Clinicopathological Features and Survival of Signet-Ring Cell Carcinoma and Mucinous Adenocarcinoma of Right Colon, Left Colon, and Rectum

Clinicopathological and prognostic features of colorectal mucinous adenocarcinomas: a systematic review and meta-analysis

BACKGROUND

Many studies have explored the clinicopathological features and prognosis between colorectal mucinous adenocarcinoma (MAC) and adenocarcinoma (AC) and have given different results. This meta-analysis summarizes previous evidence and evaluates the clinicopathological and prognostic features of MAC relative to AC in colorectal cancers (CRCs).

METHODS

The meta-analysis was conducted by searching the databases of PubMed, China National Knowledge Infrastructure (CNKI), WANFANG data, Embase, and Web of Science. Pooled odds ratios (ORs) and hazard ratios (HRs) and corresponding 95% confidence intervals (CIs) were calculated to assess the clinicopathological and prognostic differences between MAC and AC.

RESULTS

Fifty-six studies involving 803157 patients met the inclusion criteria and were included in this meta-analysis. The clinicopathological features of MAC were greatly different from AC, except for lymphatic invasion (OR = 1.07, 95% CI: 0.99-1.15, P = 0.09) and perineural invasion (OR = 0.92, 95% CI: 0.79-1.06, P = 0.09). Further investigation found that MAC predicted poor OS (HR = 1.04, 95% CI: 1.03-1.04, P < 0.01), but not DFS in CRCs (HR = 1.01,95% CI: 0.88- 1.17, P = 0.85). Subgroup analysis found that MAC was obviously correlated with OS in patients with different recruitment time, with tumor located in rectum, from different regions, with different sample sizes and with TNM stage in II, and calculated by different data types(P < 0.01).

CONCLUSIONS

This study shows that MAC displays obviously different clinicopathological features compared with AC. And MAC has a poor OS relative to AC but the DFS was comparable.

Biological and Clinical Characteristics of Proximal Colon Cancer: Far from Its Anatomical Subsite

Colorectal cancer is a heterogeneous disease which can be divided into proximal colon cancer, distal colon cancer and rectal cancer according to the anatomical location of the tumor. Each anatomical location of colorectal cancer exhibits distinct characteristics in terms of incidence, clinical manifestations, molecular phenotypes, treatment, and prognosis. Notably, proximal colon cancer differs significantly from cancers of other anatomical subsites. An increasing number of studies have highlighted the presence of unique tumor biological characteristics in proximal colon cancer. Gaining a deeper understanding of these characteristics will facilitate accurate diagnosis and treatment approaches.

Prognostic implications of T stage in different pathological types of colorectal cancer: an observational study using SEER population-based data

OBJECTIVES

Colorectal cancer (CRC) encompasses a spectrum of pathological types, each exhibiting distinct biological behaviours that challenge the conventional T-staging system's predictive efficiency. Thus, this study aims to explore the prognostic significance of the T stage across various CRC pathological types, seeking to unravel insights that could enhance prognostic assessment in this complex disease.

STUDY DESIGN

We performed a retrospective analysis using the Surveillance, Epidemiology, and End Results (SEER) database for primary CRC cases from 2010 to 2017.

SETTING

The SEER database, comprising data from various US regional and state cancer registries, identified 39 321 patients with CRC. Our analysis focused on the three most common CRC pathological types: adenocarcinoma (AC), mucinous adenocarcinoma (MC) and signet ring cell carcinoma (SR).

PRIMARY OUTCOME MEASURES

The study used Cox regression models to evaluate how different pathological characteristics impact mortality risk in patients with CRC. Time-dependent receiver operating characteristic curves were also applied to assess the prognostic accuracy of various tumour node metastasis (TNM)/non-mucinous (NM) stages.

RESULTS

We observed significant associations between T stage and mortality risk for patients with AC and MC. Notably, in comparison to those at T1 stage, patients with AC in the T4 stage demonstrated a 2.01-fold increase in mortality risk (HR=2.01, 95% CI: 1.89 to 2.15), while patients with MC at T4 stage showed a 1.42-fold increase (HR=1.42, 95% CI: 1.03 to 1.97). However, within the SR group, T stages did not independently impact survival, showing no significant distinction (HR=1.07, 95% CI: 0.59 to 1.95). Intriguingly, the traditional TNM staging systems demonstrated limited discriminatory power in predicting prognosis for patients with SR when compared with the more innovative NM staging systems.

