Characteristics in primary signet-ring cell carcinoma of the colorectum, from clinicopathological observations

Systematic review of risk factors, prognosis, and management of colorectal signet-ring cell carcinoma

BACKGROUND

Colorectal signet-ring cell carcinoma (CSRCC) is a rare clinical entity which accounts for approximately 1% of all colorectal cancers. Although multiple studies concerning this specific topic have been published in the past decades, the pathogenesis, associated risk factors, and potential implications on treatment are still poorly understood. Besides the low incidence, historically confusing histological criteria have resulted in confusing data. Nevertheless, the rising incidence of CSRCC along with relatively young age at presentation and associated dismal prognosis, highlight the actual interest to synthesize the known literature regarding CSRCC.

AIM

To provide an updated overview of risk factors, prognosis, and management of CSRCC.

METHODS

A literature search in the MEDLINE/PubMed database was conducted with the following search terms used: 'Signet ring cell carcinoma' and 'colorectal'. Studies in English language, published after January 1980, were included. Studies included in the qualitative synthesis were evaluated for content concerning epidemiology, risk factors, and clinical, diagnostic, histological, and molecular features, as well as metastatic pattern and therapeutic management. If possible, presented data was extracted in order to present a more detailed overview of the literature.

RESULTS

In total, 67 articles were included for qualitative analysis, of which 54 were eligible for detailed data extraction. CSRCC has a reported incidence between 0.1%-2.4% and frequently presents with advanced disease stage at the time of diagnosis. CSRCC is associated with an impaired overall survival (5-year OS: 0%-46%) and a worse stage-corrected outcome compared to mucinous and not otherwise specified adenocarcinoma. The systematic use of exploratory laparoscopy to determine the presence of peritoneal metastases has been advised. Surgery is the mainstay of treatment, although the rates of curative resection in CSRCC (21%-82%) are lower compared to those in other histological types. In case of peritoneal metastasis, cytoreductive surgery with hyperthermic intraperitoneal chemotherapy should only be proposed in selected patients.

CONCLUSION

CSRCC is a rare clinical entity most often characterized by young age and advanced disease at presentation. As such, diagnostic modalities and therapeutic approach should be tailored accordingly.

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.

Characteristics of primary signet ring cell carcinoma of colon and rectum: a case control study

Background

Primary signet ring cell carcinoma of the colon and rectum (PSRCCR) is rare, usually diagnosed at advanced stage with poor outcomes. We aimed to find possible diagnostic clues in order to help diagnosis.

Methods

A retrospective study of PSRCCR patients from 1993 to 2018 was reviewed at a single tertiary center. Colorectal adenocarcinoma patients as control group with 1:4 ratio was also enrolled.

Results

18 patients with PSRCCR were identified. The prevalence rate was 0.16% (18 of 11,515). The mean age was 50.2 years-old in PSRCCR group and 63 years-old in non-SRCC colorectal cancer patients (p < 0.001). Diagnosis tool depends on colonoscopy were much less in PSRCCR group than control group (44.4% vs 93%, p < 0.001). SRCC patients had higher level of CEA (68.3 vs 17.7 ng/mL, p = 0.004) and lower level of Albumin (3.4 vs 4.3 g/dL, p < 0.001). The majority of PSRCCR tumor configuration was ulcerative and infiltrative. More PSRCCR pathology presented as high-grade carcinoma (66.7 vs 1.4%, p < 0.001) and lymphovascular invasion (77.8 vs 44.4%, p = 0.011) than control group. More PSRCCR patients were diagnosed at advanced stage (88.8 vs 40.3%, p = 0.001). Higher mortality was also noticed in PSRCCR group than control group (72.2 vs 20.8%, p < 0.001).

Conclusion

For young patients with long segment colonic stenosis and ulcerative/ infiltrative mucosa but endoscopic biopsy failed to identify malignant cells, earlier operation or non-colon site biopsy is suggested for diagnosing the PSRCCR.

Signet ring cell component in pretreatment biopsy predicts pathological response to preoperative chemoradiotherapy in rectal cancer

PURPOSE

Neoadjuvant therapy is routinely used in the management of locally advanced rectal cancer. This study aimed to evaluate the predictive value of pathological parameters in tumor response after treatment.

METHODS

We reviewed the hematoxylin-eosin slides from pretreatment biopsies of 150 rectal cancer patients who received preoperative chemoradiotherapy (PCRT) at Sun Yat-sen University Cancer Center between May 2013 and June 2016. Pathological and clinical parameters were both studied. The tumor response after chemoradiotherapy was evaluated using the tumor regression grade (TRG). Logistic regression was used to evaluate the relevance between these parameters and tumor response.

RESULTS

Complete tumor response (TRG0 and pCR) to PCRT was identified in 40 (26.7%) patients. The pCR rate was 93.33% (14 of 15) in cases with signet ring cell component versus 19.26% (26 of 135) in those without signet ring cell component (p < 0.001). Four cases with signet ring cell component were evaluated as clinical complete response (cCR), all of whom also achieved pCR; in contrast, only 9 of 15 (60%) cCR cases without signet ring cell achieved pCR.

CONCLUSION

Our data suggest that the signet ring cell component in pretreatment biopsies may be a potential predictor of tumor response to PCRT in rectal cancer. This suggests patients with clinical complete response are more suitable for a wait-and-watch approach.

Does signet ring cell carcinoma component signify worse outcomes for patients with colorectal cancer?

AIM

The purpose of this study was to elucidate the differences in clinical pathology and prognosis between signet ring cell carcinoma component and adenocarcinoma in colorectal cancer.

MATERIALS AND METHODS

From April 2007 to December 2016, a total of 4348 patients with colorectal cancer underwent surgery, of which 3283 were included in the study. One patient was diagnosed with signet ring cell carcinoma (SRCC); 16 were diagnosed with signet ring cell carcinoma component (SRCCc); and 3266 patients were diagnosed with adenocarcinoma (ADC). We matched SRCCc and ADC with a propensity score of 1:3 and analyzed overall survival rates (OS) and cancer-specific survival rate (CSS) between the 2 groups before and after matching.

RESULTS

Before matching, patients in the SRCCc group had more advanced cancer (stage III-IV: 87.5% vs 45.6%; P < .001), more perineural invasion (75.0% vs 44.2%; P = .013), and higher lymphatic invasion (87.5% vs 42.4%; P < .001) than those in the ADC group. Consequently, the OS (P < .001) and CSS (P = .049) of the SRCCc group were worse than the ADC group. Peritoneal metastasis was found in 4 (57%) patients with stage IV disease. However, after tumor staging and all background factors were matched, there were no significant differences in prognosis for OS (P = .127) and CSS (P = .932) between the 2 groups.

