The prognostic influence of tumour budding in Western patients with stage II colorectal cancer.

BACKGROUND: Tumour budding (TB) refers to loss of tumour cohesiveness and is defined as isolated cells or a cell cluster of up to four tumour cells at the microscopic analysis. The International Tumour Budding Consensus Conference (ITBCC) in 2016 proposed a scoring system to standardise the pathology evaluation of TB in colorectal cancer (CRC) as high (H), intermediate (I) and low (L) TB. OBJECTIVE: To evaluate the recurrence-free survival (RFS) of stage II CRC patients as per the ITBCC 2016 classification and associations between TB and clinical pathological features. METHODS: Cases of stage II CRC undergoing surgery with available tumour tissue underwent central pathology review for TB. Prognostic factors, retrospectively retrieved from electronic medical charts, were evaluated in univariate and multivariate Cox regression analyses for RFS (primary end point). RESULTS: Among 137 patients included, L-TB was observed in 107 (78.1%), I-TB in 21 (15.3%) and H-TB in 9 (6.6%). In a median follow-up of 69 months, the median RFS was 134 months, with 14 patients (10.2%) presenting with tumour recurrence: 10 (9.3%) with L-TB, 2 (9.5%) with I-TB and 2 (22.2%) with H-TB. Perineural invasion was more commonly seen in the H-TB group. In multivariate analysis, TB (H and I versus L; HR = 2.6; p = 0.059) and not receiving adjuvant chemotherapy (HR 3.7; p = 0.020) were independently associated with RFS. Adjuvant chemotherapy was associated longer RFS (HR = 3.7; p = 0.022). CONCLUSION: In this series of Western patients, TB grade was associated with perineural invasion and increased risk of disease relapse.

MLH1 intronic variants mapping to + 5 position of splice donor sites lead to deleterious effects on RNA splicing.

Germline pathogenic variants in the DNA mismatch repair genes (MMR): MLH1, MSH2, MSH6, and PMS2, are causative of Lynch syndrome (LS). However, many of the variants mapping outside the invariant splice site positions (IVS ± 1, IVS ± 2) are classified as variants of unknown significance (VUS). Three such variants (MLH1 c.588+5G>C, c.588+5G>T and c.677+5G>A) were identified in 8 unrelated LS families from Argentina, Brazil and Chile. Herein, we collected clinical information on these families and performed segregation analysis and RNA splicing studies to assess the implication of these VUS in LS etiology. Pedigrees showed a clear pattern of variant co-segregation with colorectal cancer and/or other LS-associated malignancies. Tumors presented deficient expression of MLH1-PMS2 proteins in 7/7 of the LS families, and MSI-high status in 3/3 cases. Moreover, RNA analyses revealed that c.588+5G>C and c.588+5G>T induce skipping of exon 7 whereas c.677+5G>A causes skipping of exon 8. In sum, we report that the combined clinical findings in the families and the molecular studies provided the evidences needed to demonstrate that the three MLH1 variants are causative of LS and to classify c.588+5G>C and c.677+5G>A as class 5 (pathogenic), and c.588+5G>T as class 4 (likely-pathogenic). Our findings underline the importance of performing clinical and family analyses, as well as RNA splicing assays in order to determine the clinical significance of intronic variants, and contribute to the genetic counseling and clinical management of patients and their relatives.

Clinical factors related to severe enterocolitis after adjuvant CAPOX for colorectal cancer: a retrospective analysis.

