Mismatch repair status predicts survival after adjuvant treatment in stage II colon cancer patients.

BACKGROUND AND OBJECTIVES: Stage II colon cancer is primarily a surgical disease. Only a still not well-defined subset of patients may benefit from postoperative adjuvant chemotherapy. The relationship between adjuvant chemotherapy and survival after relapse is furthermore still not definitely explored in this group of patients. A number of reports suggest some association between defective mismatch repair (dMMR) and colorectal cancer stage II prognosis, but due to contradictory results from existing studies, the exact predictive role is still not fully understood. METHODS: Retrospective multicenter study including 451 stage II colon cancer patients. The proficiency or deficiency of mismatch repair was tested using immunohistochemistry and analyzed in relationship to two survival outcomes: overall survival (OS) and postrelapse survival. RESULTS: Patients with dMMR (20.4%) derived no OS benefit from adjuvant chemotherapy (hazard ratio [HR], 1.05; 95% confidence interval [CI], 0.47-2.38; P = .897). Patients with proficient mismatch repair (pMMR) tumors receiving adjuvant chemotherapy had the significantly better OS in comparison to those not receiving chemotherapy (HR, 0.54; 95% CI, 0.35-0.82; P = .004). This relationship remained significant in multivariable analysis (HR, 0.42; 95% CI, 0.22-0.78; P = .007). Patients with pMMR relapsing after adjuvant treatment lived significantly longer than those relapsing without previous adjuvant treatment (HR, 0.55; 95% CI, 0.32-0.96; P = .033) and this result remained significant in the multivariable model (HR, 0.49; 95% CI, 0.26-0.93; P = .030). CONCLUSION: In stage II CC patients, adjuvant chemotherapy improves therapeutic outcomes only in patients with pMMR tumors. Survival after relapse in patients having received adjuvant chemotherapy is significantly longer for patients with pMMR. No survival benefit from adjuvant chemotherapy was seen among patients with dMMR tumors.

Patients with longstanding ulcerative colitis in remission do not have more irritable bowel syndrome-like symptoms than controls.

BACKGROUND: Irritable bowel syndrome (IBS) is more common in patients with ulcerative colitis (UC) than expected. The prevalence of IBS in patients with UC with longstanding disease is not known. We investigated the prevalence of IBS-like symptoms in patients with UC in remission and longstanding disease in comparison to control subjects. METHODS: Sixty-eight patients with UC and 33 patients with hereditary familiar colon cancer and who underwent colonoscopy surveillance were included. Faecal calprotectin (FC), Gastrointestinal Symptoms Rating Scale-Irritable Bowel Syndrome (GSRS-IBS) and Hospital Anxiety and Depression scale were fulfilled prior to endoscopy. UC in remission was define by steroid-free clinical remission, a Mayo Score ≤ 1 on endoscopy, a FC ≤ 200 µg/g and no significant active inflammation on colon biopsies. RESULTS: Fifty-five UC patients met the criteria for being in remission. The median disease duration was 17 years. The patients with UC in remission tended to have lower scores on total GSRS-IBS score (6 vs 10.5; p = 0.062) and lower or equal scores on all specific IBS symptoms in comparison to controls. There was a moderate but significant correlation between diarrhoea scores and FC levels (in the span ≤ 200 µg/g) (rs 0.38; p = 0.004) in the UC in remission group. CONCLUSION: Patients with UC with longstanding disease and in remission do not have more IBS symptoms than controls. In UC patients in remission the FC level in the lower span showed a moderate correlation to symptoms of diarrhoea.

The intratumoural subsite and relation of CD8(+) and FOXP3(+) T lymphocytes in colorectal cancer provide important prognostic clues.

