TY - JOUR T1 - Clinical Impact of Primary Tumor Site in Stage IV Colorectal Cancer: A Statewide Cohort Study JF - Anticancer Research JO - Anticancer Res SP - 5693 LP - 5702 DO - 10.21873/anticanres.15385 VL - 41 IS - 11 AU - HIDETAKA KAWAMURA AU - MICHITAKA HONDA AU - KOICHI TAKIGUCHI AU - TAKAHIRO KAMIGA AU - KATSUMASA SAITO AU - ATSUSHI MUTO AU - SATORU SHIRASO AU - NAOYUKI YAMASHITA AU - TOSHIYASU IWAO AU - SHIGEHIRA SAJI AU - KOJI KONO AU - SHINICHI KONNO Y1 - 2021/11/01 UR - http://ar.iiarjournals.org/content/41/11/5693.abstract N2 - Background/Aim: We investigated the clinical impact of the primary tumor site in stage IV colorectal cancer (CRC). Patients and Methods: In this statewide multicenter retrospective cohort, patients with stage IV CRC from nine hospital-based cancer registries across the Fukushima Prefecture (2008-2015) were categorized based on three primary tumor sites: right colon cancer (RCC), left colon cancer (LCC), and rectal cancer. Overall survival was assessed using Cox regression analysis. Results: A total of 1,211 patients were included. The most common clinical symptom was obstruction in LCC and bleeding in rectal cancer. Liver metastases were multiple and larger in LCC, while lung metastases were multiple in rectal cancer. Compared to LCC, the adjusted hazard ratio (HR) for overall survival was 1.19 [95% confidence interval (CI)=1.01-1.39, p=0.032] in RCC and 1.03 (95% CI=0.86-1.23, p=0.77) in rectal cancer. Conclusion: RCC was independently associated with a worse prognosis in stage IV CRC. ER -