Predictors of pathologic complete response after preoperative concurrent chemoradiotherapy of rectal cancer: a single center experience

Factors associated with pathological complete remission after neoadjuvant chemoradiotherapy in locally advanced rectal cancer: a real-world clinical setting

Objective

This study aims to identify factors associated with achieving a pathological complete remission (pCR) in patients with locally advanced rectal cancer (LARC) after neoadjuvant chemoradiotherapy (nCRT).

Methods

We conducted a cohort analysis of 171 LARC patients who underwent curative resection post-nCRT at the First Affiliated Hospital of Guangxi Medical University between January 2015 and December 2021. The data encompassed clinical and pathological information. Univariate and binary logistic regression multivariate analyses were employed to examine the factors influencing pCR achievement after nCRT. Kappa value tests were utilized to compare clinical staging after nCRT with postoperative pathological staging.

Results

Postoperative histopathology revealed that of the 171 patients, 40 (23.4%) achieved TRG 0 grade (pCR group), while 131 (76.6%) did not achieve pCR, comprising 36 TRG1, 42 TRG2, and 53 TRG3 cases. Univariate analysis indicated that younger age (p=0.008), reduced tumor occupation of intestinal circumference (p =0.008), specific pathological types (p=0.011), and lower pre-nCRT CEA levels (p=0.003) correlated with pCR attainment. Multivariate analysis identified these factors as independent predictors of pCR: younger age (OR=0.946, p=0.004), smaller tumor occupation of intestinal circumference (OR=2.809, p=0.046), non-mucinous adenocarcinoma pathological type (OR=10.405, p=0.029), and lower pre-nCRT serum CEA levels (OR=2.463, p=0.031). Clinical re-staging post-nCRT compared to postoperative pathological staging showed inconsistent MRI T staging (Kappa=0.012, p=0.718, consistency rate: 35.1%) and marginally consistent MRI N staging (Kappa=0.205, p=0.001, consistency rate: 59.6%).

Conclusion

LARC patients with younger age, presenting with smaller tumor circumferences in the intestinal lumen, lower pre-nCRT serum CEA levels, and non-mucinous adenocarcinoma are more likely to achieve pCR after nCRT. The study highlights the need for improved accuracy in clinical re-staging assessments after nCRT in LARC.

"WATCH AND WAIT" STRATEGY IN RECTAL CANCER PATIENTS WITH A COMPLETE CLINICAL RESPONSE AFTER NEOADJUVANT CHEMORADIATION THERAPY: A SINGLE-CENTER EXPERIENCE

BACKGROUND

The non-operative management of rectal adenocarcinoma (RA) after neoadjuvant chemoradiation therapy (nCRT) has gained increasing attention. The "Watch and Wait" ("W&W") strategy allows one to avoid surgery-related reduction in the quality of life due to permanent pelvic organ dysfunction or irreversible stoma. Still, the oncological safety of this strategy is under evaluation.

AIM

To share a single-center experience of the "W&W" strategy.

MATERIALS AND METHODS

The retrospective analysis of 125 patients who received nCRT in 2016-2021 was performed. Patients who met the European Society for Medical Oncology (ESMO, 2017) criteria of clinical complete response (cCR) and received non-operative management were analyzed.

RESULTS

Ten patients (8%) were re-staged after nCRT as cCR and followed the "W&W" strategy. Patients' characteristics: 7 female, 3 male; mean age 67.3 years. Tumor characteristics: pre-treatment N+ was present in 7 cases; G1 adenocarcinoma in a majority of cases; mean tumor distance from the anal verge - 5.85 cm; mean tumor circumference - 71%; mean tumor length - 3.87 cm. The mean follow-up time was 30 months. Local regrowth or/and distant metastases developed in 3 cases. The 2-year disease-free survival was 70%.

CONCLUSIONS

Most of the patients following the "W&W" strategy have benefited. However, to reduce the number of relapses, it is necessary to perform a more careful selection of patients.

