Lateral node metastasis in low rectal cancer as a hallmark to predict recurrence patterns.

BACKGROUND: Lateral node metastasis confers a poor prognosis in rectal cancer. Several multidisciplinary treatments have been proposed with favorable outcomes. However, appropriate neoadjuvant/adjuvant treatments or follow-up plans based on information about the probable recurrence site have not been specified. We aimed to clarify the distinctive features of recurrence patterns for lateral node-positive low rectal cancer according to the lateral and mesorectal lymph node status. METHODS: We retrospectively analyzed 508 patients with stage III low rectal cancer who underwent lateral node dissection. We investigated the impact of lateral and mesorectal lymph node status on site-specific recurrence rates and patient survival. RESULTS: Analyses for relapse-free survival revealed the prognostic impact of lateral node positivity in stage III low rectal cancer (p < 0.0001). Lateral node-positive patients exhibited higher risk of overall recurrence, local recurrence, and recurrence in extra-regional nodes than lateral node-negative patients (p < 0.0001, p = 0.001, and p < 0.0001, respectively). However, lateral node positivity was not statistically associated with a hematogenous recurrence rate. In lateral node-positive patients, both tumor-node-metastasis (TNM)-N status and number of lateral nodes involved were revealed as significant prognostic factors (p < 0.0001, both). In addition, the number of lateral nodes involved could be a discriminatory indicator of probabilities of local recurrence and recurrence in extra-regional nodes (p = 0.02, and p < 0.0001, respectively). CONCLUSIONS: Lateral node-positive low rectal cancer exhibits higher local recurrence and extra-regional node recurrence rates that correlate with the number of lateral nodes involved.

HLA Class I Analysis Provides Insight Into the Genetic and Epigenetic Background of Immune Evasion in Colorectal Cancer With High Microsatellite Instability.

BACKGROUND & AIMS: A detailed understanding of antitumor immunity is essential for optimal cancer immune therapy. Although defective mutations in the B2M and HLA-ABC genes, which encode molecules essential for antigen presentation, have been reported in several studies, the effects of these defects on tumor immunity have not been quantitatively evaluated. METHODS: Mutations in HLA-ABC genes were analyzed in 114 microsatellite instability-high colorectal cancers using a long-read sequencer. The data were further analyzed in combination with whole-exome sequencing, transcriptome sequencing, DNA methylation array, and immunohistochemistry data. RESULTS: We detected 101 truncating mutations in 57 tumors (50%) and loss of 61 alleles in 21 tumors (18%). Based on the integrated analysis that enabled the immunologic subclassification of microsatellite instability-high colorectal cancers, we identified a subtype of tumors in which lymphocyte infiltration was reduced, partly due to reduced expression of HLA-ABC genes in the absence of apparent genetic alterations. Survival time of patients with such tumors was shorter than in patients with other tumor types. Paradoxically, tumor mutation burden was highest in the subtype, suggesting that the immunogenic effect of accumulating mutations was counterbalanced by mutations that weakened immunoreactivity. Various genetic and epigenetic alterations, including frameshift mutations in RFX5 and promoter methylation of PSMB8 and HLA-A, converged on reduced expression of HLA-ABC genes. CONCLUSIONS: Our detailed immunogenomic analysis provides information that will facilitate the improvement and development of cancer immunotherapy.

Enhanced Clinical Utility of Molecular Budding Signature as a Recurrence Risk Determinant in Stage II and III Colon Cancer Patients.

BACKGROUND: A molecular budding signature (MBS), which consists of seven tumor budding-related genes, was recently presented as a prominent prognostic indicator in colon cancer (CC) using microarray data acquired from frozen specimens. This study aimed to confirm the predictive power of MBS for recurrence risk based on formalin-fixed, paraffin-embedded (FFPE) materials. METHODS: This research utilized the same microarray data from a prior multicenter study using FFPE whole tissue sections, which retrospectively reviewed 232 stage II CC patients without adjuvant chemotherapy and 302 stage III CC patients with adjuvant chemotherapy. All patients underwent upfront curative surgery without neoadjuvant therapy between 2009 and 2012. An MBS score was calculated using the mean of log2 [each signal] of seven genes (MSLN, SLC4A11, WNT11, SCEL, RUNX2, MGAT3, and FOXC1) as described before. RESULTS: The MBS-low group exhibited a better relapse-free survival (RFS) than the MBS-high group in stage II (P = 0.0077) and in stage III CC patients (P = 0.0003). Multivariate analyses revealed that the MBS score was an independent prognostic factor in both stage II (P = 0.0257) and stage III patients (P = 0.0022). Especially among T4, N2, or both (high-risk) stage III patients, the MBS-low group demonstrated markedly better RFS compared with the MBS-high group (P = 0.0013). CONCLUSIONS: This study confirmed the predictive power of the MBS for recurrence risk by employing FFPE materials in stage II/III CC patients.

