Tissue-Based Markers as a Tool to Assess Response to Neoadjuvant Radiotherapy in Rectal Cancer-Systematic Review

According to current guidelines, the current treatment for locally advanced rectal cancer is neoadjuvant therapy, followed by a total mesorectal excision. However, radiosensitivity tends to differ among patients due to tumor heterogeneity, making it difficult to predict the possible outcomes of the neoadjuvant therapy. This review aims to investigate different types of tissue-based biomarkers and their capability of predicting tumor response to neoadjuvant therapy in patients with locally advanced rectal cancer. We identified 169 abstracts in NCBI PubMed, selected 48 reports considered to meet inclusion criteria and performed this systematic review. Multiple classes of molecular biomarkers, such as proteins, DNA, micro-RNA or tumor immune microenvironment, were studied as potential predictors for rectal cancer response; nonetheless, no literature to date has provided enough sufficient evidence for any of them to be introduced into clinical practice.

Automated summary

According to current guidelines, neoadjuvant therapy followed by total mesorectal excision is the standard treatment for locally advanced rectal cancer. However, predicting the response to neoadjuvant therapy is challenging due to tumor heterogeneity. This review examines various tissue-based biomarkers and their potential for predicting tumor response in patients with locally advanced rectal cancer. While proteins, DNA, micro-RNA, and tumor immune microenvironment have been studied, there is currently insufficient evidence to introduce these biomarkers into clinical practice.