Locally Advanced Rectal Cancer Patients Research Articles

Prognostic value of neutrophil-to-lymphocyte ratio (NLR) and platelet-neutrophil (PN) index in locally advanced rectal cancer patients: a retrospective cohort study.

In locally advanced rectal cancers (LARC), tumour node metastasis (TNM) staging is far from optimal. The authors aimed to investigate the value of previously described circulating biomarkers as predictors of prognosis. Retrospective analysis of 245 LARC patients diagnosed between January 2010 and December 2022, who underwent neoadjuvant chemoradiotherapy and surgery at two centres. A Cox regression and Kaplan-Meier analysis were performed. Post-treatment platelet-to-lymphocyte ratio (PLR) predicted pathological complete response. The neutrophil-to-lymphocyte ratio (NLR) in two timepoints of the treatment significantly predicted overall survival, whereas the platelet-neutrophil (PN) index significantly predicted disease-free survival. In pathological stage II, the PN index predicted patients with a higher risk of disease-free survival. Blood parameters might allow the definition of subgroups of risk beyond TNM for the application of different therapeutic strategies.

A retrospective cohort study of neoadjuvant chemoradiotherapy combined with immune checkpoint inhibitors in locally advanced rectal cancer

IntroductionThis study aimed to investigate the safety and efficacy of neoadjuvant chemoradiotherapy combined with immune checkpoint inhibitors (ICIs) in patients with locally advanced rectal cancer (LARC). Patients diagnosed with LARC and treated with programmed cell death protein-1 (PD-1) inhibitors were recruited. MethodsFour different treatment strategies were employed in this study: plan A [long-course radiotherapy + PD-1 inhibitor/capecitabine + PD-1 inhibitor/XELOX+ total mesorectal excision (TME)], plan B (long-course radiotherapy + capecitabine + PD-1 inhibitor/XELOX + TME), plan C (short-course radiotherapy + PD-1 inhibitor/XELOX + TME), and plan D (PD-1 inhibitor/XELOX + short-course radiotherapy + TME). The basic information about patients, pathological indicators, adverse events, and efficacy indexes of treatment plans were analyzed. Results96.8% of patients were mismatch repair proficient (pMMR) and only 2 patients belonged to mismatch repair deficient (dMMR). The 2 patients with dMMR showed a pathological complete response (pCR) rate of 100%, while the pCR rate of pMMR patients was 43.3%. The overall tumor descending rate reached 79%, and the anus-retained rate was 88.7% in all LARC patients. Plan A exhibited the highest pCR rate of 60%, and plan C had the highest tumor descending rate and anal preservation rate. Radiation enteritis was the most common adverse event in LARC patients after neoadjuvant therapy, and its incidence was the highest in Plan A. ConclusionNeoadjuvant chemoradiotherapy combined with ICIs demonstrated favorable efficacy and safety in treating LARC patients.

Clinicopathological factors predict residual lymph node metastasis in locally advanced rectal cancer with ypT0-2 after neoadjuvant chemoradiotherapy

PurposeResidual lymph node metastases (RLNM) remained a great concern in the implementation of organ-preserving strategies and led to poor prognosis in locally advanced rectal cancer (LARC). In this study, we aimed to identify the clinicopathological factors correlated with RLNM in LARC patients with ypT0-2 after neoadjuvant chemoradiotherapy (NCRT).MethodsWe retrospectively analyzed 417 patients histologically diagnosed middle-low LARC after NCRT and total mesorectal excision (TME), whose pathological staging was ypT0-2. All patients received pelvic magnetic resonance imaging (MRI) before NCRT. The radiation doses were 50–50.6 Gy for the planning gross tumor volume and 41.8–45 Gy for the planning target volume, respectively. A nomogram for predicting RLNM was constructed using a binary logistic regression. Nomogram performance was assessed by receiver operating characteristic (ROC) curve, calibration curve, decision curve analysis (DCA) and clinical impact curve (CIC).ResultsAfter surgery, 191 patients (45.8%) were ypT0, 43 patients (10.3%) were ypT1 and 183 patients (43.9%) were ypT2, and a total of 49 patients (11.8%) were found the presence of RLNM. Multivariable analyses identified MRI-defined mesorectal fascia (MRF)-positive, high-grade histopathology at biopsy, advanced ypT-category, and the presence of perineural invasion (PNI) as the predictive factors. The nomogram, incorporating all these predictors, showed good discrimination and calibration efficacy, with the areas under the ROC curve of 0.690 (95% CI: 0.610–0.771). Both DCA and CIC demonstrated that this nomogram has good clinical usefulness.ConclusionThe nomogram model can predict RLNM in patients with ypT0-2 tumors. It can help select suitable patients for performing organ-preserving strategies after NCRT.