CONCLUSION

SRCCc is more likely to be associated with lymphatic invasion and perineural infiltration than ADC, leading to significantly poorer survival outcomes. However, when all background factors are matched with ADC, the prognosis of SRCCc is not worse than ADC. Improving the treatment outcomes of peritoneal metastasis may be pivotal in the treatment of SRCCc.

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.

Histotype influences emergency presentation and prognosis in colon cancer surgery

AIM

To investigate whether differences in histotype in colon cancer correlate with clinical presentation and if they might influence oncological outcomes and survival.

METHODS

Data regarding colon cancer patients operated both electively or in emergency between 2009 and 2014 were retrospectively collected from a prospectively maintained database and analyzed for the purpose of this study. Rectal cancer was excluded from this analysis. Statistical univariate and multivariate analyses were performed to investigate possible significant variables influencing clinical presentation, as well as oncological outcomes and survival.

RESULTS

Data from 219 patients undergoing colorectal resection for cancer of the colon only were retrieved. One hundred seventy-four patients had an elective procedure and forty-five had an emergency colectomy. Emergency presentation was more likely to occur in mucinous (p < 0.05) and signet ring cell (p < 0.01) tumors. No definitive differences in 5-year overall (44.7% vs. 60.6%, p = 0.078) and disease-free (51.2% vs. 64.4%, p = 0.09) survival were found between the two groups as a whole, but the T3 emergency patients showed worse prognosis than the elective (p < 0.03). Lymph node invasion, laparoscopy, histology, and blood transfusions were independent variables found to influence survival. Distribution assessed for pTNM stage showed T3 cancers were more common in emergency (p < 0.01).

CONCLUSIONS AND DISCUSSION

Mucinous and signet ring cell tumors are related to emergency presentation, pT3 stage, poorest outcomes, and survival. Disease-free survival in patients who had emergency surgery for T3 colon cancer seems related to the histotype.

Genomic alterations in signet ring and mucinous patterned colorectal carcinoma

BACKGROUND

The genetic alterations (GAs) in two specific histological subtypes of colorectal cancer (CRC), signet ring cell colorectal carcinoma (SRC) and mucinous colorectal carcinoma (MC), are not well known. In the present study, we employed next-generation sequencing to perform genetic profiling of SRC and MC, and compared the spectrum of GAs with the alterations found in conventional type colorectal cancer (CON).

MATERIALS AND METHODS

We selected 46 CRCs comprising 17 SRCs and mucinous carcinoma with signet ring cell component (SRCCs), 17 MCs, and 12 CONs with microsatellite stability or microsatellite instability-low. Deep sequencing was performed using a targeted cancer panel composed of 171 cancer-related genes. SMAD4 protein expression was evaluated by immunohistochemical staining.

RESULTS

We detected 108 mutations in 18 different genes. Overall, 2.34 GAs were detected per tumor (range, 0-14). The overall frequency of GA and alteration in targetable genes was less prevalent in SRC/SRCC compared to the frequency of alteration in MC/CON (p = 0.040 and p < 0.001, respectively). The GA profile of SRC/SRCC included TP53 (8/17, 47.1%), SMAD4 (5/17, 29.4%), KRAS (4/17.23.5%), APC (4/17.23.5%), PIK3CA, ATM, BRAF, and PIK3R1 (1/17, 5.9%, each). KRAS mutation was significantly less prevalent in SRC/SRCC compared to the number of KRAS mutations in MC (12/17, 70.6%) and CON (9/12, 75.0%) (p = 0.015 and 0.01, respectively). Compared to the 152 non-hypermutated CONs from TCGA database, SMAD4 alteration was predominant in SRC/SRCC (p = 0.045) with aberrant loss of SMAD4 expression (13/17, 76.5%) compared to the SMAD4 alterations in CON (5/15, 33.3%) (p = 0.031). Accordingly, KRAS (12/17, 70.6%), APC (6/17, 35.3%), SMAD4, TP53 (4/17, 23.5%, each), PIK3CA (3/17, 17.6%), AKT1, ATM, BRAF, EGFR, and EZH2 (1/17, 5.9%, each) were altered in MC. APC and TP53 mutations were less frequent in MC compared to those in TCGA-CON (p < 0.001 and 0.003, respectively) whereas KRAS mutation was prevalent (p = 0.041).

CONCLUSION

Alterations of known cancer associated genes and targetable genes in SRC/SRCC are infrequent. The profile of GAs in SRC/SRCC and MC differs from the GA profile of CON. Specifically, SMAD4 mutation and loss of SMAD4 expression is frequently found in SRC/SRCC. The genetic profiles revealed in the present study may aid in developing precision medicine for CRC treatment based on histological subtype.

Prognosis of three histological subtypes of colorectal adenocarcinoma: A retrospective analysis of 8005 Chinese patients

BACKGROUND AND OBJECTIVES

To evaluate the effect of the varied histological subtypes on clinical outcomes and to determine the prognostic implications of mucinous adenocarcinomas (MAC) and signet ring cell carcinomas (SRCC) compared with classic adenocarcinomas (AC).

METHODS

A total of 8005 patients, including 7502 AC, 428 MAC and 75 SRCC, who underwent definitive surgery between 2007 and 2015 at Fudan University Shanghai Cancer Center were remained for analysis in this study.

RESULTS

MAC and SRCC were more common in right-sided colon cancer, in males and in young patients, compared to AC; moreover, MAC and SRCC led to a higher probability to develop lymph node metastasis, lymphovascular invasion and perineural invasion. For survival outcomes, we found that the 5-year overall survival (OS) of SRCC was significantly lower than that of MAC and AC, while the 5-year OS of MAC is much lower than that of AC. However, in multivariable analysis, the difference in survival between SRCC, MAC and AC was no longer significant, especially when stratified by N stage.

CONCLUSIONS

MAC and SRCC are rare subtypes of colorectal cancer with a higher T stage, N stage as well as higher incidence of lymphovascular and nerve invasion. However, neither MAC nor SRCC was an independent predictor of decreased survival in multivariate analysis.

