Management of asymptomatic primary tumours in stage Ⅳ colorectal cancer: Review of outcomes

AIM: To compare outcomes for patients presenting withstage IV colorectal cancer and an asymptomatic primary tumour, undergoing primary tumour resection(PTR) plus palliative chemotherapy vs primary chemotherapy up-front.METHODS: A literature search was conducted using MEDLINE and EMBASE. The primary outcome was overall survival. Secondary outcomes included perioperative mortality, morbidity and delayed surgical intervention rates in patients undergoing PTR and subsequent complication rates in patients with an un-resected primary tumour. Tertiary outcomes included impact on systemic treatment and identification of prognostic factors relevant for survival in this cohort. RESULTS: Twenty non-randomised studies met the inclusion criteria. Eleven studies included comparative overall survival data. Three studies showed an overall survival advantage for PTR, 7 studies showed no statistically significant advantage, and 1 study showed a significant worsening in survival in the surgical group. The perioperative mortality rate ranged from 0% to 8.5%, and post-operative morbidity rate from 10% to 35%, mainly minor complications that did not preclude subsequent chemotherapy. The rate of delayed primarytumour related symptoms, most commonly obstruction, in patients with an un-resected primary tumour ranged from 3% to 46%. The strongest independent poor prognostic factor was extensive hepatic metastases, in addition to poor performance status, M1 b stage and non-use of modern chemotherapy agents.CONCLUSION: Based on the current literature, both PTR and up front chemotherapy appear appropriate initial management strategies, with a trend towards an overall survival advantage with PTR. The procedure has a low post-operative mortality, and most complications are transient and minor. The results of recruiting randomised trials are eagerly anticipated.