BACKGROUND: CAPOX regimen is a standard option in stage III adjuvant colon cancer. Gastrointestinal toxicity is well described with fluoropyrimidine regimens and can be life-threatening. Identification of risk factors associated with severe gastrointestinal toxicity may help clinicians when choosing the adjuvant regimen. MATERIALS AND METHODS: We retrospectively analysed 61 patients treated with adjuvant CAPOX. Our primary objective was to estimate the incidence of severe chemotherapy-induced enterocolitis among patients treated with CAPOX. A secondary objective was to describe the main demographic and clinical characteristics of these patients. A univariate logistic regression was performed to estimate the odds ratio (OR) with a 95% CI to identify a predictor for severe enterocolitis. RESULTS: Grade 3 diarrhoea was reported in 10 patients (16.3%). Admissions to hospital due to toxicity occurred in nine cases. Reasons for hospitalisation were severe enterocolitis in eight cases (13.1%) and rectal bleeding plus thrombocytopenia in one case. Age > 70 years (OR 9.6; 95% CI 1.81-50.6; p = 0.008), primary surgery involving right/transverse colon (OR 16.8; 95% CI 2.88-98.8; p = 0.002) and Angiotensin II Receptor Blocker (ARB) use (OR 8.14; 95% CI 1.64-40.3; p = 0.010) were associated with severe enterocolitis. CONCLUSION: Our data showed that adjuvant CAPOX induced severe enterocolitis in 13.1% of patients. In addition, we found that advanced age, right colectomy and concurrent use of ARB were statistically associated with these events. Awareness of these factors could be easily incorporated into the treatment decision and patient orientation.

From colorectal cancer pattern to the characterization of individuals at risk: Picture for genetic research in Latin America.

Colorectal cancer (CRC) is one of the most common cancers in Latin America and the Caribbean, with the highest rates reported for Uruguay, Brazil and Argentina. We provide a global snapshot of the CRC patterns, how screening is performed, and compared/contrasted to the genetic profile of Lynch syndrome (LS) in the region. From the literature, we find that only nine (20%) of the Latin America and the Caribbean countries have developed guidelines for early detection of CRC, and also with a low adherence. We describe a genetic profile of LS, including a total of 2,685 suspected families, where confirmed LS ranged from 8% in Uruguay and Argentina to 60% in Peru. Among confirmed LS, path_MLH1 variants were most commonly identified in Peru (82%), Mexico (80%), Chile (60%), and path_MSH2/EPCAM variants were most frequently identified in Colombia (80%) and Argentina (47%). Path_MSH6 and path_PMS2 variants were less common, but they showed important presence in Brazil (15%) and Chile (10%), respectively. Important differences exist at identifying LS families in Latin American countries, where the spectrum of path_MLH1 and path_MSH2 variants are those most frequently identified. Our findings have an impact on the evaluation of the patients and their relatives at risk for LS, derived from the gene affected. Although the awareness of hereditary cancer and genetic testing has improved in the last decade, it is remains deficient, with 39%-80% of the families not being identified for LS among those who actually met both the clinical criteria for LS and showed MMR deficiency.

Late assessment of quality of life in patients with rectal carcinoma: comparison between sphincter preservation and definitive colostomy.

PURPOSE: Patients with cancer of the lower and middle rectum who are candidates for curative surgery often have negative opinions on definitive colostomy. The purpose of this study is to compare the quality of life (QoL) of patients who undergo standard treatment for rectal cancer with sphincter preservation or definitive colostomy. METHODS: A total of 125 patients with adenocarcinoma of the lower or middle rectum who underwent radical surgery with curative intent with a follow-up ≥ 1 year were recruited: 83 patients (group 1) were subjected to low anterior resection and low colorectal or coloanal anastomosis-thus preserving their sphincter-and 42 (group 2) were treated with abdominoperineal resection, followed by terminal definitive colostomy. QoL was assessed with the EORTC QLQ-C30 and QLQ-CR29 questionnaires. RESULTS: Health and global quality of life were similar between groups; however, patients who underwent definitive colostomy had higher scores on the emotional (p value = 0.016) and cognitive function scales (p value = 0.017). Patients with sphincter preservation presented with more symptoms that were related to stool frequency (p value < 0.001), intestinal constipation (p value = 0.005), fecal incontinence (p value = 0.001), buttock pain (p value = 0.023), and nausea and vomiting (p value = 0.036), whereas patients with permanent colostomy had higher scores for dysuria (p value = 0.033). CONCLUSION: Although global QoL scores did not differ between groups, patients who underwent definitive colostomy had significantly better functional and symptom scale scores, reflecting greater function with fewer symptoms.