Colorectal signet ring cell carcinoma: Influence of EGFR, E-cadherin and MMP-13 expression on clinicopathological features and prognosis

Signet ring cell carcinoma (SRCC) is unique rare subtype of mucin-producing colorectal adenocarcinoma characterized by presence of signet ring cells, in >50% of the tumor tissue. This study aims to investigate expression of EGFR, E-cadherin and MMP-13 expression on clinicopathological features of signet ring cell type and its prognostic effect using manual tissue microarray technique. In this work, we studied tumor tissue specimens from 150 patients with colorectal cancer cases among which 19 cases of SRCC. High density manual tissue microarrays were constructed using modified mechanical pencil tips technique and immunohistochemistry for EGFR, E-cadherin and MMP-13 expression was done. We found that SRCC was significantly associated with younger age and more frequency of LN metastasis than all other groups. SRCC was also significantly associated with annular gross picture, more depth of invasion, advanced stage, more lymphovascular emboli, more perineural invasion and less arousal from an overlying adenoma. In conclusion, colorectal SRCC has distinctive clinicopathological and histological features with different unique mechanisms of carcinogenesis and more aggressive biologic behavior than other colorectal carcinoma subtypes. Negative/low expressions of EGFR and E-cadherin and MMP-13 were found in SRCC with no effect on the prognosis.

Outcome of young patients with rectal adenocarcinoma

BACKGROUND

There is an increase in the incidence of rectal carcinoma (RC) in young patients.

METHODS

We analyzed 175 patients with sporadic RC which were divided in two groups according their age: 24 patients ≤40 years and 151 patients >40 years and the two groups were compared in order to determine if the outcomes (especially overall 5-year survival) were different.

RESULTS

Overall 5-year survival was similar between groups (67.1% for patients over 40 years and 70.4% for those under 40 years, P=0.803). The only differences found were in some clinicopathologic features: patients <40 years showed more dissected lymph nodes (LNs) (21 vs. 15, P=0.035) and more LN metastasis (54.2% vs. 39.1%, P=0.048). In multivariate analysis factors associated with worse survival were incomplete resection and no use of neoadjuvant therapy. Age did not demonstrate prognostic value (P=0.077).

CONCLUSIONS

RC in people ≤40 years demonstrated greater number of LN harvested and LN metastases but oncologic outcomes, especially 5-year overall survival, were similar between groups.

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.

What is hiding in the hindgut sac? Looking beyond rectal carcinoma

Objectives

Although rectal cancer is by far and large the most common pathology involving the rectum that needs imaging, there are many other important but less common pathological conditions affecting anorectal region. The objective of this pictorial review is to discuss the cross-sectional imaging features of less common anorectal and perirectal diseases.

Results

Although a specific histological diagnosis cannot usually be made due to considerable overlap in the imaging appearances of anorectal diseases, this review illustrates the cross-sectional imaging findings with emphasis on magnetic resonance imaging (MRI) that can help in narrowing down the differentials to a reasonable extent.

Teaching points

• Variety of pathology exists in the anorectum apart from common rectal carcinoma

• Anorectal diseases present as non-specific wall thickening indistinguishable from rectal carcinoma

• Computed tomography (CT) and MRI can help in narrowing down the differentials, although often biopsy is warranted.

Insight into mucinous colorectal carcinoma: clues from etiology

The prognostic impact of mucinous carcinoma (MC) in colorectal cancer (CRC) has been subject to debate ever since the introduction of the classification of tumors according to their histological differentiation. MC is a distinct clinical and pathological entity within the spectrum of CRC and accounts for approximately 10-15 % of cases. Factors involved in MC development have not been completely understood, but clinical observations may lead to a better insight into the etiology of MC. In this article, we provide an in-depth review of the literature regarding etiological aspects of MC. We show that there are worldwide differences in the prevalence of MC, with low rates in Asian countries and higher rates in the western world. Moreover, MC is more commonly diagnosed in patients suffering from inflammatory bowel diseases or Lynch syndrome and an increased rate of MC is observed in patients with radiotherapy-induced CRCs. These findings are suggestive of a different oncogenic development. Identification of conditions that are associated with MC generates insight into the etiological pathways leading to the development of this special subtype.

Clinicopathological features and survival outcomes of primary signet ring cell and mucinous adenocarcinoma of colon: retrospective analysis of VACCR database

BACKGROUND

Signet ring cell carcinoma (SRCC) accounts for less than 1% of all colon cancers. We examined the clinicopathological features and prognosis of signet ring cell and mucinous adenocarcinoma (MCC) of colon.

METHODS

A total of 206 patients diagnosed with SRCC from 1995 to 2009 were identified from the VA Central Cancer Registry (VACCR) database. Age, race, histology, grade, lymph node status, stage and type of treatment received data were collected.

RESULTS

Out of 206 patients, 173 (84%) were white, 31 (15%) were black, and 2 patients were listed as unknown. Median age of diagnosis was 67 years as compared to 70 years for both mucinous cell (MCC) and non-mucinous adenocarcinoma (NMCC) of colon. Pathological T-stages were as follows: T1 =3%, T2 =5%, T3 =34%, T4 =26%, and unknown 32%. Of the total, 22.3% were located in cecum, 7.7% in appendix, 21.8% in ascending colon, 7.7% in hepatic flexure of colon, 11% in transverse colon, 2.9% in splenic flexure 4.4% in descending colon, and 15.5% in sigmoid colon. 46.5% were lymph node positive, 21% were lymph node negative, and 32.5% were unknown. SRCC were in general poorly differentiated tumors (57%), small proportion of patients included were well-differentiated tumors with focal signet ring cell pathology (10%) and in 33% grade was unknown. Among stage 3 patients, 34% patients received only surgery while 64% received surgery with adjuvant chemotherapy and 2% received chemotherapy alone. The stage specific 5-year survivals for SRCC, MCC and NMCC were--Stage I: 100%, 61%, and 41% respectively (P<0.0001); Stage II: 42%, 58% and 32% respectively (P<0.0001); Stage III: 19%, 41% and 47% respectively (P=0.0002); Stage IV: 1.5%, 7% and 31% respectively (P<0.0001). Median survival of SRCC compared to NMCC was 18.6 vs. 46 months (P<0.0001) and mucinous cell adenocarcinoma versus NMCC was 47.8 and 46 months (P=0.63) respectively.

