TTP1.03 The impact of Neo-adjuvant chemotherapy on muscle mass of colorectal cancer patients with curative intent- a single trust observational study

Aim To investigate the impact of neoadjuvant chemotherapy on skeletal muscle mass in colorectal cancer prior to surgery. Methods Patients underwent surgical treatment of colorectal cancers between2017 and 2022 were retrospectively recruited, where they have been randomised and double blinded into two groups; a neoadjuvant chemotherapy group (chemo+surgery) and a control group (surgery only). The cross sectional muscle area (cm2) was measured by computed tomography images. Results Among 100 patients, 50 patients received neoadjuvant chemotherapy prior to assigned surgical procedure and 50 patients underwent surgical treatment only. Rectus muscles mass didn’t show significant difference between neoadjuvant chemo and surgery only groups at baseline pre-chemotherapy (4.33±3.8 and 4.8±2.06 respectively, p=0.444); however, psoas muscles mass was lower among the group (8.85±1.97 and 10.21±2.3 respectively, p=0.002). Muscle mass didn’t show significant reduction after applying chemotherapy for both rectus and psoas muscles masses; (4.33±3.8 and 8.85±1.97 Vs. 4.03±1.96 and 8.91±1.96, p=0.567 and 0.745, with p=0.567 and 0.745 respectively). Postoperative muscle mass was lower among neoadjuvant chemo group than surgery group for both rectus and psoas muscles mass (3.77±1.36 and 9.09±1.93 Vs. 4.52±1.66 and 10.13±2.86 with p=0.016 and 0.037 respectively). Patients who received neoadjuvant chemotherapy reported more fall (12%, p=0.027) and more muscle weakness (22%, p=0.0004) in postoperative period than those who underwent surgical treatment only. Conclusion The current study shows that skeletal muscle decrease due to neoadjuvant chemo which impairs post operative long term outcome of colorectal cancer patients.