Development of a Diagnostic Artificial Intelligence Tool for Lateral Lymph Node Metastasis in Advanced Rectal Cancer.

BACKGROUND: Metastatic lateral lymph node dissection can improve survival in patients with rectal adenocarcinoma, with or without chemoradiotherapy. However, the optimal imaging diagnostic criteria for lateral lymph node metastases remain undetermined. OBJECTIVE: To develop a lateral lymph node metastasis diagnostic artificial intelligence tool using deep learning, for patients with rectal adenocarcinoma who underwent radical surgery and lateral lymph node dissection. DESIGN: Retrospective study. SETTINGS: Multicenter study. PATIENTS: A total of 209 patients with rectal adenocarcinoma, who underwent radical surgery and lateral lymph node dissection at 15 participating hospitals, were enrolled in the study and allocated to training (n = 139), test (n = 17), or validation (n = 53) cohorts. MAIN OUTCOME MEASURES: In the neoadjuvant treatment group, images taken before pretreatment were classified as baseline images and those taken after pretreatment as presurgery images. In the upfront surgery group, presurgery images were classified as both baseline and presurgery images. We constructed 2 types of artificial intelligence, using baseline and presurgery images, by inputting the patches from these images into ResNet-18, and we assessed their diagnostic accuracy. RESULTS: Overall, 124 patients underwent surgery alone, 52 received neoadjuvant chemotherapy, and 33 received chemoradiotherapy. The number of resected lateral lymph nodes in the training, test, and validation cohorts was 2418, 279, and 850, respectively. The metastatic rates were 2.8%, 0.7%, and 3.7%, respectively. In the validation cohort, the precision-recall area under the curve was 0.870 and 0.963 for the baseline and presurgery images, respectively. Although both baseline and presurgery images provided good accuracy for diagnosing lateral lymph node metastases, the accuracy of presurgery images was better than that of baseline images. LIMITATIONS: The number of cases is small. CONCLUSIONS: An artificial intelligence tool is a promising tool for diagnosing lateral lymph node metastasis with high accuracy. DESARROLLO DE UNA HERRAMIENTA DE INTELIGENCIA ARTIFICIAL PARA EL DIAGNSTICO DE METSTASIS EN GANGLIOS LINFTICOS LATERALES EN CNCER DE RECTO AVANZADO: ANTECEDENTES:Disección de nódulos linfáticos laterales metastásicos puede mejorar la supervivencia en pacientes con adenocarcinoma del recto, con o sin quimiorradioterapia. Sin embargo, aún no se han determinado los criterios óptimos de diagnóstico por imágenes de los nódulos linfáticos laterales metastásicos.OBJETIVO:Nuestro objetivo fue desarrollar una herramienta de inteligencia artificial para el diagnóstico de metástasis en nódulos linfáticos laterales mediante el aprendizaje profundo, para pacientes con adenocarcinoma del recto que se sometieron a cirugía radical y disección de nódulos linfáticos laterales.DISEÑO:Estudio retrospectivo.AJUSTES:Estudio multicéntrico.PACIENTES:Un total de 209 pacientes con adenocarcinoma del recto, que se sometieron a cirugía radical y disección de nódulos linfáticos laterales en 15 hospitales participantes, se inscribieron en el estudio y se asignaron a cohortes de entrenamiento (n = 139), prueba (n = 17) o validación (n = 53).PRINCIPALES MEDIDAS DE RESULTADO:En el grupo de tratamiento neoadyuvante, las imágenes tomadas antes del tratamiento se clasificaron como imágenes de referencia y las posteriores al tratamiento, como imágenes previas a la cirugía. En el grupo de cirugía inicial, las imágenes previas a la cirugía se clasificaron como imágenes de referencia y previas a la cirugía. Construimos dos tipos de inteligencia artificial, utilizando imágenes de referencia y previas a la cirugía, ingresando los parches de estas imágenes en ResNet-18. Evaluamos la precisión diagnóstica de los dos tipos de inteligencia artificial.RESULTADOS:En general, 124 pacientes se sometieron a cirugía solamente, 52 recibieron quimioterapia neoadyuvante y 33 recibieron quimiorradioterapia. El número de nódulos linfáticos laterales removidos en los cohortes de entrenamiento, prueba y validación fue de 2,418; 279 y 850, respectivamente. Las tasas metastásicas fueron 2.8%, 0.7%, y 3.7%, respectivamente. En el cohorte de validación, el área de recuperación de precisión bajo la curva fue de 0.870 y 0.963 para las imágenes de referencia y antes de la cirugía, respectivamente. Aunque tanto las imágenes previas a la cirugía como las iniciales proporcionaron una buena precisión para diagnosticar metástasis en los nódulos linfáticos laterales, la precisión de las imágenes previas a la cirugía fue mejor que la de las imágenes iniciales.LIMITACIONES:El número de casos es pequeño.CONCLUSIÓN:La inteligencia artificial es una herramienta prometedora para diagnosticar metástasis en los nódulos linfáticos laterales con alta precisión. (Traducción-Dr. Aurian Garcia Gonzalez ).

