Abstract
There are still debates regarding the appropriate primary treatment policy for asymptomatic primary colorectal lesions in cases of unresectable metastatic colorectal cancer. Even though there are patients with asymptomatic primary tumors when starting chemotherapy, those patients may still undergo surgery due to complications related to primary tumors in the middle of chemotherapy; therefore, controversy exists regarding surgical resection of primary colorectal lesions in cases where symptoms are absent when making a diagnosis. Thus, based on the published literature, we discuss opinions that prefer first-line surgery for primary tumors as well as opinions favoring first-line chemotherapy for treating unresectable synchronous metastatic colorectal cancer. Although the upfront chemotherapy including targeted agents is suggested as an effective treatment in recent years, the first line surgery has been a preferred treatment for decades. The first line surgery is beneficial to prolong the survival duration given the retrospective analysis of randomized trial data. So far, no prospective comparison study has only focused on the first-line treatment modality; thus, future clinical studies focusing on the survival duration and the quality of life should be performed as soon as possible. Furthermore, at this point, multidisciplinary team approaches would be helpful in finding the appropriate therapy. Regardless of symptoms, the performance status and the tumor burden should be taken into consideration as well. In case of surgical resection, minimally invasive surgery, such as laparoscopic surgery, is recommended.