Predicting prognosis according to preoperative chemotherapy response in patients with locally advanced lower rectal cancer

Abstract

Background: Neoadjuvant chemoradiotherapy is regarded as the standard of treatment for locally advanced lower rectal cancer although some of these cases are systemic, and local control may be inadequate. We aimed to stratify patients into prognostic groups based on preoperative factors, including response to neoadjuvant chemotherapy. Methods: We retrospectively analyzed patients with locally advanced lower rectal adenocarcinoma (clinical stage II/III with high-risk features of distant metastasis) who were treated with neoadjuvant chemotherapy followed by curative resection between 2010 and 2017 and those, who did not receive neoadjuvant chemoradiotherapy. Reduction in tumor volume (before vs. after neoadjuvant chemotherapy) was measured using magnetic resonance imaging. Recurrence and overall survival were also evaluated.Results: The cohort was composed of 105 patients. Good response to neoadjuvant chemotherapy was associated with better 5-year recurrence-free survival (good responders: 83.3%, poor responders: 50.9%; p=0.001) and 5-year overall survival (good responders: 95.8%, poor responders: 82.5%; p=0.04). In a multivariate analysis, extramural venous invasion on magnetic resonance imaging before neoadjuvant chemotherapy was significantly and independently associated with worse recurrence-free survival (hazard ratio: 2.57, 95% confidence interval: 1.32–5.03, p=0.006). Good responders without extramural venous invasion had the best 5-year recurrence-free and overall survival (89.7% and 94.9%, respectively). Poor responders with extramural venous invasion had the worst 5-year recurrence-free and overall survival (26.7% and 60.0%, respectively).Conclusions: Reductions in tumor volume after neoadjuvant chemotherapy were associated with better prognosis in patients with locally advanced lower rectal cancer. Extramural venous invasion was a preoperative prognostic factor.

Prognostic Importance of MRI-Detected Extramural Venous Invasion in Rectal Cancer: A Literature Review and Systematic Meta-Analysis

“…None of the trials had been established to investigate the effect of mrEMVI on prognosis, but did report mrEMVI status as part of a multivariate analysis. After qualitative analysis, a consensus decision among authors (JT and RC) was made to exclude 13 articles owing to overlapping patient populations (n = 4), [23][24][25][26] high selection bias (n = 1), 27 high attrition bias (n = 3), [28][29][30] poor quality (n = 2), 31,32 no differentiation between baseline mrEMVI and post-treatment mrEMVI (n = 2), 14,15 and results not being comparable with other studies in the meta-analysis (n = 1). 33 Attrition bias was considered significant if median follow-up was short but 3-or 5-year survival outcomes were still reported.…”

“…In 2 papers, the quality of the studies was considered poor, with limited or unclear methodology. 31,32 Two papers only analyzed a "final" mrEMVI score, which included both baseline and posttreatment imaging. 14,15 These papers were excluded from the final analysis because there was no subgroup analysis of baseline and posttreatment imaging separately.…”

MRI-detected extramural venous invasion of rectal cancer: Multimodality performance and implications at baseline imaging and after neoadjuvant therapy

“…8) [29,59]. MRI-detected EMVI after neoadjuvant chemotherapy has also been shown to be a predictor of decreased disease-free survival (hazard ratio: 1.97-2.68) [25,29], recurrence-free survival (hazard ratio: 2.74) [60] and overall survival (hazard ratio: 1.98-4.23) [29,59,60] (Table 3). Rectal cancer MRI can also demonstrate in situ evidence of response or progression of EMVI after neoadjuvant therapy.…”

The Role of Micro-RNAs and Circulating Tumor Markers as Predictors of Response to Neoadjuvant Therapy in Locally Advanced Rectal Cancer

“…Moreover, most of the published literature reports information on the implication of the miRNAs on the local response to therapy, but not on prognosis. Only recently, it has been demonstrated that responder patients to the preoperative CRT had a better prognosis, with lower rates of recurrence and metastasis [ 70 ].…”