Analysis of Circulating DNA to Assess Prognoses for Metastatic Colorectal Cancer Patients Treated with Regorafenib Dose-Escalation Therapy: A Retrospective, Exploratory Analysis of the RECC Trial.

INTRODUCTION: Regorafenib is a multi-kinase inhibitor approved for patients with metastatic colorectal cancer (mCRC) who were previously treated with standard therapies. A few reports showed the impact of KRAS mutation on therapeutic efficacy of regorafenib. Only one study reported poor prognoses for patients treated with regorafenib who had large amounts of circulating cell-free DNA (cfDNA). In the present study, we evaluated the impact of KRAS mutations in tissue or plasma and amounts of cfDNA on prognoses of mCRC patients treated with regorafenib. METHOD: This is a biomarker investigation of the RECC study, which evaluated efficacy of regorafenib dose-escalation therapy. Plasma samples were obtained just before initiation of treatment with regorafenib. KRAS mutations were evaluated using tissue and plasma samples. cfDNA was extracted from plasma samples and quantified. RESULTS: Forty-five patients were enrolled in this biomarker study. Median progression-free survival (PFS) and overall survival (OS) of patients without KRAS mutations in tissues were 1.9 months (95% confidence interval [CI] 1.7-2.0) and 8.9 months (95% CI: 6.5-11.2), and those of patients with KRAS mutations were 1.4 months (95% CI: 1.3-1.5) and 6.8 months (95% CI: 5.0-8.5). Median PFS and OS of patients with plasma KRAS mutations were 1.9 months (95% CI: 1.8-1.9) and 7.0 months (95% CI: 5.3-8.7), respectively. Median PFS and OS of patients without plasma KRAS mutations were 1.7 months (95% CI: 1.1-2.3) and 8.9 months (95% CI: 6.7-11.2), respectively. Prior to administration of regorafenib, KRAS mutations were detected in 6 of 16 (37.5%) patients who had no tissue KRAS mutations. Median OS of patients with high cfDNA concentration (>median) was significantly poorer than that of patients with low cfDNA. CONCLUSION: KRAS mutations in the tissue or plasma have no impact on efficacy of regorafenib. KRAS emerging mutations were observed in quite a few patients. Large amounts of cfDNA may indicate poorer prognoses for patients receiving late-line regorafenib chemotherapy.

Impact of early tumor shrinkage on quality of life in patients treated with first-line cetuximab plus chemotherapy for unresectable metastatic colorectal cancer: results of Phase II QUACK trial.

PURPOSE: Although early tumor shrinkage (ETS) is a predictor of improved overall survival (OS), the association between ETS and health-related quality of life (HRQOL) remains unclear for patients with metastatic colorectal cancer (mCRC) treated with first-line cetuximab plus chemotherapy. METHODS: The data were collected from a prospective trial that assessed HRQOL using the EORTC QLQ-C30. The impact of ETS on HRQOL was estimated using a linear mixed-effects model for repeated measures. RESULTS: ETS was achieved in 82 (64.1%) of 128 mCRC patients treated with first-line cetuximab plus chemotherapy, and these patients had a significantly longer OS than those without ETS (HR, 0.38; 95% CI, 0.20-0.72; P = .002). Asymptomatic patients with ETS had a favorable OS, while symptomatic patients without ETS had a worse OS (2-year OS rates, 77.8% vs. 42.5%). Symptomatic patients with ETS had similar outcomes as asymptomatic patients without ETS (2-year OS rates, 64.1% vs. 67.0%). For symptomatic patients, ETS was associated with improved HRQOL scores between baseline and 8 weeks: the mean changes for patients with and without ETS were 5.86 and -4.94 for global health status (GHS)/QOL, 26.73 and 3.79 for physical functioning, and 13.58 and -3.10 for social functioning, respectively. The improved HRQOL was comparable to that of asymptomatic patients without ETS. For asymptomatic patients, ETS showed a decreased deterioration in HRQOL. CONCLUSION: Our findings highlight the importance of ETS for HRQOL and prognostic estimates, and assessing ETS may provide clinically useful information for physicians and patients to make more informed decisions.

