MS-N150 · Nutrition · Muscle support · Colorectal cancer · Randomized pilot · Appraised 27 October 2026

Does counseling toward 2.0 rather than 1.0 g/kg/day of protein preserve muscle during chemotherapy for stage II–IV colorectal cancer?

Evidence at a glance

• Evidence label: Feasibility signal; no demonstrated between-group muscle or function benefit
• Benefit: Counseling increased protein intake, but the randomized groups did not differ significantly in appendicular lean tissue or physical function at 12 weeks.
• Certainty: Low. This 50-person pilot had incomplete target separation, attrition and exploratory analyses.
• Risk: High protein targets require individualization for kidney disease, fluid limits, swallowing problems and overall calorie adequacy.

What was studied

The PRIMe pilot randomized 50 adults starting chemotherapy for stage II–IV colorectal cancer to individualized counseling targeting 2.0 or 1.0 g/kg/day of protein for 12 weeks. Forty participants completed week 12. Lean soft tissue was measured by DXA and function by the Short Physical Performance Battery.

What the evidence found

At week 12, achieved intake averaged 1.6 versus 1.2 g/kg/day. The difference in appendicular lean soft tissue change was not significant (0.5% versus −0.4%; P=0.619), and physical function did not differ. Fifty-nine percent versus 44% maintained or gained muscle mass (P=0.523). A 2026 post hoc analysis suggested inflammation, particularly IL-6, may blunt anabolic response; it cannot establish a treatment rule.

How to interpret it

This supports access to individualized oncology nutrition but does not prove that a 2.0 g/kg/day target improves muscle, treatment tolerance or survival. The 2026 inflammation analysis is hypothesis-generating and based partly on achieved intake rather than the randomized assignment.

Practical safety context

Protein targets should be set with an oncology dietitian, especially with chronic kidney disease, hepatic encephalopathy risk, dehydration, poor intake or rapid weight loss. Increasing protein without enough total energy may not prevent catabolism.

Questions for the care team

• What is the current intake in g/kg/day and is total energy adequate?
• Is kidney or liver function a reason to modify the target?
• How will muscle, weight, strength and treatment tolerance be tracked?

Funding and conflicts

Several authors reported relationships with nutrition-product companies; disclosures included honoraria or consultancy involving Abbott, Nutricia and Nestlé Health Science. The 2026 analysis was published August 10, 2026 online.

Sources

• PRIMe randomized pilot (PMID 38935990)
• PRIMe full text (PMCID PMC11260369)
• 2026 inflammation analysis (PMID 42575283)
• ClinicalTrials.gov NCT02788955

Last literature search: 27 October 2026. Record appraisal: 27 October 2026. This page is educational and does not replace individualized medical advice. Symptom, biomarker, immune-marker or nutritional changes must not be interpreted as proof of tumor control, recurrence prevention or longer survival unless those outcomes were directly tested.