The prognostic model and immune landscape based on cancer-associated fibroblast features for patients with locally advanced rectal cancer

BackgroundThis study aimed to construct a nomogram based on CAF features to predict the cancer-specific survival (CSS) rates of locally advanced rectal cancer (LARC) patients. MethodsThe EPIC algorithm was employed to calculate the proportion of CAFs. based on the differentially expressed genes between the high and low CAF proportion subgroups, prognostic genes were identified via LASSO and Cox regression analyses. They were then used to construct a prognostic risk signature. Moreover, the GSE39582 and GGSE38832 datasets were used for external validation. Lastly, the level of immune infiltration was evaluated using ssGSEA, ESTIMATE, CIBERSORTx, and TIMER. ResultsA higher level of CAF infiltration was associated with a worse prognosis. Additionally, the number of metastasized lymph nodes and distant metastases, as well as the level of immune infiltration were higher in the high CAF proportion subgroup. Five prognostic genes (SMOC2, TUBAL3, C2CD4A, MAP1B, BMP8A) were identified and subsequently incorporated into the prognostic risk signature to predict the 1-, 3-, and 5-year CSS rates in the training and validation sets. Differences in survival rates were also determined in the external validation cohort. Furthermore, independent prognostic factors, including TNM stage and risk score, were combined to established a nomogram. Notably, our results revealed that the proportions of macrophages and neutrophils and the levels of cytokines secreted by M2 macrophages were higher in the high-risk subgroup. Finally, the prognostic genes were significantly associated with the level of immune cell infiltration. ConclusionHerein, a nomogram based on CAF features was developed to predict the CSS rate of LARC patients. The risk model was capable of reflecting differences in the level of immune cell infiltration.

Abstract 2506: Novel biomarkers that predict response to neoadjuvant chemoradiotherapy in locally advanced rectal cancer

Abstract Background: Neoadjuvant chemoradiotherapy (nCRT) followed by surgery is standard of care for locally advanced rectal cancer (LARC). About 20% patients receiving nCRT alone experience a pathologic complete response (pCR), while up to 25% patients exhibit a poor response. Currently, there is no biomarker to predict response to nCRT. We hypothesized that inherited ability to recognize and repair DNA damage, especially lethal double-strand breaks (DSBs), manifest in lymphocytes, would yield a reproducible test predicting therapeutic response to nCRT. Methods: Expression of DNA damage response (DDR) proteins was studied using peripheral blood lymphocytes (PBLs) from LARC patients and healthy controls. PBLs from LARC patients collected either before nCRT or after a standard course of ~5.5 weeks of nCRT were assessed by immunofluorescence (IF) for phospho-γH2AXSer139 and by Luminex multi-analyte platform (xMAP) approaches. The xMAP assay was modified from a qualitative to a semi-quantitative assay that measures the following DDR-associated proteins- total ATR, phospho-γH2AXSer139, total MDM2, phospho-Chk1S345, phospho-Chk2T68, phospho-p53S15, total p21. The analytical performance of the assay was assessed with vendor-provided reference controls and banked PBLs from healthy controls (n=50). LARC patients were segregated by neoadjuvant rectal (NAR) score to determine if tested biomarkers correlated with nCRT response. We used two independent sets of LARC biospecimens for xMAP analysis (set 1, n=48; set 2, n=44). Results: IF-based assessment: Using PBLs from LARC patients, we found that poor responders (PoR; NAR score>14; n=21) had significantly lower γH2AX foci than complete responders (CR; NAR score<1; n=21) (P<0.0001, logistic regression). No significant difference was observed in positive γH2AX foci from PBLs drawn pre-nCRT versus post-nCRT from the same patient (p=0.4961, n=11, Wilcoxon test). xMAP assay performance: The performance assessment showed linear sample curves, precision with acceptable inter- and intra-assay coefficients of variability, and high reproducibility with ~1% outliers identified in replicates. Clinical associations using xMAP assay: levels of six proteins (ATR, p-γH2AXSer139, MDM2, p-Chk1S345, p-Chk2T68, p-p53S15) significantly differentiated CRs from PoRs (p-values and False Discovery Rate ⇐ 1e-5). The strongest associations with nCRT response were observed for: ATR, MDM2 and γH2AX. Conclusion: 1) we standardized an xMAP assay to assess DDRs in human PBLs, and 2) found novel biomarkers that predict response to nCRT in LARC patients using minimally invasive PBL biospecimen. In ongoing work, we are using a larger biospecimen set to establish clinical validity parameters. Citation Format: Adria Hasan, Elena V. Demidova, Philip Czyzewicz, Karthik Devarajan, Margret B. Einarson, Donald Baldwin, Erica A. Golemis, Joshua E. Meyer, Sanjeevani Arora. Novel biomarkers that predict response to neoadjuvant chemoradiotherapy in locally advanced rectal cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 2506.