CONCLUSIONS

SRCC of colon has poor survival rates compared to other histological subtypes. SRCC presents at an earlier age, has higher tumor grade and advanced stage at diagnosis when compared to mucinous and NMCC of colon. Due to rarity of this disease further prospective multi-institute studies are required for in-depth understanding of this disease.

Impact of aggressive histology and location of primary tumor on the efficacy of surgical therapy for peritoneal carcinomatosis of colorectal origin

BACKGROUND

Cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemoperfusion (HIPEC) for peritoneal carcinomatosis (PC) of colorectal origin increases survival (OS) compared to systemic chemotherapy alone. Signet ring histology demonstrates aggressive behavior with poor survival. We sought to determine whether CRS/HIPEC increases survival in this subset of patients.

METHODS

We reviewed 67 patients with PC of appendiceal (AP, n = 37) or colorectal origin (CRC, n = 30) with signet cell histology from a prospective database between May 2001 and August 2011. Survival analysis and multivariate Cox regression were used to determine prognostic factors for survival.

RESULTS

Complete CRS (CC-0/1) was achieved in 77 % (CRC) and 73 % (AP) of patients. Progression-free survival (PFS) and OS were 9 and 12 months in CRC and 12 and 21 months in AP patients. In the CRC group, univariate predictors of poor survival included female gender, age, American Society of Anesthesiologists score, preoperative albumin, completeness of cytoreduction, and morbidity. In a multivariate Cox regression model, incomplete cytoreduction (CC-2/3) and female gender were joint significant predictors of poor survival. In the AP group, significant univariate predictors of poor survival included higher EBL and PCI score. In a multivariate Cox regression model, blood loss of >500 ml and a body mass index of <25 kg/m(2) were joint significant predictors of poor survival.

CONCLUSIONS

AP signet cell tumors demonstrate a more favorable outcome than CRC signet cell tumors after CRC/HIPEC for carcinomatosis, suggesting an underlying difference in biology. CRS/HIPEC does not confer survival benefit in colorectal signet ring carcinomatosis unless complete cytoreduction can be achieved, whereas appendiceal signet ring carcinomatosis may benefit, regardless of resectability.

Signet cell carcinoma of the colon in a 17 year old child

Signet cell carcinomas of the colon are well documented in the adult population, but this cancer incidence is very low in the adolescent population. A 17 year old male child presented with one month of progressive abdominal pain. CT scan of the abdomen showed significant abnormality involving the ascending colon characterized as marked mural thickening. Biopsy results indicated signet ring cell carcinoma. Signet cell carcinoma is presumed to be caused by genetic mutations just like the other colorectal cancers. Treatment for signet cell carcinoma is the same as other colorectal cancer. Surgery is part of the standard management of patients with colon and rectal cancer stages I, II and III. Signet cell cancer has a poor survival with the median survival period of about 9 months. The incidence among adolescence is much lower than that of the adult population.

Mucinous differentiation in colorectal cancer--indicator of poor prognosis?

AIMS

  To analyse the prognostic impact of mucinous differentiation in colorectal mucinous adenocarcinomas and adenocarcinomas with a mucinous component.

METHODS AND RESULTS

  A total of 381 tumours were reviewed for mucinous differentiation by two independent pathologists. Mismatch repair status was assessed by immunohistochemistry. Prognostic significance was assessed by univariate and multivariate analyses. Eighty-one (21%) tumours were Union Internationale Contre le Cancer (UICC) Stage I, 120 (31%) Stage II, 126 (33%) Stage III and 54 (14%) Stage IV. Mucinous adenocarcinomas accounted for 12% and adenocarcinomas with a mucinous component for 19% of tumours. Mucinous differentiation was associated significantly with mismatch repair protein deficiency. The presence of extracellular mucin, regardless of extent, did not affect patients' outcome, while tumour grade, vascular and perineural invasion, tumour border configuration and budding were associated significantly with outcome. Cox analysis proved venous invasion to be an independent predictor of outcome in mucinous adenocarcinomas and both venous invasion and tumour budding as independent predictors of outcome in adenocarcinomas with any amount of mucin.

CONCLUSIONS

  Mucinous adenocarcinomas and/or adenocarcinomas with mucinous component do not differ from conventional adenocarcinomas with respect to prognosis and histological predictors of outcome. Hence, recording of mucinous differentiation may be used as an indicator of mismatch repair deficiency, but not for prognostic stratification.

Expression of NHERF1 in colonic tumors induced by 1,2-dimethylhydrazine in rats is independent of plasma ovarian steroids

In normal embryonic fibroblasts, the Na(+)/H(+) exchanger regulator factor 1 (NHERF1) stabilizes E-cadherin/β-catenin binding and the lack of NHERF1 expression promotes cell transformation thus acting as a tumor suppressor gene. We here tested the hypothesis that NHERF1 could act as a tumor suppressor gene in colon cancer as a mediator of estrogens' protective actions in colon carcinogenesis. We studied the expression and localization of NHERF1 and β-catenin by immunohistochemistry in colonic tumors induced by 1,2 dimethylhidrazine (DMH) in Sprague-Dawley rats. One group of the rats treated with the carcinogen was ovariectomized (OVX) in the middle of the tumor induction, simulating a human menopausal condition. We observed a protective role of estrogens in colon cancer, as non-ovariectomized rats (DMH) had a reduced tumor area compared with the ovariectomized group (DMH + OVX; mean ± SE) 28.98 ± 4.65 vs. 67.58 ± 8.69 (p < 0.00380). Despite the lack of plasma estrogen stimulation, we found abundant expression of NHERF1 in colon tumors from ovariectomized rats. NHERF1 was mainly localized in the cytoplasm of the adenocarcinoma cells and lost the apical localization previously reported in normal colon tissue. We also detected expression of NHERF1 by western blot in the SW48, CACO-2, and HT29 colon cancer cell lines. Non-estrogenic factors in plasma or the tumor microenvironment may regulate NHERF1 expression in transformed colon epithelial cells. Further studies are required to understand the regulation of NHERF1 expression in colon cancer tissue.