Efficacy and safety of regorafenib dose-escalation therapy for Japanese patients with refractory metastatic colorectal cancer (RECC study).

BACKGROUND: Regorafenib significantly improves overall survival in previously treated metastatic colorectal cancer patients. However, various toxicities, such as hand-foot skin reaction (HFSR), fatigue, and liver dysfunction have limited the use of regorafenib. These toxicities appear soon after treatment initiation. The ReDOS study demonstrated the effectiveness of a weekly dose-escalation therapy of regorafenib starting with a lower daily dose; however, its usefulness in Asian subjects is unknown. We conducted a phase II study to evaluate the safety and survival benefit of regorafenib dose-escalation therapy for Japanese patients. METHODS: Patients with sufficient organ function, who had previously received more than two lines of chemotherapy were included. Regorafenib was started at 80 mg/day and escalated to 120 mg/day in Week 2 and 160 mg/day in Week 3, if no severe drug-related toxicities were observed. The primary endpoint was cancer progression-free survival (PFS). Tumor response and progression were assessed radiologically every 8 weeks. This study was registered in the University Hospital Medical Information Network (UMIN#UMIN000028933). RESULTS: 57 patients were enrolled and all started regorafenib at 80 mg/day. 32 patients (56.1%) were subsequently escalated to 120 mg/day and 19 (33.3%) to 160 mg/day. Only 8 patients (14.0%) discontinued treatment because of adverse events. Median PFS was 1.9 months. Median overall survival was 8.9 months, the response rate was 0%, and the disease control rate was 31.6%. The most frequent adverse event greater than grade 3 was hypertension (19.3%), followed by HFSR (14.0%). CONCLUSIONS: Regorafenib dose-escalation therapy is well tolerated with PFS-like regorafenib standard therapy.

Evaluation of a 55-gene classifier as a prognostic biomarker for adjuvant chemotherapy in stage III colon cancer patients.

BACKGROUND: Adjuvant chemotherapy reduces the risk of recurrence of stage III colon cancer (CC). However, more effective prognostic and predictive biomarkers are needed for better treatment stratification of affected patients. Here, we constructed a 55-gene classifier (55GC) and investigated its utility for classifying patients with stage III CC. METHODS: We retrospectively identified patients aged 20-79 years, with stage III CC, who received adjuvant chemotherapy with or without oxaliplatin, between the years 2009 and 2012. RESULTS: Among 938 eligible patients, 203 and 201 patients who received adjuvant chemotherapy with and without oxaliplatin, respectively, were selected by propensity score matching. Of these, 95 patients from each group were analyzed, and their 5-year relapse-free survival (RFS) rates with and without oxaliplatin were 73.7 and 77.1%, respectively. The hazard ratios for 5-year RFS following adjuvant chemotherapy (fluoropyrimidine), with and without oxaliplatin, were 1.241 (95% CI, 0.465-3.308; P = 0.67) and 0.791 (95% CI, 0.329-1.901; P = 0.60), respectively. Stratification using the 55GC revealed that 52 (27.3%), 78 (41.1%), and 60 (31.6%) patients had microsatellite instability (MSI)-like, chromosomal instability (CIN)-like, and stromal subtypes, respectively. The 5-year RFS rates were 84.3 and 72.0% in patients treated with and without oxaliplatin, respectively, for the MSI-like subtype (HR, 0.495; 95% CI, 0.145-1.692; P = 0.25). No differences in RFS rates were noted in the CIN-like or stromal subtypes. Stratification by cancer sidedness for each subtype showed improved RFS only in patients with left-sided primary cancer treated with oxaliplatin for the MSI-like subtype (P = 0.007). The 5-year RFS rates of the MSI-like subtype in left-sided cancer patients were 100 and 53.9% with and without oxaliplatin, respectively. CONCLUSIONS: Subclassification using 55GC and tumor sidedness revealed increased RFS in patients within the MSI-like subtype with stage III left-sided CC treated with fluoropyrimidine and oxaliplatin compared to those treated without oxaliplatin. However, the predictive power of 55GC subtyping alone did not reach statistical significance in this cohort, warranting larger prospective studies. TRIAL REGISTRATION: The study protocol was registered in the University Hospital Medical Education Network (UMIN) clinical trial registry (UMIN study ID: 000023879 ).

