Circulating cell-free DNA as predictor of pathological complete response in locally advanced rectal cancer patients undergoing preoperative chemoradiotherapy

Rectal Cancer: Exploring Predictive Biomarkers Through Molecular Pathways Involved in Carcinogenesis

In 2022, colorectal cancer (CCR) had the second-highest incidence in Europe, preceded only by breast cancer [...].

ctDNA as a predictor of outcome after curative resection for locally advanced rectal cancer: systematic review and meta-analysis

AIM

To assess the efficacy of ctDNA measurement at different time intervals in predicting response and prognosis in patients diagnosed with locally advanced rectal cancer (LARC) who underwent neoadjuvant treatment prior to curative resection.

METHOD

English language randomized controlled trials and observational studies, published from 1946 to January 2024, comparing outcomes between ctDNA-positive and ctDNA-negative patients with LARC undergoing neoadjuvant treatment prior to curative surgical resection were included in the search. The search included Ovid MEDLINE, Embase, Cochrane Central Register of Controlled Trials (CENTRAL), and the Cochrane Database of Systematic Reviews (CDSR).

RESULTS

Data for 1022 patients were analysed. Patients with positive ctDNA in the preoperative period had more than five times the risk of developing distant metastasis (RR [95% CI] 5.03 [3.31-7.65], p < 0.001), while those with positive ctDNA in the postoperative period had more than six times the risk (RR [95% CI] 6.17 [2.38-15.95], p < 0.001). There was no significant relationship between ctDNA status at baseline, pre-, or postoperative periods and achievement of pCR (RR [95% CI] 1.21 [0.86-1.7], 1.82 [0.94-3.55], 1.48 [0.78-2.82], p = 0.27, 0.08, and 0.23, respectively). However, patients with positive ctDNA in the pre- and postoperative periods had more than 13 and 12 times the risk of overall disease relapse after curative-intent treatment (RR [95% CI] 13.55 [7.12-25.81], 12.14 [3.19-46.14], p < 0.001), respectively.

CONCLUSION

ctDNA could potentially guide treatment and follow-up in LARC, predicting high-risk patients for disease relapse, allowing individualized surveillance and treatment strategies. Prospective studies are needed for standardization.

Assessing circulating tumour DNA (ctDNA) as a prognostic biomarker in locally advanced rectal cancer: a systematic review and meta-analysis

INTRODUCTION

Circulating tumour DNA (ctDNA) has emerged as a promising biomarker in various cancer types, including locally advanced rectal cancer (LARC), offering potential insights into disease progression, treatment response and recurrence. This review aims to comprehensively evaluate the utility of ctDNA as a prognostic biomarker in LARC.

METHODS

PubMed, EMBASE and Web of Science were searched as part of our review. Studies investigating the utility of ctDNA in locally advanced rectal cancer (LARC) were assessed for eligibility. Quality assessment of included studies was performed using the Newcastle Ottawa Scale (NOS) risk of bias tool. Outcomes extracted included basic participant characteristics, ctDNA details and survival data. A meta-analysis was performed on eligible studies to determine pooled recurrence-free survival (RFS).

RESULTS

Twenty-two studies involving 1676 participants were included in our analysis. Methodological quality categorised by the Newcastle Ottawa Scale was generally satisfactory across included studies. ctDNA detected at various time intervals was generally associated with poor outcomes across included studies. Meta-analysis demonstrated a pooled hazard ratio of 8.87 (95% CI 4.91-16.03) and 15.15 (95% CI 8.21-27.95), indicating an increased risk of recurrence with ctDNA positivity in the post-neoadjuvant and post-operative periods respectively.

CONCLUSION

Our systematic review provides evidence supporting the prognostic utility of ctDNA in patients with LARC, particularly in identifying patients at higher risk of disease recurrence in the post-neoadjuvant and post-operative periods.

Construction and validation of a progression prediction model for locally advanced rectal cancer patients received neoadjuvant chemoradiotherapy followed by total mesorectal excision based on machine learning

Background

We attempted to develop a progression prediction model for local advanced rectal cancer(LARC) patients who received preoperative neoadjuvant chemoradiotherapy(NCRT) and operative treatment to identify high-risk patients in advance.

Methods

Data from 272 LARC patients who received NCRT and total mesorectal excision(TME) from 2011 to 2018 at the Fourth Hospital of Hebei Medical University were collected. Data from 161 patients with rectal cancer (each sample with one target variable (progression) and 145 characteristic variables) were included. One Hot Encoding was applied to numerically represent some characteristics. The K-Nearest Neighbor (KNN) filling method was used to determine the missing values, and SmoteTomek comprehensive sampling was used to solve the data imbalance. Eventually, data from 135 patients with 45 characteristic clinical variables were obtained. Random forest, decision tree, support vector machine (SVM), and XGBoost were used to predict whether patients with rectal cancer will exhibit progression. LASSO regression was used to further filter the variables and narrow down the list of variables using a Venn diagram. Eventually, the prediction model was constructed by multivariate logistic regression, and the performance of the model was confirmed in the validation set.

