Impact of glucocorticoids on the efficacy of neoadjuvant chemoradiotherapy and survival of patients with locally advanced rectal cancer: a retrospective study

BACKGROUND: Preclinical studies suggest that glucocorticoids (GCs) promote the proliferation and development of colorectal cancer. Because GCs are broadly prescribed for treatment-related adverse events in patients with locally advanced rectal cancer (LARC) receiving neoadjuvant chemoradiotherapy (NCRT), it’s essential to assess the effect of GCs on clinical outcomes. METHODS: LARC cases treated with NCRT followed by surgery were assessed retrospectively. Evaluation of the relationship between GCs use (GCs vs. non-GCs) and neoadjuvant rectal (NAR) score (as a three-level categorical dependent variable) was performed using multivariable multinomial logistic regression (MLR). We also examined the relationship between the accumulated dose of GCs and NAR using multivariate MLR. Survival analysis of disease-free survival (DFS) and overall survival (OS) was performed using the Kaplan–Meier method. Multivariate Cox regression was used to assess confounding factors that could influence OS and DFS. RESULTS: This retrospective cohort study included 790 patients with newly diagnosed non-metastatic LARC (T3-4/N + M0) who received NCRT followed by surgery between January 2012 and April 2017. The end of the follow-up period was May 11, 2022. Among the 790 patients with LARC, 342 (43.2%) received GCs treatment and 448 (56.8%) did not during the NCRT-to-surgery period. GCs medication was significantly different between mid-NAR (8–16) and low-NAR (< 8) (odds ratio [OR], 0.615; 95% CI, 0.420–0.901; P = 0.013), and the high-NAR (> 16) and low-NAR (0.563; 0.352–0.900; 0.016). Patients exposed to GCs, had a decreased 5-year OS (GCs vs. non-GCs = 80.01% (95% CI, 75.87%–84.37%) vs. 85.30% (82.06%–88.67%), P = 0.023) and poorer 5-year DFS (73.99% (69.45%–78.82%) vs. 78.7% (75.14%–82.78%), P = 0.045). The accumulated dose of GCs was an independent risk factor for OS (hazard ratio [HR], 1.007 [1.001–1.014], 0.036) and DFS (1.010 [1.004–1.017], 0.001). CONCLUSIONS AND RELEVANCE: Our study revealed that GCs were associated with reduced efficacy of NCRT and worse clinical outcomes in patients with LARC during the NCRT-to-surgery period. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12885-023-10592-0.