Promises and Challenges of Predictive Blood Biomarkers for Locally Advanced Rectal Cancer Treated with Neoadjuvant Chemoradiotherapy

The treatment of locally advanced rectal cancer (LARC) requires a multimodal approach combining neoadjuvant radiotherapy or chemoradiotherapy (CRT) and surgery. Predicting tumor response to CRT can guide clinical decision making and improve patient care while avoiding unnecessary toxicity and morbidity. Circulating biomarkers offer both the advantage to be easily accessed and followed over time. In recent years, biomarkers such as proteins, blood cells, or nucleic acids have been investigated for their predictive value in oncology. We conducted a comprehensive literature review with the aim to summarize the status of circulating biomarkers predicting response to CRT in LARC. Forty-nine publications, of which forty-seven full-text articles, one review and one systematic review, were retrieved. These studies evaluated circulating markers (CEA and CA 19-9), inflammatory biomarkers (CRP, albumin, and lymphocytes), hematologic markers (hemoglobin and thrombocytes), lipids and circulating nucleic acids (cell-free DNA [cfDNA], circulating tumor DNA [ctDNA], and microRNA [miRNA]). Post-CRT CEA levels had the most consistent association with tumor response, while cfDNA integrity index, MGMT promoter methylation, ERCC-1, miRNAs, and miRNA-related SNPs were identified as potential predictive markers. Although circulating biomarkers hold great promise, inconsistent results, low statistical power, and low specificity and sensibility prevent them from reliably predicting tumor response following CRT. Validation and standardization of methods and technologies are further required to confirm results.

Evaluation and Predictive Factors of Complete Response in Rectal Cancer after Neoadjuvant Chemoradiation Therapy

The response to neoadjuvant chemoradiation therapy is an important prognostic factor for locally advanced rectal cancer. Although the majority of the patients after neoadjuvant therapy are referred to following surgery, the clinical data show that complete clinical or pathological response is found in a significant proportion of the patients. Diagnostic accuracy of confirming the complete response has a crucial role in further management of a rectal cancer patient. As the rate of clinical complete response, unfortunately, is not always consistent with pathological complete response, accurate diagnostic parameters and predictive markers of tumor response may help to guide more personalized treatment strategies and identify potential candidates for nonoperative management more safely. The management of complete response demands interdisciplinary collaboration including oncologists, radiotherapists, radiologists, pathologists, endoscopists and surgeons, because the absence of a multidisciplinary approach may compromise the oncological outcome. Prediction and improvement of rectal cancer response to neoadjuvant therapy is still an active and challenging field of further research. This literature review is summarizing the main, currently known clinical information about the complete response that could be useful in case if encountering such condition in rectal cancer patients after neoadjuvant chemoradiation therapy, using as a source PubMed publications from 2010–2021 matching the search terms “rectal cancer”, “neoadjuvant therapy” and “response”.

Can we optimize CEA as a response marker in rectal cancer?

BACKGROUND AND AIM

carcinoembryonic antigen (CEA) is a biomarker commonly used in colorectal cancer. However, its prognostic value is still controversial. Recent studies demonstrate that CEA produced locally by tumor cells has a higher prognostic value compared to serum CEA. This study aimed to determine whether there was an association between the CEA/tumor size ratio (CEA/ExT) and the pathological tumor response in patients with rectal adenocarcinoma (ADC), who underwent neoadjuvant chemoradiotherapy (N-CRT), followed by surgical tumor resection.

METHODS

a retrospective study was performed of rectal ADC patients who underwent N-CRT followed by curative surgery between March/2012 and October/2017. CEA and tumor extension for pre-treatment CEA/ExT calculation and the pathological response in the surgical specimen after treatment were analyzed.

RESULTS

eighty-nine patients were included, 60.7 % were male and the mean age was 63.8 ± 10.42. There was a good response to N-CRT in 41.6 % of the patients, tumor downstaging occurred in 83.1 % and a complete pathological response in 23.6 % of cases. The average CEA/ExT was 2.01 ng/ml/cm. In the univariate analysis, higher CEA/ExT values were related to a lower frequency of pathological response (p = 0.04) and to a lower frequency of tumor downstaging (p = 0.02). In the multivariate analysis, CEA/ExT was independently related to tumor downstaging (OR: 0.72; 95 % IC: 0.53-0.98, p-0.036).

CONCLUSIONS

lower pre-treatment CEA/ExT values seem to be associated with tumor downstaging and this parameter may be a promising predictor of a more favorable response in patients with rectal ADC undergoing treatment with N-CRT.

