Evolution of long-term outcome of liver resection for colorectal metastases: analysis of actual 5-year survival rates over two decades.

Background: Liver resection (LR) is the only potentially curative treatment of colorectal liver metastases (CRLM). Its outcome over the past 2 decades was studied using actual 5-year survival rates.

Methods: Data of 393 consecutive patients who underwent LR for CRLM at Mauriziano Umberto I (Turin) until June 2005 were analyzed. Excluding R2 resections (n = 4) or incomplete 5-year follow-up (n = 13), 376 patients were divided according to LR date into groups A (before 1995: 90 patients), B (1995-2000: 94 patients), C (2001-2005: 192).

Results: Group C presented increased multiple and bilobar metastases compared with combined group A and B (C vs AB: 54.7% vs 40.2%, P = 0.005; 28.1% vs 19.0%, P = 0.038, respectively), decreased metastases diameter (C vs AB: 32 vs 40 mm, P = 0.0001). The 5-year overall survival, calculated excluding 4 operative mortalities (group AB), increased over the years (A, 20.5%; B, 32.6%; C, 46.4%; P < 0.0001). Early recurrences (1 year) were not decreased, extrahepatic recurrences even increased (C vs AB: 17.2% vs 8.6%, P = 0.015). Recurrence-free 5-year survival improved (C vs AB: 23.4% vs 13.9%, P = 0.019) linked to decreased liver recurrences (C vs AB: 26.8% vs 37.4%, P = 0.023). Resection rate (59% overall for liver recurrence) increased along with 5-year survival after recurrence (A, 4.0%; B, 14.2%; C, 21.4%; P < 0.0001). Survival improvement was confirmed for multiple (P = 0.003) and synchronous metastases (P = 0.008), N+ tumors (P = 0.005), and in patients without chemotherapy (P = 0.001).

Conclusions: Long-term outcome of LR for CRLM improved over 20 years, even in patients with negative prognostic factors, linked to hepatic recurrences reduction and increased survival after recurrence.