Key Points
• Conclusion/Relevance: “The 21-gene RS [recurrence risk score] was related to favorable metabolic profiles including lower BMI, HOMA-IR, insulin, and C-peptide, and higher HDL in Chinese breast cancer patients, and its prognostic impact on breast cancer recurrence was more likely to present among patients with relatively favorable metabolic profiles.”
• In this large, prospective study, Chinese researchers found that every 10-unit increase in the 21-gene RS was related to a 28% increase in the recurrence of breast cancer. They also observed this association in patients with favorable metabolic profiles, which were characterized by the absence of obesity, insulin resistance, hyperglycemia, hypertension, or dyslipidemia (28–44% higher risk), as well as in women with a decreased level of insulin, C-peptide, or the IGF1/IGFBP3 ratio (41–155% higher risk).
• “To the best of our knowledge, this is the first study to elaborate the potential interplay between the 21-gene RS and comprehensive metabolic profiles including common metabolic disorders and insulin and the IGF axis biomarkers in relation to the risk of breast cancer recurrence,” wrote the authors. “Convincing evidence has supported the clinical utility of the 21-gene RS assay as both a prognostic and predictive tool in ER-positive, HER2-negative early-stage breast cancer, independent of clinical characteristics.”
• The authors noted that risk factors such as obesity, insulin resistance, hyperglycemia, dyslipidemia, and high blood pressure may facilitate adverse breast cancer prognosis via adipose inflammation and alterations in the tumor microenvironment
• Strengths of the current study include its large sample size, robust measures of metabolic profiles, and good validation of breast cancer events. Weaknesses of the study include its short follow-up period and small number of events, as well as potential for residual/unmeasured confounders and reverse causality.