Association Between Pathological Complete Response and Tumor Location in Patients with Rectal Cancer After Neoadjuvant Chemoradiotherapy, a Prospective Cohort Study

Background: Colorectal cancers are the third common malignancies after lung and breast neoplasms. Some contributing factors for pathological complete response (pCR) to neoadjuvant therapy of rectal cancer have been defined. Despite various studies in this era, there are few studies on the location of tumors. Objectives: Regarding the high prevalence of colorectal cancer in Iran and the importance of neoadjuvant chemoradiation for survival and morbidity, this study was carried out to determine the association between pathologic complete response and tumor location in patients with rectal cancer after neoadjuvant chemoradiotherapy. Methods: In this prospective cohort, 100 cases with rectal adenocarcinoma from 2017 to 2019 were enrolled. Distance between anal verge and tumor was measured by clinical examination, colonoscopy, endo-sonography, and MRI. Tumors were defined as distal (less than 5 cm from the anal verge) and none distal (more than 5 cm from the anal verge). Another subdivision was inferior (0 - 4.99 cm), middle (5 - 9.99 cm), and superior (10 - 15 cm). The pathological response was compared across the groups. Results: In this study, the pCR was seen in 30%. In univariate analysis body mass index (BMI), grade, N-stage, and distance from anal verge were related to pCR. In cases with BMI over 25 kg/m2 and in tumors with low to medium grade N0/N1, and distance less than 5 cm from the anal verge (low lying tumors) the pCR to neoadjuvant treatment was higher. In multivariate analysis tumor grade, N stage, and distance from anal verge were still related to pCR. Conclusions: According to the obtained results in this study, there may be some association between rectal tumor location and pathologic complete response.

Pathological Complete Response After Neoadjuvant Therapy in Rectal Adenocarcinoma: a 5-Year Follow-up

Neoadjuvant therapy is the gold standard treatment of locally advanced rectal cancer. It may induce complete sterilization of tumor cell and decreases its local recurrence rate. While 15–20% of patients were found to have pathological complete response (pCR) with combined multimodal therapy, Asian data were generally scarce. pCR rate can indicate the suitability of applying the “watch-and-wait” strategy, which advocates deferment of surgery that can alleviate surgery-associated morbidity.To determine the percentage of pCR of rectal cancer after neoadjuvant therapy. Patients diagnosed with rectal cancer underwent treatment from 2013 to 2017 were retrieved retrospectively. Demographic data, tumor localization, pre- and post-operative pathological reports, neoadjuvant therapy, and pCR status were collected from patients’ records. A total of 242 out of 259 patients were treated with definitive rectal surgery. Mean age was 67.1 years old. Chinese ethnicity and male gender were predominant (n = 131, 54.1% and n = 146, 64.3% respectively). More than half (n = 124, 51.2%) had tumor located at mid or low rectum. Histologically, moderate differentiated adenocarcinoma was predominant (n = 227, 93.8%). Merely half (n = 123, 50.8%) of the patients received neoadjuvant chemoradiation therapy, but only 12 (9.8%) had a pCR. From follow-up on these 12 pCR patients, most had 2-year disease-free survival but 1 (8.3%) of the pCR had distant metastasis within 1-year post-surgery. The pathological complete response rate in our center was lower than reported. Stringent patient selection with close follow-up for patients should be carried out if the “watch-and-wait” strategy is implemented in our population.

Clinical predictors of response to chemoradiotherapy for rectal cancer as an aid to organ preservation

AIM

Clinical predictors of pathological response to chemoradiotherapy for rectal cancer can influence patient management including selection for organ preservation. This study aimed to identify clinical predictors at a tertiary referral hospital.

METHODS

A retrospective review of clinical records was undertaken after identifying all patients with stage 1-3 rectal cancer treated with long course chemoradiotherapy and total mesorectal excision from 2013 to 2018. Clinicopathological factors were recorded and multivariate analysis performed to identify predictors of pathological complete response (pCR) and good response (AJCC TRG 0-1).

RESULTS

A total of 470 patients with rectal cancer were identified of which 164 met the inclusion criteria for the study. The pCR rate was 14.6% and good response (TRG 0-1) rate 43.7%. On univariate analysis, lower T stage, older age, node negative status, anterior tumour position and shorter tumour length on magnetic resonance imaging (MRI) were associated with good response (TRG 0-1). On univariate analysis cN stage, carcinoembryonic antigen <5 and shorter tumour length on MRI were associated with pCR. On binary logistic regression shorter length on MRI and lower clinical nodal stage were predictive of pCR and lower body mass index, anterior tumour position and higher haemoglobin were predictive of good response (TRG 0-1).

CONCLUSION

Anterior tumour position is newly identified as an independent predictor of good response (TRG 0-1) to nCRT for rectal cancer and this should be explored in future studies. Higher haemoglobin and lower body mass index were also independent predictors of good response (TRG 0-1) and optimisation of these factors should be considered when using neoadjuvant chemoradiotherapy for rectal cancer.

