Adjuvant Chemotherapy in Rectal Cancer Patients Treated With Preoperative Chemoradiation and Total Mesorectal Excision: A Multicenter and Retrospective Propensity-Score Matching Study

Harnessing Minimal Residual Disease as a Predictor for Colorectal Cancer: Promising Horizons Amidst Challenges

Minimal Residual Disease (MRD) detection has emerged as an independent factor in clinical and pathological cancer assessment offering a highly effective method for predicting recurrence in colorectal cancer (CRC). The ongoing research initiatives such as the DYNAMIC and CIRCULATE-Japan studies, have revealed the potential of MRD detection based on circulating tumor DNA (ctDNA) to revolutionize management for CRC patients. MRD detection represents an opportunity for risk stratification, treatment guidance, and early relapse monitoring. Here we overviewed the evolving landscape of MRD technology and its promising applications through the most up-to-date research and reviews, underscoring the transformative potential of this approach. Our primary focus is to provide a point-to-point perspective and address key challenges relating to the adoption of ctDNA-based MRD detection in the clinical setting. By identifying critical areas of interest and hurdles surrounding clinical significance, detection criteria, and potential applications of basic research, this article offers insights into the advancements needed to evaluate the role of ctDNA in CRC MRD detection, contributing to favorable clinical options and improved outcomes in the management of CRC.

ctDNA as a prognostic biomarker in resectable CLM: Systematic review and meta-analysis

Cell-free circulating tumor DNA (ctDNA) is synthesized by tumor cells, including metastatic tumors, and circulates in the bloodstream. Evidence suggests that ctDNA is a potential predictive and prognostic biomarker for colorectal cancer (CRC), but its predictive efficacy in detecting CRC liver metastasis (CLM) remains unclear. Additionally, its utility in the clinical setting needs further investigation. We conducted a meta-analysis to determine the utility of ctDNA as a biomarker for predicting the prognosis of CLM and investigate the relationship between CLM and ctDNA positivity. A literature search was performed in electronic databases to identify relevant studies published up to March 19, 2022. We retrieved data on overall survival (OS), disease-free survival (DFS), and recurrence-free survival (RFS) for both ctDNA-positive and ctDNA-negative colorectal liver metastasis (CLM) patients from the selected articles. Hazard ratios (HRs) were also calculated for these survival outcomes analysis was also performed. The stability of the combined meta-analysis was verified by sensitivity analysis and publication bias evaluation. Ten trials were included, and 615 patients were evaluated. In patients with CLM, pooled HRs revealed a substantial link between ctDNA positivity and RFS/DFS. Subgroup analysis revealed that ctDNA had a prospective detection value. Sensitivity analysis and publication bias evaluation indicated stable results. Although the results on pooled HR for OS suggested that ctDNA-positive patients had a shorter survival time, their pooled HRs had a relatively evident heterogeneity, and sensitivity analysis and publication bias evaluation indicated that pooled HRs were extremely unstable. In conclusion, our results demonstrate that ctDNA appears to be a prognostic biomarker for resectable CLM patients.

Combination of Changes in CEA and CA199 Concentration After Neoadjuvant Chemoradiotherapy Could Predict the Prognosis of Stage II/III Rectal Cancer Patients Receiving Neoadjuvant Chemoradiotherapy Followed by Total Mesorectal Excision

Background

Previous studies have shown that the levels of serum tumor markers CEA and CA19-9 were related to chemoradiotherapy. Therefore, it has been assumed that dynamic monitoring of these markers could predict the prognosis of stage II/III rectal cancer (RC). Therefore, this study proposed to evaluate the prognostic value of changes in serum tumor biomarkers for stage II/III RC patients undergoing neoadjuvant chemoradiotherapy (NCRT) followed by total mesorectal excision (TME).

Methods

A total of 217 patients with stage II/III RC receiving NCRT followed by TME were retrospectively analyzed. Serum CEA and CA199 levels were measured within one week before NCRT and one week before TME. The optimal cut-off points of ∆CEA% and ∆CA199% for prognosis prediction were calculated by receiver operating characteristics (ROC) analysis. Independent prognostic predictors were identified by univariate and multivariate Cox regression analyses. To avoid the efficiency of ∆CEA% and ∆CA199% on serum tumor biomarker change (STBC) score, two models including and excluding ∆CEA% and ∆CA199% were established separately in multivariate analysis.

