Annual hazard rate of relapse of stage II and III colorectal cancer after primary therapy.

PURPOSE: To report the annual hazard of relapse in stages II and III colorectal cancer (CRC) Tunisian patients treated with curative intent. We also aim to evaluate impact of oxaliplatine according to anatomo-clinical features.

METHODS: We collected data about clinico-pathological parameters of 331 CRCs. We analyzed annual hazard of recurrence (locoregional and/or distant) of the overall population and several subgroups: colon cancer vs rectal cancer and stage II vs stage III. We also analyzed impact of adjuvant oxaliplatine on recurrence within these subgroups.

RESULTS: Relapse rate was 38.1%, with a mean time to relapse of 27.6 months. We noted 23.8% local recurrence, 69.8% distant recurrence, and 6.4% both. We observed higher local relapse rate in rectal cancer (26.8 vs 3.2%) vs colon cancer (p = 0.004). Stage III had a higher metastatic relapse rate vs stage II (31.6 vs 20.8%, p = 0.043). Annual hazard of recurrence for the overall population showed two peaks: [1-2] year-interval by 10.1% and [3-4] year-interval by 11.3%. Stage III showed significantly higher and earlier recurrence hazard peak compared to stage II (16.3 vs 8.1% in [1-2] year-interval). Oxaliplatine significantly improved annual hazard of recurrence in each year-interval from year 1-4, in colon cancer and in stage III but without impact in rectal cancer and stage II.

CONCLUSION: Extended follow-up to 4 years should be considered in Tunisian population. Impact of oxaliplatine showed same features to reported occidental series.