RESUMO
BACKGROUND: Long-term survival from metastatic colorectal cancer is partly dependent on favourable tumour biology. Large case series have shown improved survival following hepatectomy for colorectal liver metastases (CRLM) in patients diagnosed with metastases more than 12 months after index colorectal surgery (metachronous), compared with those with synchronous metastases. This study investigated whether delayed hepatic resection for CRLM affects long-term survival. METHODS: Consecutive patients undergoing hepatic resection for CRLM in a single centre (1987-2007) were grouped according to the timing of hepatectomy relative to index bowel surgery: less than 12 months (synchronous; group 1), 12-36 months (group 2) and more than 36 months (group 3). Cancer-specific survival was calculated using Kaplan-Meier analysis. RESULTS: There were 577 patients (48·0 per cent) in group 1, 467 (38·9 per cent) in group 2 and 158 (13·1 per cent) in group 3. The overall 5-year cancer-specific survival rate after liver surgery was 42·3 per cent, with no difference between groups. However, when measured from the time of primary colorectal surgery, group 3 showed a survival advantage at both 5 and 10 years (94·1 and 47·6 per cent respectively) compared with groups 1 (46·3 and 24·9 per cent) and 2 (57·1 and 35·0 per cent) (P = 0·003). Survival graphs showed a steeper negative gradient from 5 to 10 years for group 3 compared with groups 1 and 2 (-0·80 versus - 0·34 and - 0·37), indicating an accelerated mortality rate. CONCLUSION: Patients undergoing delayed liver resection for CRLM have a survival advantage that is lost during long-term follow-up.