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The role of adjuvant chemotherapy for patients with rectal cancer after preoperative (chemo)radiotherapy and surgery is uncertain. We did a meta-analysis of individual patient data to compare adjuvant chemotherapy with observation for patients with rectal cancer. We searched PubMed, Medline, Embase, Web of Science, the Cochrane Library, CENTRAL, and conference abstracts to identify European randomised, controlled, phase 3 trials comparing observation with adjuvant chemotherapy after preoperative (chemo)radiotherapy and surgery for patients with non-metastatic rectal cancer. The primary endpoint of interest was overall survival. We analysed data from four eligible trials, including data from 1196 patients with (y)pTNM stage II or III disease, who had an R0 resection, had a low anterior resection or an abdominoperineal resection, and had a tumour located within 15 cm of the anal verge. We found no significant differences in overall survival between patients who received adjuvant chemotherapy and those who underwent observation (hazard ratio [HR] 0·97, 95% CI 0·81–1·17; p=0·775); there were no significant differences in overall survival in subgroup analyses. Overall, adjuvant chemotherapy did not significantly improve disease-free survival (HR 0·91, 95% CI 0·77–1·07; p=0·230) or distant recurrences (0·94, 0·78–1·14; p=0·523) compared with observation. However, in subgroup analyses, patients with a tumour 10–15 cm from the anal verge had improved disease-free survival (0·59, 0·40–0·85; p=0·005, pinteraction=0·107) and fewer distant recurrences (0·61, 0·40–0·94; p=0·025, pinteraction=0·126) when treated with adjuvant chemotherapy compared with patients undergoing observation. Overall, adjuvant fluorouracil-based chemotherapy did not improve overall survival, disease-free survival, or distant recurrences. However, adjuvant chemotherapy might benefit patients with a tumour 10–15 cm from the anal verge in terms of disease-free survival and distant recurrence. Further studies of preoperative and postoperative treatment for this subgroup of patients are warranted. None.

Use of aspirin after diagnosis of colon cancer has been associated with improved survival. Identification of cancer subtypes that respond to aspirin treatment may help develop personalized treatment regimens. The aim of this study was to investigate the influence of BRAF and KRAS mutation status on the association between aspirin use and overall survival after colon cancer diagnosis. A random selection of 599 patients with colon cancer were analyzed, selected from the Eindhoven Cancer Registry, and BRAF and KRAS mutation status was determined. Data on aspirin use (80 mg) were obtained from the PHARMO Database Network. Parametric survival models with exponential (Poisson) distribution were used. Aspirin use after colon cancer diagnosis was associated with improved overall survival in wild-type BRAF tumors, adjusted rate ratio (RR) of 0.60 (95% CI 0.44-0.83). In contrast, aspirin use in BRAF mutated tumors was not associated with an improved survival (RR 1.11, 95% CI 0.57-2.16). P-value for interaction was non-significant. KRAS mutational status did not differentiate in the association between aspirin use and survival. Low-dose aspirin use after colon cancer diagnosis was associated with improved survival in BRAF wild-type tumors only. However, the large confidence interval of the rate ratio for the use of aspirin in patients with BRAF mutation does not rule out a possible benefit. These results preclude BRAF and KRAS mutation status to be used as a marker for individualized treatment with aspirin, if aspirin becomes regular adjuvant treatment for colon cancer patients in the future.

ObjectiveAs the development and progression of colorectal cancer (CRC) are known to be affected by the immune system, cell subsets such as T cells, natural killer (NK) cells, and natural killer T (NKT) cells are considered interesting targets for immunotherapy and clinical biomarker research. Until now, the role of systemic immune profiles in tumor progression remains unclear. In this study, we aimed to characterize the immunophenotype of circulating T cells, NK cells, and NKT-like cells in patients with CRC, and to subsequently correlate these immunophenotypes to clinical follow-up data.MethodsUsing multiparameter flow cytometry, the subset distribution and immunophenotype of T cells (CD3+CD56−), CD56dim NK cells (CD3−CD56dim), CD56bright NK cells (CD3−CD56bright), and NKT-like (CD3+CD56+) cells were investigated in peripheral blood mononuclear cell (PBMC) samples from 71 CRC patients and 19 healthy donors.ResultsCRC patients showed profound differences in immune cell subset distribution and their immunophenotype compared to healthy donors, as characterized by increased percentage of regulatory T cells, and reduced expression level of the natural cytotoxicity receptors NKp44 and NKp46 on both CD56dim NK cells and NKT-like cells. Finally, we showed in a multivariate analysis that above-median percentage of CD16+ NKT-like cells was independently associated with shorter disease-free survival in CRC patients.ConclusionThe altered phenotype of circulating immune cell subsets in CRC and its association with clinical outcome highlight the potential use of PBMC subsets as prognostic biomarkers in CRC, thereby contributing to better insight into the role of systemic immune profiles in tumor progression.

Genome-wide DNA hypomethylation is associated with a worse prognosis in early-stage colorectal cancer. To measure genome-wide DNA methylation levels, long interspersed nucleotide element (LINE-1) repeats are used as a surrogate marker. Cohort studies on the clinical impact of genome-wide DNA methylation level in patients with only early-stage colon cancer, are currently lacking. This study aimed to investigate the prognostic value of LINE-1 methylation in a stage II colon cancer cohort (n = 164). Manual needle microdissection of tumor areas was performed on formalin-fixed paraffin-embedded tumor tissue sections followed by DNA extraction. Bisulfite converted DNA was used to assess tumor LINE-1 methylation level by qPCR. Patients with LINE-1 hypomethylated tumors had a significantly worse overall survival compared to patients with a higher level of LINE-1 tumor DNA methylation (HR 1.68, 95% CI 1.03–2.75; p = 0.04). This effect was more prominent in patients aged over 65 years (HR 2.00, 95% CI 1.13–3.52; p = 0.02), although the test for age interaction was not significant. No significant effect on recurrence-free survival was observed. Based on these results, tumor LINE-1 hypomethylation is associated with a worse overall survival in stage II colon cancer. Whether the origin of this causation is cancer-specific or age-related can be debated.

The improved overall survival in patients aged 70 years or older treated with adjuvant chemotherapy contradicts Bujko's hypothesis, although we think this association is probably the result of selection rather than a real effect of adjuvant chemotherapy. In subgroup analyses, patients with a tumour between 10-15 cm from the anal verge who received adjuvant chemotherapy had improved disease-free survival (hazard ratio 0·50, 95% CI 0·33-0·76, p=0·001).

Although most cancer types have been viewed as immunologically silent until recently, it has become increasingly clear that the immune system plays key roles in the course of tumor development. Remarkable progress towards understanding cancer immunogenicity and tumor-immune system interactions has revealed important implications for the design of novel immune-based therapies. Natural immune responses, but also therapeutic interventions, can modulate the tumor phenotype due to selective outgrowth of resistant subtypes. This is the result of heterogeneity of tumors, with genetic instability as a driving force, and obviously changes the immunogenicity of tumors. In this review, we discuss the immunogenicity of colorectal cancer (CRC) in relation to tumor development and treatment. As most tumors, CRC activates the immune system in various ways, and is also capable of escaping recognition and elimination by the immune system. Tumor-immune system interactions underlie the balance between immune control and immune escape, and may differ in primary tumors, in the circulation, and in liver metastases of CRC. Since CRC immunogenicity varies between tumors and individuals, novel immune-based therapeutic strategies should not only anticipate the molecular profile, but also the immunological profile of a specific tumor.