van der Kruijssen DEW, Elias SG, Vink GR, et al. - In order to clarify the role of primary tumor resection (PTR) in synchronous patients with metastatic colorectal cancer (mCRC) who had unresectable metastases and few or absent symptoms of their primary tumor, researchers herein compared patients randomized to systemic treatment only vs PTR followed by systemic treatment with respect their 60-day mortality.

• In CAIRO4, which is a randomized phase 3 trial, patients with mCRC underwent either systemic treatment only or PTR followed by systemic treatment with palliative intent.

• Significantly lower 60-day mortality was recorded for patients randomized to systemic treatment compared with patients randomized to surgery.

• Within the surgery arm, patients with raised levels of serum lactate dehydrogenase, aspartate aminotransferase, alanine aminotransferase, neutrophils, and/or right-sided tumor had the highest 60-day mortality; hence PTR should be considered cautiously in patients with these risk factors.