Prognostic significance and molecular features of signet-ring cell and mucinous components in colorectal carcinoma

Individualized prediction of conditional survival for colorectal signet-ring cell carcinoma patients

Background

Conditional survival (CS) considers the time already survived after surgery and may provide additional survival information. The authors sought to construct and validate novel conditional survival nomograms for the prediction of conditional overall survival (OS) and cancer-specific survival (CSS) of colorectal signet-ring cell carcinoma (SRCC) patients.

Methods

Patients diagnosed with stage I-III SRCC between 2010 and 2019 were identified from the Surveillance, Epidemiology, and End Results database. The formula calculating CS was: CS(x|y) = S(x+y)/S(x), where S(x) represents the survival at x years. CS nomograms were then constructed to predict the 5-year conditional OS and CSS, followed by internal validation.

Results

A total of 944 colorectal SRCC patients were finally identified in this study. The 5-year OS and CSS improved gradually with additional survival time. Univariate and multivariate Cox regression analysis conducted in training set revealed that age, race, T stage, LNR, and perineural invasion were independent risk factors for both OS and CSS. Two nomograms with considerable predictive ability were successfully constructed [area under the curve (AUC) for OS: 0.788; AUC for CSS: 0.847] and validated (AUC for OS: 0.773; AUC for CSS: 0.799) for the prediction of 5-year OS and CSS, based on the duration of 1-4 years post-surgery survival.

Conclusions

The probability of achieving 5-year OS and 5-year CSS in colorectal SRCC patients improved gradually with additional time. Conditional nomograms considering survival time will be more reliable and informative for risk stratification and postoperative follow-up.

Location Has Prognostic Impact on the Outcome of Colorectal Mucinous Adenocarcinomas

Mucinous (colloid) adenocarcinomas (MAs) are a rare histological subtype of tumors defined by extracellular mucin comprising more than 50% of the tumor. These tumors are on a continuum of mucin-producing malignancies with signet ring cell adenocarcinomas (SRCCs), which instead produce intracellular mucin. Mucin-containing cancers occur primarily in the stomach and colon, where for SRCCs, outcomes are relatively worse in the proximal stomach and the rectum. It is not known if MAs have similar outcomes. In this study, we use the Surveillance, Epidemiology, and End Results (SEER) database to examine the effects of tumor localization, age, sex, and stage on colorectal and gastric cancer outcomes for MAs. For right colon cancers, MAs are more common, particularly in females, and have slightly better or equivalent outcomes across all stages and ages compared to conventional adenocarcinomas, but outcomes are progressively worse compared to conventional adenocarcinomas for left colon and rectal cancers. Unlike SRCCs, MAs have similar outcomes to conventional adenocarcinomas in all stomach locations. Overall, these results suggest that MAs have an intrinsically different tumor biology in the left colon and rectum that promotes pathogenesis. Decoding this phenomenon could lead to more effectively tailored patient treatment regimens.

The percentages of signet-ring cells (SRCs) affects the prognosis after radical gastrectomy for advanced gastric cancer

PURPOSE

Only recently has the percentage of signet-ring cells (SRCs) been shown to affect the prognosis following gastric cancer surgery. It is uncertain whether the SRC percentage has a role in tumour biology or prognosis of gastric signet-ring cell carcinoma (GSRCC). For this research, we assessed the effect of the SRC percentage on the clinicopathological and prognostic characteristics of gastric cancer (GC) tumours and created and verified a prognostic nomogram to assess the overall survival (OS) of GSRCC patients.

METHODS

In our study, 1100 GC patients with signet-ring cell carcinoma (SRCC) at Zhejiang Cancer Hospital from December 2013 to December 2018 who underwent curative gastric cancer resection were retrospectively analysed. The patients were separated into two groups: those with SRCC (SRC percentage >50%; n = 157) and those with partial signet-ring cell carcinoma (PSRCC) (SRC percentage ≤50%; n = 943). We compared the clinicopathological characteristics of both groups. To estimate OS and determine correlations with the SRC percentage, the Kaplan-Meier method and log-rank test were used. To develop the prognostic nomogram, independent prognostic indicators for OS were identified using Cox regression analyses. Predictions were assessed using the calibration curve and C-index.

RESULTS

Our research showed that there was no discernible difference in OS between the two groups. The preoperative CA242 level, pT stage, pN stage, age, nerve invasion, neoadjuvant chemotherapy, postoperative chemotherapy, and maximum tumour diameter were independent prognostic risk factors for OS for GC (all p < 0.05). However, for advanced GC, the SRC percentage (HR = 1.571, 95% CI 1.072-2.302, p = 0.020) was an independent prognostic factor of OS. Other independent prognostic risk factors were age, pT stage, pN stage, nerve invasion, tumour location, neoadjuvant chemotherapy, postoperative chemotherapy, preoperative CA50 level, and preoperative CEA level (all p < 0.05). On these bases, nomograms were constructed for GC and advanced GC, with C-indexes of 0.806 (95%CI 0.782-0.830) and 0.728 (95%CI 0.697-0.759), respectively.

CONCLUSIONS

In cases of advanced gastric cancer, the SRC percentage served as a standalone prognostic indicator for OS. An effective tool for assessing the prognosis of GSRCC was offered by the nomogram.

Bayesian risk prediction model for colorectal cancer mortality through integration of clinicopathologic and genomic data

Routine tumor-node-metastasis (TNM) staging of colorectal cancer is imperfect in predicting survival due to tumor pathobiological heterogeneity and imprecise assessment of tumor spread. We leveraged Bayesian additive regression trees (BART), a statistical learning technique, to comprehensively analyze patient-specific tumor characteristics for the improvement of prognostic prediction. Of 75 clinicopathologic, immune, microbial, and genomic variables in 815 stage II-III patients within two U.S.-wide prospective cohort studies, the BART risk model identified seven stable survival predictors. Risk stratifications (low risk, intermediate risk, and high risk) based on model-predicted survival were statistically significant (hazard ratios 0.19-0.45, vs. higher risk; P < 0.0001) and could be externally validated using The Cancer Genome Atlas (TCGA) data (P = 0.0004). BART demonstrated model flexibility, interpretability, and comparable or superior performance to other machine-learning models. Integrated bioinformatic analyses using BART with tumor-specific factors can robustly stratify colorectal cancer patients into prognostic groups and be readily applied to clinical oncology practice.

Signet Ring Cell Colorectal and Appendiceal Cancer: A Small Signet Ring Cell Component Is Also Associated with Poor Outcome

BACKGROUND

Colorectal signet ring cell (SRC) carcinoma with ≥50% SRCs (SRC ≥ 50) has a poor prognosis, but the prognostic role of SRCs < 50% (SRC < 50) is unclear. The aim of this study was to provide a clinicopathological characterization of SRC colorectal and appendiceal tumours and analyse the importance of the SRC component size.

METHODS

All patients in the Swedish Colorectal Cancer Registry diagnosed with colorectal or appendiceal cancer in 2009-2020 at Uppsala University Hospital, Sweden, were included. The SRCs were verified, and the components estimated by a gastrointestinal pathologist.

RESULTS

Of the 2229 colorectal cancers, 51 (2.3%) had SRCs, with a median component size of 30% (interquartile range of 12.5-40) and 10 (0.45%) had SRC ≥ 50. The SRC tumours were primarily localized in the right colon (59%) and appendix (16%). No patients with SRCs had stage I disease, and 26 (51%) had stage IV, of whom, 18 (69%) had peritoneal metastases. The SRC tumours were often high grade with perineural and vascular invasion. The 5-year overall survival (OS) rate for patients with SRC ≥ 50 were 20% (95% confidence interval (CI) 6-70), for SRC < 50, 39% (95% CI 24-61); and for non-SRCs, 55% (95% CI 55-60). Among the patients with SRC < 50 and <50% extracellular mucin, the 5-year OS was 34% (95% CI 19-61), while those with ≥50% extracellular mucin had an OS of 50% (95% CI 25-99). The 5-year recurrence-free survival rates were 51% (95% CI 13-83) for patients with SRC tumours, as compared to 83% (95% CI 77-89) and 81% (95% CI 79-84) for mucinous and non-mucinous adenocarcinoma, respectively.

CONCLUSIONS

The presence of SRCs was strongly associated with aggressive clinicopathological features, peritoneal metastases, and poor prognosis, also when they make up <50% of a tumour.

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.

Comparison of clinicopathological characteristics of mucinous adenocarcinoma and conventional adenocarcinoma of gallbladder

BACKGROUND

Gallbladder mucinous adenocarcinoma (GBMAC) is a rare type of gallbladder malignant tumor, whereas little is known regarding the clinicopathological features and surgical outcomes of GBMAC.

METHODS

From January 2000 till December 2015, 54 GBMAC patients who underwent curative-intent surgical resection at our institution were retrospectively reviewed. We compared the clinicopathological features and surgical outcomes of these GBMAC patients with a relatively large cohort of surgically resected conventional gallbladder adenocarcinoma (GBAC) patients without existence of mucinous components.