BACKGROUND: To find improved tools for prognostic evaluation in patients with colorectal cancer (CRC), we have analysed how infiltration of cytotoxic T lymphocytes (CD8(+)) and regulatory T lymphocytes (FoxP3(+)) correlates to prognosis, not only according to quantity and relation, but also to subsite within tumours of different molecular characteristics (microsatellite instability and CpG island methylator phenotype status). METHODS: CD8 and FOXP3 expression was evaluated by immunohistochemistry in 426 archival tumour tissue samples from patients surgically resected for CRC. The average infiltration of CD8(+) and FOXP3(+) cells was assessed along the tumour invasive front, in the tumour centre and within the tumour epithelium (intraepithelial). RESULTS: We found that infiltration of CD8(+) T lymphocytes within the tumour epithelium provided the strongest prognostic information (P<0.001). At the tumour invasive front and tumour centre, FOXP3 expression withheld the strongest association to prognosis (P<0.001), suggesting FOXP3(+) T-lymphocyte infiltration to be a better prognostic tool than CD8(+) T lymphocytes at these intratumoural subsites. We further analysed the possible prognostic impact of the relation between these T-cell subsets, finding that a high intraepithelial CD8 expression was associated with a better patient outcome, independent of FOXP3 infiltration. In groups of low intraepithelial CD8 expression, however, a high infiltration rate of FOXP3(+) cells at the tumour invasive front, significantly improved prognosis. CONCLUSIONS: Analyses of intraepithelial infiltration of CD8(+) T lymphocytes, infiltration of FOXP3(+) T lymphocytes at the tumour front or centre, and the relation between these subsets, may be a valuable tool for predicting prognosis in colon cancer.

The prognostic role of KRAS, BRAF, PIK3CA and PTEN in colorectal cancer.

BACKGROUND: Mutations in KRAS, BRAF, PIK3CA and PTEN expression have been in focus to predict the effect of epidermal growth factor receptor-blocking therapy in colorectal cancer (CRC). Here, information on these four aberrations was collected and combined to a Quadruple index and used to evaluate the prognostic role of these factors in CRC. PATIENTS: We analysed the mutation status in KRAS, BRAF and PIK3CA and PTEN expression in two separate CRC cohorts, Northern Sweden Health Disease Study (NSHDS; n=197) and Colorectal Cancer in Umeå Study (CRUMS; n=414). A Quadruple index was created, where Quadruple index positivity specifies cases with any aberration in KRAS, BRAF, PIK3CA or PTEN expression. RESULTS: Quadruple index positive tumours had a worse prognosis, significant in the NSHDS but not in the CRUMS cohort (NSHDS; P=0.003 and CRUMS; P=0.230) in univariate analyses but significance was lost in multivariate analyses. When analysing each gene separately, only BRAF was of prognostic significance in the NSHDS cohort (multivariate HR 2.00, 95% CI: 1.16-3.43) and KRAS was of prognostic significance in the CRUMS cohort (multivariate HR 1.48, 95% CI: 1.02-2.16). Aberrations in PIK3CA and PTEN did not add significant prognostic information. CONCLUSIONS: Our results suggest that establishment of molecular subgroups based on KRAS and BRAF mutation status is important and should be considered in future prognostic studies in CRC.

Lymph node tissue kallikrein-related peptidase 6 mRNA: a progression marker for colorectal cancer.

BACKGROUND: A most important characteristic feature for poor prognosis in colorectal cancer (CRC) is the presence of lymph node metastasis. Determination of carcinoembryonic antigen (CEA) mRNA levels in lymph nodes has proven powerful for quantification of disseminated tumour cells. Here, we investigate the utility of human tissue kallikrein-related peptidase 6 (KLK6) mRNA as a progression biomarker to complement CEA mRNA, for improved selection of patients in need of adjuvant therapy and intensified follow-up after surgery. METHODS: Lymph nodes of pTNM stage I-IV CRC- (166 patients/503 lymph nodes) and control (23/108) patients were collected at surgery and analysed by quantitative RT-PCR. RESULTS: Lymph node KLK6 positivity was an indicator of poor outcome (hazard ratio 3.7). Risk of recurrence and cancer death increased with KLK6 lymph node levels. Patients with KLK6 lymph node levels above the 90th percentile had a hazard ratio of 6.5 and 76 months shorter average survival time compared to patients with KLK6 negative nodes. The KLK6 positivity in lymph nodes with few tumour cells, that is, low CEA mRNA levels, also indicated poor prognosis (hazard ratio 2.8). CONCLUSION: In CRC patients, lymph node KLK6 positivity indicated presence of aggressive tumour cells associated with poor prognosis and high risk of tumour recurrence.