Results

Eventually, data from 135 patients including 45 clinical characteristic variables were included in the study. Data were randomly divided in an 8:2 ratio into a data set and a validation set, respectively. Area Under Curve (AUC) values of 0.72 for the decision tree, 0.97 for the random forest, 0.89 for SVM, and 0.94 for XGBoost were obtained from the data set. Similar results were obtained from the validation set. Twenty-three variables were obtained from LASSO regression, and eight variables were obtained by considering the intersection of the variables obtained using the previous four machine learning methods. Furthermore, a multivariate logistic regression model was constructed using the data set; the ROC indicated its good performance. The ROC curve also verified the good predictive performance in the validation set.

Conclusions

We constructed a logistic regression model with good predictive performance, which allowed us to accurately predict whether patients who received NCRT and TME will exhibit disease progression.

A Review of Circulating Tumor DNA as a Biomarker Guide for Total Neoadjuvant Therapy in Patients with Locally Advanced Rectal Cancer

PURPOSE

Non-operative management of patients with locally advanced rectal cancer (LARC) is emerging as a popular approach for patients that have no evidence of disease following neoadjuvant therapy. However, high rates of local recurrence or distant metastases have highlighted the urgent need for robust biomarker strategies to aid clinical management of these patients.

METHODS

This review summarizes recent advances in the utility of cell-free (cf) and circulating tumor (ct) DNA as potential biomarkers to help guide individualized non-operative management strategies for LARC patients receiving neoadjuvant therapy.

RESULTS

Liquid biopsies and the detection of cfDNA/ctDNA is an emerging technology with the potential to provide a non-invasive approach to monitor disease response and improve the identification of patients with LARC that would best benefit from non-operative management.

CONCLUSIONS

Substantial work is still needed before cfDNA/ctDNA monitoring can be widely adopted in the clinical setting. Studies reviewed herein highlight several areas of opportunity for improving the effectiveness and utility of cfDNA/ctDNA for managing patients with LARC.

Circulating tumor DNA detection after neoadjuvant treatment and surgery predicts recurrence in patients with early-stage and locally advanced rectal cancer

INTRODUCTION

Patients with early-stage and locally advanced rectal cancer are often treated with neoadjuvant therapy followed by surgery or watch and wait. This study evaluated the role of circulating tumor DNA (ctDNA) to measure disease after neoadjuvant treatment and surgery to optimize treatment choices.

MATERIALS AND METHODS

Patients with rectal cancer treated with both chemotherapy and radiotherapy were included and diagnostic biopsies were analyzed for tumor-specific mutations. Presence of ctDNA was measured in plasma by tracing the tumor-informed mutations using a next-generation sequencing panel. The association between ctDNA detection and clinicopathological characteristics and progression-free survival was measured.

RESULTS

Before treatment ctDNA was detected in 69% (35/51) of patients. After neoadjuvant therapy ctDNA was detected in only 15% (5/34) of patients. In none of the patients with a complete clinical response who were selected for a watch and wait strategy (0/10) or patients with ypN0 disease (0/8) ctDNA was detected, whereas it was detected in 31% (5/16) of patients with ypN + disease. After surgery ctDNA was detected in 16% (3/19) of patients, of which all (3/3) developed recurrent disease compared to only 13% (2/16) in patients with undetected ctDNA after surgery. In an exploratory survival analysis, both ctDNA detection after neoadjuvant therapy and after surgery was associated with worse progression-free survival (p = 0.01 and p = 0.007, respectively, Cox-regression).

CONCLUSION

These data show that in patients with early-stage and locally advanced rectal cancer tumor-informed ctDNA detection in plasma using ultradeep sequencing may have clinical value to complement response prediction after neoadjuvant therapy and surgery.

Circulating tumour DNA as biomarker for rectal cancer: A systematic review and meta-analyses

Background

Circulating tumour DNA (ctDNA) has been established as a promising (prognostic) biomarker with the potential to personalise treatment in cancer patients. The objective of this systematic review is to provide an overview of the current literature and the future perspectives of ctDNA in non-metastatic rectal cancer.

Methods

A comprehensive search for studies published prior to the 4^th of October 2022 was conducted in Embase, Medline, Cochrane, Google scholar, and Web of Science. Only peer-reviewed original articles and ongoing clinical trials investigating the association between ctDNA and oncological outcomes in non-metastatic rectal cancer patients were included. Meta-analyses were performed to pool hazard ratios (HR) for recurrence-free survival (RFS).

Results

A total of 291 unique records were screened, of which 261 were original publications and 30 ongoing trials. Nineteen original publications were reviewed and discussed, of which seven provided sufficient data for meta-analyses on the association between the presence of post-treatment ctDNA and RFS. Results of the meta-analyses demonstrated that ctDNA analysis can be used to stratify patients into very high and low risk groups for recurrence, especially when detected after neoadjuvant treatment (HR for RFS: 9.3 [4.6 - 18.8]) and after surgery (HR for RFS: 15.5 [8.2 - 29.3]). Studies investigated different types of assays and used various techniques for the detection and quantification of ctDNA.

Conclusions

This literature overview and meta-analyses provide evidence for the strong association between ctDNA and recurrent disease. Future research should focus on the feasibility of ctDNA-guided treatment and follow-up strategies in rectal cancer. A blueprint for agreed-upon timing, preprocessing, and assay techniques is needed to empower adaptation of ctDNA into daily practice.