In asymptomatic Stage 4 colorectal cancer, the treatment varies between many hospitals and countries. Some studies found that primary tumor resection had better survival rates and a lower risk of mortality. But many studies found significant benefits in survival in sub groups of the population such as age less than 70 years, WHO performance status <2, no extra-hepatic metastasis, liver tumor burden <50%. However some studies showed no survival benefits in primary tumor resection. So this study will focus on survival, adverse events, complications in primary tumor resection and no primary tumor resection in asymptomatic Stage 4 colorectal cancer.

The retrospective study of patients in asymptomatic Stage 4 colorectal cancer received treatment at Ramathibodi Hospital and excluded symptomatic primary tumors such as obstruction, perforation that required surgery, carcinomatosis peritoneii, and patients with secondary cancer diagnosis in the past 5 years.

Inclusion Criteria:

• Asymptomatic stage IV colorectal cancer
• pathological prove adenocarcinoma
• age >18 years
• no primary tumor related symptom
• ECOG performance status <2

Exclusion Criteria:

• symptomatic primary tumor such as obstruction , perforation that required surgery
• carcinomatosis peritoneii
• patients with secondary cancer diagnosis in 5 years

Medical records of stage IV colorectal cancer with unresectable distant metastasis received treatment in Ramathibodi hospital between 1 September 2006 - 31 August 2016.