Mucinous histology of colon cancer predicts poor outcomes with FOLFOX regimen in metastatic colon cancer

Clinicopathological features and prognosis analysis of proximal colonic mucinous adenocarcinoma

Mucinous adenocarcinoma (MAC) is a distinct subtype of colorectal cancer. Previous studies have confirmed the poor prognosis of rectal or left-sided colon MAC, while the prognosis and response to chemotherapy in proximal colon MAC remains controversial. The aim of this study was to investigate the clinicopathological characteristics, prognosis, response to chemotherapy, and risk prediction factors of proximal colon MAC. Patients with proximal colon MAC and non-mucinous adenocarcinoma (NMAC) were retrospectively analyzed in this study. The analyzed variables included gender, age, smoking, drinking, chemotherapy, metastasis, pathological stage, and tumor size. Overall survival (OS) was the primary outcome. Kaplan-Meier analysis was used to assess the impact of mucinous subtype and chemotherapy on OS. We conducted univariate and multivariate Cox regression analyses to determine prognosis factors for proximal colon MAC and NMAC. A total of 284 cases of proximal colon MAC and 1384 cases of NMAC were included in the study. Compared to NMAC, proximal colon MAC was diagnosed at a younger age. The proportion of synchronous and metachronous metastasis was also higher, as well as the pathological stage and tumor size. Proximal colon MAC had a worse prognosis than NMAC, especially in stage 3. Moreover, the prognosis of proximal colon NMAC improved after chemotherapy, while MAC showed no improvement in prognosis after chemotherapy. Advanced age, N1 and N2 stage were independent prognostic factors for adverse outcomes in MAC. For proximal colon adenocarcinoma, the independent predictors of adverse outcomes included mucinous subtype, order age, N1 and N2 stages, and pathological stage 4. Proximal colon MAC had a worse prognosis compared to NMAC. Chemotherapy did not improve the prognosis of proximal colon mucinous adenocarcinoma.

Survival Benefits of Postoperative Chemotherapy in Patients With Colorectal Mucinous Adenocarcinoma: An Analysis Utilizing Propensity Score Matching From the Surveillance, Epidemiology, and End Results Database

OBJECTIVE

This study aimed to investigate the characteristics of patients with colorectal mucinous adenocarcinoma (MAC) who benefit from postoperative chemotherapy (POCT) and to develop effective postoperative survival nomograms for predicting overall survival (OS) in colorectal MAC patients.

METHODS

Data of colorectal MAC patients who underwent surgery from the Surveillance, Epidemiology, and End Results (SEER) database between 2010 and 2020 were collected. Patients were grouped based on POCT, and intergroup analysis was performed using 1:1 propensity score matching (PSM). Kaplan-Meier (K-M) curves were used to compare the prognosis between the 2 groups. Cox analysis was employed to identify factors associated with OS in patients with colorectal MAC who underwent POCT. The variance inflation factor (VIF) and bilateral stepwise regression were used to determine factors included in the model. Additionally, a nomogram was constructed to predict postoperative survival outcomes for patients. The discriminative ability of the nomograms was evaluated using the C-index and calibration curve analysis, the decision curve analysis (DCA) assessed the clinical utility of the nomogram, and the receiver operating characteristic (ROC) curve evaluated the nomograms' performance.

RESULTS

This study encompassed 6829 patients with colorectal MAC, among whom 2258 received POCT, and 4571 did not. Whether pre or post PSM, patients in the POCT group consistently exhibited a superior median OS compared to those in the postoperative non-chemotherapy group (P < .0001). For colorectal MAC patients undergoing POCT, OS was correlated with factors such as patient age, carcinoembryonic antigen levels, tumor deposits, perineural invasion (PNI), lymph node examination count, T staging, and Grade staging. Notably, a significant chemotherapy advantage was observed in patients without perineural invasion, those with lymph node examination counts exceeding 12, and patients with moderately differentiated tumors. The overall colorectal MAC patient postoperative OS predictive nomogram demonstrated a C-index of .74, with a calibration curve near the diagonal and a DCA curve indicating positive net benefits. In comparison to TNM staging, the ROC curves of the nomogram at 1 year, 3 years, and 5 years demonstrated superior predictive capabilities (AUC: .80 vs .71, .78 vs .71, .77 vs .70).

CONCLUSION

This study revealed the characteristics of colorectal MAC patients who benefit from POCT and established effective prognostic nomograms, which can aid clinicians in designing personalized treatment plans for individual patients and promote precision medicine.

Mucinous Differentiation in Colorectal Cancer: A 10-Year Experience Audit at King Faisal Specialist Hospital and Research Centre, Jeddah

Given that colorectal cancer is one of the leading causes of mortality, mucinous adenocarcinoma is one of the subtypes and is characterized by the presence of mucin-producing tumor cells with mucin components and is more challenging to manage. In Saudi Arabia, it represents approximately 10-15% of all colorectal carcinoma. The main etiological cause of mucinous adenocarcinoma is yet not well understood. The main goal of our study is to discuss the histopathology and the molecular background of mucinous colorectal adenocarcinoma and also to provide an update on its prognosis and therapeutics from recent published literature. It is a retrospective cohort study that was conducted at King Faisal Specialist Hospital, Jeddah, Saudi Arabia. The study included 68 adult patients diagnosed with mucinous colon cancer, who did surgical resection alone or with or without adjuvant chemotherapy following from January 2011 to December 2020. The mucinous subtypes are found more commonly in the proximal colon. In our study, 26 patients (38.2% of the cases) were right-sided and 35 patients (51.5%) were from the left side, but these included the rectum as well and this reflects the higher incidence of diagnosis of rectal cancer in the region. Most tumors were classified as Grade II in 56 patients (82.4%), consistent with the intermediate differentiation status often associated with the mucinous subtypes. The most common symptom at presentation was abdominal pain in 38 patients (55.9%) followed by per rectal bleeding and abdominal mass. The management in our study was in line with the standard established practice and surgical resection as expected was the primary potentially curative approach. Notably of patients presenting with locally advanced rectal cancer, six patients underwent concomitant chemoradiotherapy followed by surgery and four patients had upfront surgery. The duration of the median follow-up was 32 months. At the time of analysis, 30 patients (44.1%) were alive and remained on regular follow-up, 17 patients (25%) had succumbed to the disease, and 21 patients (30.9%) were lost to follow-up. The median overall survival was not reached, and notably, 49 patients (71.6%) remained alive at the four-year mark. Whilst our study contributes to the current understanding of mucinous adenocarcinomas of the colon, further research in molecular profiling and genomic testing and larger clinical trials with tailored treatments is necessary to refine treatment strategies and improve outcomes.