CONCLUSIONS

This study uncovers important insights about the prognostic significance of the T stage in different types of CRC, highlighting the need for personalised assessments based on specific histological subtypes.

Clinicopathological characteristics and outcomes of colorectal mucinous adenocarcinoma: a retrospective analysis from China

Background

Mucinous adenocarcinoma (MAC) is a unique subtype of colorectal cancer and its prognostic value remains controversial. This study aimed to compare the clinicopathological characteristics and prognostic differences between patients with MAC and non-mucinous adenocarcinoma (NMAC).

Methods

674 patients with NMAC, 110 patients with adenocarcinoma with mucinous component (ACWM) and 77 patients with MAC between 2016-2019 were enrolled in the study. Univariate and multivariate Cox regression were performed to analyze the factors associated with prognosis. Predictive nomograms of overall survival (OS) and cancer-specific survival (CSS) for patients with colorectal adenocarcinoma were constructed. Confounding factors were eliminated by propensity score matching (PSM).

Results

Compared with patients with NMAC, patients with MAC were more likely to have a tumor located at the proximal colon, present with a larger tumor diameter, more advanced T stage, higher frequency of metastasis, deficiency of mismatch repair, and elevated preoperative carcinoembryonic antigen. Patients with MAC were related to worse OS (HR=2.53, 95%CI 1.73-3.68, p<0.01) and CSS (HR=3.09, 95%CI 2.10-4.57, p<0.01), which persisted after PSM. Subgroup analysis demonstrated that patients with left-sided or stage III/IV MAC exhibited a comparatively worse OS and CSS than those with NMAC. Furthermore, in patients with stage II with a high-risk factor and stage III MAC, adjuvant chemotherapy was associated with an improved OS, CSS, and RFS.

Conclusion

Compared with the NMAC phenotype, the MAC phenotype was an independent risk factor for poor prognosis in colorectal adenocarcinoma with worse OS and CSS, particularly patients with left-sided colorectal cancer and stage III/IV. However, patients with MAC can still benefit from adjuvant chemotherapy.

Preoperative metabolic parameters of 18F-FDG PET/CT are associated with TNM stage and prognosis of colorectal cancer patients

Background

Colorectal cancer (CRC) is the third most frequent cause of cancer-related death, while tumor/node/metastasis (TNM) stage of American Joint Committee on Cancer is the guideline of making treatment strategy and predicting survival. The aim of this study is to investigate the association of preoperative 2-deoxy-2[18F]fluoro-D-glucose positron emission tomography/computed tomography (18F-FDG PET/CT), TNM stage, and prognosis of patients with CRC.

Methods

From September 2016 to August 2022, a total of 132 patients were retrospectively and consecutively enrolled in this cross-sectional study, who were diagnosed as CRC by histopathology and received preoperative 18F-FDG PET/CT. Firstly, the correlation between the metabolic parameters and clinicopathological features of the primary tumors was investigated. Secondly, univariate and multivariate logistic regression analyses were used to estimate the odds ratio of the association between the clinical and metabolic parameters and the advanced TNM stage (stage III-IV). Thirdly, progression-free survival (PFS) was analyzed using Kaplan-Meier curves and Log-rank test.

Results

The results revealed that the metabolic tumor volume (MTV) >6.6 cm3 and serum carcinoembryonic antigen (CEA) >5.84 ng/mL were independently associated with advanced TNM stage (P=0.0009, 0.0011, respectively). Larger tumor size, higher tumor-to-liver standardized uptake value ratio, MTV, and total lesion glycolysis (TLG) were significantly correlated with advanced pT stage (stage 4), and higher TLG and MTV were significantly correlated with advanced pN stage (stage 1-2) (P<0.05), while no metabolic parameters were significantly correlated with metastasis status (P>0.05). Higher serum CEA and carbohydrate antigen 19-9 levels were significantly correlated with advanced pT, pN stage, and metastasis status (P<0.05). Patients were followed up for at least 1 year. The MTV >6.6 cm3 was significantly associated with worse PFS (P=0.032).