Linoleic acid, a dietary n-6 polyunsaturated fatty acid, and the aetiology of ulcerative colitis: a nested case-control study within a European prospective cohort study.

OBJECTIVE: Dietary linoleic acid, an n-6 polyunsaturated fatty acid, is metabolised to arachidonic acid, a component of colonocyte membranes. Metabolites of arachidonic acid have pro-inflammatory properties and are increased in the mucosa of patients with ulcerative colitis. The aim of this investigation was to conduct the first prospective cohort study investigating if a high dietary intake of linoleic acid increases the risk of developing incident ulcerative colitis. DESIGN AND SETTING: Dietary data from food frequency questionnaires were available for 203 193 men and women aged 30-74 years, resident in the UK, Sweden, Denmark, Germany or Italy and participating in a prospective cohort study, the European Prospective Investigation into Cancer and Nutrition (EPIC). These participants were followed up for the diagnosis of ulcerative colitis. Each case was matched with four controls and the risk of disease calculated by quartile of intake of linoleic acid adjusted for gender, age, smoking, total energy intake and centre. RESULTS: A total of 126 participants developed ulcerative colitis (47% women) after a median follow-up of 4.0 years (range, 1.7-11.3 years). The highest quartile of intake of linoleic acid was associated with an increased risk of ulcerative colitis (odds ratio (OR) = 2.49, 95% confidence interval (CI) = 1.23 to 5.07, p = 0.01) with a significant trend across quartiles (OR = 1.32 per quartile increase, 95% CI = 1.04 to 1.66, p = 0.02 for trend). CONCLUSIONS: The data support a role for dietary linoleic acid in the aetiology of ulcerative colitis. An estimated 30% of cases could be attributed to having dietary intakes higher than the lowest quartile of linoleic acid intake.

Plasma folate and total homocysteine levels are associated with the risk of myocardial infarction, independently of each other and of renal function.

OBJECTIVES: To investigate the relationship between plasma folate, vitamin B12 and total homocysteine concentrations, dietary intake of folate and vitamins B12, B6 and B2, and the risk of first acute myocardial infarction (MI). DESIGN: Nested case-referent study with up to 13 years of follow-up. SETTING: The population-based Northern Sweden Health and Disease Study, with 73 879 participants at the time of case ascertainment. SUBJECTS: A total of 571 MI cases (406 men) and 1569 matched referents. Of the cases, 530 had plasma samples available, and 247 had dietary B-vitamin intake data. RESULTS: Plasma concentrations of folate were inversely associated, and total homocysteine positively associated, with the risk of MI, independently of each other and of a number of established and novel cardiovascular risk factors, including renal function [multivariate odds ratio for highest vs. lowest quintile of folate 0.52 (95% CI 0.31-0.84), P for trend = 0.036, and homocysteine 1.92 (95% CI 1.20-3.09), P for trend = 0.006]. For plasma vitamin B12 concentrations, and vitamin B12, B6 and B2 intake, no clear risk relationship was apparent. Though not statistically significant, the results for folate intake were consistent with those for plasma concentrations. CONCLUSIONS: In this large prospective study of a population without mandatory folic acid fortification, both folate and homocysteine were strongly associated with the risk of myocardial infarction, independently of each other and of renal function. Although randomized trials of folic acid supplementation are needed to determine causality, our findings highlight the potential importance of folate, or sources of folate, in incident cardiovascular disease.

Components of the metabolic syndrome and colorectal cancer risk; a prospective study.