Mucinous colorectal adenocarcinoma with signet-ring cells: immunohistochemical and ultrastructural study

A primary mucinous colorectal adenocarcinoma tissue with signet-ring cells, as revealed after histological evaluation, was examined ultrastructurally. The authors also analyzed the immunohistochemical data of the tissue for serotonin, vasoactive intestinal polypeptide (VIP), bombesin, somatostatin, and glucagon, using the peroxidase anti-peroxidase (PAP) method and the immunogold labeling method for light and electron microscope, respectively. Electron microscopically mucinous adenocarcinoma was characterized by the formation of small lumen. Adenocarcinoma cells were full of mucous granules of varying electron density, providing a good environment for the tumor cells to grow. They also exhibited a significant loss of microvilli and intracytoplasmic junctions, which could allow the cells to disseminate. Signet-ring cells were located in the basal site of the ducts or in the lamina propria and appeared neoplastic, with mucin accumulation intracellularly and an eccentric crescent-shaped nucleus. The cytoplasmic organelles were decreased and at the periphery of the cell. The PAP method demonstrated that these cells were strongly positive for bombesin and also positive for vasointestinal polypeptide (VIP). The immunogold method detected bombesin immunoreactivity in the vacuoles as well as in other cytoplasmic membranes, whereas VIP was localized mainly in the plasma membrane. The location of signet-ring cells combined with the immunoreactivity for bombesin and VIP indicated that signet-ring cells were of neuroendocrine origin and probably dedifferentiated enterochromaffin-like endocrine cells. These findings have implications for understanding the biological behavior of these composite malignant tumors and could help in the knowledge of the origin of signet-ring cells.

Signet-ring cell carcinoma of colorectum--current perspectives and molecular biology

PURPOSE

Colorectal signet-ring cell carcinoma (SRCC) is rare, and very little detailed information on the molecular biology of the disease is available.

METHODS

The literature on the clinical, pathological and, in particular, the molecular biology of this rare entity was critically reviewed. The reviewed articles take into account a total of 1,817 cases of SRCC, but only 143 cases have molecular data available. The characteristics of two patients with colorectal SRCC were also discussed.

RESULTS

Colorectal SRCC mostly occurs in younger patients, is larger and has different site predilection compared with conventional colorectal adenocarcinoma. It can occur as one of the synchronous cancers in the colorectum. The cancer is usually diagnosed at advanced stages because of the late manifestation of symptoms, and aggressive treatment strategy is required. Limited reports in the literature have shown that the variant of colorectal cancer demonstrated a different pattern of genetic alterations of common growth kinase-related oncogenes (K-ras, BRAF), tumour suppressor genes (p53, p16), gene methylation and cell adhesion-related genes related to the Wingless signalling pathway (E-cadherin and beta-catenin) from conventional colorectal adenocarcinoma. Colorectal SRCC also showed high expression of mucin-related genes and genes related to the gastrointestinal system. There was also a higher prevalence of microsatellite instability-high tumours and low Cox-2 expression in colorectal SRCC as opposed to conventional adenocarcinoma.

CONCLUSIONS

Colorectal SRCC has unique molecular pathological features. The unique molecular profiles in SRCC may provide molecular-based improvements to patient management in colorectal SRCC.

Gene expression profiling of colorectal mucinous adenocarcinomas

PURPOSE

Although mucinous adenocarcinomas represent 6% to 19% of all colorectal adenocarcinomas, little is known about the genome-wide alterations associated with this malignancy. We have sought to characterize both the gene expression profiles of mucinous adenocarcinomas and their clinicopathologic features.

METHODS

Tumors from 171 patients with primary colorectal cancer were profiled using the Affymetrix HG-U133Plus 2.0 GeneChip with characterization of clinicopathologic data. Gene ontology software was used to identify altered biologic pathways.

RESULTS

Twenty (11.7%) mucinous adenocarcinomas and 151 (89.3%) nonmucinous adenocarcinomas were identified. Mucinous adenocarcinomas were more likely to be diagnosed with lymph node (LN) metastases (75% vs 51%, P = .04) and at a more advanced stage (85% vs 54%, P = .006) but long-term survival (5-y survival 58.9% vs 58.7%, P = NS) was similar. Mucinous adenocarcinomas displayed 182 upregulated and 135 downregulated genes. The most upregulated genes included those involved in cellular differentiation and mucin metabolism (eg, AQP3 + 4.6, MUC5AC +4.2, MUC2 + 2.8). Altered biologic pathways included those associated with mucin substrate metabolism (P = .002 and .02), amino acid metabolism (P = .02), and the mitogen-activated protein kinase cascade (P = .02).

DISCUSSION

Using gene expression profiling of mucinous adenocarcinomas, we have identified the differential upregulation of genes involved in differentiation and mucin metabolism, as well as specific biologic pathways. These findings suggest that mucinous adenocarcinomas represent a genetically distinct variant of colorectal adencarcinoma and have implications for the development of targeted therapies.

Significance of signet-ring cells in patients with colorectal cancer

PURPOSE

We performed a retrospective study to determine the pattern of metastases and overall outcome of patients with tumors exhibiting a component of signet-ring cells comprising < 50 percent of the tumor mass.

METHODS

Medical records of 753 patients with primary colorectal cancer were retrospectively studied. Patients who had tumors with < 50 percent signet-ring cells were classified as having a component of signet-ring cells. The outcome of patients with a component of signet-ring cells was compared to all patients with mucinous adenocarcinoma (defined as adenocarcinomas with > or = 50 percent mucin) to all patients with adenocarcinomas with a component of mucin (defined as adenocarcinomas with < 50 percent mucin) and to 100 randomly selected patients with adenocarcinomas lacking mucin or signet-ring cells.

RESULTS

Five percent of patients had a component of signet-ring cells, 3 percent had mucinous adenocarcinoma, 9 percent had a component of mucinous adenocarcinoma, and 83 percent had adenocarcinoma lacking mucinous or signet components. Patients with a component of signet-ring cells and mucinous adenocarcinomas metastasized predominantly to the peritoneum/ovaries (75 and 56 percent of metastatic cases, respectively) and rarely to liver/lungs. The pattern of metastases of patients with adenocarcinoma without mucinous or signet components predominantly involved the liver/lungs and rarely the peritoneum/ovaries (12.5 percent). The pattern of metastases for patients with a component of mucinous adenocarcinoma was intermediate between mucinous adenocarcinoma and adenocarcinoma without mucin or signet-ring component. No differences in survival in Stage IV patients were seen among the four subgroups.

CONCLUSIONS

Patients with a component of signet-ring cells cancers, similar to mucinous adenocarcinoma, have a predisposition to metastasize to the peritoneum/ovaries.

