Impact of Primary Tumor Location on Postoperative Recurrence and Subsequent Prognosis in Nonmetastatic Colon Cancers: A Multicenter Retrospective Study Using a Propensity Score Analysis.

Abstract

We aimed to clarify the prognostic impact of primary tumor location on recurrence after curative surgery and subsequent survival in patients with nonmetastatic colon cancer. Right and left colon cancers are suggested to be oncologically different; however, their prognostic differences have been conflictingly reported. A total of 5664 patients with curatively resected stage II-III colon cancer were reviewed, retrospectively. Relapse-free survival (RFS) after primary surgery and cancer-specific survival (CSS) after recurrence were compared between patients with right and left colon cancer. Patients' backgrounds were matched using propensity scores. Although patients with right colon cancer had more advanced disease, their 5-year RFS rate was significantly superior compared with that in those with left colon cancer (83.9% vs 81.1%, P = 0.019). However, the 5-year CSS after recurrence rate was significantly inferior in patients with right colon cancer compared with that in those with left colon cancer (30.6% vs 43.6%, P = 0.016). The primary tumor location of nonmetastatic colon cancer might have different prognostic implications for the rates of recurrence after curative resection and cancer-specific mortality after recurrence.