Table 1 Summary of studies evaluating the impact of muscle on breast cancer outcomes

Sheehan et al. [20]

Retrospective

Stage IV, ER negative

n = 152

CT scan

Sarcopenia (SMI ≤ 41 cm²/m²)

Low SMD (< 41 HU, < 33 HU if BMI ≥ 25)

Sarcopenia at diagnosis not associated with OS. Low SMD reduced 2 year OS, HR 1.72 (1.09–2.72)

Caan et al. [21]

Retrospective

Stage II, III

n = 3241

CT scan

Sarcopenia (SMI < 40 cm²/m²)

Low SMD (< 37.8 HU)

Sarcopenia associated with OS, HR 1.41 (95% CI 1.18–1.69)

SMD not associated with OS

Deluche et al. [22]

Retrospective

Stage I–III

n = 119

CT scan

Sarcopenia (SMI < 41 cm²/m²)

Absence of sarcopenia associated with better DFS (HR 0.3, 95% CI 0.1–0.8, p = 0.02) and OS (HR 0.3, 95% CI 0.1–0.99, p = 0.05)

Shachar et al. [23]

Retrospective

Stage IV, taxane chemotherapy

n = 40

CT scan

Sarcopenia (SMI < 41 cm²/m²)

Sarcopenia associated with higher grade 3–4 toxicity (18% vs. 57%, p = 0.02). No association with survival

Rier et al. [24]

Retrospective

Stage IV, first line chemotherapy

n = 166

CT scan

Sarcopenia (SMI < 41 cm²/m²)

Low SMD (< 41 HU, < 33 HU if BMI ≥ 25)

Low SMD associated with lower OS (HR 2.04, 95% CI 1.34–3.12, p = 0.001). SMI had no association with OS

Villasenor et al. [25]

Prospective

Stage 0–III

n = 471

DEXA scan

Sarcopenia (SMI < 5.45 kg/m²)

Sarcopenia associated with OS (HR 2.86, 95% CI 1.67–4.89)

Prado et al. [26]

Retrospective

Stage IV, capecitabine chemotherapy

n = 55

CT scan

Sarcopenia (SMI < 38.5 cm²/m²)

Low SMD (< 41 HU, < 33 HU if BMI ≥ 25)

Sarcopenia associated with grade 3–4 toxicity (20% vs. 50%, p = 0.03) and shorter TTP (173 vs 101 days, p = 0.05)