RESULTS

The clinicopathological features of GBMAC were significantly different from conventional GBAC, including poorer tumor differentiation (P < 0.001), higher CA19-9 levels (P < 0.001), larger tumor sizes (P = 0.020), advanced AJCC tumor stage (P = 0.002), higher frequency of liver parenchyma invasion (P = 0.020), portal vein invasion (P = 0.003), lymph node metastasis (P = 0.016), lympho-vascular invasion (P < 0.001) and perineural invasion (P = 0.025). Relative to conventional GBAC patients, GBMAC patients showed significantly worse overall survival (OS) (29.0 vs 15.0 months; P < 0.001). Multivariate analysis confirmed the surgical margin (P = 0.046), tumor differentiation grade (P = 0.018), lymph node metastasis (P = 0.024), and presence of signet-ring cell component (P = 0.005) as independent prognostic factors influencing OS of patients with GBMAC.

CONCLUSION

GBMAC always had more aggressive biological behaviors and poor survival outcomes even after curative surgery. GBMAC patients with the presence of signet-ring cell component showed even worse survival outcome.

Correlation of clinical, pathologic, and genetic parameters with intratumoral immune milieu in mucinous adenocarcinoma of the colon

Mucinous adenocarcinoma (MAD), the most common subtype of colonic adenocarcinoma (CA), requires >50% intratumoral mucin. There is limited data regarding the impact of MAD on key lymphocyte subsets and therapeutically critical immune elements. In this study we address: (1) the definition of MAD, (2) grading of MAD, and (3) the impact of MAD and extracellular mucin on intratumoral immune milieu. Estimation of the percentage of intratumoral mucin was performed by two pathologists. Tissue microarrays were stained for immune markers including CD8, CD163, PD-L1, FoxP3, β2 microglobulin, HLA class I, and HLA class II. Immunohistochemistry for BRAF V600E was performed. MMR status was determined on immunohistochemistry for MSH2, MSH6, MLH1, PMS2. Manual and automated HALO platforms were used for quantification. The 903 CAs included 62 (6.9%) MAD and 841 CA with ≤ 50% mucin. We identified 225 CAs with mucinous differentiation, defined by ≥10% mucin. On univariate analysis neither cut point, 50% (p = 0.08) and 10% (p = 0.08) mucin, correlated with disease-specific survival (DSS). There were no differences in key clinical, histological and molecular features between MAD and CA with mucinous differentiation. On univariate analysis of patients with MAD, tumor grade correlated with DSS (p = 0.0001) while MMR status did not (p = 0.86). There was no statistically significant difference in CD8 (P = 0.17) and CD163 (P = 0.05) positive immune cells between MAD and conventional CA. However, deficient (d) MMR MADs showed fewer CD8 (P = 0.0001), CD163 (P = 0.0001) and PD-L1 (P = 0.003) positive immune cells compared to proficient (p)MMR MADs, a finding also seen with at 10% mucin cut point. Although MAD does not impact DSS, this study raises the possibility that the immune milieu of dMMR MADs and tumors with > =10% mucin may differ from pMMR MADs and tumors with <10% mucin, a finding that may impact immune-oncology based therapeutics.

Western-Style Diet, pks Island-Carrying Escherichia coli, and Colorectal Cancer: Analyses From Two Large Prospective Cohort Studies

BACKGROUND & AIMS

Evidence supports a carcinogenic role of Escherichia coli carrying the pks island that encodes enzymes for colibactin biosynthesis. We hypothesized that the association of the Western-style diet (rich in red and processed meat) with colorectal cancer incidence might be stronger for tumors containing higher amounts of pks+E coli.

METHODS

Western diet score was calculated using food frequency questionnaire data obtained every 4 years during follow-up of 134,775 participants in 2 United States-wide prospective cohort studies. Using quantitative polymerase chain reaction, we measured pks+E coli DNA in 1175 tumors among 3200 incident colorectal cancer cases that had occurred during the follow-up. We used the 3200 cases and inverse probability weighting (to adjust for selection bias due to tissue availability), integrated in multivariable-adjusted duplication-method Cox proportional hazards regression analyses.

RESULTS

The association of the Western diet score with colorectal cancer incidence was stronger for tumors containing higher levels of pks+E coli (Pheterogeneity = .014). Multivariable-adjusted hazard ratios (with 95% confidence interval) for the highest (vs lowest) tertile of the Western diet score were 3.45 (1.53-7.78) (Ptrend = 0.001) for pks+E coli-high tumors, 1.22 (0.57-2.63) for pks+E coli-low tumors, and 1.10 (0.85-1.42) for pks+E coli-negative tumors. The pks+E coli level was associated with lower disease stage but not with tumor location, microsatellite instability, or BRAF, KRAS, or PIK3CA mutations.

CONCLUSIONS

The Western-style diet is associated with a higher incidence of colorectal cancer containing abundant pks+E coli, supporting a potential link between diet, the intestinal microbiota, and colorectal carcinogenesis.

Predictors of Long-Time Survivors in Nonmetastatic Colorectal Signet Ring Cell Carcinoma: A Large Population-Based Study

Background

Colorectal signet ring cell carcinoma (SRCC) is a rare and distinct subtype of colorectal cancer (CRC), with extremely poor prognosis and aggressive tumor biological behavior. In this study, we aimed to analyze the clinicopathological characteristics and to identify the independent predictors of long-time survivors (LTSs) of nonmetastatic colorectal SRCC.

Methods

Patients diagnosed with nonmetastatic colorectal SRCC were extracted from the Surveillance, Epidemiology, and End Results (SEER) database. We compared and analyzed the clinicopathological characteristics between LTSs (patients survived over 5 years) and non-LTSs (patients survived of or less than 5 years). Afterwards, multivariate logistic regression analysis was used to identify independent predictors of LTSs, which were further used to construct a nomogram model to predict the probability of being LTSs.

Results

We enrolled 2050 patients with nonmetastatic colorectal SRCC, consisting of 1441 non-LTSs and 609 LTSs. Multivariate logistic regression analysis revealed that race, marital status, tumor infiltration, lymph node involvement, and primary tumor treatment were independent predictors of LTSs. In addition, these five parameters were incorporated into a nomogram model to predict the probability of being LTSs. In terms of the model performance, the calibration curve revealed good agreement between observed and predicted probability of LTSs, and receiving operator characteristic curve showed acceptable discriminative capacity in the training and validation cohorts.

Conclusion

Collectively, we analyzed and profiled the clinicopathological characteristics of LTSs in patients with nonmetastatic colorectal SRCC. Race, marital status, T stage, N stage, and primary tumor treatment were independent predictors of LTSs.

The Molecular Associations of Signet-Ring Cell Carcinoma in Colorectum: Meta-Analysis and System Review

Background: Signet ring cell carcinoma (SC) accounts for 1% of total colorectal cancer (CRC) cases and is associated with aggressive behaviors, such as lymphatic invasion and distant metastases, resulting in poor prognosis. To date, there is still a lack of consensus on the genetic etiology underpinning this cancer subtype. This study aimed to clarify the molecular associations of SC by using meta-analysis and a systematic review. Methods: PubMed, Embase, and Cochrane Library were searched for studies evaluating the KRAS, BRAF, P53 statuses, and microsatellite instability (MSI) in CRC patients with different histological subtypes, including SC. The diagnosis of SC is defined as the signet ring cells comprising ≥50 percent of the tumor mass. By dividing the studies into subgroups based on the composition of control groups, such as classic adenocarcinoma (AC; no SC components) and non-SC (including those with SC components < 50%), the relative risk (RR) of molecular alterations for SC in each study were pooled using a random-effects model. Two reviewers identified trials for inclusion, assessed quality, and extracted data independently. Results: Data from 29 studies consisting of 9366 patients were included in this analysis. SC was associated positively with MSI (RR 1.78, 95% CI 1.34 to 2.37; 95% CI 0.77 to 4.15; p = 0.0005), BRAF mutation (RR 1.99, 95% CI 1.21 to 3.26; 95%CI 0.68 to 5.82; p = 0.0146), and negatively with KRAS mutation (RR 0.48, 95% CI 0.29 to 0.78; 95% CI 0.09 to 2.49; p = 0.0062). No association was found between SC and P53 expression (RR 0.92, 95% CI 0.76 to 1.13; 95%CI 0.61 to 1.39; p = 0.3790). Moreover, it was associated negatively with P53 gene mutations (RR 0.92, 95% CI 0.77 to 1.09; 95% CI 0.46 to 1.82; p = 0.1568), and P53 protein (RR 0.93, 95% CI 0.58 to 1.49; 95% CI 0.40 to 2.17; p = 0.6885). Conclusions: The molecular etiology of SC may be associated with the BRAF and MSI pathways. Its features, such as the high frequency of BRAF mutation, could partly explain its less favorable outcomes and limited effects of traditional chemotherapy.