The robust performance of carcinoembryonic antigen levels after adjuvant chemotherapy for the recurrence risk stratification in patients with colorectal cancer.

BACKGROUND AND OBJECTIVES: Most guidelines of colorectal cancers (CRCs) recommend evaluating the serum carcinoembryonic antigen (CEA) level during postoperative surveillance to detect tumor recurrence, which originates from postsurgery residual tumor cells. We hypothesized that the postadjuvant chemotherapy CEA level may be the most accurate biomarker to predict tumor recurrence, and we evaluated the prognostic significance of the postadjuvant chemotherapy CEA level in patients with stage II and III CRCs. PATIENTS AND METHODS: We retrospectively analyzed the cases of 150 Stage II-III CRC patients who had undergone curative surgery and adjuvant chemotherapy. Preoperative, postoperative, and postadjuvant chemotherapy CEA levels were evaluated, and their associations with recurrence-free survival (RFS) were assessed. RESULTS: The Kaplan-Meier curves showed that a high preoperative CEA level, high postoperative CEA, and high postadjuvant chemotherapy CEA were associated with poor RFS (p = .001, .0001, and .001, respectively). The multivariate analysis demonstrated that high postadjuvant chemotherapy CEA was an independent factor for poor RFS (HR 2.55, 95% confidence interval: 1.08-6.05, p = .033), whereas high preoperative and postoperative CEA levels were not. CONCLUSIONS: The serum levels of postadjuvant chemotherapy CEA were a strong prognostic biomarker in patients with Stage II-III CRCs who had undergone surgery followed by adjuvant chemotherapy.

Proposal for a post-operative surveillance strategy for stage I colorectal cancer patients based on a novel recurrence risk stratification: a multicenter retrospective study.

BACKGROUND: The recurrent risk of stage I colorectal cancer (CRC) is not clear, and the data regarding appropriate post-operative surveillance schedules in stage I CRC are scarce. OBJECTIVES: We aimed to stratify stage I CRC based on the recurrence risk and evaluate optimal post-operative surveillance durations based on this stratification. METHODS: We retrospectively analyzed the cases of 6607 stage I CRC patients from 24 institutions. To assess the patients' clinicopathological factors that impact recurrence-free survival (RFS), we performed univariate and multivariate analyses using Cox proportional hazards models. We divided the patients into classes based on their numbers of factors that were associated with poor RFI in the multivariate analysis. RESULTS: Recurrence occurred in 3.9% patients. The multivariate analysis revealed the independent factors for poor RFS: rectal cancer, T2 depth, presence of lymphatic invasion, high level of pre-operative carcinoembryonic antigen, and absence of D2-3 lymphadenectomy. We also divided the patients into three classes based on their numbers of these risk factors; the 3-year and 5-year RFS rates were 99.3% and 99.1% in the no-risk patients, 97.4% and 96.5% in the patients with 1-2 risks, and 92.1% and 90.0% in the patients with 3-5 risks, respectively. In the patients with no risk and in the patients with 1-2 risks after 3 years post-surgery, ≤ 1% recurrence occurred. Thus, post-operative surveillance may be omitted in these populations. CONCLUSIONS: Our new classification properly stratified the recurrence risks of stage I CRC patients, and may help reduce unnecessary post-operative surveillance.

Japanese Society for Cancer of the Colon and Rectum (JSCCR) guidelines 2020 for the Clinical Practice of Hereditary Colorectal Cancer.

Hereditary colorectal cancer (HCRC) accounts for < 5% of all colorectal cancer cases. Some of the unique characteristics commonly encountered in HCRC cases include early age of onset, synchronous/metachronous cancer occurrence, and multiple cancers in other organs. These characteristics necessitate different management approaches, including diagnosis, treatment or surveillance, from sporadic colorectal cancer management. There are two representative HCRC, named familial adenomatous polyposis and Lynch syndrome. Other than these two HCRC syndromes, related disorders have also been reported. Several guidelines for hereditary disorders have already been published worldwide. In Japan, the first guideline for HCRC was prepared by the Japanese Society for Cancer of the Colon and Rectum (JSCCR), published in 2012 and revised in 2016. This revised version of the guideline was immediately translated into English and published in 2017. Since then, several new findings and novel disease concepts related to HCRC have been discovered. The currently diagnosed HCRC rate in daily clinical practice is relatively low; however, this is predicted to increase in the era of cancer genomic medicine, with the advancement of cancer multi-gene panel testing or whole genome testing, among others. Under these circumstances, the JSCCR guidelines 2020 for HCRC were prepared by consensus among members of the JSCCR HCRC Guideline Committee, based on a careful review of the evidence retrieved from literature searches, and considering the medical health insurance system and actual clinical practice settings in Japan. Herein, we present the English version of the JSCCR guidelines 2020 for HCRC.

