Exploring potential predictors of low muscle mass and muscle loss in adults with cancer: A scoping review.

The scoping review included 292 studies from 22,270 identified, covering adults undergoing or previously treated for cancer.

• Databases searched: Medline Complete, CINAHL Complete, and Embase, from January 2000 to October 2024.
• 22,270 studies were initially identified; 292 were ultimately included.
• Most studies involved patients with upper and/or lower gastrointestinal cancers (50%).
• The most common treatment contexts were surgery (44%) and chemotherapy (27%).

Computed tomography (CT) at the third lumbar vertebra was the predominant method used to assess muscle mass in the included studies.

• Two-thirds (65%) of studies assessed muscle mass using CT at the third lumbar vertebra (L3).
• Other methods included CT-defined muscle mass of single muscles such as the psoas (15%).
• Bioelectrical impedance analysis or spectroscopy was used in 12% of studies.
• Dual-energy x-ray absorptiometry (DXA) was used in 7% of studies, and other methods in 3%.
• Results were focused on CT-defined muscle mass as the benchmark, with comparison to other methods.

Twenty factors were identified as associated with low muscle mass or muscle loss in adults with cancer, of which 13 showed consistent associations.

• A total of 20 factors were identified across the 292 included studies.
• Thirteen factors showed a consistent association in unadjusted and/or adjusted analysis.
• The 13 consistent factors were: age, body mass index (BMI), performance status, muscle strength, physical function, arm and leg circumference, body weight, body fat, weight loss, fatigue, energy or protein intake, and physical inactivity.
• Seven additional factors were identified but did not show consistent associations across studies.

Age was consistently associated with low muscle mass or muscle loss in adults with cancer.

• Age was identified as one of 13 factors consistently associated with CT-defined muscle loss.
• This association was observed in both unadjusted and/or adjusted analyses.
• Age was identified as a routinely assessed clinical measure with potential utility in screening.

BMI and body weight were consistently associated with low muscle mass or muscle loss in adults with cancer.

• Both BMI and body weight were among the 13 factors consistently associated with CT-defined muscle loss.
• These associations were observed in unadjusted and/or adjusted analyses.
• BMI and body weight are routinely assessed clinical measures, supporting their potential use in screening.

Nutritional factors including body fat, weight loss, fatigue, and energy or protein intake were consistently associated with muscle loss in cancer patients.

• Body fat, weight loss, fatigue, and energy or protein intake were among the 13 consistently identified factors.
• These factors were identified across studies predominantly involving gastrointestinal cancer patients.
• The findings highlight the nutritional dimension of cancer-related muscle loss risk.

Physical measures including muscle strength, physical function, arm and leg circumference, and physical inactivity were consistently associated with low muscle mass or muscle loss in adults with cancer.

• Muscle strength, physical function, arm and leg circumference, and physical inactivity were each identified as consistent factors.
• These associations were found in unadjusted and/or adjusted analyses across the included studies.
• Performance status was also consistently associated, representing a combined functional and clinical measure.

The review identified that early identification of cancer-related muscle loss using routinely assessed clinical measures could enable timely referral for evidence-based nutrition and exercise interventions.

• The 13 identified factors are described as potentially helping to identify patients with cancer who are at risk and require further assessment.
• The review aimed to identify measures 'routinely assessed' in clinical settings to inform future global screening and assessment.
• Timely referral for 'evidence-based nutrition and exercise interventions' is highlighted as a key goal.
• Early identification is stated to be 'essential to enable timely interventions and mitigate adverse outcomes, including mortality.'