Molecular profiling of signet-ring-cell carcinoma (SRCC) from the stomach and colon reveals potential new therapeutic targets

Signet ring cell carcinoma (SRCC) is rare: about 10% of gastric cancer (GC) and 1% of colorectal cancer (CRC). SRCC is associated with poor prognosis, however the underlying molecular characteristics are unknown. SRCCs were analyzed using NGS, immunohistochemistry, and in situ hybridization. Tumor mutational burden (TMB) was calculated based on somatic nonsynonymous missense mutations, and microsatellite instability (MSI) was evaluated by NGS of known MSI loci. A total of 8500 CRC and 1100 GC were screened. Seventy-six SRCC were identified from the CRC cohort (<1%) and 98 from the GC cohort (9%). The most frequently mutated genes in CRC-SRCC were TP53 (47%), ARID1A (26%), APC (25%); in GC-SRCC were TP53 (42%), ARID1A (27%), CDH1 (11%). When compared to non-SRCC histology (N = 3522), CRC-SRCC (N = 37) more frequently had mutations in BRCA1 (11% vs 1%, P < 0.001) and less frequently mutations in APC (19% vs 78%, P < 0.001), KRAS (22% vs 51%, P = 0.001) and TP53 (47% vs 73%, P = 0.001). Among the GC cohort, SRCC (N = 54) had a higher frequency of mutations in CDH1, BAP1, and ERBB2, compared to non-SRCC (N = 540). Our data suggest that SRCCs harbor a similar molecular profile, regardless of the tumor location. Tailored therapy may become available for these patients.

Signet ring cell component predicts the response to neoadjuvant chemoradiotherapy in rectal cancer. Long interim results of a single institution experience

There are limited studies evaluating the correlation between the presence of signet ring carcinoma and tumor response to neoadjuvant therapy in the rectum. Hereby, we aimed to report for the first time our experience from Upper Egypt through assessing the predictive role of signet ring cell component (SRCC) in the response to preoperative chemoradiotherapy (PCRT) and the impact of histological types (SRCC versus other types) on survival. This retrospective study analysed the medical records of 195 patients with locally advanced rectal cancer treated from 2011, to 2018. Patients were divided into two groups according to histological types: SRCC group and non SRCC group. All patients received PCRT followed by surgery. SRCC group was associated with significant higher rate of complete clinical response (cCR) and pathologic complete response (pCR) (83.3% and 88.9% respectively) as compared to non SRCC group (9.0% and 10.2% respectively); P<0.0001. Fifteen cases (93.8%) who were diagnosed by magnetic resonance tumor regression grade (mrTRG) and diffusion weighted imaging (DWI) as cCR after PCRT, also achieved pCR, in contrast to 88.9% of cases without SRCC. Signet ring histology was the only predictor of pCR in multivariate analysis (P=0.027). There was no statistically significant difference between both histological groups as regard to survival. SRCC is an important predictor of pCR and assessing their response to PCRT using mrTRG and DWI showed high sensitivity for the detection of cCR, making them good candidates for watch-and-wait approach. Histological types did not significantly affect the survival outcome.

Metastatic colorectal carcinoma with signet-ring cells: Clinical, histological and molecular description from an Association des Gastro-Entérologues Oncologues (AGEO) French multicenter retrospective cohort

BACKGROUND

Metastatic signet-ring cell colorectal carcinoma is rare. We analyzed its clinicopathological and molecular features, prognostic factors and chemosensitivity.

METHODS

Retrospective study from 2003 to 2017 in 31 French centers, divided into three groups: curative care (G1), chemotherapy alone (G2), and best supportive care (G3).

RESULTS

Tumors were most frequently in the proximal colon (46%), T4 (71%), and poorly differentiated (86%). The predominant metastatic site was peritoneum (69%). Microsatellite instability and BRAF mutation were found in 19% and 9% (mainly right-sided) of patients and RAS mutations in 23%. Median overall survival (mOS) of the patients (n = 204) was 10.1 months (95%CI: 7.9;12.8), 45.1 for G1 (n = 38), 10.9 for G2 (n = 112), and 1.8 months for G3 (n = 54). No difference in mOS was found when comparing tumor locations, percentage of signet-ring cell contingent and microsatellite status. In G1, relapse-free survival was 14 months (95%CI: 6.5-20.9). In G2, median progression-free survival (PFS) was 4.7 months (95%CI: 3.6;5.9]) with first-line treatment. Median PFS was higher with biological agents than without (5.0 vs 3.9 months, p = 0.016).

CONCLUSIONS

mSRCC has a poor prognosis with specific location and molecular alterations resulting in low chemosensitivity. Routine microsatellite analysis should be performed because of frequent MSI-high tumors in this population.

Clinical significance of mucinous component in colorectal adenocarcinoma: a propensity score-matched study

Background

This study aims to investigate the clinical significance and prognostic value of mucinous component (MC) in colorectal adenocarcinoma (AC).

Methods

Patients with colorectal AC and AC with MC (ACMC) (1–100%) underwent surgical resection between January 2007 and February 2018 were retrospectively reviewed. Propensity score matching (PSM) was performed according to a 1:1 ratio. Receiver-operating characteristic (ROC) curve was used to identify the optimal cut-off value of MC ratio for prognostic prediction. The clinicopathological features and 3-year overall survival (OS) of AC patients, mucinous adenocarcinoma (MAC) (MC > 50%) patients, and ACMC (1–50%) patients were compared before and after matching. Multivariable analysis was used for analyzing independent risk factors related to prognosis.

Results

A total of 532 patients were enrolled in this study. Patients with AC, MAC, and ACMC (1–50%) exhibited different clinicopathological features. However, their 3-year OS rates were similar (82.00% vs. 74.11% vs. 81.48%, P = 0.38). After matching, ROC curve determined 70% as the optimal cut-off value. And patients with ACMC > 70% had a much poorer 3-year OS compared with ACMC (1–70%) patients and AC patients (47.37% vs. 86.15% vs. 79.76%, P < 0.001). In addition, ACMC > 70% was revealed as a risk factor for poor survival in univariate analysis (HR = 1.643, 95%CI = 1.025–2.635, P = 0.039), though not an independent risk factor in multivariable analysis (HR = 1.550, 95%CI = 0.958–2.507, P = 0.074).

Conclusions

MAC is usually diagnosed at an advanced stage. MAC has a similar survival with AC and ACMC (1–50%) patients before and after matching. Patients with ACMC > 70% exhibited a much poorer OS, and should be given more clinical attention.

Clinical Features, Molecular Alterations and Prognosis of Colorectal Adenocarcinoma With Mucinous Component in Chinese Patients

Mucinous adenocarcinoma (MAC) is conventionally diagnosed by WHO definition when the extracellular mucin is >50% of the tumor area, while tumors with <50% mucin are designated as having a mucinous component. The study is aimed at analyzing the clinicopathologic characteristics, mutation spectrum, and prognosis of colorectal adenocarcinoma with mucinous component (CAWMC). Mutation analyses for exon 2 to 4 of KRAS gene and exon 15 of BRAF gene were performed by Sanger sequencing. Expression of DNA mismatch repairs and P53 proteins were evaluated by immunohistochemistry. Density of tumor-infiltrating lymphocyte (TIL) status was scored. We also evaluated the percentage of glands producing mucin and the morphology of the different tumor cell types in mucin pools. We retrospectively analyzed the prognosis of 43 patients with stage II/III. The overall frequencies of KRAS and BRAF mutations were 36% and 8%, respectively. Patients with MAC exhibiting high levels of mucin were related to the increase of tumor diameter (P=0.038) but were not associated with any of the other clinicopathologic parameters. The proportion or variable morphology of mucinous component did not stratify progression-free survival in stage II/III cases. TIL was the most significant predictor of progression-free survival among stage II/III CAWMC. It is interesting to note that signet ring cell carcinoma does not portend a worse prognosis for patients with high TIL levels. Combining use the grade of TIL status with the WHO grade of the entire tumor can help identify patients with a high risk of recurrence more accurately.

Signet ring cell carcinoma of the gastrointestinal tract: National trends on treatment effects and prognostic outcomes

BACKGROUND

Signet ring cell carcinoma (SRCC) is a distinct malignancy occurring across the tubular gastrointestinal tract (tGIT). We comprehensively examined the outcomes of patients diagnosed with SRCC across tGIT.

METHODS

SRCC and not-otherwise-specified adenocarcinoma (NOS) patients reported to the National Cancer Database from 2004 to 2015 were included. Baseline characteristics, outcomes and site-specific adjusted hazard ratios (aHR) derived from Cox models of SRCC patients were compared to those of NOS patients. Overall survival (OS) was primary endpoint.