Recurrence and Survival Following Cytoreductive Surgery and Hyperthermic Intraperitoneal Chemotherapy for Synchronous and Metachronous Peritoneal Metastases of Colorectal Origin

Cytoreductive surgery (CRS) with hyperthermic intraperitoneal chemotherapy (HIPEC) has improved the 5-year survival for colorectal cancer (CRC) patients with peritoneal metastases (PM). Little is known about recurrence patterns and recurrence rates between synchronous (S) and metachronous (M) PM following CRS+HIPEC. We aimed to describe the recurrence patterns, overall survival (OS) and disease-free survival (DFS) in S-PM and M-PM patients after complete CRS+HIPEC. From June 2006 to December 2020, a prospective cohort study included 310 CRC patients, where 181 patients had S-PM (58.4%) and 129 patients had M-PM (41.6%). After a median 10.3-month follow-up, 247/310 (79.7%) patients experienced recurrence, and recurrence sites included isolated peritoneal (32.4%), multifocal (peritoneal and liver and/or lung(s)) (22.7%), isolated liver (17.8%), isolated lung (10.5%) and other (16.6%) sites. Recurrence patterns did not differ between S-PM and M-PM. M-PM patients had an impaired DFS compared to S-PM patients (9.4 months (95% CI: 7.3-12.1) vs. 12.5 months (95% CI: 11.2-13.9), p = 0.01). The median OS was similar for S-PM and M-PM (38.4 months (95% CI: 31.2-46.8) vs. 40.8 months (95% CI: 28.8-46.8), p = 0.86). Despite frequent recurrence at extraperitoneal locations, long-term survival was achievable after CRS+HIPEC in CRC patients with PM. The recurrence patterns and OS did not differ between groups, yet M-PM patients had a shorter DFS.

Survival Benefit of Primary Tumor Resection Combined With Chemotherapy in Patients With Unresectable Colorectal Mucinous Adenocarcinoma With Liver Metastasis

OBJECTIVE

To evaluate the survival benefit of combining primary tumor resection (PTR) and chemotherapy in patients with unresectable colorectal mucinous adenocarcinoma with liver metastasis (UCR-MAC-LM).

METHODS

We obtained data from the surveillance, epidemiology, and end results database for patients with UCR-MAC-LM from 2010 to 2017. Clinicopathological characteristics were analyzed using the χ2 test. Propensity score matching was performed to balance baseline characteristics. Kaplan-Meier analysis and log-rank tests were used to estimate and compare survival outcomes. Univariate and multivariate Cox regression analyses were conducted to identify the prognostic factors.

RESULTS

A total of 10,178 patients with unresectable colorectal adenocarcinoma with liver metastasis were included, of whom 6.01% (n=612) had UCR-MAC-LM. The UCR-MAC-LM group had a higher proportion of female patients, a greater number of elderly patients, an increased incidence of right colon localization, larger tumor size, and higher T and N staging than the unresectable colorectal non-mucinous adenocarcinoma with liver metastasis group (P<0.05). Multivariate analysis identified several independent prognostic factors (P<0.05). Patients with unresectable colorectal adenocarcinoma with liver metastasis who underwent PTR+C had superior survival rates compared with those who received PTR/C alone or no treatment (cancer-specific survival, P<0.05; overall survival, P<0.05). Subgroup analysis revealed that 17 of 22 groups of patients with UCR-MAC-LM who received PTR+C had significantly prolonged long-term survival compared with those who received PTR/C alone.

CONCLUSIONS

This surveillance, epidemiology, and end results-based study indicates that PTR+C may offer a survival advantage for a specific subgroup of patients with UCR-MAC-LM compared with PTR/C alone. Nonetheless, additional clinical trials are necessary to validate these findings.

FAP promotes metastasis and chemoresistance via regulating YAP1 and macrophages in mucinous colorectal adenocarcinoma

Mucinous colorectal adenocarcinoma (MC) is less likely to respond to chemotherapy and is associated with poorer prognosis compared with non-MC (NMC). Fibroblast activation protein (FAP) was found and validated to be upregulated in MC patients and was negatively correlated with prognosis and therapeutic outcomes in colorectal cancer (CRC) patients who were treated with adjuvant chemotherapy. Overexpression of FAP promoted CRC cell growth, invasion and metastasis, and enhanced chemoresistance. Myosin phosphatase Rho-interacting protein (MPRIP) was identified as a direct interacting protein of FAP. FAP may influence the efficiency of chemotherapy and prognosis by promoting the crucial functions of CRC and inducing tumor-associated macrophages (TAMs) recruitment and M2 polarization through regulating theRas Homolog Family Member/Hippo/Yes-associated protein (Rho/Hippo/YAP) signaling pathway. Knockdown of FAP could reverse tumorigenicity and chemoresistance in CRC cells. Thus, FAP may serve as a marker for prognosis and therapeutic outcome, as well as a potential therapeutic target to overcome chemoresistance in MC patients.