Conclusions

18F-FDG PET-CT can serve as a noninvasive tool for preoperatively staging CRC. The MTV >6.6 cm3 might be associated with advanced TNM stage and worse PFS.

Signet-ring cell carcinoma of the caecum: A case report

Colorectal cancer (CRC) ranks as the third most prevalent cancer globally, with adenocarcinomas being the most frequent type. Signet ring cell carcinoma (SRCC) is a very rare subtype of adenocarcinoma, it commonly occurs in the stomach. However, other digestive localizations are possible including the colon, rectum, and gallbladder. Herein, we report a rare case of a metastatic caecal SRCC in a young male patient, presented to our department for abdominal diffuse pain and distention evolving for 3 months, associated with remarkable weight loss and asthenia. The clinical examination revealed abundant ascites and abdominal tenderness. Laboratory tests showed an elevated C-reactive protein at 35 mg/l (normal value: <6 mg/l), a microcytic hypochromic anemia at 11.2 g/dl (normal value for a man > 13 g/dl), increased carcinoembryonic antigen (CEA) levels, as well as CA 19-9 and CA-125.The abdominal scan showed irregular and asymmetrical thickening with peripheral speculation of the caecum measuring 2.1 cm *5.8 cm. Additionally, adjacent adenopathies, abundant ascites, and peritoneal carcinomatosis were observed to be associated with suspicious bilateral pulmonary nodules and micronodules. The colonoscopy identified a bulging ulcerative tumor of the ileocecal valve extended to the ileum. Further histologic examination confirmed the presence of signet-ring cell carcinoma. The patient was referred to the medical oncology department to initiate palliative chemotherapy following a multidisciplinary consultation meeting. We can underline that SRCC of the caecum is a rare entity with a bad prognosis. Usually, the diagnosis is made at late stages due to the lack of obvious symptoms earlier.

Signet-ring colorectal carcinoma

Introduction. Colorectal cancer is the third most common cancer worldwide. Signet-ring carcinoma is an extremely rare subtype of colorectal cancer, with frequency ranges 0.3?4.6%. The diagnosis of this type of cancer is based on pathohistological analysis. Case outline. A 58-year-old patient was admitted due to abdominal pain and abdominal swelling. The physical findings indicated abdomen above the level of the chest, soft, painfully sensitive in the left hemiabdomen, with positive clinical signs of ascites. Laboratory analyzes indicated positive inflammatory syndrome, elevation of D-dimer and CA-19-9. Ascites analysis showed the presence of malignant cells. Computed tomography revealed hepatomegaly, liver steatosis, as well as multiple secondary deposits in the liver, ascites, and peritoneal implants. Colonoscopy showed ulceration of the right colon, which was covered with fibrin. The pathohistological findings indicated poorly differentiated, invasive adenocarcinoma of the signet ring carcinoma type. The patient was treated with analgesics, diuretics, proton pump inhibitors, beta 2 blockers, angiotensin-converting enzyme inhibitors, low-molecular-weight heparin, antibiotics, and supportive therapy. The patient was discharged after 10 days of hospitalization. He was presented to the multidisciplinary team, which decided on further symptomatic therapy. Conclusion. Signet-ring colon cancer is a rare, aggressive tumor with a poor prognosis. Although it is most often localized in the stomach, it is necessary to think about the colorectal localization of this tumor in the differential diagnosis of patients with colonic complaints, especially if they have ?alarm symptoms? and if they are younger.