RESULTS

A total of 41,686 SRCC (4.6%) and 871,373 NOS patients (95.4%) were included. SRCC patients were younger (63.1 ± 14.7 vs. 67.0 ± 13.4 y, p < 0.001) and more likely to present with Stage IV disease than NOS patients (42.5% vs. 24.5%, p < 0.001). Stomach (n = 24,433) and colon (n = 9,914) contributed highest frequency of SRCC. SRCC histology was associated with shorter OS (aHR = 1.377, p < 0.001) in multivariate model. There was an interaction between SRCC and chemotherapy effects on risk of death (interaction aHR = 1.072, p_interaction< 0.001) and between SRCC histology and disease site, suggesting that the effect of SRCC on OS is site-dependent, with a higher increased risk of death in patients with rectal SRCC (aHR = 2.378, p_interaction< 0.001).

CONCLUSION

Significant negative prognostic effect associated with SRCC is site-dependent across the GIT. Surgical and or systemic therapy was associated with improved OS among SRCC patients, but remained lower than NOS patients. Further understanding of gastrointestinal SRCC molecular profile is needed to better inform future treatment strategies.

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.

Prognostic Significance of Signet-Ring Cell Components in Patients With Gastric Carcinoma of Different Stages

Background: Gastric carcinoma (GC), which contains signet ring cell (SRC) components are frequently observed in postoperative pathological assessment. This study aims to study the prognostic significance of SRC components in GC patients.

Methods: From 2003 to 2017, surgically resected primary GC patients were retrospectively reviewed. All enrolled patients were divided into three groups according to the proportion of SRC. The overall survival (OS) and disease-free survival (DFS) of GC patients with different tumor stages were analyzed.

Results: Patients with SRC or mixed-SRC were more associated with female, younger age, middle or lower third of the stomach, larger tumor, higher pN stage, and more lymphovascular invasion. For GC patients in stage I, multivariate survival analysis showed that age >60, SRC components >50%, and pT stage were independent prognostic factors for OS (all p < 0.05). The 5-year OS of patients with SRC were higher than that of patients with pure adenocarcinoma (p = 0.021). For GC patients in stage II/III, multivariate survival analysis showed that age >60, SRC proportion, surgical types, Borrmann's type, pT stage, pN stage, and lymphovascular invasion were independent prognostic factors for OS (all p < 0.05). The 5-year OS/DFS of patients with SRC were lower than that of patients with pure adenocarcinoma (p < 0.001).

Conclusions: SRC seemed to be a favorable prognostic factor in GC patients in stage I. However, for GC patients in stage II/III, the SRC components were associated with poor prognosis, independent of other clinicopathological factors.

Prognostic nomograms for predicting overall survival and cause-specific survival of signet ring cell carcinoma in colorectal cancer patients

BACKGROUND

Signet ring cell carcinoma (SRCC) is an uncommon subtype in colorectal cancer (CRC), with a short survival time. Therefore, it is imperative to establish a useful prognostic model. As a simple visual predictive tool, nomograms combining a quantification of all proven prognostic factors have been widely used for predicting the outcomes of patients with different cancers in recent years. Until now, there has been no nomogram to predict the outcome of CRC patients with SRCC.

AIM

To build effective nomograms for predicting overall survival (OS) and cause-specific survival (CSS) of CRC patients with SRCC.

METHODS

Data were extracted from the Surveillance, Epidemiology, and End Results database between 2004 and 2015. Multivariate Cox regression analyses were used to identify independent variables for both OS and CSS to construct the nomograms. Performance of the nomograms was assessed by concordance index, calibration curves, and receiver operating characteristic (ROC) curves. ROC curves were also utilized to compare benefits between the nomograms and the tumor-node-metastasis (TNM) staging system. Patients were classified as high-risk, moderate-risk, and low-risk groups using the novel nomograms. Kaplan-Meier curves were plotted to compare survival differences.

RESULTS

In total, 1230 patients were included. The concordance index of the nomograms for OS and CSS were 0.737 (95% confidence interval: 0.728-0.747) and 0.758 (95% confidence interval: 0.738-0.778), respectively. The calibration curves and ROC curves demonstrated good predictive accuracy. The 1-, 3-, and 5-year area under the curve values of the nomogram for predicting OS were 0.796, 0.825 and 0.819, in comparison to 0.743, 0.798, and 0.803 for the TNM staging system. In addition, the 1-, 3-, and 5-year area under the curve values of the nomogram for predicting CSS were 0.805, 0.847 and 0.863, in comparison to 0.740, 0.794, and 0.800 for the TNM staging system. Based on the novel nomograms, stratified analysis showed that the 5-year probability of survival in the high-risk, moderate-risk, and low-risk groups was 6.8%, 37.7%, and 67.0% for OS (P < 0.001), as well as 9.6%, 38.5%, and 67.6% for CSS (P < 0.001), respectively.

CONCLUSION

Convenient and visual nomograms were built and validated to accurately predict the OS and CSS rates for CRC patients with SRCC, which are superior to the conventional TNM staging system.

Rising incidence of early-onset colorectal cancer - a call to action

The incidence of early-onset colorectal cancer (CRC), which occurs in individuals <50 years of age, has been increasing worldwide and particularly in high-income countries. The reasons for this increase remain unknown but plausible hypotheses include greater exposure to potential risk factors, such as a Western-style diet, obesity, physical inactivity and antibiotic use, especially during the early prenatal to adolescent periods of life. These exposures can not only cause genetic and epigenetic alterations in colorectal epithelial cells but also affect the gut microbiota and host immunity. Early-onset CRCs have differential clinical, pathological and molecular features compared with later-onset CRCs. Certain existing resources can be utilized to elucidate the aetiology of early-onset CRC and inform the development of effective prevention, early detection and therapeutic strategies; however, additional life-course cohort studies spanning childhood and young adulthood, integrated with prospective biospecimen collections, omics biomarker analyses and a molecular pathological epidemiology approach, are needed to better understand and manage this disease entity. In this Perspective, we summarize our current understanding of early-onset CRC and discuss how we should strategize future research to improve its prevention and clinical management.

The Predictive and Guidance Value of Signet Ring Cell Histology for Stage II/III Colon Cancer Response to Chemotherapy

PURPOSE

To evaluate the predictive and guidance value of signet-ring cell carcinoma for chemotherapy response in stage II/III colon cancer.

METHODS

Eligible patients were recruited from the Surveillance, Epidemiology and End Results (SEER) database. The differences between adenocarcinoma (AD) and SRCC groups in the incidence of patients' demographic and clinical characteristics were analyzed by Pearson's chi-squared (×2) test. Survival was analyzed using the Kaplan-Meier method, and the differences were determined by the log-rank test. Some Cox regression models were built to assess hazard ratios (HRs) of different variables with 95% confidence intervals (95% CIs).

RESULTS

In stage II AD, it was found that the receipt of chemotherapy had significantly 12.6% decreased risk of cancer-specific mortality (HR = 0.874, 95% CI = 0.825-0.927, P < 0.001). In stage II SRCC, however, the receipt of chemotherapy had significantly 70.00% increased risk of cancer-specific mortality (HR = 1.700, 95% CI = 1.032-2.801, P = 0.037). In stage III AD, it was found that the receipt of chemotherapy had significantly 45.3% decreased risk of cancer-specific mortality (HR = 0.547, 95% CI = 0.530-0.564, P < 0.001). In stage III SRCC, the receipt of chemotherapy had significantly 24.6% decreased risk of cancer-specific mortality (HR = 0.754, 95% CI = 0.632-0.900, P = 0.002).

CONCLUSIONS

The cancer-specific survival (CSS) difference between AD and SRCC was not statistically significant in stage II colon cancer. We provided the first compelling evidence that chemotherapy should not be treated in stage II SRCC, while stage III SRCC should be treated with chemotherapy.

Clinicopathological, molecular features and prognosis of colorectal cancer with mucinous component

Background: Colorectal cancer (CRC) with mucinous component is associated with distinct characteristics and controversial prognosis. Patients & methods: A total of 1800 CRC patients were retrospectively enrolled and grouped by the mucinous content of the primary tumors. The clinicopathological characteristics and overall survival rate were compared between groups. Results: Mucinous adenocarcinoma (MAC) and adenocarcinoma with mucinous component (AMC) had higher frequencies of DNA mismatch repair protein deficiency, KRAS, BRAF and PIK3CA mutations as compared to those of conventional adenocarcinoma (CAC). MAC had worse prognosis than CAC. However, MAC was not an independent prognostic factor in multivariable analysis. Conclusion: Molecular features of AMC and MAC were similar, which were different from those of CAC. Neither MAC nor AMC were independent prognostic factors for CRC.

Clinical impact of non-predominant histopathological subtypes on the long-term prognosis of colorectal cancer patients in Japan

PURPOSE

We performed a retrospective study to clarify the long-term prognosis of patients with histopathological high-grade colorectal cancer (CRC).

METHODS

We reviewed data from 24 institutions for 18,360 patients with pStage I to III CRC who had undergone curative surgery between 2004 and 2012. The patients were classified into seven groups according to the proportion of the histopathological component: classical adenocarcinoma (CAC) group, M-l and M-h groups (< 50% and ≥ 50% mucinous adenocarcinoma, respectively), P-l and P-h groups (< 50% and ≥ 50% poorly differentiated adenocarcinoma, respectively), and S-l and S-h groups (< 50% and ≥ 50% signet-ring cell carcinoma (SRCC), respectively).