Primary renal mucinous adenocarcinoma masquerading as a giant renal cyst: a case report

Mucinous adenocarcinoma of the kidney is rarely reported in the literature. We present a previously unreported mucinous adenocarcinoma arising from the renal parenchyma. A 55-year-old male patient with no complaints showed a large cystic hypodense lesion in the upper left kidney on contrast-enhanced computed tomography (CT) scan. A left renal cyst was initially considered, and a partial nephrectomy (PN) was performed. During the operation, a large amount of jelly-like mucus and bean-curd-like necrotic tissue was found in the focus. The pathological diagnosis was mucinous adenocarcinoma, and further systemic examination revealed no clinical evidence of primary disease elsewhere. Then the patient underwent left radical nephrectomy (RN), and the cystic lesion was found in the renal parenchyma, while neither the collecting system nor the ureters were involved. Postoperative sequential chemotherapy and radiotherapy were administered, and no signs of disease recurrence were observed over 30 months of follow-up. Based on a literature review, we summarize the lesion with rarity and the associated dilemma in preoperative diagnosis and treatment. Given the high degree of malignancy, a careful history analysis accompanied by dynamic observation of imaging and tumor markers is recommended for the diagnosis of the disease. Comprehensive treatment based on surgery may improve its clinical outcomes.

The Long Noncoding RNA Cytoskeleton Regulator RNA (CYTOR)/miRNA-24-3p Axis Facilitates Nasopharyngeal Carcinoma Progression by Modulating GAD1 Expression

Nasopharyngeal carcinoma (NPC) is a head and neck epithelial carcinoma that is unusually prevalent in Southeast Asia. Noncoding RNAs, including lncRNA and miRNA, and their target genes are considered vital regulators of tumorigenesis and the progression of NPC. However, the detailed underlying mechanisms of GAD1 involved in the regulation of NPC need to be further elucidated. In the present study, we identified that GAD1 was significantly upregulated in NPC tissues. GAD1 overexpression is promoted, while genetic knockdown of GAD1 suppresses proliferation, colony formation, migration, and invasion of NPC cells. Bioinformatics analysis and a luciferase reporter assay demonstrated that GAD1 is a direct target gene of miR-24-3p. In NPC tissues, miR-24-3p was downregulated and the lncRNA CYTOR was upregulated. CYTOR was sponged to suppress the function of miR-24-3p. CYTOR regulates GAD1 expression via modulating miR-24-3p. The CYTOR/miR-24-3p/GAD1 axis is converged to modulate the growth, migration, and invasion of NPC cells. In conclusion, the study identified a novel axis for the regulation of NPC cell growth, providing new insights into the understanding of NPC.

Impact of histological subtype on prognosis in stage IV colorectal cancer: A population-based cohort study

BACKGROUND

There are a few established prognostic factors for stage IV colorectal cancer. Thus, this study aimed to evaluate the impact of histological subtypes on prognosis and metastatic patterns in patients with stage IV colorectal cancer.

METHODS

This was a population-based, multicenter, cohort study. We included consecutive patients diagnosed with stage IV colorectal cancer between 2008 and 2015 at all designated cancer hospitals in Fukushima prefecture, Japan. Patients were classified into two groups according to histological subtypes as follows: poorly differentiated adenocarcinoma (Por), mucinous adenocarcinoma (Muc), or signet-ring cell carcinoma (Sig) and well (Wel) or moderately differentiated adenocarcinoma (Mod). We evaluated the relationship between these histological groups and survival time. After adjusting for other clinical factors, we calculated the hazard ratio for Por/Muc/Sig.

RESULTS

A total of 1,151 patients were enrolled, and 1,031 and 120 had Wel/Mod and Por/Muc/Sig, respectively. The median overall survival was 19.2 and 11.9 months for Wel/Mod and Por/Muc/Sig, respectively (p < 0.001). The adjusted hazard ratio for Por/Muc/Sig with regard to survival time was 1.42 (95% confidence interval: 1.13-1.77). Por/Muc/Sig had a lower incidence of liver and lung metastases and a higher incidence of peritoneal dissemination and metastasis to rare organs, such as the bone and brain.

CONCLUSIONS

The Por/Muc/Sig histological subtype was an independent prognostic factor for poor prognosis among patients with stage IV colorectal cancer. The histological subtype may be useful for predicting the prognosis of patients with stage IV colorectal cancer and designing the treatment strategy.

An Analysis of Clinicopathological Outcomes and the Utility of Preoperative MRI for Patients Undergoing Resection of Mucinous and Non-Mucinous Colorectal Cancer Liver Metastases

Background and Aims

Mucinous colorectal cancer has traditionally been associated with high rates of recurrence and poor long-term survival. There is limited published data on outcomes for patients undergoing liver resection for metastatic mucinous colorectal cancer. The aim of this study was to compare the clinicopathological outcomes for patients with mucinous colorectal cancer liver metastases (CRCLM) undergoing liver resection to a matched group of patients with adenocarcinoma not otherwise specified (NOS) and to evaluate the accurary of preoperative magnetic resonance imaging (MRI) at detecting the presence of mucin in liver metastases.

Materials and Methods

Patients with mucinous CRCLM undergoing liver resection were matched 1:3 to patients with adenocarcinoma NOS CRCLM. Clinicopathological data from the primary tumour and metastatic lesion were collected and compared between the groups. Hepatic recurrence-free, disease-free and overall survival were compared between the groups. The ability of preoperative MRI to detect mucin in CRCLM was also evaluated.

Results

A total of 25 patients with mucinous CRCLM underwent surgery over the 12-year period and were matched to 75 patients with adenocarcinoma NOS. Clinicopathological findings were similar between the groups. Resection of mucinous CRCLM was feasible and safe with similar levels of morbidity to adenocarcinoma NOS. There were no differences identified in hepatic recurrence-free (p=0.85), disease-free (p=0.25) and overall survival (p=0.98) between the groups. MRI had a sensitivity of 31.3% in detecting the presence of mucin in CRCLM.

Conclusion

Patients with mucinous CRCLM in this study had similar outcomes to patients with adenocarcinoma NOS. Based on our findings, histological subtype should not be taken into account when deciding on resectability of CRCLM.

