Should noncurative resection of the primary tumour be performed in patients with stage IV colorectal cancer? A systematic review and meta-analysis

Purpose Surgical resection of the primary tumour in patients with advanced colorectal cancer (CRC) remains controversial. This review compares survival in patients with advanced CRC who underwent surgical resection of the primary tumour with that in patients not undergoing resection, and determines rates of postoperative mortality and nonfatal complications, the primary tumour complication rate, the non-resection surgical procedures rate, and quality of life (QOL). Methods Reports in the central, MEDLINE, and EMBASE databases were searched for relevant studies, which were selected using pre-specified eligibility criteria. The search was also restricted to publication dates from 1980 onward, the English language, and studies involving human subjects. Screening, evaluation of relevant articles, and data abstraction were performed in duplicate, and agreement between the abstractors was assessed. Articles that met the inclusion criteria were assessed for quality using the Newcastle-Ottawa Scale. Data were collected and synthesized per protocol. Results From among the 3379 reports located, fifteen retrospective observational studies were selected. Of the 12,416 patients in the selected studies, 8620 (69%) underwent surgery. Median survival was 15.2 months (range: 10-30.7 months) in the resection group and 11.4 months (range: 3-22 months) in the non-resection group. Hazard ratio for survival was 0.69 [95% confidence interval (CI): 0.61 to 0.79] favouring surgical resection. Mean rates of postoperative mortality and nonfatal complications were 4.9% (95% CI: 0% to 9.7%) and 25.9% (95% ci: 20.1% to 31.6%) respectively. The mean primary tumour complication rate was 29.7% (95% CI: 18.5% to 41.0%), and the non-resection surgical procedures rate in the non-resection group was 27.6% (95 CI: 15.4% to 39.9%). No study provided QOL data. Conclusions Although this review supports primary tumour resection in advanced CRC, the results have significant biases. Randomized trials are warranted to confirm the findings.