.8 months and the median OS 16.5 months. In general, therapy was well tolerated; main non-hematological toxicities were fatigue and diarrhea.

CONCLUSION: S-1 monotherapy, SOx and IRIS were well tolerated for older patients with mCRC and could become alternative regimens in older mCRC patients. These regimens are now further evaluated in the randomized ongoing NORDIC9 trial.