3572 - Impact of Subcutaneous Adipose Tissue Area Change during Neoadjuvant Chemoradiotherapy on Disease-Free Survival and Tumor Response in Patients with Locally Advanced Rectal Cancer
Presenter(s)
Q. Yang1,2, S. Lu1,2, R. Qu1,2, N. Zhang3, Z. Zhang1,4, H. Wang4,5, and W. Fu1,4; 1Department of General Surgery, Peking University Third Hospital, Haidian, Beijing, China, 2Cancer Center, Peking University Third Hospital, Haidian, Beijing, China, 3Institute of Medical Technology, Health Science Center of Peking University, Haidian, Beijing, China, 4Beijing Key Laboratory for Interdisciplinary Research in Gastrointestinal Oncology, Haidian, Beijing, China, 5Department of Radiation Oncology, Peking University Third Hospital, Haidian, Beijing, China
Purpose/Objective(s): The heterogeneity observed in patients with locally advanced rectal cancer (LARC) necessitates the identification of predictive markers for response to neoadjuvant chemoradiotherapy (nCRT) to enable personalized treatment strategies. Adipose tissue, reflecting nutritional status, is implicated in tumorigenesis and disease progression. This study investigates the potential of adipose tissue as a predictive marker for nCRT response and prognosis in LARC patients.
Materials/Methods: We conducted an analysis of noncontrast CT scan images taken pre- and post-nCRT at the third lumbar vertebral level to quantify the area of adipose tissue in LARC patients. We examined the relationship between changes in subcutaneous adipose tissue area (SATA) and treatment outcomes, including disease-free survival (DFS), tumor regression grade (TRG), and tumor downstaging, using multivariate logistic regression and Cox proportional hazards analysis.
Results: The study included 290 patients with LARC aged between 22 and 82 years, presenting with clinical American Joint Committee on Cancer (AJCC) TNM stages II-IV. Patients who demonstrated significant increases in SATA exhibited improved DFS outcomes (P = 0.002), as well as enhanced short-term treatment response, including better TRG (P = 0.019) and more favorable tumor downstaging (P = 0.005). Multivariate analyses revealed that the gain of SATA emerged as an independent prognostic factor for both long-term outcome (DFS, P = 0.018) and short-term treatment response (TRG: P = 0.020; Downstaging: P = 0.008). Furthermore, calibration and decision curve analysis demonstrated the effective predictive ability of the nomogram incorporating SATA gain in terms of DFS.
Conclusion: An increase in SATA during nCRT is associated with improved short-term and long-term outcomes in LARC patients, indicating its potential as a predictive marker for identifying individuals who may benefit from nCRT.