Abstract 5143: Molecular investigation of a polymorphic variant in JMJD1C that associates with chemoradiotherapy outcomes in locally advanced rectal and head and neck cancer

Abstract Background: Neoadjuvant chemoradiotherapy (nCRT) is standard therapy for locally advanced rectal cancer (LARC). While only a minority of patients are expected to have a complete response, all are at risk of toxicity. Currently no biomarkers reliably predict response to nCRT in LARC. Further, standard therapy in locally advanced head and neck squamous cell carcinoma (HNSCC) is adjuvant CRT. A major cause of poor outcomes in HNSCC is regional persistence or recurrence post-CRT. No biomarkers, apart from HPV, predict CRT response in HNSCC. CRT causes double-strand breaks (DSBs) and methylation of histones on lysine residues is known to affect chromatin, influencing DSB repair. We hypothesized that single nucleotide polymorphisms (SNP) in the histone 3 lysine 9 (H3K9) demethylase-encoding JMJD1C influenced CRT response. Methods: LARC patients (n=84) were divided into poor (PoR) and complete (CR) responders based on Neoadjuvant Rectal score. Lymphocyte DNA was sequenced, and LARC patient-derived cells were treated with DSB-inducing agents to assess viability. Sequencing was confirmed in an independent cohort of CRT-treated HNSCC patients (n=90) divided into: disease-free (n=30), recurrent disease (n=28), and never-disease-free (n=32). HNSCCs were in the larynx or oral cavity. Not all patients received HPV-testing; p16 expression was positive for 19/43 tumors. CRISPR/Cas9 editing of HPV-negative HNSCC lines (SCC9, Cal27) generated JMJD1C WT or SNP isogenic pairs. Bulk RNA-sequencing, colony survival, and immunofluorescence studies were performed. Results: In LARC patients, CRs were enriched for a coding, missense germline SNP in JMJD1C versus PoRs (discovery n=30, p<0.00001; validation n=54, p=0.001, Fisher’s Exact). When subjected to DSB, LARC patient-derived cells with the SNP displayed greater sensitivity than their WT counterparts (n=12, p<0.001, Mann-Whitney). In HNSCC, a correlation was identified between the same JMJD1C SNP and no recurrence (p=0.0003, Fisher’s Exact). HNSCC SNP cells showed changes in mRNA levels of DNA repair and immune response genes versus HNSCC WT cells (q-value<0.05). Upon irradiation, kinetics of foci resolution of the DNA damage response protein MDC1, specific to DSBs, were slower in SNP versus WT HNSCC cells (p<0.05, Mann Whitney). Further, there was reduced colocalization of BRCA1 with RAP80, a crucial factor for homology-directed DSB repair, in SNP versus WT HNSCC cells (p<0.01, Mann-Whitney).Targeted introduction of the SNP into HNSCC cell lines reduced viability and radiation response. Conclusion: Our study identifies a polymorphic coding variant in JMJD1C, as a predictive biomarker for CRT effectiveness in LARC and HNSCC, and defines a DNA repair mechanism by which JMJD1C influences response to irradiation. Citation Format: Adria Hasan, Elena V. Demidova, Philip Czyzewicz, Shreya M. Shah, Karthik Devarajan, Thomas J. Galloway, Margret B. Einarson, Barbara Burtness, Erica A. Golemis, Joshua E. Meyer, Sanjeevani Arora. Molecular investigation of a polymorphic variant in JMJD1C that associates with chemoradiotherapy outcomes in locally advanced rectal and head and neck cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 5143.

Abstract 1172: Association between CD8+ PD-1+ T cell infiltration levels and improved response to total neoadjuvant therapy in mismatch-repair proficient locally advanced rectal cancer

Abstract Background: The tumor microenvironment plays a major role in colorectal cancer progression, dissemination, and response to therapy. As a mechanism of tumor immunity, CD8+ tumor infiltrating lymphocytes have been shown to express PD-1 in response to clonal neoantigens of tumors. We hypothesized that high levels of CD8+ PD-1+ T cell infiltration prior to treatment initiation may correlate with improved response to total neoadjuvant therapy (TNT) in patients with locally advanced rectal cancer (LARC). Methods: We analyzed untreated endoscopic biopsies from 159 patients diagnosed with stage II (n=25) or III (n=134), mismatch-repair proficient rectal adenocarcinoma. All patients were treated with TNT, consisting of either induction chemotherapy followed by chemoradiation (n=108) or chemoradiation followed by consolidative chemotherapy (n=51). FFPE blocks from each biopsy were sectioned into slides for H&E and immunohistochemistry staining with antibodies for CD8 and PD-1 in a CLIA certified lab. CD8+ and PD-1+ cells were quantified using established protocols from the College of American Pathologists. We evaluated associations between response to TNT and tertiles of intratumoral CD8 and PD-1 expression (low/mid/high). Disease free survival (DFS) from the start of TNT and rate of sustained complete response (CR, either clinical or pathologic) were used as primary endpoints. Results: Median follow-up was 40.3 months. The overall CR rate was 42% and the 5-year DFS rate was 77%. Intratumoral CD8 levels were significantly correlated with improved response rates (56% in the top tertile vs. 27% in the bottom tertile, p=0.003, Fisher’s test) and improved 5-year DFS (92% vs. 67% for the top vs. bottom tertiles, respectively; p=0.006, log-rank test). Patients in the highest tertile of intratumoral PD-1 expression also had improved response (56% vs. 25%, p=0.002) and DFS (88% vs. 67%, p=0.034). CD8 and PD-1 levels were strongly correlated with each other (R=0.72, p<0.001, Spearman correlation). Finally, the 41 patients who met criteria for top tertiles of CD8 and PD-1 expression had higher CR rates (66% vs. 32%, p<0.001) and better 5-year DFS (97% vs. 70%, p=0.002) than the other patients. Conclusions: Higher levels of CD8+ and PD-1+ tumor infiltrating lymphocytes on pre-treatment biopsies are associated with improved response to TNT and disease free survival in LARC patients. Citation Format: Christina Lee, Chin-Tung Chen, Nil Urganci, Fan Wu, Canan Firat, Hannah Williams, Evan Seffar, Parisa Malekzadeh, Walid K. Chatila, Jinru Shia, Julio Garcia-Aguilar, Francisco Sanchez-Vega. Association between CD8+ PD-1+ T cell infiltration levels and improved response to total neoadjuvant therapy in mismatch-repair proficient locally advanced rectal cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 1172.