Gastrointestinal signet ring cell malignancy: current advancement and future prospects

Globally, gastrointestinal cancer is the most widespread neoplastic disease and the primary contributor to cancer-associated fatalities. Gastrointestinal signet ring cell carcinoma (SRCC) exhibits unique distinguishing features in several aspects when compared to adenocarcinomas (ACs). The scarcity of signet ring cell carcinoma has resulted in a heightened significance of related clinical and molecular investigations. However, a comprehensive and systematic review of the clinical, molecular, therapeutic, and research aspects of this disease is currently absent. This review provides an overview of the latest developments in our understanding of the clinical and molecular features of gastrointestinal signet ring cell carcinoma (SRCC). Additionally, we have compiled a list of potential therapeutic targets or biomarkers, as well as an examination of the current treatment options and the possible mechanisms of formation.

Comparison of survival outcomes and survival prediction in patients with primary colorectal MANEC and primary colorectal SRCC: a population-based propensity-score matching study

PURPOSE

Primary mixed adeno-neuroendocrine carcinoma (MANEC) and primary signet-ring cell cancer (SRCC) are two rare but highly malignant tumors in colorectal cancer. Therefore, we attempted to compare the tumors' survival outcomes, identify risk factors, and ultimately evaluate the prognosis by developing a nomogram.

METHODS

We identified 755 MANEC and 5836 SRCC patients of colorectal cancer. PSM was used to balance the influence of baseline clinical and pathological differences. Kaplan-Meier method was used to compare the prognosis of different pathological grades and AJCC stages. Cox proportional hazards model was used to identify potential prognostic factors for the two groups. Finally, we developed a nomogram and evaluated the feasibility of the model.

RESULTS

After PSM, the median OS and CSS of MANEC patients were significantly better than those of SRCC patients in stage III-IV (P < 0.001) but similar in stage I-II. The median OS and CSS of MANEC patients in each pathological grade were also greater than those of SRCC patients. Patients with MANEC and SRCC who underwent lymph node dissection in more than four areas had longer survival time. MANEC patients benefited from postoperative chemotherapy and radiotherapy; among SRCC patients, those who received preoperative and postoperative comprehensive chemotherapy and radiotherapy had benefits in OS and CSS.

CONCLUSION

Both MANEC and SRCC are often diagnosed in advanced stages, highlighting the importance of early screening. Despite the better prognosis of MANEC compared to SRCC, both types of patients require the formulation of personalized treatment strategies based on different risk factors combined with column charts.

Influence of goal-directed fluid therapy guided by the Vigileo-FloTracTM system on intestinal mucosal barrier function in elderly patients with colorectal cancer

Introduction

Colorectal cancer is a clinically common malignancy arising in the digestive tract.

Aim

To evaluate the influence of goal-directed fluid therapy (GDFT) guided by the Vigileo-FloTracTM system on intestinal mucosal barrier function in elderly patients with colorectal cancer.

Material and methods

A prospective study was conducted on 106 elderly patients with colorectal cancer. They were divided into control and research groups (n = 53) using a random number table, and subjected to conventional fluid therapy and Vigileo-FloTracTM system-guided GDFT, respectively. Their intraoperative indicators, postoperative indicators, and changes of haemodynamics, oxygen metabolism, intestinal mucosal barrier function at different time points, and incidence rates of complications were compared.

Results

Compared with the control group, the intraoperative urine volume, colloid fluid volume, crystalloid fluid volume, and total infusion volume were lower, and the first postoperative exhaust time, first postoperative feeding time, and hospital stay were shorter in the research group (p < 0.05). At T1 and T2, mean artery pressure, heart rate, central venous pressure, oxygen consumption, oxygen delivery, and oxygen extraction ratio in the research group were lower than in the control group, but all of them first rose and then fell in the 2 groups (p < 0.05). On the 3rd day after surgery, the levels of serum endothelin, diamine oxidase and D-lactate declined in both groups, and the decline was more obvious in the research group (p < 0.05).

Conclusions

GDFT guided by the Vigileo-FloTracTM system is beneficial to the prognosis of patients by effectively decreasing fluid infusion.