RESULTS

The 5-year recurrence-free survival (RFS) rates of the M-l, P-l, and S-l groups were 75.5%, 68.4%, and 52.4%, respectively, and were significantly lower than those of the CAC group (83.5%, hazard ratio [HR] 1.22, 95% confidence interval [CI] 1.01-1.48, p = 0.0365; HR 1.60, 95% CI 1.32-1.91, p < 0.0001; HR 2.61, 95% CI 1.30-4.57, p = 0.0090, respectively). The 5-year RFS of the P-l and S-l groups was as poor as that of the P-h and S-h groups, respectively (HR 0.87, 95% CI 0.68-1.10, p = 0.25; HR 0.90, 95% CI 0.37-2.13, p = 0.81, respectively). The histopathological component of the S-l group was an independent factor affecting overall survival in multivariate analysis.

CONCLUSION

The long-term prognoses of the non-predominant poorly differentiated adenocarcinoma (PAC) groups were as poor as those of the predominant group. In particular, the histopathological component of the P-l and S-l groups could be classified into predominant PAC and SRCC subtypes for appropriate prognostic predictions.

Epidemiology of Mucinous Adenocarcinomas

Simple Summary

Mucinous adenocarcinomas are a very uncommon type of cancer that is poorly studied. These cancers overexpress a jelly-like substance called mucin outside their cells. These cancers share characteristics to another group of cancers called signet ring cell adenocarcinomas, which express mucin inside their cells, and these cancers almost invariability have a worse outcome compared to conventional adenocarcinomas. In our study, we show that patient outcomes with mucinous adenocarcinomas depend largely on the site of the cancer, with both similarities and differences to cancers arising from signet ring cells. This work, along with our recent study on signet ring cell cancers, provides a solid epidemiological reference for future work to motivate investigations as to how recognizing this tumor histology should lead to more tailored cancer treatments in order to improve patient outcomes.

Abstract

Mucinous (colloid) adenocarcinomas (MAs) are a rare histological subtype of adenocarcinomas where extracellular mucin comprises more than 50% of the tumor. Most literature on MAs relate to cancers from colorectal and breast sites; however, the literature lacks a standardized overview of the MA disease entity. Particularly in colorectal cancer, some MAs may have signet ring cells floating within the mucin, which may represent a highly metastatic phenotype. MAs and signet ring cell adenocarcinomas represent a spectrum of mucin-producing neoplastic conditions where in the latter most mucin is intracellular rather than extracellular. We recently published a standardized overview of signet ring cells, and in this companion work, using a retrospective cohort approach, we summarize the clinicodemographic and mortality outcomes of MAs in sixteen primary sites, comprising 95.6% of all MAs in the Surveillance, Epidemiology, and End Results Program (SEER), a population-level cancer database covering nearly one-third of the United States population. Compared to matching nonvariant adenocarcinomas, MAs have a slightly earlier age of onset with increased rates of regional and distant disease at presentation. Survival outcomes are highly dependent on tumor location, illustrating our poor understanding of MA tumor biology. The clinical significance of MA histology depends largely on tumor site.

Tumour infiltrating lymphocyte status is superior to histological grade, DNA mismatch repair and BRAF mutation for prognosis of colorectal adenocarcinomas with mucinous differentiation

Mucinous colorectal adenocarcinoma (CRC) is conventionally defined by extracellular mucin comprising >50% of the tumour area, while tumours with ≤50% mucin are designated as having a mucinous component. However, these definitions are largely arbitrary and comparisons of clinico-molecular features and outcomes by proportion of mucinous component are limited. A cohort of 1643 patients with stage II/III cancer was examined for tumour mucinous component, DNA mismatch repair (MMR) status, BRAF mutation and tumour infiltrating lymphocytes (TILs). Tumours with ≤50% mucinous component exhibited similar characteristics as mucinous tumours, including association with female gender, proximal location, high grade, TIL-high, defective MMR (dMMR) and BRAF mutation. Proportion of mucinous component did not stratify disease-free survival (DFS). In univariate analysis dMMR status, but not histological grade, stratified survival for mucinous and mucinous component tumours; however, in multivariate analysis dMMR status was not an independent predictor. BRAF mutation prognostic value depended on mucinous differentiation and MMR status, with poor prognosis limited to non-mucinous pMMR tumours (HR 2.61, 95% CI 1.69-4.03; p < 0.001). TIL status was a strong independent predictor of DFS in mucinous/mucinous component tumours (HR 0.40, 95% CI 0.23-0.67; p < 0.001), and a superior predictor of prognosis compared with histological grade, MMR and BRAF mutation. Mucinous component and mucinous stage II/III CRCs exhibit clinico-molecular resemblances, with histological grade and BRAF mutation lacking prognostic value. Prognosis for these tumours was instead strongly associated with TIL status, with the most favourable outcomes in TIL-high dMMR tumours, whilst TIL-low tumours had poor outcomes irrespective of MMR status.

Primary signet ring cell carcinoma with tubular adenoma of the rectum: A case report and a review of the literature

RATIONALE

Among the various forms of colorectal carcinomas, primary signet ring cell carcinoma (SRCC) of rectum is infrequent. Primary SRCC with adenoma is even rarer. Due to its low morbidity and lack of obvious manifestations at early stages, it is difficult to make an early diagnosis and perform surgical intervention in time. Herein, we reported a case of primary SRCC with tubular adenoma of rectum and also performed a review of the literature of such cases, in hopes of expanding the general understanding regarding such cases.

PATIENT CONCERNS

A 61-year-old male patient presented with rectal bleeding for 1 week.

DIAGNOSES

A neoplasm could be palpated through a rectal examination, with a size of 4.0 cm by 3.0 cm, at a distance of 5 cm from the anal edge. Magnetic resonance imaging examination and colonoscopies were performed to confirm the finding, and 4 tissue specimens were obtained for histopathologic biopsy. The result of biopsy was high-grade intraepithelial neoplasia with an adenoma component.

INTERVENTIONS

Surgical resection was performed, and histopathologic and immunohistochemical staining examination of the resection confirmed the diagnosis of SRCC with tubular adenoma.

OUTCOMES

The patient was discharged from hospital 12 days postsurgery, without any complications. Further chemotherapy and supportive treatments were suggested to him and will be followed at a local hospital.

LESSONS

Primary rectal SRCC has a rather low morbidity. Furthermore, a rectal SRCC with adenoma which was presenting in this case is even more rare. Besides lack of clinical characters, delay of diagnosis and treatment frequently occur. So far, a surgical procedure has still been one of the most effective treatments. Considering of metastasis and the poor prognosis, early diagnosis, in-time radical resection, and a comprehensive followed treatment are recommended for a higher 5-year overall survival.

CDH1 gene mutation in early-onset, colorectal signet-ring cell carcinoma

AIM

Colorectal signet-ring cell carcinomas (SRCC) are highly malignant tumours with poor prognosis that disproportionately affect younger patients. There is growing evidence of a unique set of molecular features that separate SRCC from conventional colorectal adenocarcinoma. Identification of these distinct features may have diagnostic and prognostic significance for patients and families. CDH1, which encodes E-cadherin, a cell adhesion protein, is commonly mutated in gastric SRCC and our study aimed to identify whether CDH1 mutation was also a common phenomenon in colorectal SRCC.

METHODS

DNA was extracted from formalin-fixed paraffin embedded tumour tissue, the CDH1 gene was analysed by next generation sequencing and the pathogenicity of mutations assessed in silico. Sections cut from the same blocks were immunostained to identify the presence of the E-cadherin protein.

RESULTS

We found 8 CDH1 mutations that meet our inclusion criteria in seven of 11 samples. Of these, five (from four patients), were likely to be germline mutations. E-cadherin staining was absent or markedly reduced in all of the seven samples with CDH1 mutation.

CONCLUSION

Our finding of CDH1 mutations in a proportion of signet-ring cell carcinomas and associated reduction in E-cadherin in these tumours supports previous findings of a role for mutation of this gene in the development of this disease. In addition, the finding of likely germline mutations suggests that a subset of these tumours may be familial. Loss of E-cadherin staining in the absence of CDH1 mutations however also suggests a role for environmental factors in a subset of these tumours.

Three-Dimensional CT Texture Analysis to Differentiate Colorectal Signet-Ring Cell Carcinoma and Adenocarcinoma

Purpose

The objective of this research was to validate the diagnostic value of three-dimensional texture parameters and clinical characteristics in the differentiation of colorectal signet-ring cell carcinoma (SRCC) and adenocarcinoma (AC).