Radiomics-enhanced early regression index for predicting treatment response in rectal cancer: a multi-institutional 0.35T MRI-guided radiotherapy study.

The accurate prediction of treatment response in locally advanced rectal cancer (LARC) patients undergoing MRI-guided radiotherapy (MRIgRT) is essential for optimising treatment strategies. This multi-institutional study aimed to investigate the potential of radiomics in enhancing the predictive power of a known radiobiological parameter (Early Regression Index, ERITCP) to evaluate treatment response in LARC patients treated with MRIgRT. Patients from three international sites were included and divided into training and validation sets. 0.35T T2*/T1-weighted MR images were acquired during simulation and at each treatment fraction. The biologically effective dose (BED) conversion was used to account for different radiotherapy schemes: gross tumour volume was delineated on the MR images corresponding to specific BED levels and radiomic features were then extracted. Multiple logistic regression models were calculated, combining ERITCP with other radiomic features. The predictive performance of the different models was evaluated on both training and validation sets by calculating the receiver operating characteristic (ROC) curves. A total of 91 patients was enrolled: 58 were used as training, 33 as validation. Overall, pCR was observed in 25 cases. The model showing the highest performance was obtained combining ERITCP at BED = 26Gy with a radiomic feature (10th percentile of grey level histogram, 10GLH) calculated at BED = 40Gy. The area under ROC curve (AUC) of this combined model was 0.98 for training set and 0.92 for validation set, significantly higher (p = 0.04) than the AUC value obtained using ERITCP alone (0.94 in training and 0.89 in validation set). The integration of the radiomic analysis with ERITCP improves the pCR prediction in LARC patients, offering more precise predictive models to further personalise 0.35T MRIgRT treatments of LARC patients.

Predictive effect of the systemic inflammation response index (SIRI) on the efficacy and prognosis of neoadjuvant chemoradiotherapy in patients with locally advanced rectal cancer

BackgroundInflammation is a part of tumours, and inflammatory cells can affect the proliferation, invasion, and development of tumour cells. An increasing number of peripheral blood inflammatory markers have been found to play very important roles in the treatment and prognosis of cancer patients. The systemic inflammatory response index (SIRI) is a newer inflammatory marker, and its role in colorectal cancer, especially in locally advanced rectal cancer, is still unclear.MethodsFrom 2015 to 2020, 198 patients with locally advanced rectal cancer (LARC) who underwent surgery following neoadjuvant chemoradiotherapy (Neo-CRT) were analysed. Patients were categorized into good- and poor- response groups according to their pathological results, and clinical characteristics and baseline parameters were compared between the two groups. The optimal cutoff values for inflammatory indicators were determined using receiver operating characteristic (ROC) analysis. Univariate and multivariate analyses were performed using the Cox proportional hazard model. Survival analysis was performed via the Kaplan‒Meier method.ResultsAfter patients were grouped into good and poor response groups, indicator differences were found in CEA, neutrophil-to-lymphocyte ratio (NLR), systemic immune-inflammation index (SII), and SIRI. According to the ROC analysis, the NLR (P = 0.015), SII (P = 0.001), and SIRI (P = 0.029) were significant prognostic factors. After univariate and multivariate analyses of the Cox proportional hazards regression model, only the SIRI was found to be an independent prognostic factor for overall survival (OS) and disease-free survival (DFS). Finally, Kaplan‒Meier survival curves also confirmed the ability of the SIRI to predict survival.ConclusionThe preoperative SIRI can be used to predict the response to Neo-CRT in LARC patients and is an independent predictor of OS and DFS in postoperative patients. A high SIRI was associated with poor radiotherapy response and predicted poor OS and DFS.