Gut Microbiome Composition Is Associated with a Pathologic Response After Preoperative Chemoradiation in Patients with Rectal Cancer

PURPOSE

There are ongoing investigations to find promising biomarkers for predicting a complete response (CR) after concurrent chemoradiation (CCRT) in rectal cancer. We aimed to find the predictive value in the gut microbiome in terms of response after preoperative CCRT.

METHODS AND MATERIALS

We collected a total of 45 fecal samples from patients with rectal cancer before CCRT. Tumor response after CCRT was assessed according to the American Joint Committee on Cancer tumor regression grading system. Analysis of linear discriminant analysis effect size and MetaCyc pathway abundance predictions were performed to compare composition and metabolic function of microbiome between patients with and without CR. We also established a Bayesian network model to identify microbial networks and species to be related with CCRT response.

RESULTS

Seven patients (15.6%) demonstrated pathologically CR, and 38 patients (84.4%) showed non-CR after preoperative CCRT. Between CR and non-CR patients, there was a significant difference in terms of β-diversity (P = .028), but no difference in α-diversity was found. Bacteroidales (Bacteroidaceae, Rikenellaceae, Bacteroides) were relatively more abundant in patients with non-CR than those with CR. Pathways related to anabolic function predominated in CR patients. According to Bayesian network analysis, Duodenibacillus massiliensis was linked with the improved CR rate.

CONCLUSIONS

From the fecal microbiome using samples obtained before preoperative CCRT, differences in microbial community composition and functions were observed between patients with and without CR in rectal cancer. However, the finding that a specific taxon may be linked with the improved therapeutic response should be verified in a prospective setting.

Baseline neutrophil-lymphocyte ratio and platelet-lymphocyte ratio in rectal cancer patients following neoadjuvant chemoradiotherapy

PURPOSE

There is uncertainty over the effect of systemic inflammatory response on oncologic outcomes in patients who underwent neoadjuvant chemoradiotherapy and surgery for rectal cancer. We investigated the association between neutrophil-lymphocyte ratio (NLR) and platelet-lymphocyte ratio (PLR) as markers of systemic inflammation and tumor response and prognosis after treatment.

METHODS

A total of 176 patients who underwent neoadjuvant chemoradiotherapy and curative surgery for rectal cancer were analyzed retrospectively. Pretreatment hematologic parameters and the main clinical factors for patients and tumors were investigated with respect to their relationship with tumor regression and survival.

RESULTS

In the receiver operating characteristic analysis, NLR 2.0 and PLR 133.4 had the highest sensitivity and specificity in predicting tumor response. NLR <2.0 and PLR <133.4 were significantly correlated with good tumor response (odds ratio [OR] 2.490, 95% confidence interval [CI] 1.264-4.904, p = .008; OR 3.009, 95% CI 1.477-6.127, p < .001). Patients with NLR <2.0 had significantly better 5-year disease-free survival rate and overall survival rate compared to patients with NLR ⩾2.0 in multivariate analysis (86.8% vs 70.7%, p = .014; 92.4% vs 71.9%, p = .027).

CONCLUSIONS

Elevated NLR and PLR levels can be considered as predictors of poor pathologic response, and NLR can be considered a prognosticator in patients who underwent neoadjuvant chemoradiotherapy for locally advanced rectal cancer.

A qualitative signature for predicting pathological response to neoadjuvant chemoradiation in locally advanced rectal cancers

BACKGROUND AND PURPOSE

The standard therapy for locally advanced rectal cancers (LARCs) is neoadjuvant chemoradiation (nCRT) followed by surgical resection. Pathological response to nCRT varies among patients, and it remains a challenge to predict pathological response to nCRT in LARCs.

MATERIAL AND METHODS

Using 42 samples as the training cohort, we searched a signature by screening the gene pairs whose within-sample relative expression orderings are significantly correlated with the pathological response. The signature was validated in both a public cohort of 46 samples and a cohort of 33 samples measured at our laboratory.

RESULTS

A signature consisting of 27 gene pairs was identified in the training cohort with an accuracy of 92.86% and an area under the receiver operating characteristic curve (AUC) of 0.95. The accuracy was 89.13% for the public test cohort and 90.91% for the private test cohort, with AUC being 0.95 and 0.91, respectively. Furthermore, the signature was used to predict disease-free survival benefits from 5Fu-based chemotherapy in 285 locally advanced colorectal cancers.

CONCLUSIONS

The signature consisting of 27 gene pairs can robustly predict clinical response of LARCs to nCRT.

