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Background:

Branched-chain amino acids (BCAAs; leucine, isoleucine, and valine) are essential amino acids involved in immune responses, and may have roles in protein malnutrition and sarcopenia. Furthermore, certain liver diseases have been associated with a decreased Fischer’s ratio (BCAAs to aromatic amino acids; phenylalanine, tyrosine, and tryptophan). We aimed to evaluate the safety and efficacy of BCAAs use in patients with cancer undergoing surgery.

Methods:

MEDLINE, Embase, and CENTRAL were searched (inception to July 24, 2020) for randomized controlled trials (RCTs) and comparative observational studies in English evaluating BCAAs (alone or in combinations) during the oncological peri-operative period. Study selection, data extraction, and quality appraisal were done in duplicate. RCT risk-of-bias was appraised using Cochrane Risk-of-Bias tool, and observational studies’ quality assessment was conducted with Newcastle-Ottawa Scale. Meta-analyses were conducted when appropriate.

Results:

20 articles were included comprising 13 RCTs and 6 observational cohort studies in 7 reports and 2019 total participants overall. Among 13 RCTs, 77% involved liver cancer. Methodological study quality scored substantial risk-of-bias across most RCTs. Meta-analysis of RCTs found a 38% decreased risk of post-operative infections in BCAAs group compared to controls (RR = 0.62; 95% CI = 0.44 to 0.87;ÌýP = .006; number of RCTs,Ìýk = 6; total sample size, N = 389;ÌýI2 = 0%). BCAAs were also found to be beneficial for ascites (RR = 0.55; 95% CI = 0.35 to 0.86;ÌýP = .008;Ìýk = 4; N = 296;ÌýI2 = 0%), body weight (MD = 3.24 kg; 95% CI = 0.44 to 6.04;ÌýP = .02;Ìýk = 3; N = 196;ÌýI2 = 24%), and hospitalization length (MD = −2.07 days; 95% CI = −3.97 to −0.17;ÌýP = .03;Ìýk = 5; N = 362;ÌýI2 = 59%). No differences were found between BCAAs and controls for mortality, recurrence, other post-operative complications (liver failure, edema, pleural effusion), blood loss, quality of life, ammonia level, and prothrombin time. No serious adverse events were related to BCAAs; however, serious adverse events were reported due to intravenous catheters. No safety concerns from observational studies were identified.

Conclusions:

Branched-chain amino acids during the oncological surgical period demonstrated promise in reducing important post-operative morbidity from infections and ascites compared to controls. Blinded, placebo-controlled confirmatory trials of higher methodological quality are warranted, especially using oral, short-term BCAAs-enriched supplements within the context of recent ERAS programs.

PROSPERO registration:

CRD42018086168.