Efficacy and safety of PD-1 blockade plus long-course chemoradiotherapy in locally advanced rectal cancer (NECTAR): a multi-center phase 2 study

Adding PD-1 blockade in the neoadjuvant regimens for locally advanced rectal cancer (LARC) patients with microsatellite stable (MSS) / mismatch repair-proficient (pMMR) tumors is an attractive, but debatable strategy. This phase 2, multicenter, prospective, single-arm study enrolled patients from 6 centers from June 2021 to November 2022. Locally advanced rectal cancer (LARC, cT3-4aN0M0 and cT1-4aN1-2M0) patients aged ≥18 years with the distance from distal border of tumor to anal verge ≤10 cm (identified by Magnetic Resonance Imaging) were qualified for inclusion. The patients received long-course radiotherapy (50 Gy/25 fractions, 2 Gy/fraction, 5 days/week) and three 21-day cycles capecitabine (850–1000 mg/m2, bid, po, day1–14) and three 21-day cycles tislelizumab (200 mg, iv.gtt, day8) as neoadjuvant. Total mesorectal excision (TME) was 6–12 weeks after the end of radiotherapy to achieve radical resection. A total of 50 patients were enrolled in this study. The pathological complete response rate was 40.0% [20/50, 95% confidence interval (CI): 27.61–53.82%], while 15 (30.0%, 95% CI: 19.1–43.75%), 9 (18.0%, 95% CI: 9.77–30.8%), 2 (4.0%, 95% CI: 1.10–13.46%) patients respectively achieved grade 1, 2, and 3 tumor regression. Treatment-related adverse events (TRAEs) occurred in 28 (56.0%) LARC patients, including 26(52.0%) with grade I-II and 2 (4.0%) with grade III (1 with grade 3 immune-related colitis and 1 with grade 3 rash). PD-1 blockade plus long-course chemoradiotherapy (CRT) showed promising therapeutic effects according to pathological complete response rate and is well-tolerated in LARC patients. A larger randomized controlled study is desired to further validate the above findings.

Prediction of pathologic complete response to neoadjuvant chemoradiation in locally advanced rectal cancer.

To investigate the predictive factors of pathologic complete response (pCR) in locally advanced rectal cancer (LARC) patients who had been treated with neoadjuvant chemoradiation (nCRT). For this retrospective study, 53 LARC patients (37 males and 16 females; age range 25 to 79 years) were selected. Clinical characteristics, baseline mrTNM staging, MR gross tumor volumes (GTV), and pCR were evaluated. The diagnostic accuracy of GTV for predicting pCR was calculated. Among 53 LARC patients, 15 patients achieved pCR (28.3%), while 38 patients achieved non-pCR. Only three (5.7%) out of 53 patients did not downstage after nCRT. GTV and tumor differentiation were the significant prognostic parameters for predicting pCR. A tumor volume threshold of 21.1 cm3 was determined as a predictor for pCR, with a sensitivity of 84% and specificity of 47%. In addition, GTV was associated with mrN stage, circumferential resection margin (CRM) status, extramural vascular invasion (EMVI) status, and pretreatment serum CEA level. Tumor volume and tumor differentiation have significant predictive values in preoperative assessment of pCR among LARC patients. These findings aid clinicians to discriminate those patients who may likely benefit from preoperative regimens and to make optimal treatment plans.

Artificial intelligence measured 3D body composition to predict pathological response in rectal cancer patients.

The treatment of locally advanced rectal cancer (LARC) is moving towards total neoadjuvant therapy and potential organ preservation. Of particular interest are predictors of pathological complete response (pCR) that can guide personalized treatment. There are currently no clinical biomarkers which can accurately predict neoadjuvant therapy (NAT) response but body composition (BC) measures present as an emerging contender. The primary aim of the study was to determine if artificial intelligence (AI) derived body composition variables can predict pCR in patients with LARC. LARC patients who underwent NAT followed by surgery from 2012 to 2023 were identified from the Australian Comprehensive Cancer Outcomes and Research Database registry (ACCORD). A validated in-house pre-trained 3D AI model was used to measure body composition via computed tomography images of the entire Lumbar-3 vertebral level to produce a volumetric measurement of visceral fat (VF), subcutaneous fat (SCF) and skeletal muscle (SM). Multivariate analysis between patient body composition and histological outcomes was performed. Of 214 LARC patients treated with NAT, 22.4% of patients achieved pCR. SM volume (P = 0.015) and age (P = 0.03) were positively associated with pCR in both male and female patients. SCF volume was associated with decreased likelihood of pCR (P = 0.059). This is the first study in the literature utilizing AI-measured 3D Body composition in LARC patients to assess their impact on pathological response. SM volume and age were positive predictors of pCR disease in both male and female patients following NAT for LARC. Future studies investigating the impact of body composition on clinical outcomes and patients on other neoadjuvant regimens such as TNT are potential avenues for further research.

Expression of Mitochondrial Long Non-Coding RNAs, MDL1 and MDL1AS, Are Good Prognostic and/or Diagnostic Biomarkers for Several Cancers, Including Colorectal Cancer.