OBJECTIVE: To examine the relation of well-known factors of the metabolic syndrome (MetS) as well as related circulating factors, with risk of colorectal cancer. METHODS: We performed a case control study of 306 colorectal cancer cases and 595 matched controls nested in the Northern Sweden Health and Disease Cohort. Levels of C-peptide, glycated haemoglobin (HbA1c), leptin and adiponectin were measured in cryopreserved samples. Body mass index (BMI), systolic and diastolic blood pressure and fasting and post-load plasma glucose, had been measured in a subcohort. Conditional logistic regression was used to calculate odds ratios (OR) of disease, including risk assessments for the MetS factors: obesity (BMI>30 kg m(-2)), hypertension (blood pressure > or =140/90 mmHg or use of anti-hypertensive drugs) and hyperglycaemia (fasting glucose > or =6.1 mmol l(-1) or post-load glucose in capillary plasma > or =8.9 mmol l(-1)). RESULTS: None of the studied variables were significantly associated with risk across quartiles. Presence of obesity, hypertension and hyperglycaemia significantly increased the risk of colorectal cancer; OR for three vs null factors was 2.57 (95% Confidence Interval [CI] 1.20-5.52; P (trend)=0.0021), as compared to a 30 to 70% increased risk for the factors in single. Similarly, top decile levels of C-peptide, HbA1c and leptin/adiponectin ratio were associated with an increased risk; ORs for top vs deciles 1-9 were 1.56 (95% CI 0.93-2.62; P=0.090), 1.83 (95% CI 1.00-3.36; P=0.051) and 1.50 (95% CI 0.83-2.71; P=0.18), respectively. CONCLUSIONS: Our study support the view that components of the MetS increase risk of colorectal cancer, and further suggests that only very high levels of metabolic factors confer an increased risk.

Polymorphisms in the genes of the urokinase plasminogen activation system in relation to colorectal cancer.

BACKGROUND: Extracellular matrix degradation, mediated by the urokinase plasminogen activation (uPA) system, is a critical step in tumor invasion and metastasis. High tumor levels of uPA and its inhibitor PAI-1 have been correlated with poor cancer prognosis. We examined four single nucleotide polymorphisms (SNPs) with a potential effect on expression of genes in the uPA system for their role in colorectal cancer susceptibility and prognosis. PATIENTS AND METHODS: We genotyped the SNPs in 308 Swedish incident colorectal cancer patients with up to 16 years of follow-up and in 585 age- and sex-matched controls. We evaluated the associations between genotypes and colorectal cancer and Dukes' stage. Survival probabilities were compared between different subgroups. RESULTS: Patients with PAI-1 -675 5G/5G genotype had better survival than patients with 4G/4G or 4G/5G genotypes when they had Dukes' stage A or B tumors (P = 0.023 and P = 0.015, respectively). No statistically significant association was observed between the SNPs and the risk of colorectal cancer or Dukes' stage. CONCLUSIONS: Our results suggest a role for the PAI-1 genotype in colorectal cancer prognosis, but further studies are needed to evaluate the impact of our finding in the clinic.

Low folate levels may protect against colorectal cancer.

BACKGROUND AND AIMS: Dietary folate is believed to protect against colorectal cancer (CRC). However, few studies have addressed the role of circulating levels of folate. The aim of this study was to relate prediagnostic plasma folate and homocysteine concentrations and the methylenetetrahydrofolate reductase (MTHFR) 677C>T and 1298A>C polymorphisms to the risk of developing CRC. SUBJECTS: Subjects were 226 cases and 437 matched referents from the population based Northern Sweden Health and Disease Cohort. RESULTS: We observed a bell-shaped association between plasma folate concentrations and CRC risk; multivariate odds ratio for middle versus lowest quintile 2.00 (95% confidence interval (CI) 1.13-3.56). In subjects with follow up times greater than the median of 4.2 years however, plasma folate concentrations were strongly positively related to CRC risk; multivariate odds ratio for highest versus lowest quintile 3.87 (95% CI 1.52-9.87; p trend = 0.007). Homocysteine was not associated with CRC risk. Multivariate odds ratios for the MTHFR polymorphisms were, for 677 TT versus CC, 0.41 (95% CI 0.19-0.85; p trend = 0.062), and for 1298 CC versus AA, 1.62 (95% CI 0.94-2.81; p trend = 0.028). Interaction analysis suggested that the result for 1298A>C may have been largely due to linkage disequilibrium with 677C>T. The reduced CRC risk in 677 TT homozygotes was independent of plasma folate status. CONCLUSIONS: Our findings suggest a decreased CRC risk in subjects with low folate status. This possibility of a detrimental component to the role of folate in carcinogenesis could have implications in the ongoing debate in Europe concerning mandatory folate fortification of foods.