The prognostic ability of radiotherapy of different colorectal cancer histological subtypes and tumor sites

The prognostic significance of radiotherapy (RT) for colorectal cancer (CRC) has shown conflicting results, particularly among different pathological subtypes, including adenocarcinoma (AC), mucinous adenocarcinoma (MC), and signet-ring cell carcinoma (SR). This study analyzed the prognosis of three pathological CRC types and focused on the prognostic significance of RT on three CRC histological subtypes. Patients diagnosed with AC (n = 54,174), MC (n = 3813), and SR (n = 664) in the National Cancer Institute's Surveillance, Epidemiology, and End Results (SEER) database (2010-2017) were evaluated. Cox regression models and competitive risk models were built to assess the effect of RT on the risk of CRC-associated death. Potential interactions between RT and stratified variables including age, sex, and tumor location were examined by multiplicative models. Compared with AC patients, SR patients had the worst overall survival (OS) among 3 subtypes of CRC (log-rank test, p < 0.001). Compared with patients who did not receive radiotherapy, RT was associated with a 1.09-fold (HR = 1.09, 95%[CI]: 1.03, 1.15) elevated risk of death among AC patients. In the SR group, RT significantly reduced the risk of death by 39% (HR = 0.61, 95%[CI]: 0.39-0.95). However, RT did not appear to independently influence survival in the MC group (HR = 0.96, 95%[CI]: 0.77, 1.21). In the subgroup analysis, tumor location (colon and rectum) significantly modified the association between RT and the risk of death among the AC and SR patients (p for interaction < 0.05). SR patients exhibited a worse OS (overall survival) than AC patients, and the effect of RT varied according to CRC histological subtypes. This can ultimately lead to more personalized and effective treatment strategies for CRC patients.

EARLY-ONSET COLORECTAL CANCER: AN ELEVEN-YEAR ANALYSIS OF CLINICOPATHOLOGICAL CHARACTERISTICS AT A TERTIARY HEALTHCARE CENTER

•The incidence of early-onset colorectal cancer (EO-CRC) has significantly increased worldwide, often leading to advanced disease at the time of diagnosis. •This study investigates the clinicopathological characteristics of EO-CRC cases at an academic healthcare center in Spain. •The majority of patients with EO-CRC were diagnosed between 40-49 years of age. •Left-sided tumors were more common, and most patients were diagnosed at advanced stages. •Moderately differentiated adenocarcinoma was the most frequent histological type, with 18.8% showing KRAS mutation and 11.9% showing BRAF mutation. Background - Early-onset colorectal cancer (EO-CRC) incidence has increased significantly worldwide in recent years, and these individuals frequently have advanced disease at the time of diagnosis. This study examines the clinicopathological characteristics of EO-CRC cases diagnosed at an academic healthcare center in Spain. Methods - A retrospective record review study of patients diagnosed with EO-CRC from 2010 to 2021 was performed. Clinical and pathological data were collected. Results - A total of 101 patients were included. The majority of cases (75.3%) were diagnosed in the age group between 40 and 49 years, specifically within the subgroup of 46-49 years. A family history of colorectal cancer was found in 23% of patients. Left-sided tumors were more common (43.6%), and most patients were diagnosed at advanced stages (34.7% at stage III and 32.7% at stage IV). The majority of patients (94.1%) were symptomatic, with rectal bleeding being the most prevalent clinical presentation. The most frequent histological type was moderately differentiated adenocarcinoma (44.6%). KRAS mutant tumors were found in 18.8% and BRAF mutant tumors in 11.9%. 67.3% had microsatellite stability. Tumor recurrence occurred in 24.8% of the patients, while 27.7% of the patients died. Conclusion - From 2010 to 2021, EO-CRC accounted for 3% of all colorectal cancer cases. To improve early diagnosis and treatment, physicians should maintain a high suspicion of red flag symptoms in young patients. To decrease EO-CRC morbidity and mortality, starting diagnostic screening tests at age 45 should be considered.

Watch-and-Wait Approach to Rectal Cancer: The Role of Imaging

The diagnosis and treatment of rectal cancer have evolved dramatically over the past several decades. At the same time, its incidence has increased in younger populations. This review will inform the reader of advances in both diagnosis and treatment. These advances have led to the watch-and-wait approach, otherwise known as nonsurgical management. This review briefly outlines changes in medical and surgical treatment, advances in MRI technology and interpretation, and landmark studies or trials that have led to this exciting juncture. Herein, the authors delve into current state-of-the-art methods to assess response to treatment with MRI and endoscopy. Currently, these methods for avoiding surgery can be used to detect a complete clinical response in as many as 50% of patients with rectal cancer. Finally, the limitations of imaging and endoscopy and future challenges will be discussed.