Non-coding RNAs provide new opportunities to identify biomarkers that properly classify cancer patients. Here, we study the biomarker status of the mitochondrial long non-coding RNAs, MDL1 and MDL1AS. Expression of these genes was studied in public transcriptomic databases. In addition, a cohort of 69 locally advanced rectal cancer (LARC) patients with a follow-up of more than 5 years was used to determine the prognostic value of these markers. Furthermore, cell lines of colorectal (HCT116) and breast (MDA-MB-231) carcinoma were employed to study the effects of downregulating MDL1AS in vitro. Expression of MDL1AS (but not MDL1) was significantly different in tumor cells than in the surrounding tissue in a tumor-type-specific context. Both MDL1 and MDL1AS were accurate biomarkers for the 5-year survival of LARC patients (p = 0.040 and p = 0.007, respectively) with promising areas under the curve in the ROC analyses (0.820 and 0.930, respectively). MDL1AS downregulation reduced mitochondrial respiration in both cell lines. Furthermore, this downregulation produced a decrease in growth and migration on colorectal cells, but the reverse effects on breast cancer cells. In summary, MDL1 and MDL1AS can be used as reliable prognostic biomarkers of LARC, and MDL1AS expression provides relevant information on the diagnosis of different cancers.

Predictive Value of Tumor-Infiltrating Lymphocytes and Ki-67 for Pathological Response to Total Neoadjuvant Therapy in Rectal Cancer.

Patients with locally advanced rectal cancer (LARC) who underwent total neoadjuvant therapy (TNT) showed an increase in the percentage of complete pathological response (pCR). The purpose of this study was to determine the correlation between Ki-67, tumor-infiltrating lymphocytes (TIL), and TNT in LARC patients. In total, one hundred fifty-nine patients with LARC were included in this prospective study. The international working group was used to categorize the TIL into three groups based on the percentage and density of staining: group 0 (0-10%), group 1 (11-59%), and group 2 (≥ 60%). Ki-67 expression was classified as low (≤ 50%) or high (> 50%). Most patients had tumor grade III (74.2%) and T2-T3 (78.6%). Lymph node involvement (48.7%) and tumor size ≥ 3cm were detected in approximately half of the patients. Forty-four percent of patients had a high Ki-67 index; 15.7% of patients belonged to group 1, and 21.4% belonged to group 2. pCR was detected in 18.2% of the patients. TIL and Ki-67 levels were significantly correlated with pCR (p = 0.001 and 0.003 for multivariate analysis and 0.001 and 0.03 for univariate analysis, respectively). There was a statistically significant correlation between Ki-67, TIL, and pCR following TNT protocol, which may help maximize the therapeutic outcome.

Proteomic and metabolomic signatures of rectal tumor discriminate patients with different responses to preoperative radiotherapy.

Neoadjuvant radiotherapy (neo-RT) is widely used in locally advanced rectal cancer (LARC) as a component of radical treatment. Despite the advantages of neo-RT, which typically improves outcomes in LARC patients, the lack of reliable biomarkers that predict response and monitor the efficacy of therapy, can result in the application of unnecessary aggressive therapy affecting patients' quality of life. Hence, the search for molecular biomarkers for assessing the radio responsiveness of this cancer represents a relevant issue. Here, we combined proteomic and metabolomic approaches to identify molecular signatures, which could discriminate LARC tumors with good and poor responses to neo-RT. The integration of data on differentially accumulated proteins and metabolites made it possible to identify disrupted metabolic pathways and signaling processes connected with response to irradiation, including ketone bodies synthesis and degradation, purine metabolism, energy metabolism, degradation of fatty acid, amino acid metabolism, and focal adhesion. Moreover, we proposed multi-component panels of proteins and metabolites which could serve as a solid base to develop biomarkers for monitoring and predicting the efficacy of preoperative RT in rectal cancer patients. We proved that an integrated multi-omic approach presents a valid look at the analysis of the global response to cancer treatment from the perspective of metabolomic reprogramming.

An immune-related gene prognostic prediction risk model for neoadjuvant chemoradiotherapy in rectal cancer using artificial intelligence.

This study aimed to establish and validate a prognostic model based on immune-related genes (IRGPM) for predicting disease-free survival (DFS) in patients with locally advanced rectal cancer (LARC) undergoing neoadjuvant chemoradiotherapy, and to elucidate the immune profiles associated with different prognostic outcomes. Transcriptomic and clinical data were sourced from the Gene Expression Omnibus (GEO) database and the West China Hospital database. We focused on genes from the RNA immune-oncology panel. The elastic net approach was employed to pinpoint immune-related genes significantly impacting DFS. We developed the IRGPM for rectal cancer using the random forest technique. Based on the IRGPM, we calculated prognostic risk scores to categorize patients into high-risk and low-risk groups. Comparative analysis of immune characteristics between these groups was conducted. In this study, 407 LARC samples were analyzed. The elastic net identified a signature of 20 immune-related genes, forming the basis of the IRGPM. Kaplan-Meier survival analysis revealed a lower 5-year DFS in the high-risk group compared to the low-risk group. The receiver operating characteristic (ROC) curve affirmed the model's robust predictive capability. Validation of the model was performed in the GSE190826 cohort and our institution's cohort. Gene expression differences between high-risk and low-risk groups predominantly related to cytokine-cytokine receptor interactions. Notably, the low-risk group exhibited higher immune scores. Further analysis indicated a greater presence of activated B cells, activated CD8 T cells, central memory CD8 T cells, macrophages, T follicular helper cells, and type 2 helper cells in the low-risk group. Additionally, immune checkpoint analysis revealed elevated PDCD1 expression in the low-risk group. The IRGPM, developed through random forest and elastic net methodologies, demonstrates potential in distinguishing DFS among LARC patients receiving standard treatment. Notably, the low-risk group, as defined by the IRGPM, showed enhanced activation of adaptive immune responses within the tumor microenvironment.