KRAS gene mutation in a series of unselected colorectal carcinoma patients with prognostic morphological correlations: a pyrosequencing method improved by nested PCR.

INTRODUCTION: Inhibition of EGFR is a strategy for treating metastatic colorectal cancer (CRC) patients. KRAS sequencing is mandatory for selecting wild-type tumor patients who might benefit from this treatment. DNA from formalin-fixed paraffin-embedded (FFPE) tissues is commonly used for routine clinical detection of mutations, and its amplification succeeds only when all preanalytical histological processes have been controlled. In cases that are not properly processed, the DNA results can be poor, with low peak pyrosequencing findings. We designed and tested a pair of forward and reverse primers for a nested PCR method, followed by pyrosequencing, in a single Latin American institution series of 422 unselected CRC patients, correlating KRAS mutations with pathological and clinical data. MATERIALS AND METHODS: Patient DNA samples from tumors were obtained by scraping or laser microdissection of cells from FFPE tissue and extracted using a commercial kit. DNA was first amplified by PCR using 2 primers that we designed; then, nested PCR was performed with the amplicon from the preamplification PCR using the KRAS PyroMark™ Q96 V2.0 kit (Qiagen). Pathological data were retrieved from pathology reports. RESULTS: KRAS mutation was observed in 33% of 421 cases. Codon 12 was mutated in 76% of cases versus codon 13 in 24%. Right-sided CRCs harbored more KRAS mutations than left-sided tumors, as did tumors that presented with perineural invasion. CONCLUSION: Our findings in this Latin American population are consistent with the literature regarding the frequency of KRAS mutations in CRC, their distribution between codons 12 and 13, and type of nucleotide substitution. By combining nested PCR and pyrosequencing, we achieved a high rate of conclusive results in testing KRAS mutations in CRC samples - a method that can be used as an ancillary test for failed assays by conventional PCR.

Predictive models for mutations in mismatch repair genes: implication for genetic counseling in developing countries.

BACKGROUND: Lynch syndrome (LS) is the most common form of inherited predisposition to colorectal cancer (CRC), accounting for 2-5% of all CRC. LS is an autosomal dominant disease characterized by mutations in the mismatch repair genes mutL homolog 1 (MLH1), mutS homolog 2 (MSH2), postmeiotic segregation increased 1 (PMS1), post-meiotic segregation increased 2 (PMS2) and mutS homolog 6 (MSH6). Mutation risk prediction models can be incorporated into clinical practice, facilitating the decision-making process and identifying individuals for molecular investigation. This is extremely important in countries with limited economic resources. This study aims to evaluate sensitivity and specificity of five predictive models for germline mutations in repair genes in a sample of individuals with suspected Lynch syndrome. METHODS: Blood samples from 88 patients were analyzed through sequencing MLH1, MSH2 and MSH6 genes. The probability of detecting a mutation was calculated using the PREMM, Barnetson, MMRpro, Wijnen and Myriad models. To evaluate the sensitivity and specificity of the models, receiver operating characteristic curves were constructed. RESULTS: Of the 88 patients included in this analysis, 31 mutations were identified: 16 were found in the MSH2 gene, 15 in the MLH1 gene and no pathogenic mutations were identified in the MSH6 gene. It was observed that the AUC for the PREMM (0.846), Barnetson (0.850), MMRpro (0.821) and Wijnen (0.807) models did not present significant statistical difference. The Myriad model presented lower AUC (0.704) than the four other models evaluated. Considering thresholds of ≥ 5%, the models sensitivity varied between 1 (Myriad) and 0.87 (Wijnen) and specificity ranged from 0 (Myriad) to 0.38 (Barnetson). CONCLUSIONS: The Barnetson, PREMM, MMRpro and Wijnen models present similar AUC. The AUC of the Myriad model is statistically inferior to the four other models.