Prognosis and Sensitivity of Adjuvant Chemotherapy in Mucinous Colorectal Adenocarcinoma without Distant Metastasis

In colorectal cancer, whereas mucinous adenocarcinoma (MAC) has several poor clinical prognostic factors compared to adenocarcinoma (AC), the prognosis of MAC remains controversial. We evaluated the prognosis of MAC without distant metastasis and the effects of adjuvant chemotherapy using health insurance registry data managed by South Korea. Patients with colorectal cancer between January 2014 and December 2016 were included (AC, 22,050 [96.8%]; MAC, 729 [3.2%]). We observed no difference in overall survival (OS) between AC and MAC in stages I and II. However, MAC showed a worse OS than AC in stage III disease, especially in patients administered chemotherapy (p < 0.001). These findings persisted after propensity score matching of clinical characteristics between AC and MAC. In addition, transcriptome analysis of The Cancer Genome Atlas (TCGA) data showed increased chemoresistance-associated pathways in MAC compared to AC. In consensus molecular subtypes (CMS) classification, unlike in AC, CMSs 1, 3, and 4 comprised most of MAC and the proportions of CMSs 3 and 4 increased with stage progression. These results suggest clues to overcome resistance to chemotherapy and develop targeted treatments in MAC.

Mucinous adenocarcinoma: A unique clinicopathological subtype in colorectal cancer

Mucinous adenocarcinoma (MAC) is a unique clinicopathological subtype of colorectal cancer, which is characterized by extracellular mucinous components that comprise at least 50% of the tumor tissue. The clinical characteristics, molecular features, response to chemo-/radiotherapy, and prognosis of MAC are different from that of non-MAC (NMAC). MAC is more common in the proximal colon, with larger volume, higher T-stage, a higher proportion of positive lymph nodes, poorer tumor differentiation, and a higher proportion of peritoneal implants compared to NMAC. Although biopsy is the main diagnostic method for MAC, magnetic resonance imaging is superior in accuracy, especially for rectal carcinoma. The aberrant expression of mucins, including MUC1, MUC2 and MUC5AC, is a notable feature of MAC, which may be related to tumor invasion, metastasis, inhibition of apoptosis, and chemo-/radiotherapy resistance. The genetic origin of MAC is mainly related to BRAF mutation, microsatellite instability, and the CpG island methylator phenotype pathway. In addition, the poor prognosis of rectal MAC has been confirmed by various studies, and that of colonic MAC is still controversial. In this review, we summarize the epidemiology, clinicopathological characteristics, molecular features, methods of diagnosis, and treatments of MAC in order to provide references for further fundamental and clinical research.

Loss of ZNF677 expression is a predictive biomarker for lymph node metastasis in Middle Eastern Colorectal Cancer

Zinc-finger proteins are transcription factors with a “finger-like” domain that are widely involved in many biological processes. The zinc-finger protein 677 (ZNF677) belongs to the zinc-finger protein family. Previous reports have highlighted the tumor suppressive role of ZNF677 in thyroid and lung cancer. However, its role in colorectal cancer (CRC) has not been explored. ZNF677 protein expression was analyzed by immunohistochemistry in a large cohort of 1158 CRC patients. ZNF677 loss of expression was more frequent in CRC tissues (45.3%, 525/1158), when compared to that of normal tissue (5.1%, 11/214) (p < 0.0001) and was associated with mucinous histology (p = 0.0311), advanced pathological stage (p < 0.0001) and lymph node (LN) metastasis (p = 0.0374). Further analysis showed ZNF677 loss to be significantly enriched in LN metastatic CRC compared to overall cohort (p = 0.0258). More importantly, multivariate logistic regression analysis showed that ZNF677 loss is an independent predictor of LN metastasis in CRC (Odds ratio = 1.41; 95% confidence interval 1.05–1.87; p = 0.0203).The gain- and loss-of-function studies in CRC cell lines demonstrated that loss of ZNF677 protein expression prominently increased cell proliferation, progression of epithelial-mesenchymal transition and conferred chemoresistance, whereas its overexpression reversed the effect. In conclusion, loss of ZNF677 protein expression is common in Middle Eastern CRC and contributes to the prediction of biological aggressiveness of CRC. Therefore, ZNF677 could not only serve as a marker in predicting clinical prognosis in patient with CRC but also as a potential biomarker for personalized targeted therapy.

Risk Factors for Recurrence of Radically Resected Mucinous Colorectal Adenocarcinoma

Background

Mucinous adenocarcinoma (MA) is a subtype of colorectal cancer (CRC) associated with a higher incidence of local extension and worse survival compared to non-mucinous adenocarcinoma, but few studies have investigated surgery-related predictors for recurrence of MA. Therefore, we aimed to elucidate the predictors for local recurrence and remote metastasis of MA after surgery.

Patients and Methods

This study retrospectively analyzed 162 patients with mucinous colorectal adenocarcinoma (MAC) after radical resection. Analysis variables included demographics, clinical indicators, pathologic stage, surgical procedure, adjuvant therapy, and recurrence. Univariate and multivariate analyses were performed to investigate the risk factors for local and distant tumor relapse.

Results

A total of 162 patients (86 male) with a mean age of 58.26 years were included; 70.37% of patients had colonic tumors, and 29.63% had rectal tumors. The 5-year disease-free survival (DFS) rates for these patients were as follows: 100% for TNM stage I, 71.2% for stage II, and 47.8% for stage III. Five-year DFS rates of MAC, colonic and rectal MA were 62.0%, 65.8%, and 51.7%, respectively. Local recurrence occurred in 38 patients and distant metastasis in 33 patients. In univariate analysis, predictors for local recurrence of MAC were intraoperative blood loss, intraoperative transfusion, and N2 stage; and predictors for distant metastasis were male sex, CA199, CEA, intraoperative blood loss, T4 stage, and N2 stage. In multivariate analysis, predictors for local recurrence of MAC were intraoperative transfusion (P=0.04, OR=4.175) and N2 stage (P=0.000, OR=5.291), and predictors for distant metastasis were male sex (P=0.049, OR=2.410), CA199 (P=0.02, OR=1.003), and T4 stage (P=0.007, OR=4.006).

Conclusion

Intraoperative transfusion and N2 stage were significant predictors for local recurrence. Male sex, CA199, and T4 stage were significant predictors for distant metastasis. Knowledge of the risk factors for postoperative recurrence provides a basis for logical approaches to treatment and follow-up of MAC.