Efficacy and Safety of Preoperative Transcatheter Rectal Arterial Chemoembolisation in Patients with Locally Advanced Rectal Cancer: Results from a Prospective, Phase II PCAR Trial

AimsThe PCAR study aimed to assess the efficacy and safety of preoperative transcatheter rectal arterial chemoembolisation (TRACE) in patients with locally advanced rectal cancer (LARC). Materials and methodsThis was a single-centre, prospective, phase II trial conducted in China. Eligible patients were adults aged 18 years and older with histologically confirmed stage II or III rectal carcinoma and an Eastern Cooperative Oncology Group performance status of 0–1. Patients received TRACE with oxaliplatin, followed by radiotherapy with a cumulative dose of 45 Gy (1.8 Gy/time/day, five times a week for 5 weeks) and received oral S1 capsules twice daily (7 days a week for 4 weeks). Patients underwent total mesorectal excision 4–8 weeks after the completion of chemoradiotherapy, followed by mFOLFOX6 or CAPOX regimens for 4–6 months. The hypothesis of this study was that adding TRACE to preoperative neoadjuvant chemoradiotherapy would improve tumour regression and prognosis. The primary end point was the pathological complete response rate; secondary end points included the major pathological response rate, anal preservation rate, 5-year disease-free survival (DFS), 5-year overall survival and treatment-related adverse events. ResultsIn total, 111 LARC patients received TRACE and subsequent scheduled treatment plans. The pathological complete response and major pathological response rates were 20.72% and 48.65%, respectively. The 5-year DFS and 5-year overall survival were 61.89% (95% confidence interval 51.45–74.45) and 74.80% (95% confidence interval 65.05–86.01), respectively. Grade 3–4 toxicities were reported in 29 patients (26.13%). The postoperative complication rate was 21.62%, without serious surgical complications. Multivariate Cox regression analysis showed that ypN stage (hazard ratio = 4.242, 95% confidence interval 2.101–8.564, P = 0.00017) and perineural invasion (hazard ratio = 2.319, 95% confidence interval 1.058–5.084, P = 0.0487) were independent risk factors associated with DFS, whereas ypN stage (hazard ratio = 3.164, 95% confidence interval 1.347–7.432, P = 0.0101), perineural invasion (hazard ratio = 4.118, 95% confidence interval 1.664–10.188, P = 0.0134) and serum carbohydrate antigen 199 (CA199; hazard ratio = 4.142, 95% confidence interval 1.290–13.306, P = 0.0344) were independent predictors for overall survival. ConclusionThe current study provides evidence that adding TRACE to neoadjuvant chemoradiotherapy can improve the pathological remission rate in LARC patients with acceptable toxicity. Given its promising effectiveness and safe profile, incorporating TRACE into the standard treatment strategy for patients with LARC should be considered.

No operation after short course radiotherapy followed by consolidation chemotherapy in locally advanced rectal cancer: The prospective, single arm NOAHS-ARC trial.

TPS237 Background: A Watch and Wait (W&W) strategy has been advocated for selected patients with a locally advanced rectal cancer (LARC) and a clinical complete response (cCR) after neoadjuvant treatment (NAT). In this context, total neoadjuvant therapy (TNT) has emerged as a strategy to enhance treatment response. Currently, TNT has reported higher rates of pathological complete response (pCR) and organ preservation when compared to long course radiotherapy (LCRT). However, the best TNT strategy is still unknown. We therefore hypothesize that in LARC patients, the use of a TNT strategy based on short course radiotherapy (SCRT) followed by consolidation chemotherapy is associated with a higher rate of pCR and sustained (>1year) cCR when compared to an historic cohort treated with LCRT. Methods: This is a prospective, single arm, phase II study that is currently enrolling patients with LARC (AJCC TNM cT3-T4 w/wo secondary lymph nodes according to clinical staging) > 18 years old from a tertiary hospital from Santiago, Chile. We included patients with biopsy proven palpable (<7cm from anal verge) adenocarcinoma from the middle-lower rectum. We excluded patients with contraindications to SCRT and/or chemotherapy. All patients receive SCRT (5x5 Gy) followed by systemic consolidation chemotherapy 7-14 days after last dose of SCRT, using either 9 cycles of FOLFOX or 6 cycles of CAPOX. Patients will be evaluated to determine the degree of response at 3 time points during TNT: baseline, mid-TNT (9 weeks after TNT beginning) and post-TNT (18 weeks after TNT beginning). At each time point, patients will be clinically evaluated with a DRE, flexible sigmoidoscopy (photos & video) and a magnetic resonance image of the rectum. CT scan will be performed at baseline and complete TNT. Treatment response will be categorized as cCR, near-cCR and incomplete response (IR) according to the Memorial Sloan Kettering Regression Schema previously validated in the OPRA Trial. Patients with an IR will be offered TME. Patients with a cCR will be offered a W&W strategy, if accepted. Patients with a near-cCR will be evaluated again in 4 weeks to define cCR versus IR. In cases of TME, surgical specimens will be processed in a standardized manner and tumor regression grade will be assessed using the American College of Pathologist’s Scale. Additionally, validated quality of life questionnaires will be administered at the baseline, post-NAT and at 6,12 and 24 months of follow-up. Finally, a repository for endoscopic/MRI imaging, tumoral tissue and serum will be obtained. For statistical analysis, an α level of error of 5% will be set. For sample size calculation , a pCR rate of 12% was used based in historic data. Using a previously reported design and considering a 30% of combined pCR/sustained cCR, sample size to prove statistical significance with β power of 80% and error of 10% will be 73 patients. Clinical trial information: NCT04864067 .

