Exploring the dietary protein intake and skeletal muscle during first-line anti-neoplastic treatment in patients with non-small cell lung cancer

Background: Loss of skeletal muscle mass is the corner stone of cancer cachexia, but no effective therapies are yet identified. The optimal protein quantity and pattern to support muscle mass maintenance in cancer patients is unknown. The aim of the current exploratory study was to observe the pattern and quantity of dietary protein intake as well as the prevalence of muscle wasting in patients with inoperable non-small cell lung cancer (NSCLC) undergoing primary anti-neoplastic treatment. The secondary aim was to assess the potential contributory factors associated with maintenance of muscle mass. Method: A longitudinal observational study was conducted in patients with NSCLC undergoing first line of anti-neoplastic treatment. Nutrient intake was assessed by repeated 24-h recalls and skeletal muscle by routine thoraco-abdominal CT scans at baseline and after three cycles of treatment. Descriptive analyses, paired samples t-test, binomial logistic and linear regression analyses were performed. Results: Out of 186 consecutively screened patients, 62 were included and 52 patients were available for analysis. Protein intake increased from baseline to follow up, but were lower in muscle wasters (1.0 g/kg/d) than in muscle maintainers (1.4 g/kg/d). The majority of the meals contributed less than 20 g of protein and less than 10% of the meals contributed at least 40 g of protein. Significant loss of skeletal muscle area was observed in 26 out of 52 patients. A higher protein intake (OR 18.7, p = 0.01), energy intake (OR 1.1, p = 0.04) and stable body weight (OR 1.2, p = 0.03) were associated with muscle maintenance in the univariate regression, whereas age, sex, cachexia, tumour stage, treatment adherence and response did not. In the multivariate regression, a trend was seen for protein intake (OR 35.2, p = 0.08) and body weight (OR 1.2, p = 0.06). Conclusion: Muscle wasting occurred frequently and early during primary anti-neoplastic treatment. Protein intake seems important for maintaining skeletal muscle. Validated dietary methods in cancer patients must be identified and the optimal protein quantity and intake pattern to support muscle maintenance should be explored in future trials.