Clinicopathological factors associated with synchronous distant metastasis and prognosis of stage T1 colorectal cancer patients

It is rare and understudied for patients with stage T1 colorectal cancer to have synchronous distant metastasis. This study was to determine the clinicopathological factors associated with distant metastasis and prognosis. T1 colorectal cancer patients diagnosed between 2010 and 2015 were obtained from the SEER database. Logistic regression was applied to determine risk factors related to distant metastasis. Cox-proportional hazard models were used to identify the prognostic factors for patients with distant metastasis. Among 21,321 patients identified, 359 (1.8%) had synchronous distant metastasis and 1807 (8.5%) had lymph node metastasis. Multivariate analysis revealed that younger age, positive serum CEA, larger tumor size, positive tumor deposit, perineural invasion, lymph node metastasis, histology of non-adenocarcinoma and poorer differentiation were significantly associated with the increased risk of synchronous distant metastasis. Older age, female, Black, positive CEA, positive lymph node metastasis, positive tumor deposit, larger tumor size, no chemotherapy, inadequate lymph node harvesting and no metastasectomy were correlated with worse survival in these patients with synchronous distant metastasis. Patients with metastasis to the liver displayed the highest rate of positive CEA. We conclude that T1 colorectal cancer patients with multiple risk factors need thorough examinations to exclude synchronous distant metastasis. Chemotherapy, adequate lymph node cleaning and metastasectomy are associated with improved survival for those patients with distant metastases. Positive serum CEA may be useful in predicting distant metastases in patients at stage T1.

Outcomes of Laparoscopic Surgery for Mucinous Colorectal Adenocarcinoma

Background: Mucinous colorectal adenocarcinoma (MAC) has a higher incidence of local extension, leading to lower overall resection rates. Few studies have investigated the outcomes of laparoscopic surgery for MACs to date. Therefore, we aimed to elucidate the validity of laparoscopic surgery for mucinous adenocarcinoma (MAC). Methods: This study analyzed short-term and long-term outcomes between laparoscopic and open surgery for MACs from 2008 to 2018. Multivariate analyses were used to define prognostic factors of overall survival (OS) and disease-free survival (DFS). Results: Patients in the laparoscopy (LAP) group had significantly less blood loss, fewer days to first flatus and to diet, and shorter length of hospital stay. The 3-year and 5-year DFS rates for all stages combined were 65.7% and 62.5% in the LAP group compared with 60.5% and 57.6% in the open (OPEN) surgery group (P = .521). The 3-year and 5-year OS rates for all stages combined were 72.3% and 67.3% in the LAP group compared with 72.6% and 67.8% in the OPEN group (P = .934). OS and DFS in stage II, stage III, and pathological T4 (pT4) stage patients who underwent laparoscopic surgery did not differ from patients who underwent open surgery. Multivariate analysis showed that stage pT4, pN2, and carcinoembryonic antigen (CEA) were significant predictors of OS. Independent factors, including intraoperative blood transfusion, stage pT4, pN2, CEA, and CA19-9, carbohydrate antigen 19-9, have a great effect on DFS. Conclusions: Laparoscopic surgery is a safe and feasible option for mucinous colorectal AC, which provides faster postoperative recovery and less intraoperative blood loss.

Does the efficacy of regorafenib differ in chemotherapy refractory metastatic colorectal cancer patients who had mucinous pathology compared to those who had non-mucinous pathology?

PURPOSE

To investigate the importance of mucinous histopathology on the assessment of tumor response in patients with metastatic colorectal cancer (mCRC) receiving regorafenib.

MATERIALS AND METHOD

All patients diagnosed with histologically confirmed mCRC in 2 oncology centers between 2013 and 2018 were retrospectively analyzed. Among 678 patients diagnosed with mCRC, 103 patients were treated with regorafenib. Ninety-four of these patients who had used at least 2 cycles of regorafenib and evaluable for treatment response were included in the analysis. Histopathologically, 18 patients with mucinous adenocarcinoma and 76 patients with nonmucinous adenocarcinoma were compared in terms of response rate and survival durations.

RESULTS

Median follow-up duration of 6 months, median age of the patients was 61 (34-77) years. While 19.1% of the patients had mucinous histology, 80.9% had nonmucinous histology. The overall response rate was significantly lower in the mucinous subgroup than the nonmucinous subgroup (5.6% vs 43.4%, respectively, P = 0.003). Similarly, both progression-free survival (3.0 vs 4.0 months, respectively, P = 0.011) and overall survival duration were shorter in the mucinous subgroup (3.0 vs 7.0 months, P = 0.016, respectively) compared with the nonmucinous subgroup.

CONCLUSION

The histological subgroup may predict tumor response in mCRC patients receiving regorafenib. Its efficacy on nonmucinous histology had significantly more favorable than mucinous subtype.

Prognostic implications of mucinous histology in stage III colon cancer with the receipt of adjuvant chemotherapy

Background

There is still a debate about the survival benefit of chemotherapy in stage III mucinous colon cancer, we then conduct a comprehensive assessment of the efficacy of adjuvant chemotherapy in this population.

Methods

The data used in the current study were extracted from the Surveillance, Epidemiology and End Results (SEER) database. Chi-squared (χ²) test was used to compared patient characteristics according to the histology. The outcome of the survival analysis used in the current study was cancer-specific survival (CSS). Univariable and multivariable analyses were carried out using the Cox proportional hazards regression models to evaluate the prognostic characteristics associated with CSS of colon cancer. And the risks of mortality were presented as hazard ratios (HRs) with 95% confidence intervals (CIs).

Results

A total of 68,976 patients diagnosed with stage III colon cancer were included in our analyses, including mucinous adenocarcinoma (MAC, N=6,592) and non-mucinous adenocarcinoma (NMA, N=62,384). In NMA, the receipt of chemotherapy had 46.0% independently decreased risk of colon cancer-specific mortality compared to non-chemotherapy group (HR =0.540, 95% CI: 0.523-0.558, P<0.001). In MAC, the receipt of chemotherapy had 37.7% independently decreased risk of colon cancer-specific mortality compared to non-chemotherapy group (HR =0.623, 95% CI: 0.566-0.685, P<0.001).