A Multicenter Phase 2 Trial to Evaluate the Efficacy of mFOLFOX6 + Cetuximab as Induction Chemotherapy to Achieve R0 Surgical Resection for Advanced Colorectal Liver Metastases (NEXTO Trial).

BACKGROUND: The effect of cetuximab plus mFOLFOX on downsizing of the tumors for curative resection has yet to be assessed for patients with advanced colorectal liver metastases (CRLMs). This study aimed to assess the oncologic benefit of cetuximab plus mFOLFOX for wild-type KRAS patients with advanced CRLMs. METHODS: In this multicenter phase 2 trial, patients with technically unresectable tumor and/or five or more CRLMs harboring wild-type KRAS were treated with mFOLFOX plus cetuximab. The patients were assessed for resectability after 4 treatments, and then every 2 months up to 12 treatments. Patients with resectable disease were offered surgery after a waiting period of 1 month. The primary end point of the study was the R0 resection rate. The secondary end points were safety, progression-free survival (PFS), and overall survival (OS). The study is registered with the University Hospital Medical Information Network-Clinical Trials Registry Clinical Trials Registry (no. C000007923). RESULTS: Between 2012 and 2015, 50 patients from 13 centers were enrolled in this trial. Two patients were excluded because they had not received induction therapy. The 48 patients had a complete response rate of 0% and a partial response rate of 64.6%. For 26 R0 resections (54.2%) and 5 R1 resections (10.4%), no mortality occurred. During a median follow-up period of 31 months, the median OS for all the patients was calculated to be 41 months (95% confidence interval, 28-not reached). The 3-year OS rate was 59%. CONCLUSION: For patients with advanced CRLMs harboring wild-type KRAS, cetuximab administered in combination with mFOLFOX yields high response rates, leading to significantly high R0 resection rates and favorable prognoses.

A Validation Study for Recurrence Risk Stratification of Stage II Colon Cancer Using the 55-Gene Classifier.

INTRODUCTION: DNA microarrays, such as the consensus molecular subtype (CMS) classification using >600 genes, are used to predict cancer patient prognosis. We recently constructed a simple 55-gene classifier (55GC) system to risk stratify colon cancer (CC). OBJECTIVE: Here, we validate the 55GC specifically for stage II CC and compare it with CMS categories. METHODS: Tissue sections from 232 stage II CC patients who underwent curative surgery without adjuvant chemotherapy between 2009 and 2012 were subjected to DNA microarray analysis. RESULTS: Based on the 55GC, patients were classified into microsatellite instability-like (27%), chromosomal instability-like (41%), and stromal (32%) subtypes with 5-year relapse-free survival (RFS) rates of 88.5, 83.3, and 71.2%, respectively (stromal vs. others: p = 0.0049). Multivariate analysis by Cox's proportional hazard model revealed that the stromal subtype, pT4, and the number of lymph nodes examined (<12) were independent poor prognostic factors. The overall concordance rate between 55GC and CMS was 72%, and 5-year RFS rates of patients with CMS1, CMS2, CMS3, and CMS4 cancers were 100, 85.5, 92.3, and 73.0%, respectively (p = 0.0113). CONCLUSIONS: We conclude that the 55GC is a useful and reproducible grading system for stage II CC recurrence risk stratification.

Significance of the 7th postoperative day neutrophil-to-lymphocyte ratio in colorectal cancer.