Results

The optimal cut-off point for ∆CEA% and ∆CA199% were −30.29% and 20.30%, respectively. Univariate analysis showed that ∆CEA%, ∆CA199%, STBC score, ypT staging and yN staging could predict OS. ypT staging and STBC score could predict DFS. In multivariate analysis, only ∆CA199% (HR = 0.468, 95% CI: 0.220–0.994, p = 0.048), ypT staging (HR = 0.420, 95% CI: 0.182–0.970, p = 0.042), and STBC score (HR = 0.204, 95% CI: 0.078–0.532, p = 0.001) were independently related to OS; and STBC score (HR = 0.412, 95% CI: 0.216–0.785, p=0.007) and ypT staging (HR = 0.421, 95% CI: 0.224–0.792, p = 0.007) were independently related to DFS.

Conclusion

We established a combined STBC score to predict the prognosis of stage II/III RC patients receiving NCRT followed by TME. The predictive value of the combined score was stronger than a single marker alone and even stronger than several pathological indicators.

The Utility of ADC First-Order Histogram Features for the Prediction of Metachronous Metastases in Rectal Cancer: A Preliminary Study

Simple Summary

Metachronous metastases are the main factors affecting survival in rectal cancer, and 15–25% of patients will develop them at a 5-year follow-up. Early identification of patients with higher risk of developing distant metachronous metastases would help to improve therapeutic protocols and could allow for a more accurate, personalized management. Apparent diffusion coefficient (ADC) represents an MRI quantitative biomarker, which can assess the diffusion characteristics of tissues, depending on the microscopic mobility of water, showing information related to tissue cellularity. First-order histogram-based features statistics describe the frequency distribution of intensity values within a region of interest, revealing microstructural alterations. In our study, we demonstrated that whole-tumor ADC first-order features may provide useful information for the assessment of rectal cancer prognosis, regarding the occurrence of metachronous metastases.

Abstract

This study aims the ability of first-order histogram-based features, derived from ADC maps, to predict the occurrence of metachronous metastases (MM) in rectal cancer. A total of 52 patients with pathologically confirmed rectal adenocarcinoma were retrospectively enrolled and divided into two groups: patients who developed metachronous metastases (n = 15) and patients without metachronous metastases (n = 37). We extracted 17 first-order (FO) histogram-based features from the pretreatment ADC maps. Student’s t-test and Mann–Whitney U test were used for the association between each FO feature and presence of MM. Statistically significant features were combined into a model, using the binary regression logistic method. The receiver operating curve analysis was used to determine the diagnostic performance of the individual parameters and combined model. There were significant differences in ADC 90th percentile, interquartile range, entropy, uniformity, variance, mean absolute deviation, and robust mean absolute deviation in patients with MM, as compared to those without MM (p values between 0.002–0.01). The best diagnostic was achieved by the 90th percentile and uniformity, yielding an AUC of 0.74 [95% CI: 0.60–0.8]). The combined model reached an AUC of 0.8 [95% CI: 0.66–0.90]. Our observations point out that ADC first-order features may be useful for predicting metachronous metastases in rectal cancer.

Prognostic Impact of Pretreatment Elevated and Normalized Carcinoembryonic Antigen Levels After Neoadjuvant Chemoradiotherapy in Resected Locally Advanced Rectal Cancer Patients

Purpose

The prognostic significance of pretreatment elevated and normalized CEA after neoadjuvant chemoradiotherapy (nCRT) was evaluated.

Materials and Methods

The characteristics of 951 locally advanced rectal cancer patients with nCRT were retrieved and were analyzed retrospectively. Pretreatment CEA levels were defined as CEA evaluated one week prior to the nCRT. CEA after nCRT was deemed as CEA measured one week before surgery. The normal CEA levels were set at <5 ng/mL. The normal CEA group was defined as patients with normal pretreatment CEA levels. The normalized CEA group was defined as patients with elevated pretreatment CEA levels and normal CEA levels after nCRT. The elevated CEA group was defined as patients with elevated pretreatment CEA levels and elevated CEA levels after nCRT.

Results

Compared with the elevated CEA group, the normalized CEA group was associated with better overall survival (OS) (HR: 0.625, 95%CI: 0.416-0.938, P=0.022). There was no difference between the normalized CEA group and the normal CEA group (HR: 1.143, 95%CI: 0.84-1.557, P=0.395).

Conclusion

In conclusion, the study indicated that OS of the normalized CEA group and the normal CEA group was better than the elevated CEA group.

Postoperative Adjuvant Treatment Strategy for Locally Advanced Rectal Cancer after Neoadjuvant Treatment

Background

Neoadjuvant (chemo) radiotherapy is used as a standard treatment for locally advanced rectal cancer (LARC), but there is no general consensus on either the efficacy of postoperative adjuvant chemotherapy in patients with LARC after neoadjuvant treatment and surgery, or whether the addition of oxaliplatin to adjuvant chemotherapy provides survival benefits.

