van der Kruijssen DEW, Elias SG, Vink GR, et al. - In the treatment of metastatic colorectal cancer (mCRC), exercising caution is advised while considering primary tumor resection (PTR) in cases with preoperative increased serum lactate dehydrogenase, aspartate aminotransferase, alanine aminotransferase, and/or neutrophil levels.

• In this randomized phase 3 trial (CAIRO4), patients with mCRC were randomized to systemic treatment only (n=99) or PTR followed by systemic treatment (n=97) with palliative intent.

• In the systemic treatment arm vs the PTR arm, 60-day mortality was 3% vs 11%, respectively.

• In patients who received systemic treatment, the 60-day mortality was significantly lower than those randomized to surgery.

• Within the surgery arm, those with increased levels of serum lactate dehydrogenase, aspartate aminotransferase, alanine aminotransferase, neutrophils, and/or right-sided tumor were found to have the highest 60-day mortality.