Conclusions

MAC was associated with worse prognosis and was less responsive to chemotherapy compared with NMA in stage III colon cancer. However, stage III mucinous colon cancer still need to be treated with chemotherapy because of the significant survival benefit and specialized treatment plans for MAC were quite necessary in the future.

Clinicopathological characteristics and prognosis of colorectal mucinous adenocarcinoma and nonmucinous adenocarcinoma: a surveillance, epidemiology, and end results (SEER) population-based study

BACKGROUND

Mucinous adenocarcinoma (MC) is a rare histological subtype of colorectal adenocarcinoma. Previous studies investigating the prognosis of MC have conflicting results and the proper treatment of MC remains unclear.

METHODS

This retrospective study presents the clinicopathological characteristics and prognosis of MC. This cohort study collected data from April 1 through August 01, 2018. This study used data on 107,735 patients with nonmucinous adenocarcinoma (NMC) and 9,494 with MC between 2009 and 2013 from the Surveillance, Epidemiology, and End Results program (SEER). Clinicopathological features were analyzed by chi-square test and survival curves by the Kaplan-Meier method. We used propensity score matching (PSM) to account for potential bias. Logistic regression and Cox proportional hazards models were used to compare and calculate adjusted risks of MC death.

RESULTS

MC was more frequent in patients with older age, large tumor size and moderate tumor grade compared with NMC (P<0.001). Five-year survival was lower for MC patients than NMC patients (P<0.001). Older age, later tumor node metastasis (TNM) stage and multiple tumors indicated a poorer prognosis while surgery gave better survival outcomes [hazard ratio (HR) =0.38; 95% confidence interval (CI), 0.33 to 0.44; P<0.001]. Younger age, left-side colon location and early disease stage were associated with better survival after surgery (P<0.001).

CONCLUSIONS

Age, TNM stage, tumor number and treatment were indicators of prognosis and surgery gave better survival for MC patients compared with those without surgery. Our study contributes to their clinical treatment.

Predictive Impact of Mucinous Tumors on the Clinical Outcome in Patients with Poorly Differentiated, Stage II Colon Cancer: A TOSCA Subgroup Analysis

BACKGROUND

Although American Society of Clinical Oncology and European Society for Medical Oncology guidelines have identified the negative prognostic factors that clinicians have to consider when treating their patients with stage II colon cancer (CC), the role of histological subtype is controversial.

SUBJECTS, MATERIALS, AND METHODS

The randomized, multicenter, phase III TOSCA trial compared 3 versus 6 months of fluoropyrimidine-oxaliplatin adjuvant chemotherapy in 3,759 patients with high-risk stage II or stage III CC. The objective of this substudy was to evaluate the influence of histological subtypes on the impact of the treatment duration of adjuvant chemotherapy in terms of relapse-free survival (RFS) and overall survival (OS) in 85 mucinous adenocarcinoma (MUC) and 389 nonmucinous adenocarcinoma (NMUC) patients with high-risk stage II, grade 3 CC.

RESULTS

A significant interaction between treatment duration and histology was observed in both RFS (p = .027) and OS (p = .017). In the subgroup of patients with MUC, worse RFS (adjusted hazard ratio [HR], 3.95; 95% confidence interval [CI], 1.03-15.17; p = .045) and OS (HR, 9.56; 95% CI, 1.14-79.98; p = .037) were detected for patients treated in the 3-month arm. No statistically significant differences were found in the subgroup of patients with NMUC.

CONCLUSION

Patients with MUC, grade 3, stage II CC require special attention and may need 6 months of oxaliplatin-based chemotherapy. Larger studies are required to assess the combined use of histology and other prognostic/predictive factors to define the administration of chemotherapy in patients with stage II CC and to improve their prognosis.

IMPLICATIONS FOR PRACTICE

Although ASCO and ESMO guidelines define the prognostic factors for patients with stage II colon cancer to establish the use of adjuvant chemotherapy, the influence of histological subtypes is controversial in this population. This study underscores that patients with grade 3 mucinous adenocarcinomas may need adjuvant chemotherapy with oxaliplatin and fluoropyrimidines for a duration of 6 months rather than 3 months.

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.

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.

Advanced Mucinous Colorectal Cancer: Epidemiology, Prognosis and Efficacy of Chemotherapeutic Treatment

BACKGROUND

The clinicopathological significance of the mucinous subtype of colorectal cancer (CRC) remains controversial. As of today, none of the current guidelines differentiate treatment with respect to mucinous or nonmucinous cancer. Due to the lack of substantiated data, best treatment remains unclear and the mucinous subtype of CRC is usually treated along the lines of recommendations for adenocarcinoma of the colon.

METHODS

We investigated an East-Bavarian cohort of 8,758 patients with CRC. These included 613 (7.0%) patients with a mucinous subtype, who were analyzed for assessing their characteristics in clinical course and for evaluating the efficacy of common chemotherapy protocols.

RESULTS AND CONCLUSION

Mucinous CRC was predominantly located in the right hemicolon; it was diagnosed at more advanced stages and occurred with preponderance in women. A higher rate of G3/4 grading was observed at diagnosis (all p < 0.001). An association of mucinous CRC with younger age at initial diagnosis, previously reported by other groups, could not be confirmed. Patients with mucinous stage IV colon cancer demonstrated poorer survival (p = 0.006). In contrast, no differences in survival were observed for specific stages I-III colon cancer. Stage-dependent analysis of rectal cancer stages I-IV also showed no differences in survival. However, univariable overall analysis resulted in significant poorer survival of mucinous compared to nonmucinous rectal cancer (p = 0.029). Also, combined analysis of all patients with mucinous CRC revealed poorer overall survival (OS) of these patients compared to nonmucinous CRC patients (median 48.4 vs. 60.2 months, p = 0.049) but not in multivariable analysis (p = 0.089). Chemotherapeutic treatment showed comparable efficacy regarding OS for mucinous and nonmucinous cancers in both an adjuvant and palliative setting for colon cancer patients (p values comparing mucinous and nonmucinous cancers < 0.001-0.005).

