Radiological Markers of Sarcopenia in Colorectal Cancer Surgery – A Critical Appraisal

Abstract

This thesis explores the field of sarcopenia, its association with overall survival in patients undergoing resection of colorectal cancer, challenges in diagnosis, and impediments translating research to diagnostic tools in clinical practice.

Since the conception and evolution of the term ‘sarcopenia’ in the 1980s and 90s, understanding of the pathophysiology and health outcomes related to the condition have deepened, and it is now recognised as a disease characterised by decreased muscle mass and quality, decreased strength, and poor physical performance. In recent years, sarcopenia has been associated with poor outcomes in patients treated for colorectal cancer. Research has focused on computed tomography as the primary diagnostic modality. However, despite the body of evidence promoting this modality, routine screening for sarcopenia in patients undergoing colorectal cancer surgery has not translated into clinical practice.

Chapter 2, investigates skeletal muscle index, the most widely researched marker of sarcopenia, finding a strong association with overall survival. In addition, this Chapter highlights difficulty finding a universally agreed threshold to enable prospective application of skeletal muscle index as a diagnostic tool.

In Chapter 3, alternative parameters of sarcopenia are promoted and strong associations with overall survival . This Chapter investigates the pragmatism of these alternative parameters, finding some to be less complex to measure while maintaining prognostic value; this may help facilitate screening for sarcopenia.

This thesis adds to the evidence that sarcopenia is associated with poorer overall survival in patients undergoing resection of colorectal cancer, and reiterates the challenges in identifying a clinically-applicable and universally accepted threshold to diagnose the disease. The results of this thesis are instrumental to further research on sarcopenia, its diagnosis and understanding its associated poor health outcomes.