Signet ring cell differentiation in mucinous colorectal carcinoma

Approximately 10% of all colorectal carcinomas are mucinous carcinomas, characterized by extracellular mucin. Occasionally, mucin accumulates intracellularly in these tumours, causing signet ring cell differentiation. We hypothesized that signet ring cells arise from a separate genetic pathway. In this study the molecular background of signet ring cell differentiation was investigated by analysing genetic changes, changes in the expression of adhesion molecules, and mucin content. Furthermore, its clinical relevance was addressed. Cell lines of colorectal tumours with non-mucinous (AC), mucinous (MC), and signet ring cell phenotype (MCSRC) were used for Multiplex Ligation-dependent Probe Amplification to detect deletions and amplifications in specific oncogenes and tumour suppressor genes. Furthermore, the expression of E-cadherin, beta-catenin, ITF (intestinal trefoil factor), and MUC2 in signet ring cells was studied by immunohistochemistry, immunofluorescence, and mRNA in situ hybridization. Results were validated using a large cohort of rectal carcinomas from which clinicopathological data were available. Specific amplifications and deletions in cell lines of AC, MC, and MCSRC were detected. Bcl-2 was amplified in MCSRC and MC cell lines, but not in AC cell lines. Bcl-2 FISH analysis confirmed this in patient material. Signet ring cells had decreased expression of adhesion molecules (E-cadherin, beta-catenin) and were strongly positive for ITF and MUC2, two peptides which are normally only produced by goblet cells. RNA in situ hybridization confirmed the production of ITF. Mucinous carcinomas with signet ring cell differentiation presented at a higher T stage than adenocarcinomas and mucinous carcinomas (16% pT4 versus 3-5%, p<0.001) and were more frequently node positive (77% vs 39-44%; p<0.001). Prognosis was significantly worse. In conclusion, the presence of signet ring cells in carcinomas with mucinous differentiation correlates with increased T-stage and poor prognosis. These cells, characterized by ITF and MUC2 production, show disruption of the E-cadherin/beta-catenin complex, as well as amplification of Bcl-2.

HATH1 Expression in Mucinous Cancers of the Colorectum and Related Lesions

PURPOSE

Mucinous cancers and signet ring carcinomas are distinct classes of colon cancers characterized by their production of copious quantities of intestinal goblet cell mucin, MUC2. Deletion of transcription factor HATH1 ablates the biogenesis of goblet cells in developing mouse intestine, and forced expression of HATH1 results in elevated expression of MUC2 in colon cancer cells. The aim of this study was to assess the possible role of HATH1 in the development of mucinous cancers and signet ring carcinomas.

EXPERIMENTAL DESIGN

Immunohistochemistry and confocal microscopy was used to examine HATH1 expression and subcellular distribution in normal colon and small intestine, mucinous cancers, signet ring carcinomas, and nonmucinous cancers and in precursor lesions, including hyperplastic polyps, serrated adenomas, tubular adenomas, and villous adenomas. We also analyzed the transactivation of MUC2 promoter/reporter constructs by a HATH1 expression vector.

RESULTS

HATH1 expression transactivated MUC2 promoter/reporter constructs, an activity that was significantly inhibited by mutation of putative HATH1-binding sites. HATH1 was expressed in the nuclei of goblet cells and in the cytoplasm and nuclei of enteroendocrine cells of the colon. In the small intestine, only cytoplasmic expression of HATH1 in enteroendocrine cells was detected. HATH1 was found to be strongly expressed in the nuclei of hyperplastic polyps, serrated adenomas, villous adenomas, mucinous cancers, and signet ring carcinomas but repressed in nonmucinous cancers and tubular adenomas.

CONCLUSIONS

This study confirms the importance of HATH1 for the development of intestinal secretory cells. The results further suggest that HATH1 is an important factor in the up-regulation of MUC2 expression that occurs in mucinous cancers and signet ring carcinomas. In addition, the expression of HATH1 in hyperplastic polyps, serrated adenomas, and villous adenomas lends support to the hypothesis that these neoplasms are frequent precursors in mucinous cancer and signet ring carcinoma development.

Invasive colorectal micropapillary carcinoma: an aggressive variant of adenocarcinoma

Micropapillary carcinoma (MC) has been well described in other organs, including breast, urinary bladder, lung, ovary, and salivary gland, but has not been described in the large intestine. We compared the clinicopathologic and immunohistochemical findings of MC with those of conventional adenocarcinoma in the large intestine. Fifty-five cases of adenocarcinoma with an MC component were identified among 585 consecutive cases of colorectal cancer at the Asan Medical Center between January 2003 and June 2004 and were compared with 119 cases of conventional adenocarcinoma of colorectum without an MC component. Arrayed tissue blocks were constructed and immunostained for cytokeratin 7 and 20 and CDX2. We also compared the results of MLH-1, MSH-2, p53, and carcinoembryonic antigen immunostainings between the 2 groups. The grade of both MC and conventional adenocarcinoma was mostly moderately differentiated. The proportion of MC ranged from 5% to 80%. The presence but not extent of MC in the primary tumors was associated with more frequent lymphovascular invasion and lymph node (LN) metastases, a greater mean number of positive LNs, and a higher tumor stage with more frequent distant metastases, compared with conventional adenocarcinoma (P < .05). Cytokeratin 7 staining was occasionally observed in both MC (9.1%, 5/55 cases) and conventional adenocarcinoma (13.4%, 16/119 cases). Although MLH-1 and CDX2 expression tended to be lower in conventional adenocarcinoma, none of the immunohistochemical results was significantly different between 2 groups. Recognition of MC component is important as MC appeared to be an aggressive variant of colonic adenocarcinoma and presented at a higher stage, with frequent lymphovascular invasion, LN metastasis, and distant metastasis, compared with conventional adenocarcinoma. The proportion of MC component did not impact the prognosis, and the immunoprofiles of MC were not significantly different from those of conventional adenocarcinoma.