Methods

We performed a meta-analysis of data from the PubMed and Embase databases. We included patients with LARC who received neoadjuvant (chemo) radiotherapy and curative surgery. Overall survival (OS), disease-free survival (DFS), toxicity, and compliance were analyzed in the oxaliplatin/fluorouracil- (OX/FU-) based group compared with the FU-based group, and in the chemotherapy group compared with the observation group.

Results

Twenty studies were included in the analysis. Our results indicated that adjuvant chemotherapy prolonged OS (hazard ratio [HR] = 0.78, 95%CI = 0.67–0.91) in patients with LARC treated with neoadjuvant (chemo) radiotherapy and surgery compared with those in the observation group. Subgroup analysis showed the same results in both the ypStage II and ypStage III groups. Compared with those in the observation group, patients in the chemotherapy group also showed an increase in DFS (HR = 0.75, 95%CI = 0.60–0.93). No significant increase was observed in OS (HR = 1.04, 95%CI = 0.87–1.24) or DFS (HR = 0.98, 95%CI = 0.76–1.27) when oxaliplatin was added to FU-based adjuvant chemotherapy, as compared with the FU-based treatment, and subgroup analysis also indicated no survival benefits in the clinical stage II, clinical stage III, ypStage II, and ypStage III groups.

Conclusions

For patients with LARC who have already received neoadjuvant (chemo) radiotherapy and curative surgery, adjuvant chemotherapy improves OS over that in the observation group. Adding oxaliplatin to FU-based adjuvant chemotherapy does not confer survival benefits beyond those from FU-based adjuvant chemotherapy.

Prognostic Potential of Lymphocyte-C-Reactive Protein Ratio in Patients with Rectal Cancer Receiving Preoperative Chemoradiotherapy

PURPOSE

The systemic inflammatory response is attracting increasing attention as a predictive biomarker for oncological outcome in patients with colorectal cancer. This study is aimed at verifying if the lymphocyte-C-reactive protein (CRP) ratio (LCR) could be used as a predictor of oncological outcome in patients with rectal cancer (RC) receiving preoperative chemoradiotherapy (CRT).

METHODS

We analyzed data for 86 patients with RC who received preoperative CRT followed by total mesorectal excision at our institution. A ratio of 6000 was used as the cut-off value for LCR for further analysis.

RESULTS

The post-CRT LCR was significantly lower than the pre-CRT LCR in patients with RC. Although post-CRT LCR status was not significantly correlated with overall survival (OS), low pre-CRT LCR was significantly associated with shorter recurrence-free survival (RFS: p = 0.02) and OS (p = 0.017) in this population and was an independent prognostic factor for both RFS and OS (hazard ratio (HR) 3.19, 95% confidence interval (CI) 1.33-7.66, p = 0.009; HR 2.83, 95%CI 1.14-7.01, p = 0.025, respectively). Furthermore, low pre-CRT LCR was a stronger indicator of early recurrence (p = 0.001) and poor prognosis (p = 0.025) in RC patients without pathological lymph node metastasis compared with patients with pathological lymph node metastasis, and prognostic potential of pre-CRT LCR was clearly revealed especially RC patients receiving long-course CRT.

CONCLUSIONS

Assessment of pretreatment LCR status might aid decision-making regarding postoperative treatment strategies in patients with RC receiving CRT followed by potentially curative resection.

Delta Radiomics Can Predict Distant Metastasis in Locally Advanced Rectal Cancer: The Challenge to Personalize the Cure

PURPOSE

Distant metastases are currently the main cause of treatment failure in locally advanced rectal cancer (LARC) patients. The aim of this research is to investigate a correlation between the variation of radiomics features using pre- and post-neoadjuvant chemoradiation (nCRT) magnetic resonance imaging (MRI) with 2 years distant metastasis (2yDM) rate in LARC patients.

METHODS AND MATERIALS

Diagnostic pre- and post- nCRT MRI of LARC patients, treated in a single institution from May 2008 to June 2015 with an adequate follow-up time, were retrospectively collected. Gross tumor volumes (GTV) were contoured by an abdominal radiologist and blindly reviewed by a radiation oncologist expert in rectal cancer. The dataset was firstly randomly split into 90% training data, for features selection, and 10% testing data, for the validation. The final set of features after the selection was used to train 15 different classifiers using accuracy as target metric. The models' performance was then assessed on the testing data and the best performing classifier was then selected, maximising the confusion matrix balanced accuracy (BA).