PURPOSE: High neutrophil-to-lymphocyte ratio (NLR) is a marker of systemic inflammation and is associated with poor survival in localized or metastatic cancer. Preoperative NLR in colorectal cancer reportedly correlates with recurrence-free survival and is useful as a recurrence prediction factor. No reports have yet investigated recurrence factors using postoperative NLR. This study assessed the predictive value of NLR preoperatively and on the first (NLR1) and seventh day (NLR7) postoperatively in patients with stage II colorectal cancer. METHODS: We performed a retrospective cohort study involving patients undergoing colorectal resection at a single institution between January 2012 and December 2016; we used medical records of 176 consecutive patients with stage II colorectal cancer undergoing curative tumor resection. NLRs as well as clinical, histopathologic, and laboratory data were analyzed. Univariate and multivariate analyses were conducted to identify prognostic factors associated with recurrence-free survival (RFS). RESULTS: Univariate analysis revealed that elevated NLR, NLR7, and lymphatic invasion were significantly associated with decreased RFS (p < 0.05). NLR7 was revealed as significant via multivariate analysis (p = 0.013). The 3-year RFS rate was 87.1% for patients with normal NLR7 and 70.3% for those with elevated NLR7. CONCLUSION: Elevated seventh-day postoperative NLR is a significant independent predictor of reduced RFS for patients with stage II colorectal cancer and may be a potential biomarker for identifying candidates for adjuvant chemotherapy.

Japanese Society for Cancer of the Colon and Rectum (JSCCR) guidelines 2019 for the treatment of colorectal cancer.

The number of deaths from colorectal cancer in Japan continues to increase. Colorectal cancer deaths exceeded 50,000 in 2016. In the 2019 edition, revision of all aspects of treatments was performed, with corrections and additions made based on knowledge acquired since the 2016 version (drug therapy) and the 2014 version (other treatments). The Japanese Society for Cancer of the Colon and Rectum guidelines 2019 for the treatment of colorectal cancer (JSCCR guidelines 2019) have been prepared to show standard treatment strategies for colorectal cancer, to eliminate disparities among institutions in terms of treatment, to eliminate unnecessary treatment and insufficient treatment and to deepen mutual understanding between healthcare professionals and patients by making these guidelines available to the general public. These guidelines have been prepared by consensuses reached by the JSCCR Guideline Committee, based on a careful review of the evidence retrieved by literature searches and in view of the medical health insurance system and actual clinical practice settings in Japan. Therefore, these guidelines can be used as a tool for treating colorectal cancer in actual clinical practice settings. More specifically, they can be used as a guide to obtaining informed consent from patients and choosing the method of treatment for each patient. Controversial issues were selected as clinical questions, and recommendations were made. Each recommendation is accompanied by a classification of the evidence and a classification of recommendation categories based on the consensus reached by the Guideline Committee members. Here, we present the English version of the JSCCR guidelines 2019.

Angiotensin I-converting enzyme inhibitors/angiotensin II receptor blockers may reduce tumor recurrence in left-sided and early colorectal cancers.

BACKGROUND: Angiotensin signaling is suggested to be involved in tumorigenesis, tumor proliferation, and metastases. In colorectal cancer (CRC), it was demonstrated that angiotensin I-converting enzyme inhibitors (ACEIs) and angiotensin II receptor blockers (ARBs) may reduce the risk of CRC; however, their impact on tumor recurrence remains unknown. Therefore, in this study, we evaluated the impact of ACEIs/ARBs on tumor recurrence in CRC patients. PATIENTS AND METHODS: We retrospectively investigated the clinicopathological data of 461 stage I-III CRC patients. We divided the patients into those who took an ACEI and/or ARB (the ACEI/ARB+ group) and those who did not (the ACEI/ARB- group), and we compared the two groups' recurrence-free survival (RFS) using a Kaplan-Meier curve analysis and log rank test. We also examined the impact of AGTR1 expression on tumor recurrence, using two public CRC datasets. RESULTS: The Kaplan-Meier curves showed a trend toward improved RFS in the ACEI/ARB+ group versus the ACEI/ARB- group (p = 0.063). Subgroup analyses demonstrated that the RFS was significantly better in the ACEI/ARB+ group versus the ACEI/ARB- group in the patients with left-sided CRC (p = 0.030) and those with stage I CRC (p = 0.009). Consistent with these findings, the AGTR1 expression was higher in the left-sided versus right-sided colon (p = 0.048). High AGTR1 expression levels were associated with poor RFS in the GSE39582 dataset's stage I-III CRC patients (p < 0.001), and this finding was also validated in the GSE17536 dataset (p = 0.023). CONCLUSION: ACEI/ARB treatment may reduce tumor recurrence in left-sided CRC and early-stage CRC.

G12V and G12C mutations in the gene KRAS are associated with a poorer prognosis in primary colorectal cancer.