Distinct molecular features of colorectal carcinoma with signet ring cell component and colorectal carcinoma with mucinous component

Signet ring cell carcinoma and mucinous carcinoma are distinct subtypes of colorectal adenocarcinoma. The morphologic and molecular spectra of colorectal carcinomas with various signet ring cell components and colorectal carcinomas with various mucinous components, compared to non-mucinous adenocarcinomas, have not been examined. The study groups consisted of 39 carcinomas with various signet ring cell components ('the signet group'), 167 carcinomas with various mucinous components ('the mucinous group'), and 457 nonmucinous adenocarcinoma. We visually estimated the amounts of signet ring cell and mucinous components in tumors, and subclassified the signet and mucinous groups according to the amount of each component (< or = 19, 20-49, and > or = 50%). We sequenced BRAF and KRAS, analyzed for microsatellite instability (MSI) and 18q loss of heterozygosity (LOH), and performed immunohistochemistry for TP53, cyclooxygenase-2 (COX2), MLH1, O-6-methylguanine DNA methyltransferase (MGMT), p16 (CDKN2A), and fatty acid synthase (FASN). Signet ring cell carcinoma (> or = 50% signet ring cell tumors) and < or = 49% signet ring cell tumors showed similar molecular features. Except for MSI and MGMT, > or = 50% mucinous tumors and < or = 49% mucinous tumors also showed similar molecular features. BRAF mutations, MSI, and MLH1 loss were more frequent in both the signet and mucinous groups than nonmucinous carcinoma. More frequent KRAS mutations and less frequent p16 loss and TP53 positivity were observed in the mucinous group than nonmucinous carcinoma. 18q LOH and COX2 overexpression were less common in the signet group than nonmucinous carcinoma. FASN levels were highest in the mucinous group, followed by nonmucinous carcinoma, and lowest in the signet group. In conclusion, a minor (< or = 49%) signet ring cell or mucinous component in colorectal carcinoma suggests molecular features similar to > or = 50% signet ring cell or mucinous carcinoma, respectively. Signet ring cell carcinoma and mucinous carcinoma are related subtypes of colorectal adenocarcinoma, but have molecular features distinct from each other.

Synthesis of junctional proteins in metastasizing colon cancer cells

Various authors have reported reduced synthesis of epithelial junctional proteins during dedifferentiation, tumorigenesis and metastasis in a great variety of tumors. Consequently, it is generally accepted that loss of adhesive molecules and adhesion structures is implicated in the development of an invasive phenotype and poor patient prognosis. Colon carcinomas, on the other hand, were shown to behave differently as synthesis of main adhesive proteins continues despite the development of an invasive phenotype. In this study we used cultured cells grown under conditions that inhibited intercellular adhesion (low Ca2+ concentration) and compared these results with data obtained from metastasizing colon cancer cells (signet ring cell carcinoma). Characterization of these proteins and their structures were performed by immunoprecipitations, Western blot analysis, immunohistochemistry, pre-embedding immuno-electron microscopy, and a new method to perform immuno-electron microscopy on paraffin-embedded material, which we present in this paper. We demonstrate that synthesis carries on for both, the desmosomal and the proteins of the zonula adhaerens. While, however, the assembly of desmosomal structures in the form of half-desmosomes at the cell surface continues, those of the zonula adhaerens did not. Instead E-cadherin was found, although associated with alpha-catenin, beta-catenin, and plakoglobin, evenly distributed at the plasma membrane of the cultured cells and also at the surface of the dissociated tumor cells. We conclude from our observations that continued expression and synthesis of junctional proteins do not necessarily contribute to the suppression of tumor invasion and metastasis of colon cancer.

Primary signet-ring cell carcinoma mimicking segmental Crohn's colitis

Primary signet-ring cell carcinoma of the colon is a rare entity with a dismal prognosis, mainly due to a delay in diagnosis. Here, we present a case of a 30-year-old Filipino woman who presented with symptoms mimicking inflammatory bowel disease. A barium enema and colonoscopy demonstrated a stricture in the rectosigmoid region. A biopsy revealed granulomatous changes indicative of inflammatory bowel disease. Despite initial improvement of her symptoms on total parenteral nutrition and steroids, the patient relapsed several weeks later with recurrent left lower quadrant pain. A subsequent biopsy revealed poorly differentiated signet-ring cell carcinoma of the colon. She was treated surgically with a left hemi-colectomy and primary repair. A high degree of suspicion is necessary to correctly diagnose these, often young, patients with primary signet-ring cell carcinoma early and have a positive impact on survival. The literature on primary signet-ring cell carcinoma is reviewed.

Tonsillar metastasis revealing signet-ring cell carcinoma of the rectum

A 45-year-old man presented with a tonsillar tumor and rectal syndrome. Histology specimens revealed signet-cell adenocarcinoma of both the tonsils and rectum. The clinical course was rapidly degenerated with multiple metastases in the skin and bones. Tonsil metastasis is rare and generally develops from primary gastric or colorectal cancer, predominantly poorly-differentiated or signet-ring cell adenocarcinomas.

Signet ring cell carcinoma of the colorectum: correlations between microsatellite instability, clinicopathologic features and survival

Colorectal cancer with microsatellite instability has a characteristic clinicopathologic profile, featuring right-sided, lymphocyte-rich tumors with a better prognosis than microsatellite stable (MSS) carcinoma. Mucinous and signet ring cell carcinomas are both over-represented among microsatellite instability-high cancers. The clinicopathologic features of mucinous microsatellite instability-high cancer parallel those of the overall microsatellite instability-high set, but it is not known whether the same is true for signet ring cell carcinoma, particularly given the fact that signet ring histology is a well-documented adverse prognostic factor. We recorded age, sex, tumor size, site, grade, stage, histologic pattern, growth pattern, Crohn-like reaction, vascular invasion and tumor-infiltrating lymphocytes in 72 resected signet ring cell carcinomas of the colorectum. Microsatellite instability was determined by a combination of polymerase chain reaction and immunohistochemical stains for hMLH1, hMSH2 and hMSH6. Tumors with instability at >30% of informative markers and/or loss of hMLH1 or hMSH2 expression were designated microsatellite instability-high; all others were classified as MSS. A total of 22 (31%) signet ring cell carcinomas were microsatellite instability-high. Compared to MSS signet ring cell carcinoma, they were more likely to be right-sided (81 vs 45%, P=0.005) and to affect older patients (68 vs 26%, P=0.0007) of female sex (59 vs 28%, P=0.03). Crohn-like reaction (45 vs 16%, P=0.02) and high tumor infiltrating lymphocyte counts (32 vs 8%, P=0.03) were more common in the microsatellite instability-high setting. There was no significant difference in 5-year survival in microsatellite instability-high vs MSS patients (41 vs 34%, P=0.3). In conclusion, approximately one-third of signet ring carcinomas of the colorectum are microsatellite instability-high. Microsatellite instability-high signet ring carcinomas share clinicopathologic features with other microsatellite instability-high cancers: older age group, female preponderance, right-sided location, Crohn-like reaction and numerous tumor-infiltrating lymphocytes. Microsatellite instability status does not appear to be a significant predictor of survival in signet ring cell carcinoma of the colorectum.