Efficiency of Colorectal Cancer Surveillance in Patients with Ulcerative Colitis: 38 Years' Experience in a Patient Cohort from a Defined Population Area.

BACKGROUND AND AIMS: Ulcerative colitis increases the risk of developing colorectal cancer. Colonoscopic surveillance is recommended although there are no randomized trials evaluating the efficacy of such a strategy. This study is an update of earlier studies from an ongoing colonoscopic surveillance program. MATERIAL AND METHODS: All patients with ulcerative colitis were invited to the surveillance program that started in 1977 at Örnsköldsvik Hospital, located in the northern part of Sweden. Five principal endoscopists performed the colonoscopies and harvested mucosal sampling for histopathological evaluation. Some 323 patients from the defined catchment area were studied from 1977 to 2014. At the end of the study period, 130 patients, including those operated on, had had total colitis for more than 10 years. RESULTS: In total, 1481 colonoscopies were performed on 323 patients during the study period without any major complications. In all, 10 cases of colorectal cancer were diagnosed in 9 patients, of whom 1 died from colorectal cancer. The cumulative incidence of colorectal cancer was 1.4% at 10 years, 2.0% at 20 years, 3.0% at 30 years, and 9.4% at 40 years of disease duration, respectively. The standardized colorectal cancer incidence ratio was 3.01 (95% confidence interval: 1.42-5.91). Major surgery was performed on 65 patients; for 20 of these, the indication for surgery was dysplasia or colorectal cancer. Panproctocolectomy was performed in 43 patients. CONCLUSION: This study supports that colonoscopic surveillance is a safe and effective long-term measure to detect dysplasia and progression to cancer. The low numbers of colorectal cancer-related deaths in our study suggest that early detection of neoplasia and adequate surgical intervention within a surveillance program may reduce colorectal cancer mortality in ulcerative colitis patients.

Rearrangements of minisatellites in the human telomerase reverse transcriptase gene are not correlated with its expression in colon carcinomas.

Telomerase activation is crucial in human carcinogenesis. The limiting component of telomerase, the catalytic subunit (hTERT), is undetectable in normal somatic cells but present in most tumor cells, including the earliest stages of colon carcinoma. The mechanisms involved in the differential expression in normal and tumor cells are not understood. In normal cells hTERT expression is shut down by a repressor, and upregulation could be a consequence of cis-acting changes in the hTERT gene, making it resistant to repression. We have identified a polymorphic and a monomorphic minisatellite in the second intron of the hTERT gene, and polymorphic one in intron 6. The polymorphic minisatellite in intron 2 contains binding sites for c-Myc, which has been shown to upregulate hTERT transcription. Screening colon carcinoma DNAs for rearrangements of hTERT minisatellites we detected no changes in 33 samples from tumors, most of which express hTERT. This indicates that size rearrangements of the hTERT minisatellites are not required for telomerase expression in colon carcinomas. Minor changes and one LOH were seen in five tumors.

Expression of cyclin D1 and retinoblastoma protein in colorectal cancer.