Difference in Tumor Area as a Predictor of a Pathological Complete Response for Patients With Locally Advanced Rectal Cancer

Purpose

This study was conducted to discover the clinical factors that can predict pathologically complete remission (pCR) after neoadjuvant chemoradiotherapy (CRT), so that those factors may help in deciding on a treatment program for patients with locally advanced rectal cancer.

Methods

A total of 137 patients with locally advanced rectal cancer were retrospectively enrolled in this study, and data were collected retrospectively. The patients had undergone a total mesorectal excision after neoadjuvant CRT. Histologic response was categorized as pCR vs. non-pCR. The tumor area was defined as (tumor length) × (maximum tumor depth). The difference in tumor area was defined as pre-CRT tumor area - post-CRT tumor area. Univariate and multivariate logistic regression analyses were conducted to find the factors affecting pCR. A P-value < 0.05 was considered significant.

Results

Twenty-three patients (16.8%) achieved pCR. On the univariate analysis, endoscopic tumor circumferential rate <50%, low pre-CRT T & N stage, low post-CRT T & N stage, small pretreatment tumor area, and large difference in tumor area before and after neoadjuvant CRT were predictive factors of pCR. A multivariate analysis found that only the difference in tumor area before and after neoadjuvant CRT was an independent predictor of pCR (P < 0.001).

Conclusion

The difference in tumor area, as determined using radiologic tools, before and after neoadjuvant CRT may be important predictor of pCR. This clinical factor may help surgeons to determine which patients who received neoadjuvant CRT for locally advanced rectal cancer should undergo surgery.

Clinical and Prognostic Significance of Pathological and Inflammatory Markers in Mucinous Rectal Cancer Patients Receiving Neoadjuvant Chemoradiotherapy and Curative Surgery

Background

The aim of this study was to investigate the clinical and prognostic significance of pathological and inflammatory marker in mucinous rectal cancer patients receiving neoadjuvant chemoradiotherapy and curative surgery.

Material/Methods

We retrospectively evaluated the patient records of mucinous rectal cancer patients receiving neoadjuvant chemoradiotherapy and curative surgery at Liaoning Cancer Hospital and Institute from January 2006 to December 2013. The relationship between overall survival (OS) and clinicopathologic variables, pretreatment neutrophil-to-lymphocyte ratio (NLR), pretreatment platelet-to-lymphocyte ratio (PLR), pretreatment lymphocyte-to-monocyte ratio (LMR), and other biomarkers were analyzed by using Kaplan-Meier analysis and log-rank testing. Subsequently a Cox proportional hazard model was used to calculate hazard ratios for the risk of death.

Results

A total of 100 mucinous rectal cancer patients were included for analysis during the study period. The median age at presentation was 60.5 years (range, 26–81 years). The median overall survival (OS) for the whole group was 94 months. On univariate analysis, time interval from CCRT to operation (HR 0.37, p=0.03), lymphovascular invasion (HR 3.23, p=0.009), pretreatment NLR (HR 3.87, p=0.012), and LMR (HR 0.31, p=0.002) were significant prognostic factors for OS. In a multivariate analysis, pretreatment LMR was found to be an independent prognostic factor for overall survival (HR, 0.43; 95%CI, 0.18 to 1.00, p=0.045).

Conclusions

Pretreatment lymphocyte-to-monocyte ratio is a useful prognostic marker of OS in patients with mucinous rectal carcinoma treated with neoadjuvant chemoradiotherapy and curative surgery.

Clinical utility of pretreatment prediction of chemoradiotherapy response in rectal cancer: a review

Approximately 20% of all patients with locally advanced rectal cancer experience pathologically complete responses following neoadjuvant chemoradiotherapy (CRT) and standard surgery. The utility of radical surgery for patients exhibiting good CRT responses has been challenged. Organ-sparing strategies for selected patients exhibiting complete clinical responses include local excision or no immediate surgery. The subjects of this tailored management are patients whose presenting disease corresponds to current indications of neoadjuvant CRT, and their post-CRT tumor response is assessed by clinical and radiological examinations. However, a model predictive of the CRT response, applied before any treatment commenced, would be valuable to facilitate such a personalized approach. This would increase organ preservation, particularly in patients for whom upfront CRT is not generally prescribed. Molecular biomarkers hold the greatest promise for development of a pretreatment predictive model of CRT response. A combination of clinicopathological, radiological, and molecular markers will be necessary to render the model robust. Molecular research will also contribute to the development of drugs that can overcome the radioresistance of rectal tumors. Current treatments for rectal cancer are based on the expected prognosis given the presenting disease extent. In the future, treatment schemes may be modified by including the predicted CRT response evaluated at presentation.