van der Kruijssen DEW, van Rooijen KL, Kurk SA, et al. - In synchronous metastatic colon cancer (mCC), sidedness of the primary tumor is regarded as an important prognostic factor. Researchers sought to determine the interaction between primary tumor resection (PTR) and sidedness in synchronous mCC. They analyzed data from 2 first-line phase 3 randomized controlled trials (RCTs) and identified association of PTR with better survival in both right-sided (hazard ratio [HR] 0.59 [95% confidence interval 0.42–0.8 2]) and left-sided mCC (HR 0.70 [95% confidence interval 0.52–0.93]). Overall, sidedness did not influence the prognostic value of PTR.