The association between thoracic sarcopenia and survival is gender specific in early-stage lung cancer

Background: Sarcopenia, as measured at the 3rd lumbar (L3) level, has been shown to prognosticate survival in cancer patients. However, many patients with early-stage non-small cell lung cancer (NSCLC) do not undergo abdominal imaging. We hypothesized that preoperative thoracic sarcopenia is associated with survival in patients undergoing lung resection for early-stage NSCLC.

Methods: Patients who underwent anatomic resection for NSCLC between 2010-2019 were retrospectively identified. Exclusion criteria included induction therapy, less than 90 days of follow-up, and absence of computed tomography (CT) imaging. Cross sectional skeletal muscle area was calculated at the fifth thoracic vertebra (T5), twelfth thoracic vertebra (T12), and L3 level. Gender-specific lowest quartile values and previously defined values were used to define sarcopenia. Overall survival and disease-free survival were assessed using the Kaplan-Meier method.

Results: Overall, 221 patients met inclusion criteria with a median body mass index (BMI) of 26.5 kg/m² [interquartile range (IQR), 23.3-29.9 kg/m²], age of 69 years (IQR, 62.4-74.9 years), and follow-up of 46.9 months (IQR, 25.0-70.7 months). At the T5 level, sarcopenic males demonstrated worse overall survival [median 41.0 (IQR, 13.8-53.7) vs. 42.0 (IQR, 23.1-55.1) months, P=0.023] and disease-free survival [median 15.8 (IQR, 8.4-30.78) vs. 34.8 (IQR, 20.1-50.5) months, P=0.007] when compared to non-sarcopenic males. There was no difference in survival between sarcopenic and non-sarcopenic females when assessed at T5. Sarcopenia at T12 or L3 was associated with worse overall survival (P<0.05).

Conclusions: Sarcopenia at T5 is associated with worse survival in males, but not females. When using upper thoracic vertebral levels to assess for sarcopenia, it is necessary to account for gender.