RESULTS

Data regarding 213 LARC patients (36% female, 64% male) were collected. Overall 2yDM was 17%. A total of 2,606 features extracted from the pre- and post- nCRT GTV were tested and 4 features were selected after features selection process. Among the 15 tested classifiers, logistic regression proved to be the best performing one with a testing set BA, sensitivity and specificity of 78.5%, 71.4% and 85.7%, respectively.

CONCLUSIONS

This study supports a possible role of delta radiomics in predicting following occurrence of distant metastasis. Further studies including a consistent external validation are needed to confirm these results and allows to translate radiomics model in clinical practice. Future integration with clinical and molecular data will be mandatory to fully personalized treatment and follow-up approaches.

Adjuvant Chemotherapy Does Not Improve Recurrence-Free Survival in Patients With Stage 2 or Stage 3 Rectal Cancer After Neoadjuvant Chemoradiotherapy and Total Mesorectal Excision

BACKGROUND

Current guidelines for locally advanced stage 2/3 rectal cancer recommend neoadjuvant chemoradiotherapy followed by total mesorectal excision and adjuvant chemotherapy. The oncologic benefit of adjuvant chemotherapy has not been consistently demonstrated.

OBJECTIVE

The purpose of this study was to evaluate disease recurrence and survival in patients with rectal cancer who received adjuvant chemotherapy after chemoradiotherapy and total mesorectal excision.

DESIGN

This was a retrospective review of patients with stage 2/3 rectal cancer after chemoradiotherapy and surgery, based on receipt of adjuvant chemotherapy.

SETTINGS

The study was conducted at the Kaiser Permanente Southern California system of 14 hospitals and associated clinics.

PATIENTS

A total of 862 patients with stage 2/3 rectal cancer diagnosed and treated between January 1, 2005, and December 31, 2016, were included in this study.

INTERVENTIONS

The study involved neoadjuvant chemoradiotherapy followed by total mesorectal excision with or without adjuvant chemotherapy.

MAIN OUTCOME MEASURES

The primary end point was recurrence-free survival.

RESULTS

A total of 348 stage 2 and 514 stage 3 patients were included; 660 patients (76.6%) underwent adjuvant chemotherapy. Mean patient follow-up after surgery was 63.0 months (range, 3-160). Multivariable analysis showed that yp stage (HR for yp stage 2 = 4.74; yp stage 3 = 8.83) and en bloc resection (HR = 1.76) were the only variables that significantly predicted disease recurrence. Neither pretreatment tumor stage nor receipt of adjuvant chemotherapy was significantly associated with recurrence-free survival. Log-rank testing failed to demonstrate significant recurrence-free survival improvement after receipt of adjuvant chemotherapy in any patient subgroup.

LIMITATIONS

The study was limited by selection bias attributed to the nature of a retrospective study without patient randomization or predefined treatment protocol.