PURPOSE: The increased incidence of colorectal cancer (CRC) has necessitated the development of novel prognostic and predictive factors from which new diagnostic tests could evolve. Evidence suggests the KRAS gene represents such a factor; its mutations are considered to be early indicators of CRC progression. This study assessed the prognostic impact of specific known KRAS codon 12/13 mutations on survival in patients with CRC. METHODS: Formalin-fixed paraffin-embedded tissue blocks or sections from primary were obtained from patients registered between 2014 and 2016 for genomic DNA extraction. KRAS gene was analyzed by direct sequencing or Luminex assay. The primary endpoint was the frequency of KRAS gene mutations and the secondary endpoints were differences in KRAS mutation rates by various stratification factors. Univariate and multivariate analyses were performed to investigate relationships between KRAS mutation rates and patient background factors. RESULTS: Sequencing of 200 CRC primary tumor samples demonstrated 74 (37.5%) with KRAS mutations in codons 12 (77%; 57/74) and 13 (23%; 17/74), all of which were TNM stages I-III. Tumors with KRAS mutations were more frequently located in the right side of the colon. Multivariate analysis indicated that G12V or G12C mutations were associated with poor prognosis [hazard ratio (HR) = 3.77, 95% confidence interval (CI), 1.54-8.39 and HR = 6.57; 95% CI, 1.90-17.7, respectively] in terms of recurrence-free survival. CONCLUSION: KRAS codon 12G-to-V or G-to-C mutations are independent prognostic factors in patients with stage I-III CRC.

A case of intussusception developed at the site of ileocolic anastomosis after laparoscopic right hemicolectomy.

BACKGROUND: Intussusception is a relatively common condition seen in children. In comparison, adult intussusception is rare and usually occurs as a complication in patients with organic diseases. It is responsible for 1% of all bowel obstructions, in most of intussusceptions a malignant tumor is involved. Herein, we present an extremely unusual case of intussusception that occurred as a complication at the site of a functional end-to-end anastomosis. CASE PRESENTATION: A 57-year-old female patient was diagnosed with tumors in the ascending and descending colon and was referred to our department. Laparoscopic hemicolectomy and laparoscopic descending colectomy were performed. The mechanical intestinal obstruction occurred on the 9th day postoperatively, and computed tomography scan revealed intussusception at the site of the ileocolic anastomosis. Endoscopic reduction was attempted, but the procedure was challenging. Surgery was then performed and revealed that the site of ileocolic anastomosis firmly adhered to the side wall and right retroperitoneum. However, the intestine in the oral side of the anastomosis was not fixed. Examination of the anastomotic site revealed that the ileum had passed through the anastomosis and prolapsed into the transverse colon. The ileocolic anastomosis was resected. End-to-end anastomosis was performed, and surgery was then completed. No neoplastic lesions were observed in the resected tissue of the lead point of intussusception. The postoperative clinical course was favorable, and the patient was discharged on the 11th day after the second round of surgery. CONCLUSIONS: There are no reports the anastomosis is involved as part of the intussception, as observed in the present case. Intussusception should thus be considered as one of the causes of postoperative mechanical intestinal obstruction.

A New N Staging System for Colorectal Cancer in the Era of Extended Lymphadenectomy.

BACKGROUND: Complete mesocolic excision is becoming popular in colon cancer surgery in Western countries, and in the tumor-node-metastasis (TNM) classification of rectal cancer, a part of the lateral pelvic lymph nodes is classified as regional. However, the appropriateness of TNM staging according to the assessment of nodal status exclusively by extended lymphadenectomy remains unclear. PATIENTS AND METHODS: Using a nationwide multicenter database in Japan, we retrospectively analyzed 6866 patients with stage III colorectal cancer (CRC) treated with extended (D3) dissection. First, the best cutoff values for the number of metastatic nodes were explored. Second, the utility of the metastatic status of the main lymph nodes (i.e., at the origin of the feeding artery) and the lateral pelvic lymph nodes ("jN3" category in the Japanese staging system) as N staging criteria was evaluated. The modified N staging system that had the best risk stratification power was determined according to the Akaike information criterion (AIC). RESULTS: Excellent performance was noted when the number of metastatic nodes was categorized by cutoff values of "3/4" and "6/7." Categorization of nodal metastasis was proven the most clinically efficacious when classified as modified-N1 (N1 and jN3-negative), modified-N2a (N2a and jN3-negative), and modified-N2b (N2b and/or jN3-positive; AIC, 22,810.8), rather than the classification based on the TNM (AIC, 22,849.2) or Japanese staging system (AIC, 22,811.1). CONCLUSIONS: We structured a modified N staging system according to the number and extent of lymph node metastases. The modified system may be used in stage III cases for precise risk stratification.