Clinical significance of signet ring cell rectal carcinoma

BACKGROUND AND AIMS

Signet ring cell carcinoma of the rectum (SCCR) is a rare type of rectal carcinoma. This study examined the clinical significance of SCCR.

PATIENTS AND METHODS

From our medical records we retrospectively identified 61 SCCR patients and compared their clinical data and outcomes to those of 144 consecutive patients with non-SCCR mucinous rectal adenocarcinomas (NSMR) and 2,414 consecutive patients with nonmucinous rectal adenocarcinomas (NMR).

RESULTS

. The incidence of SCCR was 1.39% of rectal cancers. Mean patient age at onset of SCCR (48.1years, range 15-80) was significantly lower than that for NSMR (57.4 years, 9-88) and NMR (62.6 years, 12-94). The proportion of late stage (TNM III+IV) tumors was significantly higher in SCCR (90%) than in NSMR (69%) and NMR (48%). There were more tumors located in the lower rectum in SCCR (46%) than in NSMR (34%) and NMR (29%). SCCR tumors were significantly larger (5.68+/-3.84 cm) than NSMR (4.27+/-1.78 cm) and NMR tumors (3.76+/-1.71 cm). A higher percentage of patients with SCCR (42.6%) received abdominoperineal resection for treatment. In tumors with TNM stage IV the rate of tumor spread via the hematogenous route was significantly lower in SCCR (18.5%) than in NSMR (43.5%) and in NMR (69%). The rate of tumor spread via seeding to the peritoneum was lower in SCCR (22.2%) than in NSMR (43.5%) but higher than in NMR (2.7%). The rate of tumor spread via the lymphatic route was higher in SCCR (44.4%) than in NSMR (26.1%) and significantly higher than in NMR (12.3%). The 1-, 2-, and 5-year overall SCCR survival rates were 73.9%, 36.3%, and 23.3% respectively, which were significantly poorer than those of NSMR and NMR. For the 28 stage III and R0 SCCR tumors the 1-, 2-, and 5-year disease-free survival rates of SCCR were 84.0%, 44.2%, and 30.3%, respectively, which are comparable with general data of stage III rectal cancer in the world.

CONCLUSION

Diffuse infiltration of signet ring cells enhances the tendency of mucinous carcinomas of the rectum in more local extension and easier lymphatic spreading but not at peritoneal seeding. Although SCCR had the poorest prognosis, this outcome may be due to the advanced tumor stage rather than histology itself.

Introduction to colorectal cancer

OBJECTIVES

To provide an overview of colorectal carcinoma (CRC), including current treatment strategies for various stages of the disease.

DATA SOURCES

Research articles and textbooks.

CONCLUSIONS

Despite screening methods for early detection of CRC, many patients present with late-stage disease and have a poor prognosis. The approval of irinotecan for CRC changed the approach to treatment, and there are numerous agents under clinical evaluation that may soon be available for the management of patients with CRC.

IMPLICATIONS FOR NURSING PRACTICE

Recent advances in molecular targeting have led to the development of new treatments for CRC. Because nurses will ultimately administer these agents, it is important to understand how these agents target CRC.

Primary colorectal signet-ring cell carcinoma in Singapore

BACKGROUND

Primary colorectal signet-ring cell carcinoma is a rare but distinctive tumour of the colon and rectum. The clinicopathological features are still controversial. The aim of this study is to review the clinicopathological features and management of this type of tumour in our hospital.

METHODS

The clinicopathological features and survival data of all cases of primary colorectal signet-ring cell carcinoma were reviewed retrospectively.

RESULTS

There were nine cases of primary colorectal signet-ring cell carcinoma in 3000 consecutive colorectal carcinoma patients seen from 1989 to 1999. There were seven male and two female patients with a mean age of 54.7 years. Three patients were younger than 40 years. The common presenting symptoms were rectal bleeding (33%) and small bowel obstruction (33%). Two (22%) patients required emergency surgery due to acute small bowel obstruction. The most common tumour location was the right colon (44%) followed by the rectum (33%). All nine patients presented at a very late stage of disease. A majority (77%) had Dukes' C disease while two (22%) had Dukes' D disease with distant dissemination. Peritoneal spread (33%) was the most frequent way of dissemination. There was no patient with liver metastases at the time of diagnosis and initial presentation. The mean survival time was 30 (range 5-108) months. The 5-year survival rate was 12%.

CONCLUSIONS

Primary colorectal signet-ring cell carcinoma is frequently diagnosed late with a very poor prognosis. A high incidence of peritoneal seeding and low incidence of liver metastases appears to be a characteristic of signet-ring cell carcinoma of the colon and rectum.

Retrospective radiographic analysis of nonpedunculated colorectal carcinomas with special reference to tumor doubling time and morphological change

OBJECTIVE

Our aim was to characterize the development of nonpedunculated colorectal carcinomas by retrospective radiographic analysis, with special reference to tumor doubling time and morphological change.

METHODS

Eleven colorectal carcinomas, which were observed for >6 months by barium enema examinations, were collected and retrospectively reviewed. There were five early and six advanced carcinomas, including submucosally invasive, superficial depressed carcinomas.

RESULTS

Mean diameter of lesions at initial barium enema examination was 13.5 mm (early, 10.4 mm; advanced, 16.0 mm) and that at final barium enema examination was 30.9 mm (early, 18.2 mm; advanced, 41.5 mm). Initial morphology of the lesions was superficial in three, sessile in seven, and semipedunculated in 1. There was no pedunculated lesion. Macroscopic morphology of the five early carcinomas was superficial depressed (IIc) in two cases, mostly depressed but partly elevated (IIc+IIa) in one case, and superficial elevated with a depressed component (IIa+IIc) in two cases; all of the advanced carcinomas were of the ulcerated type. Mean doubling time was 6.8 months (early, 9.4 months; advanced, 4.7 months). Early carcinomas had significantly longer doubling times than advanced carcinomas (p = 0.017, Wilcoxon's text). The lesions with the longest doubling times were superficial depressed lesions.

CONCLUSIONS

Early carcinomas have longer doubling times than advanced carcinomas. Most nonpedunculated colorectal carcinomas grow without significant morphological changes. Superficial depressed type tumors grow slowly, maintaining their macroscopic morphology.