International real-world study of TOTAL neoadjuvant therapy (TNT) for locally advanced rectal cancer (LARC).

40 Background: TNT has recently emerged as a standard treatment for LARC. However, use and outcome of the different TNT regimens in real-world practice are largely unknown. Methods: This is an international, multicentre, retrospective study sponsored by the Institut Jules Bordet, Brussels. Eligibility was limited to newly diagnosed LARC patients treated with TNT between March 2013 and May 2023 and outside the context of a clinical trial. The primary objective was to describe real-word practice across international centres. Secondary objectives included treatment safety and efficacy. Data were collected into a central electronic database, and remotely monitored. Descriptive statistics were used, and survival outcomes were estimated with Kaplan-Meier curves. Results: 1,272 eligible patients were included from 47 centres across four continents (Europe, Asia, North America and South America). Baseline characteristics were as follows: 63% males, median age 60 years (range 21-88), 47% low rectum, 26% cT4, 47% cN2, 49% EMVI+, 59% CRM+. In the overall population, 21% of the resected patients had a pathological complete response (pCR), while 11.3% were managed according to a watch-&-wait (w&w) strategy. Median follow-up was 24.1 months (IQR 23.7). Local and distant recurrences after curative-intent surgery occurred in 5.5% and 16.2% of patients, respectively. 3-year event-free survival (EFS) was 68.3%, while 3-year overall survival (OS) was 89%. Serious adverse events were reported in 4.3% of patients during radiotherapy, and in 14.7% during chemotherapy. Patient distribution according to the TNT sequence/regimen, and respective efficacy outcomes are reported in the table. Conclusions: This is the largest real-world study of TNT for LARC. Our findings show substantial variation in the choice of TNT sequence and regimen. Efficacy and safety results are overall in line with those reported in clinical trials, and confirm feasibility of TNT in a real-world setting. Patient recruitment is ongoing, and updated results with propensity score matching analyses will be reported at the meeting. [Table: see text]

Impact of Neoadjuvant Radiochemotherapy on Pathological Complete Response for Locally Advanced Rectal Cancer: A Mono Institutional Experience.

Neoadjuvant radiochemotherapy followed by surgery is a standard of care in locally advanced rectal cancer (LARC). Only a subgroup of patients can obtain a pathological complete response (pCR) and achieve good local control. However, the role of pCR on patient survival is debated. The aim of the study was to evaluate the impact of pCR on clinical outcomes and toxicities in LARC patients treated with dose intensification and concomitant capecitabine treatment in a neoadjuvant radiochemotherapy schedule. This was a single Institution retrospective study including 178 patients. Mandard tumor regression grade (TRG) and pTNM staging system were used to classify pathological response and define pathological complete response (pCR). Patients were divided in: pCR (pT0N0) and Not-pCR (pT>0N>0), according to pTNM and in good responders (TRG1-2) and partial/not responders (TRG3-5), according to Mandard TRG. The Kaplan-Meier method was used to estimate OS, CSS, DFS and LC. A low severe toxicity rate was observed. Acute Grade 3 lower bowel toxicity and Grade 3 cutaneous toxicity were reported in 2 (1.1%) patients, respectively. Late Grade >3 lower bowel toxicity was reported in 6 patients (3%) and late Grade >3 cutaneous toxicity was registered in one patient. No other severe acute and late toxicities were reported. The 5- and 10-year OS, CSS, DFS and LC rates were 85% and 75%, 94% and 92%, 83% and 81%, 88% and 88%, respectively. We observed a pCR rate of 36% and a good responders rate of 62%, in our study population. Both groups showed better rates for each analyzed clinical outcome. Neoadjuvant radiochemotherapy with dose intensification in LARC patients resulted in favorable long-term oncological outcomes, pCR rate showed an optimal impact on OS and DFS with an acceptable toxicity.