ABSTRACT
BACKGROUND/AIMS: The objective of this study was to assess the prognostic roles of treatment response and tissue necrosis after chemoradiotherapy (CRT) in locally advanced rectal cancer. METHODS: A total of 243 patients with locally advanced rectal cancer who underwent neoadjuvant CRT were included. Three treatment response groups were classified by their pathological stage results: complete treatment response (CTR), intermediate treatment response (ITR), and poor treatment response (PTR). Three tissue necrosis groups were classified based on tissue pathological results: complete necrosis response (CNR), intermediate necrosis response (INR), and poor necrosis response (PNR). RESULTS: Overall survival (OS) and recurrence-free survival (RFS) rate at three years were 74.5% and 61.3%, respectively. The 3-year OS rates of the CTR, ITR, and PTR groups were 83.7%, 75.9%, and 69.7%, respectively (p < 0.001); the 3-year RFS rates were 76.7%, 69.0%, and 52.1%, respectively (p < 0.001). The 3-year OS rates of the CNR, INR, and PNR groups were 83.7%, 80.6%, and 61.8%, respectively (p < 0.001); the 3-year RFS rates were 76.7%, 68.9%, and 44.3%, respectively (p < 0.001). When compared to CTR/CNR, PTR/PNR was strongly related to an increased risk of recurrence (hazard ratio [HR], 5.53; 95% confidence interval [CI], 2.01 to 15.23 vs. HR, 6.37; 95% CI, 2.29 to 17.74, respectively) in univariate Cox regression. Both PTR and PNR were strongly associated with shorter RFS and OS when compared with CTR and CNR in the multivariate Cox regression. CONCLUSIONS: Tissue necrosis is an equally important prognostic marker as treatment response for oncologic outcomes in locally advanced rectal cancer.
Subject(s)
Aged , Female , Humans , Male , Middle Aged , Biopsy , Chemoradiotherapy, Adjuvant/adverse effects , Chi-Square Distribution , Disease Progression , Disease-Free Survival , Kaplan-Meier Estimate , Laparoscopy/adverse effects , Multivariate Analysis , Necrosis , Neoadjuvant Therapy/adverse effects , Neoplasm Recurrence, Local , Neoplasm Staging , Proportional Hazards Models , Rectal Neoplasms/mortality , Remission Induction , Retrospective Studies , Risk Factors , Time Factors , Treatment OutcomeABSTRACT
BACKGROUND/AIMS: The aim of this study was to evaluate the influence of recent chemotherapy on the patterns of the maximum-standardized uptake value (M-SUV) and sensitivity of 18F-fluoro-deoxyglucose positron emission tomography/computed tomography (18F-FDG-PET/CT) in colorectal cancer. METHODS: We retrospectively analyzed the FDG-PET/CT of 509 patients who underwent surgery for colorectal cancer. Subgroup analysis was performed according to chemotherapy status; 401 patients were not treated with chemotherapy and 108 patients were treated with chemotherapy within 6 months prior to surgery. Pathologic analysis of the surgical specimen was used as the gold standard. RESULTS: The M-SUV was significantly lower in patients treated with chemotherapy than in those not treated with chemotherapy in pathologically confirmed same stages of disease. The difference in the sensitivity of the M-SUV according to chemotherapy status was greatest using a cutoff M-SUV value of 6.4 (p<0.001). The longest diameter of the primary tumor was the most important factor that correlated with M-SUV of the primary tumor irrespective of the chemotherapy effect (p<0.001). The M-SUV of the primary tumor was not an independent predictor of lymph node metastasis in colorectal cancer. CONCLUSIONS: The results indicate that the M-SUV of FDG-PET/CT should be interpreted in the context of concurrent chemotherapy.