(HealthDay News) — For patients enrolled in metastatic colorectal cancer (mCRC) trials, low body mass index (BMI) is associated with increased risk of progression and death, according to research published online Oct. 26 in the Journal of Clinical Oncology.

Lindsay A. Renfro, Ph.D., from the Mayo Clinic in Rochester, Minn., and colleagues examined whether BMI is prognostic or predictive in mCRC using individual data from 21,149 patients enrolled into 25 first-line mCRC trials. Prognostic and predictive effects of BMI were assessed on overall and progression-free survival.

The researchers found that BMI was prognostic for overall and progression-free survival (both P < 0.001), with an L-shaped pattern. The risk of progression and/or death was highest for low BMI, decreased as BMI increased to about 28 kg/m², and then plateaued. Patients with a BMI of 18.5 kg/m² had a 27 percent increased risk of progression and a 50 percent increased risk of death compared with obese patients. Poorer survival was seen in association with low BMI for men versus women (interaction P < 0.001). BMI did not predict treatment effect.

“Possible explanations include negative effects related to cancer cachexia in patients with low BMI, increased drug delivery or selection bias in patients with high BMI, and potential for an interaction between BMI and molecular signaling pathways,” the authors write.

Several authors disclosed financial ties to the pharmaceutical industry.

Full Text (subscription or payment may be required)