Methods

We retrospectively analyzed data from 102 patients with SRCC or AC confirmed by pathology, including 51 SRCC (from January 2015 to July 2019) and 51 AC patients (from January 2019 to July 2019). CT findings and clinical data, including age, gender, clinical symptoms, serological biomarkers, tumor size, and tumor location, were compared between SRCC and AC. CT texture features were quantified on portal phase images using three-dimensional analysis. A list of texture parameters was generated with MaZda software for the classification of tumors. The texture features, clinical data and CT findings were statistically analyzed for the discrimination ability of SRCC and AC, and the potential predictive parameters that may be used to differentiate the two groups were subsequently tested using the least absolute shrinkage and selection operator (LASSO) and logistic regression analyses. The receiver operating characteristic curve (ROC) provided a range of values for establishing the cutoff value, as well as the sensitivity and specificity of prediction for each significant variable.

Results

SRCC occurred more often in men than AC did (80.39% vs 49.02%, P < 0.01). The patients were younger in the SRCC group than in the AC group, without a statistically significant difference (55.84 vs 59.20 years, P = 0.216). There were no significant differences in the clinical symptoms, tumor size, or tumor location between the two groups (P=0.505, P=0.19, P=0.843, respectively). The elevation of serological biomarker CA724 was more common in SRCC than in AC (P< 0.001). Perc.01%3D, Perc.10%3D and s(1,0,0) SumAverg were lower in the SRCC group than in the AC group during the portal phase, with the areas under curve (AUCs) of 0.892–0.929, sensitivity of 76.5–84.3% and specificity of 88.2–96.1%. In the differentiation between SRCC and AC, the 1-NN minimal classification error (MCR) was 29.41%.

Conclusion

Three-dimensional texture parameters, including Perc.01%3D, Perc.10%3D and s(1,0,0) SumAverg, exhibited a favorable discriminatory ability to distinguish SRCC from AC.

Mucosal cancer-associated microbes and anastomotic leakage after resection of colorectal carcinoma

BACKGROUND

Clinical and experimental evidence suggests that colorectal mucosal microbiota changes during colorectal carcinogenesis and may impair colorectal anastomotic wound healing. Thus, we hypothesized that amounts of colorectal cancer-associated microbes in colorectal tissue might be associated with anastomotic leakage after resection for colorectal carcinoma.

METHODS

We analyzed 256 fresh frozen tissues of colorectal cancer from patients who underwent elective colorectal resection and anastomosis. Amounts of colorectal cancer-associated microbes, including Fusobacterium nucleatum, Escherichia coli possessing the polyketide synthase (pks) gene cluster, Enterococcus faecalis, and Bifidobacterium genus, in colorectal cancer tissues were measured by quantitative polymerase chain reaction assay; we equally dichotomized positive cases (high versus low). Multivariable logistic regression analysis was conducted to assess associations of these microbes with anastomotic leakage, adjusting for patient and tumor characteristics, and surgery-related factors.

RESULTS

Fusobacterium nucleatum, pks-positive Escherichia coli, Enterococcus faecalis, and Bifidobacterium genus were detected in colorectal carcinoma tissue in 140 (54%), 94 (36%), 193 (75%), and 89 (35%) of 256 cases, respectively. Compared with Bifidobacterium genus-negative cases, Bifidobacterium genus-high cases were associated with an increased risk of anastomotic leakage (multivariable odds ratio, 3.96; 95% confidence interval, 1.50 to 10.51; P_trend = 0.004). The association of Fusobacterium nucleatum, pks-positive Escherichia coli, or Enterococcus faecalis with anastomotic leakage was not statistically significant.

CONCLUSIONS

The amount of Bifidobacterium genus in colorectal tissue is associated with an increased risk of anastomotic leakage after resection for colorectal cancer. These findings need to be validated to target gastrointestinal microflora for the prevention of anastomotic leakage after colorectal resection.

Mucinous adenocarcinoma of the colon and rectum: A genomic analysis

BACKGROUND AND OBJECTIVES

Mucinous adenocarcinoma is a distinct subtype of colorectal cancer (CRC) with a worse prognosis when compared with non-mucinous adenocarcinoma. The aim of this study was to compare somatic mutations and copy number alteration (CNA) between mucinous and non-mucinous CRC.

METHODS

Data from The Cancer Genome Atlas-colon adenocarcinoma and rectum adenocarcinoma projects were utilized. Mucinous and non-mucinous CRC were compared with regard to microsatellite status, overall mutation rate, the most frequently mutated genes, mutations in genes coding for mismatch repair (MMR) proteins and genes coding for mucin glycoproteins. CNA analysis and pathway analysis was undertaken.

RESULTS

Mucinous CRC was more likely to be microsatellite instability-high (MSI-H) and hypermutated. When corrected for microsatellite status the single-nucleotide variation and insertion-deletion rate was similar between the two cohorts. Mucinous adenocarcinoma was more likely to have mutations in genes coding for MMR proteins and mucin glycoproteins. Pathway analysis revealed further differences between the two histological subtypes in the cell cycle, RTK-RAS, transforming growth factor-β, and TP53 pathways.

CONCLUSIONS

Mucinous CRC has some distinct genomic aberrations when compared with non-mucinous adenocarcinoma, many of which are driven by the increased frequency of MSI-H tumors. These genomic aberrations may play an important part in the difference seen in response to treatment and prognosis in mucinous adenocarcinoma.

Adenocarcinoma with mixed subtypes is a rare but aggressive histologic subtype in colorectal cancer

Background

Although numerous studies have investigated the clinicopathologic and prognostic relevance of mucinous adenocarcinoma (MAC) and signet-ring cell carcinoma (SRCC) compared with classic adenocarcinoma (CA), little is known about the prognosis of adenocarcinoma with mixed subtypes (AM) and the differences among these four subtypes.

Methods

The statistics of colorectal cancer registered in the Surveillance, Epidemiology and End Results (SEER) database were retrieved and analyzed. We also compared the clinicopathologic and prognostic relevance between CA, SRCC, MAC, and AM.

Results

The frequencies of these four subtypes were 69.9% (CA, n = 15,812), 25.1% (MAC, n = 5689), 3.6% (SRCC, n = 814) and 1.4% (AM, n = 321), respectively. All of MAC, SRCC, and AM were significantly related with aggressive features. Only SRCC and AM were identified as independent poor prognostic markers for overall survival by multivariate analysis. The aggressiveness of AM was between MAC and SRCC according to the clinicopathologic associations. The prognosis of AM was significantly worse than MAC but comparable with SRCC.

Conclusions

We confirmed the clinicopathologic relevance with aggressive features of MAC and SRCC, as well as poor prognostic relevance of SRCC by analyzing a large study population data set. Furthermore, we identified AM as a rare but aggressive histologic subtype in colorectal cancer, to which particular attention should be given in clinical practice.

Prognostic significance of mucinous component in hilar cholangiocarcinoma after curative-intent resection

BACKGROUND

The presence of mucinous component has been indicated to have a prognostic value in adenocarcinoma. However, little is known regarding the clinicopathological characteristics and prognosis of hilar cholangiocarcinoma (HC) with mucinous component (HCM).

METHODS

Between January 1996 and December 2014, a total of 61 HCM patients who underwent curative-intent resection at West China Hospital were retrospectively reviewed. The clinicopathological characteristics and survival of these patients were compared with a large cohort of 217 surgically resected conventional HC patients during the same period.

RESULTS

The clinicopathological characteristics of HCM were distinct from conventional HC, including higher CA19-9 levels, larger tumor sizes, less differentiation, and a high frequency of liver parenchyma invasion, portal vein invasion, and lymphovascular invasion. HCM patients showed significantly worse recurrence-free survival (13.4 vs 23.9 months; P = .011) and overall survival (18.2 vs 32.1 months; P = .019) compared with conventional HC patients. Multivariate analysis confirmed liver parenchyma invasion, N stage, surgical margin, and histological grade as independent prognostic factors influencing overall survival in HCM patients.

CONCLUSION

HCM showed distinct clinicopathological features, more aggressive biological behaviors, and poor prognosis in comparison with conventional HC. Therefore, the mucinous component is an adverse prognostic factor for HC.

Prognoses of different pathological subtypes of colorectal cancer at different stages: A population-based retrospective cohort study

Background

Whether the prognoses of different pathological subtypes of colorectal cancer (CRC) at different stages are distinct is unclear.

Methods

We extracted data on all cases of CRC from the Surveillance, Epidemiology, and End Results database between 2004 and 2015. The incidence of different pathological subtypes, clinical characteristics, and five-year overall survival (OS) and cause-specific survival (CSS) were analyzed.