Glutamate Decarboxylase 1 Overexpression as a Poor Prognostic Factor in Patients with Nasopharyngeal Carcinoma

Background: Glutamate decarboxylase 1 (GAD1) which serves as a rate-limiting enzyme involving in the production of γ-aminobutyric acid (GABA), exists in the GABAergic neurons in the central nervous system (CNS). Little is known about the relevance of GAD1 to nasopharyngeal carcinoma (NPC). Through data mining on a data set derived from a published transcriptome database, this study first identified GAD1 as a differentially upregulated gene in NPC. We aimed to evaluate GAD1 expression and its prognostic effect on patients with early and locoregionally advanced NPC.

Methods: We evaluated GAD1 immunohistochemistry and performed an H-score analysis on biopsy specimens from 124 patients with nonmetastasized NPC receiving treatment. GAD1 overexpression was defined as an H score higher than the median value. The findings of such an analysis are correlated with clinicopathological behaviors and survival rates, namely disease-specific survival (DSS), distant-metastasis-free survival (DMeFS), and local recurrence-free survival (LRFS) rates.

Results: GAD1 overexpression was significantly associated with an increase in the primary tumor status (p < 0.001) and American Joint Committee on Cancer (AJCC) stages III-IV (p = 0.002) and was a univariate predictor of adverse outcomes of DSS (p = 0.002), DMeFS (p < 0.0001), and LRFS (p = 0.001). In the multivariate comparison, in addition to advanced AJCC stages III-IV, GAD1 overexpression remained an independent prognosticator of short DSS (p = 0.004, hazard ratio = 2.234), DMeFS (p < 0.001, hazard ratio = 4.218), and LRFS (p = 0.013, hazard ratio = 2.441) rates.

Conclusions: Our data reveal that GAD1 overexpression was correlated with advanced disease status and may thus be a critical prognostic indicator of poor outcomes in NPC and a potential therapeutic target to facilitate the development of effective treatment modalities.

Reduced rate of copy number aberrations in mucinous colorectal carcinoma

BACKGROUND

Mucinous carcinoma (MC) is found in 10%-15% of colorectal cancer (CRC) patients. It differs from the common adenocarcinoma (AC) in histopathological appearance and clinical behavior.

METHODS

Genome-wide DNA copy number and survival data from MC and AC primary CRC samples from patients from two phase III trials (CAIRO and CAIRO2) was compared. Chromosomal copy number data from The Cancer Genome Atlas (TCGA) was used for validation. Altogether, 470 ACs were compared to 57 MCs.

RESULTS

MC showed a reduced amount of copy number aberrations (CNAs) compared with AC for the CAIRO/CAIRO2 cohort, with a median amount of CNAs that was 1.5-fold lower (P = 0.002). Data from TCGA also showed a reduced amount of CNAs for MC. MC samples in both cohorts displayed less gain at chromosome 20q and less loss of chromosome 18p. A high rate of chromosomal instability was a strong negative prognostic marker for survival in MC patients from the CAIRO cohorts (hazard ratio 15.60, 95% CI 3.24-75.05).

CONCLUSIONS

Results from this study indicate that the distinct MC phenotype is accompanied by a different genetic basis when compared with AC and show a strong association between the rate of chromosomal instability and survival in MC patients.

DNA methylation reactivates GAD1 expression in cancer by preventing CTCF-mediated polycomb repressive complex 2 recruitment

Levels of γ-aminobutyric acid (GABA) and glutamic acid decarboxylase 1 (GAD1), the enzyme that synthesizes GABA, are significantly increased in neoplastic tissues. However, the mechanism underlying this increase remains elusive. Instead of silencing gene transcription, we showed that the GAD1 promoter was hypermethylated in both colon and liver cancer cells, leading to the production of high levels of GAD1. GAD1 is a target gene that is silenced by H3K27me3. The key locus responsible for GAD1 reactivation was mapped to a DNA methylation-sensitive CTCF-binding site (CTCF-BS3) within the third intron of GAD1. Chromosome configuration capture (3C) analysis indicated that an intrachromosomal loop was formed by CTCF self-dimerisation in normal cells (CTCF binds to both unmethylated CTCF-BS3 and CTCF-BS2). The CTCF dimer then interacted with suppressor of zeste 12 homologue (SUZ12), which is a domain of Polycomb repressive complex 2 (PRC2), promoting the methylation of H3K27 and the silencing of GAD1 expression. This silencing was shown to be inhibited by DNA methylation in cancer cells. These findings strongly suggest that GAD1 is reactivated by DNA methylation, which provided a model for DNA methylation and the active orchestration of oncogenic gene expression by CTCF in cancer cells.

Advances in the care of patients with mucinous colorectal cancer

The majority of colorectal cancers (CRCs) are classified as adenocarcinoma not otherwise specified (AC). Mucinous carcinoma (MC) is a distinct form of CRC and is found in 10-15% of patients with CRC. MC differs from AC in terms of both clinical and histopathological characteristics, and has long been associated with an inferior response to treatment compared with AC. The debate concerning the prognostic implications of MC in patients with CRC is ongoing and MC is still considered an unfavourable and unfamiliar subtype of the disease. Nevertheless, in the past few years epidemiological and clinical studies have shed new light on the treatment and management of patients with MC. Use of a multidisciplinary approach, including input from surgeons, pathologists, oncologists and radiologists, is beginning to lead to more-tailored approaches to patient management, on an individualized basis. In this Review, the authors provide insight into advances that have been made in the care of patients with MC. The prognostic implications for patients with colon or rectal MC are described separately; moreover, the predictive implications of MC regarding responses to commonly used therapies for CRC, such as chemotherapy, radiotherapy and chemoradiotherapy, and the potential for, and severity of, metastasis are also described.

