Non-resection versus resection for an asymptomatic primary tumour in patients with unresectable stage IV colorectal cancer.

BACKGROUND: In a majority of patients with stage IV colorectal cancer, the metastatic disease is not resectable and the focus of management is on how best to palliate the patient. How to manage the primary tumour is an important part of palliation. A small proportion of these patients present with either obstructing or perforating cancers and require urgent surgical care. However, a majority are relatively asymptomatic from their primary cancer. Chemotherapy has been shown to prolong survival in this group of patients, and a majority of patients would be treated this way. Nonetheless, A recent meta-analysis (Stillwell 2010) suggests an improved overall survival and reduced requirement for emergency surgery in those patients who undergo primary tumour resection. This review was also able to quantify the mortality and morbidity associated with surgery to remove the primary.
OBJECTIVES: To determine if there is an improvement in overall survival following resection of the primary cancer in patients with unresectable stage IV colorectal cancer and an asymptomatic primary who are treated with chemo/radiotherapy. SEARCH
METHODS: In January 2012 we searched for published randomised and non-randomised controlled clinical trials without language restrictions using the following electronic databases: CENTRAL (the Cochrane Library (latest issue)), MEDLINE (1966 to date), EMBASE (1980 to date), Science Citation Index (1981 to date), ISI Proceedings (1990 to date), Current Controlled Trials MetaRegister (latest issue), Zetoc (latest issue) and CINAHL (1982 to date). SELECTION CRITERIA: Randomised controlled trials and non-randomised controlled studies evaluating the influence on overall survival of primary tumour resection versus no resection in asymptomatic patients with unresectable stage IV colorectal cancer who are treated with palliative chemo/radiotherapy. DATA COLLECTION AND ANALYSIS: We conducted the review according to the recommendations of The Cochrane Collaboration and the Cochrane Colorectal Group. "Review Manager 5" software was used. MAIN
RESULTS: A total of 798 studies were identified following the initial search. No published or unpublished randomised controlled trials comparing primary tumour resection versus no resection in asymptomatic patients with unresectable stage IV colorectal cancer who were treated with chemo/radiotherapy were identified. Seven non-randomised studies, potentially eligible for inclusion, were identified: 2 case-matched studies, 2 CCTs and 3 retrospective cohort studies. Overall, these trials included 1.086 patients (722 patients treated with primary tumour resection, and 364 patients managed first with chemotherapy and/or radiotherapy). AUTHORS'
CONCLUSIONS: Resection of the primary tumour in asymptomatic patients with unresectable stage IV colorectal cancer who are managed with chemo/radiotherapy is not associated with a consistent improvement in overall survival. In addition, resection does not significantly reduce the risk of complications from the primary tumour (i.e.  obstruction, perforation or bleeding). Yet there is enough doubt with regard to the published literature to justify further clinical trials in this area. The results from an ongoing high quality randomised controlled trial will help to answer this question.