Results

A total of 384,996 cases diagnosed as adenocarcinoma (AC), mucinous adenocarcinoma (MAC), and signet ring cell carcinoma (SRCC) were included in this analysis. Compared with AC, MAC and SRCC were more likely to reach T4, N2, M1, stages III and IV, and grades III and IV, and patients were generally of a younger age (P < 0.001). Compared with those with AC, patients with MAC and SRCC showed poorer OS (50.6 and 26.8% vs. 60.2%, P < .001), with corresponding HR values of 1.238 (95% CI, 1.213–1.263, P < .001) and 1.592 (95% CI, 1.558–1.627, P < .001), respectively. The MAC and SRCC groups also showed poorer overall CCS (60.9 and 32.5% vs. 67.8%, P < .001), with corresponding HR values of 1.271 (95% CI, 1.242–1.302, P < .001) and 1.724 (95% CI, 1.685–1.765, P < .001), respectively. Compared with patients with AC, those with MAC showed poor OS at every stage and poor CSS at every stage except stage II (P < .05), while patients with SRCC revealed poor OS and CSS at every stage except stage 0 (P < .05).

Conclusions

Patients of different pathological subtypes minimally differed at early stages. However, patients with AC have significantly better prognoses in advanced CRC (stages III and IV) than those with MAC or SRCC. Distinct treatment strategies should be applied depending on a particular histological subtype in advanced CRC.

Immunohistochemical and genetic features of mucinous and signet-ring cell carcinomas of the stomach, colon and rectum: a comparative study

Gastric and colorectal cancers are prevalent and fatal cancers worldwide. Although mucinous adenocarcinoma (MAC) and signet-ring cell carcinoma (SRCC) are relatively uncommon, they are of critical importance because of poor prognosis. In Turkey, studies on MSI and other molecular characteristics in mucinous adenocarcinoma (MAC) and signet-ring cell carcinoma (SRCC) of stomach and colon have not been conducted. The present study aimed to investigate the similarities and differences between gastric/colorectal MACs and SRCCs. A total of 590 patients with gastric carcinoma and 1075 patients with colorectal carcinoma, in whom pathologic diagnosis was made within a period of 8 years in our hospital, were retrospectively evaluated. Tissue blocks and slides obtained from the pathology archive were used for immunohistochemical and genetic studies and for microscopic re-evaluation according to the WHO criteria. Data from a total of 135 patients, of whom 78 had been diagnosed with MAC and 57 had been diagnosed with SRCC, were analyzed. MAC patients were significantly older than those with SRCCs. While colorectal localization was more common among MACs, SRCC patients mostly showed gastric localization. Macroscopically, ulceroinfiltrative type was the most prevalent in both groups followed by fungating type in MAC and infiltrative type in SRCC. When compared with SRCC group, MAC group was associated with higher tumor invasion stage, lower rate of patients with infiltrative growth pattern and perineural invasion, and less frequent lymph node invasion. More effective approaches will be developed in the treatment and prevention of cancer along with more data about the incidence, pathogenesis, prognostic factors, and clinical course of cancers.

Signet ring cell colorectal cancer: genomic insights into a rare subpopulation of colorectal adenocarcinoma

Background

Signet ring cell carcinoma (SRCC) is a rare subtype of colorectal cancer (CRC). The aim of this study was to characterise the genomic alterations and outcomes of SRCC.

Methods

Medical records of metastatic CRC (mCRC) patients whose tumours were evaluated by NGS analysis were reviewed. SC-mCRC were classified into two groups: SRCC (>50% signet ring cells) and adenocarcinoma (AC) with SC component (≤50% signet ring cells).

Results

Six hundred and sixty-five mCRC patients were included. Of the 93 mCRC cases with SC features, 63 had slides for review. Of those 63 cases, 35 were confirmed SRCC, and 28 were AC with SC component. Compared with AC group, KRAS and PIK3CA mutations (mts) were found in only 11% (OR: 0.13) and 3% (OR: 0.15) of SRCC cases, respectively. In contrast to the 44% rate of APC mts in AC group, only 3% of SRCC patients had APC mts (OR = 0.04).

Conclusions

SRCC has distinct molecular features, including low rates of KRAS, PIK3CA and APC mts. Further study to identify activation pathways and potential therapeutic targets are needed.

Colorectal Cancer Prognosis: The Impact of Signet Ring Cell

Background

The prognosis for patients with colorectal cancer shows variation. The characteristics of colorectal cancer patients with signet-ring cell carcinoma (SRCC) are still not clear.

Materials and Methods

A retrospective comparison was made of the data of signet-ring cell colorectal carcinoma patients operated on between 2009 and 2018 in respect of clinicopathological and operative results, morbidity, mortality, and long-term survival.

Results

The study included a total of 34 patients comprising 26 (76%) males and 8 (24%) females with a mean age of 58 ± 11.7 years. Incidence of SRCC was determined as 1.8%. Lymphovascular invasion was determined in 22 (64%) patients. Tumors were determined as stage T2 in 8 (32%) patients, stage T3 in 9 (36%), and stage T4 in 8 (32%). According to the TNM classification, 5 (14.7%) patients were diagnosed with stage 1, 7 (20.6%) with stage 2, 15 (44.1%) with stage 3, and 7 (20.6%) with stage 4. The mean follow-up period was 40.6 ± 30.4 months, and mean disease-free follow-up was determined as 33.1 ± 36.1 months. Fifteen (44.1%) patients died because of the disease.

Conclusion

Although SRCC is a poor prognostic factor, it should be kept in mind when determining adjuvant therapies and prognosis of patients determined with advanced-stage SRCC.

Meta-analysis of the molecular associations of mucinous colorectal cancer

BACKGROUND

Mucinous differentiation occurs in 5-15 per cent of colorectal adenocarcinomas. This subtype of colorectal cancer responds poorly to chemoradiotherapy and has a worse prognosis. The genetic aetiology underpinning this cancer subtype lacks consensus. The aim of this study was to use meta-analytical techniques to clarify the molecular associations of mucinous colorectal cancer.

METHODS

This study adhered to MOOSE guidelines. Databases were searched for studies comparing KRAS, BRAF, microsatellite instability (MSI), CpG island methylator phenotype (CIMP), p53 and p27 status between patients with mucinous and non-mucinous colorectal adenocarcinoma. A random-effects model was used for analysis.

RESULTS

Data from 46 studies describing 17 746 patients were included. Mucinous colorectal adenocarcinoma was associated positively with KRAS (odds ratio (OR) 1·46, 95 per cent c.i. 1·08 to 2·00, P = 0·014) and BRAF (OR 3·49, 2·50 to 4·87; P < 0·001) mutation, MSI (OR 3·98, 3·30 to 4·79; P < 0·001) and CIMP (OR 3·56, 2·85 to 4·43; P < 0·001), and negatively with altered p53 expression (OR 0·46, 0·31 to 0·67; P < 0·001).

CONCLUSION

The genetic origins of mucinous colorectal adenocarcinoma are predominantly associated with BRAF, MSI and CIMP pathways. This pattern of molecular alterations may in part explain the resistance to standard chemotherapy regimens seen in mucinous adenocarcinoma.

Mucinous colorectal adenocarcinoma: clinical pathology and treatment options

Mucinous colorectal adenocarcinoma is a distinct subtype of colorectal cancer (CRC) characterized by the presence of abundant extracellular mucin which accounts for at least 50% of the tumor volume. Mucinous colorectal adenocarcinoma is found in 10%–20% of CRC patients and occurs more commonly in female and younger patients. Moreover, mucinous colorectal adenocarcinoma is more frequently located in the proximal colon and diagnosed at an advanced stage. Based on its molecular context, mucinous colorectal adenocarcinoma is associated with the overexpression of mucin 2 (MUC2) and mucin 5AC (MUC5AC) proteins. At the same time, it shows higher mutation rates in the fundamental genes of the RAS/MAPK and PI3K/Akt/mTOR pathways. Mucinous colorectal adenocarcinoma also shows higher rates of microsatellite instability (MSI) than non-mucinous colorectal adenocarcinoma which might correlate it with Lynch syndrome and the CpG island methylator phenotype. The prognosis of mucinous colorectal adenocarcinoma as to non-mucinous colorectal adenocarcinoma is debatable. Further, the impaired responses of mucinous colorectal adenocarcinoma to palliative or adjuvant chemotherapy warrant more studies to be performed for a specialized treatment for these patients. In this review, we discuss the molecular background and histopathology of mucinous colorectal adenocarcinoma, and provide an update on its prognosis and therapeutics from recent literatures.

Chemotherapy is associated with increased survival from colorectal signet ring cell carcinoma with distant metastasis: A Surveillance, Epidemiology, and End Results database analysis

Background

Colorectal signet ring cell carcinoma (SRCC) is a rare histological subtype of colorectal adenocarcinoma with high metastatic frequency compared to non‐SRCC colorectal cancer (NOS). The aim of this study was to analyze prognostic factors of colorectal SRCC with different metastatic sites and evaluate impacts of various therapies for metastatic colorectal SRCC.

Methods

Patients with NOS and SRCC were from the Surveillance, Epidemiology, and End Results (SEER) database during 2010‐2014. χ² tests were used to compare data significance. Kaplan‐Meier and COX models were used to analyze the differences in the survival. Propensity‐matched analyses were used to adjust numerical differences.