The Increasing Relevance of Tumour Histology in Determining Oncological Outcomes in Colorectal Cancer

Colorectal cancer is not just one type of cancer. Differences in outcome and reaction to treatment can at least be partly explained by different histological and molecular subtypes. Recognition of these differences may influence treatment decisions. However, there is huge variation in the amount of information that is available. Several tumour types such as mucinous carcinoma, signet ring cell carcinoma, neuroendocrine carcinoma and adenosquamous carcinoma have such a distinct phenotype that they are readily recognised. However, due to the rarity of signet ring cell carcinoma and adenosquamous carcinoma, limited data are available. More recently defined subtypes, like medullary carcinoma, serrated adenocarcinoma and micropapillary carcinoma, are not adequately diagnosed, which limits research possibilities using large-scale data from registries. In the current review, we systematically describe the histologic subtypes with the clinical and molecular background. We evaluate their prognosis compared to adenocarcinoma not otherwise specified and speculate about the clinical relevance.

A minor (<50%) signet-ring cell component associated with poor prognosis in colorectal cancer patients: a 26-year retrospective study in China

Background

We performed a retrospective study to determine the cancer-specific survival of colorectal cancer patients with a component of signet-ring cells or mucin comprising < 50% of the tumor mass.

Methods

A total of 2454 patients seen in our hospital from 1985 to 2011 were retrospectively studied. The patients were divided into five groups according to type of cancer: signet-ring cell carcinoma (with > 50% signet-ring cell, n = 36), partial signet-ring cell carcinoma (with < 50% signet-ring cell, n = 28), mucinous adenocarcinoma (with > 50% mucin lacking signet-ring cell, n = 267), partial mucinous adenocarcinoma (with < 50% mucin lacking signet-ring cell, n = 145), and classic adenocarcinoma (with absence of either mucin or signet-ring cell, n = 1978).

Results

Patients with > 50% or < 50% signet-ring cell had the lowest 5-year survival rates (35.5% and 29.7%, respectively), followed by patients with > 50% mucin (48.8%). Patients who had partial mucinous adenocarcinoma with < 50% mucin and classic adenocarcinoma patients had the highest 5-year survival rates (64.8% and 65.3%, respectively). Stratified and multivariate analysis showed that signet-ring cell carcinoma, partial signet-ring cell carcinoma and mucinous adenocarcinoma were independent predictors of decreased survival (hazard ratio 1.699, P = 0.016; hazard ratio 2.182, P = 0.005; hazard ratio 1.532, P < 0.001; respectively), and partial mucinous adenocarcinoma was not (hazard ratio 1.137, P = 0.431).

Conclusions

Patients with a component of signet-ring cells, regardless of the extent, had poor prognoses. Patients with mucinous adenocarcinoma containing >50% mucin had poor prognoses as well, whereas those with < 50% mucin had survival rates similar to those of classic adenocarcinoma patients. Therefore, in clinical practice, patients with a component of signet-ring cells, regardless of the extent, should be given significant clinical attention.

Prognostic factors in relation to racial disparity in advanced colorectal cancer survival

INTRODUCTION

Colorectal cancer mortality rates are significantly greater in AA than in EA individuals, and the disparity is worsening. We investigated the relationship between race and metastatic CRC (mCRC) survival in younger and older patients.

PATIENTS AND METHODS

Using data from the Hollings Cancer Center (Charleston, SC), we studied the role of clinical, pathologic, and treatment-related factors on the disparity in survival. We carried out a retrospective cohort study of 82 mCRC patients (26 AA, 56 EA). The data source was medical record data from June 1, 2004 through May 31, 2008 with follow-up through June 30, 2010. Using Kaplan-Meier methods, we generated median survival time according to race and age (< 61, ≥ 61 years). Cox proportional hazards regression models were used to model the risk of death according to race.

RESULTS

The median age was 56.7 years for AA and 61.6 years for EA patients. Compared with EA, median survival in AA patients was 59% worse in younger patients (12.7 vs. 31.0 months) and 29% worse in older patients (11.7 vs. 16.4 months). The risk of death among younger AA compared with EA patients was 2.45 (95% confidence interval [CI], 1.15-5.23) and among older patients was 1.16 (95% CI, 0.49-2.73).

CONCLUSION

Our results highlight the importance of considering younger age, clinical prognostic markers, and tumor phenotypes as potential sources of the disparity in advanced stage CRC.

Prognosis and value of adjuvant chemotherapy in stage III mucinous colorectal carcinoma

BACKGROUND

Colorectal mucinous adenocarcinoma (MC) has been associated with impaired prognosis compared with nonmucinous adenocarcinoma (NMC). Response to palliative chemotherapy is poor in metastatic disease, but the benefit of adjuvant chemotherapeutic treatment has never been assessed in large patient groups. This study analyses overall survival and efficacy of adjuvant chemotherapy in terms of survival in patients following radical resection for MC.

PATIENTS AND METHODS

This population-based study involved 27 251 unselected patients diagnosed with colorectal carcinoma between 1990 and 2010 and recorded in a prospective pathology-based registry. Kaplan-Meier analysis and log-rank testing were used to estimate survival. Cox proportional hazard model was used to calculate multivariate hazard ratios for death.

RESULTS

MC was found in 12.3% (N = 3052) of colorectal tumors with a different distribution compared with NMC, with 24.4% located in the rectum and 54.3% in the proximal colon (versus 38.0% and 30.6%), P < 0.0001. NMC was more often classified as stage I disease than MC (20.5% versus 10.9%), P < 0.0001. After adjustments for covariates, MC was associated with a higher risk of death only when located in the rectum [hazard ratio 1.22; 95% confidence interval (CI) 1.11-1.34]. Multivariate regression analysis showed a similar survival after adjuvant chemotherapy for stage III MC and NMC patients.

CONCLUSIONS

The poor prognosis for MC is only present in rectal cancer. In the adjuvant setting, there is no difference in the efficacy of chemotherapy between MC and NMC; therefore, current adjuvant treatment recommendations should not take histology into account.