Abnormal expression of the retinoblastoma protein (pRb) and cyclin D1 have been reported in a variety of malignancies, but the frequencies of these deregulations and their relation to prognosis in colorectal cancer has not been clarified. We characterised 90 colorectal cancers with respect to immunohistochemical expression of cyclin D1, pRb and Ki-67. Two of 90 (2%) tumours lacked nuclear pRb staining, indicating inactivation of the protein, while 10 (11%) expressed high levels of pRb. Abnormal expression of pRb was significantly correlated to low levels of nuclear cyclin D1 observed in 32% of the tumours. Strong nuclear cyclin D1 expression was detected in 12% of the tumours. Cytoplasmic staining of cyclin D1 was observed in 17% of the tumours, showing an inverse relationship (P = 0.006) to the Ki-67 labelling index. Eight of 11 tumours with high nuclear overexpression of cyclin D1 and both tumours with pRb defects were located in the right colon in comparison with zero of 25 in the rectum (P = 0.009). Regarding prognosis, neither pRb nor cyclin D1 expression correlated with patient survival.

Factors influencing the estimates of proliferative labelling indices in rectal cancer.

PURPOSE: A detailed analysis was undertaken of some of the factors influencing the estimate of the labelling index (LI). MATERIALS AND METHODS: Thirty-three human rectal carcinomas were studied for their proliferative activity as measured by the fraction of cells labelled with a single injection of IdUrd 1-8 h before surgical resection. Adjacent specimens were stained both for histological examination and for flow cytometry (FCM) assessment of labelled nuclei. RESULTS: Two major differences were found. The superficial parts of each tumour almost always had significantly higher LI values than the deep part (34 versus 21%), yielding an average LI of 27%. The flow cytometry average value was much lower (17%). This was partly due to the influence of diploid tumours. There was a marked heterogeneity in the values, both within tumours, between tumours and between techniques. The average LI for the whole group differs by a factor of three, depending on the method of assessment. CONCLUSIONS: All these values indicate a varying but rapid proliferative turnover of cells, surprisingly being more marked in the superficial region, i.e. the opposite from the proliferation pattern of the normal rectal mucosa. A biopsy, if taken from the superficial part of the tumour, would therefore be biased toward higher values. This has implications for biopsy sampling for cell kinetic analysis. Histological assessment avoids the contaminating effect of stromal cells, allows architectural arrangements to be detected and is presumably a more realistic representation of proliferative activity.

Alcohol dehydrogenase and aldehyde dehydrogenase gene polymorphisms, alcohol intake and the risk of colorectal cancer in the European Prospective Investigation into Cancer and Nutrition study.

BACKGROUND/OBJECTIVES: Heavy alcohol drinking is a risk factor of colorectal cancer (CRC), but little is known on the effect of polymorphisms in the alcohol-metabolizing enzymes, alcohol dehydrogenase (ADH) and aldehyde dehydrogenase (ALDH) on the alcohol-related risk of CRC in Caucasian populations. SUBJECTS/METHODS: A nested case-control study (1269 cases matched to 2107 controls by sex, age, study centre and date of blood collection) was conducted within the European Prospective Investigation into Cancer and Nutrition (EPIC) to evaluate the impact of rs1229984 (ADH1B), rs1573496 (ADH7) and rs441 (ALDH2) polymorphisms on CRC risk. Using the wild-type variant of each polymorphism as reference category, CRC risk estimates were calculated using conditional logistic regression, with adjustment for matching factors. RESULTS: Individuals carrying one copy of the rs1229984(A) (ADH1B) allele (fast metabolizers) showed an average daily alcohol intake of 4.3 g per day lower than subjects with two copies of the rs1229984(G) allele (slow metabolizers) (P(diff)<0.01). None of the polymorphisms was associated with risk of CRC or cancers of the colon or rectum. Heavy alcohol intake was more strongly associated with CRC risk among carriers of the rs1573496(C) allele, with odds ratio equal to 2.13 (95% confidence interval: 1.26-3.59) compared with wild-type subjects with low alcohol consumption (P(interaction)=0.07). CONCLUSIONS: The rs1229984(A) (ADH1B) allele was associated with a reduction in alcohol consumption. The rs1229984 (ADH1B), rs1573496 (ADH7) and rs441 (ALDH2) polymorphisms were not associated with CRC risk overall in Western-European populations. However, the relationship between alcohol and CRC risk might be modulated by the rs1573496 (ADH7) polymorphism.