Case Report: Intramural colonic signet ring cell carcinoma presenting as intestinal pseudo-obstruction: A case presentation and review of the literature

Colorectal cancer (CRC) is the third most common cancer in the world. Other than adenocarcinomas, exceptional tumors of the colon and rectum represent a neglected clinical issue due to their rarity. Signet ring cell carcinoma (SRCC) is a rare subtype of CRC and has an extremely poor prognosis due to its advanced stage at diagnosis. Here we report a rare case of colorectal SRCC manifested as recurrent intestinal obstruction with a negative colonoscopy. Finally, he was diagnosed with signet ring cell carcinoma of the colon by postoperative pathology. It emphasized the special feature of intramural tumor growth without penetrating the mucosa in SRCC, which requires timely surgical intervention to avoid delay in diagnosis and treatment.

Prognostic value of log odds of positive lymph nodes, lymph node ratio, and N stage in patients with colorectal signet ring cell carcinoma: A retrospective cohort study

Aim

Little attention has been paid in the prognosis of colorectal signet ring cell carcinoma (SRCC). This study aims to explore the predictive capacity of log odds of positive lymph nodes (LODDS), lymph node ratio (LNR), and pN stage in the prognosis of patients with colorectal SRCC.

Methods

A retrospective cohort study was designed, and data were extracted from the Surveillance, Epidemiology and End Results (SEER) database. Data on demographic characteristics, clinicopathological features, and treatment were extracted. Outcomes were overall survival (OS) and cancer-specific survival (CSS). Association of LODDS, LNR, and pN stage with OS and CSS were explored using Cox proportional hazard model and Cox competing risk model, respectively, with results showing as hazard ratio and 95% confidence interval (CI). Predictive performance of LODDS, LNR, and pN stage in OS and CSS was assessed by calculating C-index.

Results

A total of 2,198 patients were included in this study. LODDS, LNR, and pN stage were associated with the OS and CSS of colorectal SRCC patients (all P < 0.05). LODDS showed a good performance in the OS (C-index: 0.704, 95% CI: 0.690-0.718), which was superior to LNR (C-index: 0.657, 95% CI: 0.643-0.671) and pN stage (C-index: 0.643, 95% CI: 0.629-0.657). The C-index of LODDS, LNR, and pN stage for CSS was 0.733 (95% CI: 0.719-0.747), 0.713 (95% CI: 0.697-0.729), and 0.667 (95% CI: 0.651-0.683), respectively.

Conclusions

LODDS displayed a better predictive capacity in the OS and CSS than LNR and pN stage, indicating that LODDS may be effective to predict the prognosis of colorectal SRCC in the clinic.

Expression of Autophagic and Inflammatory Markers in Normal Mucosa of Individuals with Colorectal Adenomas: A Cross Sectional Study among Italian Outpatients Undergoing Colonoscopy

Colorectal cancer (CRC) ranks among the three most common cancers in terms of both cancer incidence and cancer-related deaths in Western industrialized countries. Lifetime risk of colorectal cancer may reach 6% of the population living in developed countries. In the current era of personalized medicine, CRC is no longer considered as a single entity. In more recent years many studies have described the distinct differences in epidemiology, pathogenesis, genetic and epigenetic alterations, molecular pathways and outcome depending on the anatomical site. The aim of our study is to assess in a multidimensional model the association between metabolic status and inflammatory and autophagic changes in the normal colorectal mucosa classified as right-sided, left-sided and rectum, and the presence of adenomas. One hundred and sixteen patients undergoing colonoscopy were recruited and underwent a complete serum lipid profile, immunofluorescence analysis of colonic biopsies for MAPLC3 and myeloperoxidase expression, matched with clinical and anthropometric characteristics. Presence of adenomas correlated with cholesterol (total and LDL) levels, IL-6 levels, and MAPLC3 tissue expression, especially in the right colon. In conclusion, serum IL-6 amount and autophagic markers could be good predictors of the presence of colorectal adenomas.