CONCLUSIONS

In stage 2/3 rectal cancer treated with chemoradiotherapy and surgery, the addition of adjuvant chemotherapy was not associated with decreased recurrence-free survival in the entire cohort or in any subgroup, whereas tumor response to chemoradiotherapy is closely associated with disease recurrence. These findings have important consequences for treatment and surveillance decisions for patients with rectal cancer. Presurgical efforts that maximize tumor downstaging, such as total neoadjuvant therapy, may produce better oncologic outcomes than traditional adjuvant chemotherapy. See Video Abstract at http://links.lww.com/DCR/B134. LA QUIMIOTERAPIA ADYUVANTE NO MEJORA LA SOBREVIDA LIBRE DE RECURRENCIA EN PACIENTES CON CÁNCER DE RECTO ESTADÍOS II O III DESPUÉS DE RADIO-QUIMIOTERAPIA NEOADYUVANTE Y ESCISIÓN TOTAL DEL MESORRECTO: Las guías actuales para el tratamiento de cáncer rectal en estadio II-III localmente avanzado, recomiendan la radio-quimioterapia neoadyuvante con escisión total del mesorrecto seguidas de quimioterapia adyuvante. El beneficio oncológico de la quimioterapia adyuvante no ha sido demostrado de manera fehaciente.Evaluar la recurrencia y sobrevida a la enfermedad en pacientes con cáncer rectal que recibieron quimioterapia adyuvante después de radio-quimioterapia y escisión total del mesorrecto.Revisión retrospectiva de pacientes con cáncer rectal en estadios II-III después de radio-quimioterapia y cirugía, basada en la recepción de quimioterapia adyuvante.Sistema Permanente de Kaiser Sur-Californiano de 14 hospitales y clínicas asociadas.862 pacientes con cáncer rectal en estadio II-III diagnosticados y tratados entre el 1 de Enero 2005 y el 31 de Diciembre 2016.Radio-quimioterapia neoadyuvante seguida de escisión total del mesorrecto +/- quimioterapia adyuvante.El objetivo primario fue la sobrevida libre de recurrencia.Fueron incluidos 348 pacientes en estadio II y 514 en estadio III. 660 pacientes (76,6%) se sometieron a quimioterapia adyuvante. El seguimiento medio de cada paciente después de la cirugía fué de 63.0 meses (rango, 3-160). El análisis multivariable mostró que la etapa yp (Cociente de riesgo para estadío yp II = 4.74 y estadío yp III = 8.83) y la resección en bloque (Cociente de riesgo = 1.76) fueron las únicas variables que predijeron significativamente la recurrencia de la enfermedad. Ni el estadío tumoral previo al tratamiento ni la recepción de quimioterapia adyuvante se asociaron significativamente con la sobrevida libre de recurrencia. Las pruebas de rango logarítmico no pudieron demostrar una mejoría significativa de la sobrevida libre de recurrencia después de recibir quimioterapia adyuvante en cualquier subgrupo de pacientes.Sesgo de selección, debido al estudio retrospectivo sin aleatorización de los pacientes o protocolo de tratamiento predefinido.En casos de cáncer de recto estadíos II-III tratados con radio-quimioterapia y cirugía, la adición de quimioterapia adyuvante no se asoció con una disminución de la sobrevida libre de recurrencia en toda la cohorte o en ningún subgrupo, mientras que la respuesta tumoral a la radio-quimioterapia está estrechamente asociada con la recurrencia de la enfermedad. Estos hallazgos tienen consecuencias importantes en la decisión del tratamiento y la vigilancia en pacientes con cáncer de recto. Los esfuerzos pre-quirúrgicos que maximizan la reducción del tamaño del tumor, como la terapia neoadyuvante total, pueden producir mejores resultados oncológicos que la quimioterapia adyuvante tradicional. Consulte Video Resumen en http://links.lww.com/DCR/B134.

Adjuvant chemotherapy for rectal cancer: Current evidence and recommendations for clinical practice

While adjuvant chemotherapy is an established treatment for pathological stage II and especially stage III colon cancer, its role in the multimodal management of rectal cancer remains controversial. As a result, there is substantial variation in the use of this treatment in clinical practice. Even among centres and physicians who consider adjuvant chemotherapy as a standard treatment, notable heterogeneity exists with regard to patient selection criteria and chemotherapy regimens. The controversy around this topic is confirmed by the lack of full consensus among national and international clinical guidelines. While most of the clinical trials do not support the contention that adjuvant chemotherapy may improve survival outcomes if pre-operative (chemo)radiotherapy is also given, these suffer from many limitations that preclude drawing definitive conclusions. Nevertheless, in the era of evidence-based medicine, physicians should be guided by the available data and refrain from extrapolating results of adjuvant colon cancer trials to inform treatment decisions for rectal cancer. Patients should be informed of the evidence gap, be given the opportunity to carefully discuss pros and cons of all the possible management options and be empowered in the decision making. In this article we review the available evidence on adjuvant chemotherapy for rectal cancer and propose a risk-adapted decisional algorithm that largely relies on informed patient preferences.

Adjuvant chemotherapy in rectal cancer patients who achieved a pathological complete response after preoperative chemoradiotherapy: a systematic review and meta-analysis

This study evaluated the prognostic impact of ACT in patients who achieved a pathological complete response (pCR). Articles published from January 1990 to September 2018 were searched in EMBASE, PubMed, Ovid, Web of Science, and Cochrane Library. Hazard ratios (HRs) and 95% confidence intervals (CIs) of overall survival (OS) were extracted. Thirteen observational studies were included. There were four National Cancer Database studies with overlapping study periods, thus individual pooled analyses of four different datasets were conducted (n = 3,182, 3,330, 3,575, and 4,739 for pooled analysis sets including Dossa et al., Polanco et al., Xu et al., and Shahab et al., respectively). Although a trend toward improved OS with ACT was observed, statistical significance was not proven (P = 0.09, P = 0.03, P = 0.12, and P = 0.10, respectively). When we performed a stratified analysis comparing the results from single institution and multicenter studies, there was no significant prognostic benefit of ACT. Publication bias was not observed. Routine use of ACT in patients with a pCR could not be warranted from the present meta-analysis. Further study of individual patient data from randomized trials is needed to clarify the role of ACT.