The reduced folate carrier (RFC1) 80G > A and folate hydrolase 1 (FOLH1) 1561C > T polymorphisms and the risk of colorectal cancer: a nested case-referent study.

OBJECTIVE: Polymorphisms in genes involved in folate uptake and metabolism may affect folate status and, thereby, the risk of cancer. In this nested case-referent study, we related two such polymorphisms, reduced folate carrier (RFC1) 80G > A and folate hydrolase 1 (FOLH1) 1561C > T, to the risk of colorectal cancer, taking into account pre-diagnostic plasma folate and total homocysteine concentrations and the MTHFR 677C > T polymorphism, which were analysed in a previous study. MATERIAL AND METHODS: Subjects were 220 cases and 414 matched referents from the population-based Northern Sweden Health and Disease Study. RESULTS: The RFC1 80A-allele was associated with reduced plasma folate and elevated plasma total homocysteine concentrations, but the result was statistically significant only for folate. In contrast, the FOLH1 1561T-allele was associated with higher plasma folate and reduced plasma total homocysteine concentrations, and the result was statistically significant only for homocysteine. Neither polymorphism was related to the risk of colorectal cancer, either in univariate analysis or after adjusting for body mass index, current smoking, recreational and occupational physical activity and alcohol intake. Further adjustment for folate or homocysteine status or the MTHFR 677C > T polymorphism did not affect risk estimates. Subjects with the RFC1 80AA genotype in combination with low plasma folate concentrations or the MTHFR 677TT genotype had a reduced risk of colorectal cancer of borderline statistical significance. CONCLUSIONS: These findings suggest that although the RFC1 80G > A and FOLH1 1561C > T polymorphisms may influence folate status, they are not likely to have a major independent role in the development of colorectal cancer.

Surgery for neoplastic changes in ulcerative colitis--can limited resection be justified? Outcome for patients who underwent limited surgery.

BACKGROUND: Patients with ulcerative colitis (UC) are at an increased risk of developing colorectal cancer (CRC). The aim of this study was to investigate the outcome for the patients who underwent limited resection of the colon and/or rectum instead of panproctocolectomy (PPC), with special attention to those with neoplastic changes. METHODS: Since 1977, all known patients with UC from our catchment area have been included in our surveillance programme. A total of 210 patients with UC have been followed up with regular colonoscopies and biopsies. Indications for surgery were severe therapy-resistant disease (TRD), high-grade dysplasia (HGD), CRC or repeated findings of low-grade dysplasia (LGD). Patient compliance was excellent. RESULTS: Fifty-one patients were operated on. In 29 of these patients, PPC was performed initially. At the end-point of the study, additionally seven patients had been radically operated on and three more patients planned to undergo such an operation. Accordingly, 22 patients had their first operation performed as a resection of either a part of or the whole colon or rectum. In this group, there were four patients diagnosed with CRC and three with dysplasia-associated lesion or mass (DALM). One of them died 6 months after surgery because of disseminated CRC, whereas the other patients were alive at the end-point of the study. One of these seven patients with CRC or DALM had at end-point been radically operated on and two patients were awaiting such a procedure (in two patients because of LGD and in one patient because of TRD). Six of the patients who had a colorectal resection performed on the indication of TRD were radically operated later on, five of them because of relapsed TRD and one patient because of LGD in the remaining rectal mucosa. Twenty-one patients gained a mean of 9.4 years with presumably better bowel function, from undergoing a limited resection instead of PPC. None of the patients who underwent a colonic and/or rectal resection died because of CRC or metachronous cancer in their remaining colon or rectum. CONCLUSION: The results of this study indicate that a limited resection of the colon and/or rectum in patients with UC, which requires surgical intervention increases the time with presumably better bowel function and may therefore be an alternative to PPC without increased risk of dying from CRC. This is dependent on the flexibility of the medical service and patient compliance.