Results

Among the 173 460 patients, 1932 (1.11%) patients had colorectal SRCC. In univariate analysis, older age, male sex, and peritoneum metastasis were associated with higher mortality risk. The peritoneum was both the site with the highest metastatic frequency and the site with the worst prognosis in SRCC. In the COX regression model, peritoneum‐metastatic SRCC patients receiving chemotherapy had better survival than patients treated with surgery.

Conclusions

Our study analyzed the unique metastatic pattern of colorectal SRCC toward different sites and found that compared to surgery, chemotherapy was associated with better survival for colorectal SRCC patients with distant metastasis, which provided insights for future SRCC patient treatment.

Practice patterns and outcomes with the use of regorafenib in metastatic colorectal cancer: Results from the Regorafenib in Metastatic colorectal cancer - An Indian exploratory analysis study

BACKGROUND

Regorafenib is considered a standard of care as third-line therapy in metastatic colorectal cancers (mCRCs).

MATERIALS AND METHODS

The study was based on a computerized clinical data form sent to oncologists across the country for entry of anonymized patient data. The data entry form was conceived and generated by the coordinating center's (Tata Memorial Hospital) gastrointestinal medical oncologists and disseminated through personal contacts at academic conferences as well as through E-mail to various oncologists across India.

RESULTS

A total of 19 physicians contributed data resulting in 80 patients receiving regorafenib who were available for the evaluation of practice patterns. The median age was 55 years (range: 24-75). Majority had received oxaliplatin-based (97.5%), irinotecan-based (87.5%), and targeted therapy (65%), previously. Patients were primarily started on reduced doses of regorafenib upfront (160 mg - 28.8%, 120 mg - 58.8%, and 80 mg - 12.5%). The median duration of treatment (treatment duration) with regorafenib was 3.1 months (range: 0.5-18), while the median progression free survival was 3.48 months (range: 2.6-4.3). Forty-five percent of patients required dose modifications due to toxicities, and the most common were (all grades) hand-foot syndrome (68.8%), fatigue (46.3%), mucositis (37.6%), and diarrhea (31.3%).

CONCLUSIONS

Majority of physicians in this collaborative study from India used a lower dose of regorafenib at the outset in patients with mCRC. Despite a lower dose, there was a significant requirement for dose reduction. Duration of treatment with regorafenib as an efficacy end point in this study is similar to available data from other regions as it is the side effect profile.

The Amount of Bifidobacterium Genus in Colorectal Carcinoma Tissue in Relation to Tumor Characteristics and Clinical Outcome

Evidence indicates a complex link between microbiota, tumor characteristics, and host immunity in the tumor microenvironment. In experimental studies, bifidobacteria appear to modulate intestinal epithelial cell differentiation. Accumulating evidence suggests that bifidobacteria may enhance the antitumor immunity and efficacy of immunotherapy. We hypothesized that the amount of bifidobacteria in colorectal carcinoma tissue might be associated with tumor differentiation and higher immune response to colorectal cancer. Using a molecular pathologic epidemiology database of 1313 rectal and colon cancers, we measured the amount of Bifidobacterium DNA in carcinoma tissue by a quantitative PCR assay. The multivariable regression model was used to adjust for potential confounders, including microsatellite instability status, CpG island methylator phenotype, long-interspersed nucleotide element-1 methylation, and KRAS, BRAF, and PIK3CA mutations. Intratumor bifidobacteria were detected in 393 cases (30%). The amount of bifidobacteria was associated with the extent of signet ring cells (P = 0.002). Compared with Bifidobacterium-negative cases, multivariable odd ratios for the extent of signet ring cells were 1.29 (95% CI, 0.74-2.24) for Bifidobacterium-low cases and 1.87 (95% CI, 1.16-3.02) for Bifidobacterium-high cases (Ptrend = 0.01). The association between intratumor bifidobacteria and signet ring cells suggests a possible role of bifidobacteria in determining distinct tumor characteristics or as an indicator of dysfunctional mucosal barrier in colorectal cancer.

The prognostic value of signet ring cell histology in stage I/II colon cancer-a population-based, propensity score-matched analysis

BACKGROUND

Previous research associated signet ring cell histology in colon cancer patients with poor survival outcomes. The aim of this study was to analyze the prognostic significance of signet ring cell histology on overall and cancer-specific survival in patients with localized colon cancer.

METHODS

Stage I and II colon cancer patients treated with surgical resection between 2004 and 2015 were identified in the Surveillance, Epidemiology, and End Results (SEER) database. Overall survival (OS) and cancer-specific survival (CSS) were assessed using risk-adjusted Cox proportional hazards regression models and propensity score methods.

RESULTS

Eighty-eight thousand nine hundred fifty-eight stage I-II colon cancer patients were identified. Overall, 446 (0.5%) showed signet ring cell histology. In unadjusted analyses, the 5-year OS and CSS rates of patients with signet ring cell histology were 65.8 and 83.1%, respectively, compared with 74.3 and 88.7% in patients with non-signet ring cell adenocarcinoma (p values: OS, p < 0.001; CSS, p < 0.001). Neither in risk-adjusted Cox proportional hazard regression analysis (OS: hazard ratio (HR), 0.96 (95% CI, 0.82-1.12%) p = 0.616; CSS: HR, 1.01 (95% CI, 0.79-1.28%) p = 0.946) nor with propensity score matching (OS: HR, 0.96 (95% CI, 0.82-1.14%) p = 0.669 and CSS: HR: 1.09 (95% CI: 0.84-1.40%) p = 0.529), a survival disadvantage was found for signet ring cell histology.

CONCLUSION

This is the first propensity score-adjusted population-based investigation on exclusively stage I and II colon cancer patients providing compelling evidence that signet ring cell histology does not negatively impact survival in stage I and II colon cancer after risk-adjusting for known prognostic factors. Therefore, standard treatment strategies can be applied in these patients.

Clinical and Histopathologic Features of Colorectal Adenocarcinoma in Crohn's Disease

GOALS

The aim of this study was to assess the histopathologic characteristics of colorectal carcinomas (CRC) in patients with Crohn's disease (CD).

BACKGROUND

A higher frequency of microsatellite instability (MSI) is seen in mucinous compared with nonmucinous CRC which suggests that its pathogenesis involves distinct molecular pathways. Several publications reported a higher percentage of mucinous adenocarcinoma in CD patients with CRC. So far, there has been no investigation of MSI in CD patients with mucinous CRC.

STUDY

The medical records of patients who underwent surgery for CRC were reviewed and those with a history of CD identified. The data of histologic classification and MSI status of the tumor were investigated.

RESULTS

Fourteen patients with CD-associated CRC were identified (5 female, 9 male) resulting in 20 CRC in total. Histologic investigation revealed 7 adenocarcinomas without a mucinous or signet ring cell component. All other CRCs harbored a mucinous (n=11) and/or signet ring cell (n=6) component. All tumors assessed for MSI were found to be microsatellite stable.

CONCLUSIONS

Our data indicate that CRCs with signet ring cell and mucinous components were much more common in patients with CD than in patients with sporadic CRC. This observation suggests that CRC in CD represent an own entity with distinct histopathologic and molecular features. This may implicate potential consequences for diagnosis and therapy of CRC in CD in the future as well as new factors to identify patients with an increased risk for developing CRC in CD.

Clinical, Pathological, and Molecular Characteristics of CpG Island Methylator Phenotype in Colorectal Cancer: A Systematic Review and Meta-analysis

BACKGROUND: CpG island methylator phenotype (CIMP) tumors, comprising 20% of colorectal cancers, are associated with female sex, age, right-sided location, and BRAF mutations. However, other factors potentially associated with CIMP have not been robustly examined. This meta-analysis provides a comprehensive assessment of the clinical, pathologic, and molecular characteristics that define CIMP tumors. METHODS: We conducted a comprehensive search of the literature from January 1999 through April 2018 and identified 122 articles, on which comprehensive data abstraction was performed on the clinical, pathologic, molecular, and mutational characteristics of CIMP subgroups, classified based on the extent of DNA methylation of tumor suppressor genes assessed using a variety of laboratory methods. Associations of CIMP with outcome parameters were estimated using pooled odds ratio or standardized mean differences using random-effects model. RESULTS: We confirmed prior associations including female sex, older age, right-sided tumor location, poor differentiation, and microsatellite instability. In addition to the recognized association with BRAF mutations, CIMP was also associated with PIK3CA mutations and lack of mutations in KRAS and TP53. Evidence of an activated immune response was seen with high rates of tumor-infiltrating lymphocytes (but not peritumoral lymphocytes), Crohn-like infiltrates, and infiltration with Fusobacterium nucleatum bacteria. Additionally, CIMP tumors were associated with advance T-stage and presence of perineural and lymphovascular invasion. CONCLUSION: The meta-analysis highlights key features distinguishing CIMP in colorectal cancer, including molecular characteristics of an active immune response. Improved understanding of this unique molecular subtype of colorectal cancer may provide insights into prevention and treatment.