Rectal Signet Ring Cell Carcinoma: Post-Chemoradiotherapy Evaluation by MRI and Corresponding to Pathology

Background

Signet ring cell carcinoma (SRCC) is recognized as an uncommon subtype of colorectal carcinoma (CRC). It showed characteristic magnetic resonance imaging (MRI) manifestations. However, the MRI features post-chemoradiotherapy (CRT) were not reported, and it is unknown whether the current tumor regression grade (TRG) system by MRI (mrTRG) is applicable to SRCC.

Purpose

To summarize the image features of rectal SRCC on post-CRT images corresponding to the pathology, and to determine the predicting value of mrTRG compared with TRG by pathology (pTRG).

Methods

We retrospectively enrolled seven patients (male: female = 3:4; mean age, 45.1 years) with biopsy-pathology proved SRCC, who underwent pre- and post-CRT MR imaging followed by surgery. An experienced gastrointestinal radiologist accessed mrTRG using a 5-point grading system by mandard standard on T2 weighted image (T2WI) and then added diffusion weighted image (DWI) in a 1-month interval. Additionally, MRI features were recorded on pre- and post-CRT images as follows: pattern (target sign) and main signal intensity of T2WI, characterized manifestation of DWI, and mean Apparent Diffusion Coefficient (ADC)values. The mrTRG and all MR image features were compared to the post-operative pathology.

Results

At post-CRT histology, five patients got a good response (TRG 1, n = 4; TRG 2, n = 1), one patient got a partial response, and one patient got a poor response. The accuracy of MRI predicted the pathology response by mandard standard was 14% and increased to 71.4% when added DWI. After CRT, different degrees of homogeneous high SI without enhancement representing acellular mucin were observed in all patients, and the thick-ring high SI turned into a thin-target sign in most good responders. Moreover, the tumor volume decreased or slightly increased in good responders, while it markedly increased in the partial and poor responder by 57% and 73.8%, respectively.

Conclusion

Homogeneous high SI on T2WI and thin target sigh on DWI were the main MRI changes of RSRCC, which was corresponding to the mucinous regression and represents for good response post-CRT. The mrTRG and tumor volume was not a reliable indicator to the pathology response. We considered that DWI should be added to T2WI to evaluate RSRCC response to CRT.

Clinicopathological and Molecular Characteristics of Colorectal Signet Ring Cell Carcinoma: A Review

Colorectal signet ring cell carcinoma (SRCC) is a rare subtype of colorectal cancer (CRC) with unique characteristics. Due to the limited researches on it, a comprehensive and in-depth understanding of this subtype is still lacking. In this article, we summarize the clinicopathological features and molecular characteristics of colorectal SRCC based on a literature review. Clinically, SRCC has been associated with young age, proximal site preference, advanced tumor stage, high histological grade, high rate of lymph node involvement, frequent peritoneal metastasis, and a significantly poor prognosis. Regarding molecular characteristics, in SRCC, the mutation burden of the classic signaling pathways that include WNT/β-catenin, RAS/RAF/MAPK, and PI3K/AKT/mTOR signaling pathways are generally reduced. In contrast, some genes related to the “epithelial-mesenchymal transition (EMT) process” and the “stem cell properties”, including RNF43, CDH1, and SMAD4, as well as the related TGF-β signaling pathway have been observed more frequently altered in SRCC than in conventional adenocarcinoma (AC). In many studies but not in others, SRCC showed a higher frequency of BRAF mutation, microsatellite instability-high (MSI-H) and CpG island methylator phenotype (CIMP) positive status compared to AC. It has been proposed that colorectal SRCC consists of two subtypes, in which the MSI⁺/CIMP⁺/BRAF⁺/CD3⁺/PD-L1⁺ hypermethylated genotype is more common in the proximal colon, and may represent the potential candidate for immunotherapy. Understanding the special molecular mechanisms related to the aggressive biology of SRCC is of great importance, which may provide a theoretical basis for the development of more targeted and effective treatments for this refractory disease.