Two Swedish founder MSH6 mutations, one nonsense and one missense, conferring high cumulative risk of Lynch syndrome.

Lynch syndrome, or hereditary non-polyposis colorectal cancer (HNPCC), is a cancer susceptibility syndrome caused by germline mutations in mismatch-repair genes, predominantly MLH1, MSH2 and MSH6. A majority of the mutations reported are truncating, but for MSH6, missense mutations constitute over one third. Few have been proven pathogenic in functional studies or shown to segregate in families. In this study, we show segregation of the putative pathogenic MSH6 missense mutation c.1346T>C p.Leu449Pro with microsatellite instability-high Lynch syndrome-related tumours lacking MSH6 expression in a large 17th century pedigree. Another large family with the MSH6 nonsense c.2931C>G, p.Tyr977X mutation is similar in tumour spectra, age of onset and cumulative risk. These MSH6 families, despite their late age of onset, have a high lifetime risk of all Lynch syndrome-related cancers, significantly higher in women (89% by age 80) than in men (69%). The gender differences are in part explained by high endometrial (70%) and ovarian (33%) cancer risks added upon the high colorectal cancer risk (60%). The several occurrences of breast cancer are not due to the MSH6 mutations. These findings are of great importance for counselling, management and surveillance of families with MSH6 mutations.

Prognostic significance of p27(Kip1) expression in colorectal cancer: a clinico-pathological characterization.

This study has evaluated the expression of the cyclin-dependent kinase inhibitor p27(Kip1) in 89 colorectal cancers (CRCs) using immunohistochemistry and has related p27 levels to clinico-pathological characteristics, tumour cell proliferation, and the expression of other G1-S transition regulatory proteins. Low levels of p27 were common in CRCs; 11 per cent of the tumours expressed very low levels and 44 per cent had p27 labelling indices (LIs) below 50 per cent. Except for depth of tumour invasion, no significant correlation was found between p27 expression and Dukes' stage, differentiation, growth pattern, tumour type or lymphocytic infiltration. Interestingly, tumours expressing low or very low p27 LIs were predominantly found in the right colon (p=0.026). Expression of p27 was a strong predictor of survival, both in univariate and in multivariate survival analyses; patients with tumours of p27 LI less than 50 per cent had an impaired prognosis (p=0.0069). p27 expression did not correlate with tumour cell proliferation, or with expression of cyclin D1 or the retinoblastoma protein (pRb). These findings support the view that p27 not merely controls cell cycle progression, but might be associated with other mechanisms responsible for aggressive tumour behaviour in colorectal cancer.

Systematic heterogeneity and prognostic significance of cell proliferation in colorectal cancer.

The prognosis of colorectal cancer has not significantly changed during the last 30 years. While evaluation of tumour cell proliferation may provide prognostic information, results obtained so far have been contradictory Heterogeneity in tumour cell proliferation may explain these contradictions. With in vivo injection of iododeoxyuridine (IdUrd), estimation of labelling index (LI), S-phase transit time (Ts) and potential doubling time (Tpot) may be performed from a single sample. A total of 109 colorectal cancers were studied after in vivo injection of IdUrd before surgical removal. From each cancer, four to eight samples were processed for both flow cytometrical (FCM) and immunohistochemical (IHC) visualization of IdUrd incorporation. LI/IHC was morphometrically quantified at both the luminal border and the invasive margin of these tumours. LI was significantly higher at the luminal border compared with the invasive margin, although they were correlated with each other. Using combined IHC and FCM methods, rapidly growing colorectal cancers (high LI and/or low Tpot) showed an increased survival (significant for LI at the invasive margin and for Tpot at both the invasive margin and the luminal border) in the entire unselected material and for radically removed Dukes' B tumours. FCM data alone did not discriminate for survival, with the exception of Ts in diploid and radically removed Dukes' B tumours.