Effect of aspirin or resistant starch on colorectal neoplasia in the Lynch syndrome

Chemoprevention in Inherited Colorectal Cancer Syndromes

Cancer prevention in hereditary gastrointestinal predisposition syndromes relies primarily on intensive screening (e.g., colonoscopy) or prophylactic surgery (e.g., colectomy). The use of chemopreventive agents as an adjunct to these measures has long been studied both in the general population and in hereditary cancer patients, in whom the risk of malignancy, and therefore the potential risk reduction, is considerably greater. However, to date only few compounds have been found to be effective, safe, and tolerable for widespread use. Furthermore, many of the studies involving these rare syndromes suffer from small sample sizes, heterogeneous patient cohorts, short follow-up duration, and lack of standardized endpoints, creating challenges to draw generalizable conclusion regarding efficacy. The following review summarizes the current data on various chemopreventive compounds used in Lynch syndrome and familial adenomatous polyposis in addition to several agents that are currently being investigated.

IMMUNOREACT 7: Regular aspirin use is associated with immune surveillance activation in colorectal cancer

BACKGROUND

Long-term daily use of aspirin reduces incidence and mortality due to colorectal cancer (CRC). This study aimed to analyze the effect of aspirin on the tumor microenvironment, systemic immunity, and on the healthy mucosa surrounding cancer.

METHODS

Patients with a diagnosis of CRC operated on from 2015 to 2019 were retrospectively analyzed (METACCRE cohort). Expression of mRNA of immune surveillance-related genes (PD-L1, CD80, CD86, HLA I, and HLA II) in CRC primary cells treated with aspirin were extracted from Gene Expression Omnibus-deposited public database (GSE76583). The experiment was replicated in cell lines. The mucosal immune microenvironment of a subgroup of patients participating in the IMMUNOREACT1 (ClinicalTrials.gov NCT04915326) project was analyzed with immunohistochemistry and flow cytometry.

RESULTS

In the METACCRE Cohort, 12% of 238 patients analyzed were aspirin users. Nodal metastasis was significantly less frequent (p = .008) and tumor-infiltrating lymphocyte infiltration was higher (p = .02) among aspirin users. In the CRC primary cells and selected cell lines, CD80 mRNA expression was increased following aspirin treatment (p = .001). In the healthy mucosa surrounding rectal cancer, the ratio of CD8/CD3 and epithelial cells expressing CD80 was higher in aspirin users (p = .027 and p = .034, respectively).

CONCLUSIONS

These data suggested that regular aspirin use may have an active role in enhancing immunosurveillance against CRC.

Oral aspirin for preventing colorectal adenoma recurrence: A systematic review and network meta-analysis of randomized controlled trials

Colorectal adenomas have the potential of malignant transformation if left untreated. Multiple randomized controlled trials have been performed to evaluate the efficacy of aspirin in preventing colorectal adenoma recurrence in a population with a history of colorectal adenoma but not colorectal cancer, however, the relationship between aspirin dose and colorectal adenoma recurrence remains unclear. We conducted pairwise meta-analysis, meta-regression, trial sequential analysis, and network meta-analysis of all eligible studies. The ROB 2.0 tool was used to assess the risk of bias in the studies. The confidence in network meta-analysis (CINeMA) approach was used to evaluate the confidence of the network meta-analysis results. The network meta-analysis included eight RCTs (nine reports), comprising four on aspirin (low or high dose) alone and four on aspirin combined with another medication, all compared with placebo. In the network meta-analysis, low-dose aspirin (LDA <300 mg per day) was more effective than high-dose aspirin (HDA ≥300 mg per day) and placebo, with risk ratios of 0.76 (95% CI: 0.58 to 0.99) and 0.7 (95% CI: 0.54 to 0.91), respectively. LDA was the optimal treatment relative to HDA and placebo (P-score = 0.99). In the trial sequential analysis, LDA was only more effective than placebo when the number of included participants exceeded the optimal information size; this was not the case for HDA. LDA has statistically significant efficacy for colorectal adenoma prevention, but compared with HDA, its efficacy remains uncertain. Further trials are therefore required.

Preventive effects of chemical drugs on recurrence of colorectal adenomas: systematic review and Bayesian network meta-analysis

BACKGROUND

The onset of colorectal adenomas (CRAs) is significantly associated with colorectal cancer. The preventive effects of chemical drugs on the recurrence of CRAs have been evaluated in a large number of randomized controlled trials (RCTs). However, there are still uncertainties about the relative effectiveness of such chemical drugs.

METHODS

We searched relevant RCTs published in six databases up to February 2023. The quality of the included studies was assessed by using the Cochrane risk of bias assessment tool and Review Manager 5.4. Pairwise comparison and network meta-analysis (NMA) were conducted using RStudio to compare the effects of chemical drugs on the recurrence of CRAs.

RESULTS

Forty-five high-quality RCTs were included. A total of 35 590 (test group: 20 822; control group: 14 768) subjects with a history of CRAs have been enrolled and randomized to receive placebo treatment or one of 24 interventions. Based on surface under the cumulative ranking values and NMA results, difluoromethylornithine (DFMO) + Sulindac significantly reduced the recurrence of CRAs, followed by berberine and nonsteroidal antiinflammatory drugs.

CONCLUSION

DFMO + Sulindac is more effective in reducing the recurrence of CRAs but has a high risk of adverse events. Considering drug safety, tolerance, and compliance, berberine has a brighter prospect of clinical development. However, further studies are needed to verify our findings.

Aspirin and nonaspirin nonsteroidal antiinflammatory drug use and occurrence of colorectal adenoma in Black American women

Evidence suggests that aspirin use reduces the occurrence of colorectal neoplasia. Few studies have investigated the association among Black Americans, who are disproportionately burdened by the disease. We assessed aspirin use in relation to colorectal adenoma among Black women. The Black Women's Health Study is a prospective cohort of self-identified Black American women established in 1995. Participants reported regular aspirin use on baseline and follow-up questionnaires. Beginning in 1999, participants reported undergoing a colonoscopy or sigmoidoscopy, the only procedures through which colorectal adenomas can be diagnosed. Multivariable logistic regression was used to estimate odds ratios (OR) and 95% confidence intervals (CI) for associations between aspirin use and colorectal adenoma among 34 397 women who reported at least 1 colonoscopy or sigmoidoscopy. From 1997 through 2018, 1913 women were diagnosed with an adenoma. Compared to nonaspirin users, regular users had 14% (OR = 0.86, 95% CI: 0.78-0.95) lower odds of adenoma. The odds of adenoma decreased with increasing duration of aspirin use (≥10 years: OR = 0.80, 95% CI: 0.66-0.96). Initiating aspirin at a younger age was associated with a reduced adenoma occurrence (age < 40 years at initiation: OR = 0.69, 95% CI: 0.55-0.86). Regular aspirin use was associated with a decreased odds of colorectal adenoma in our study of Black women. These findings support evidence demonstrating a chemopreventive impact of aspirin on colorectal neoplasia and suggest that aspirin may be a useful prevention strategy among US Black women.

Chemoprevention in hereditary digestive neoplasia: A comprehensive review

Hereditary syndromes, such as familial adenomatous polyposis (FAP), MUTYH polyposis or Lynch syndrome, are particularly predisposing to the development of colorectal cancer. These situations have necessitated the development of adapted prevention strategies based largely on reinforced endoscopic surveillance and the search for complementary prevention strategies. This is the case for chemoprevention, which is the long-term administration of chemical agents limiting carcinogenesis, used as primary or secondary prophylaxis. The aim of this review is to present the available literature and the latest advances in chemoprevention in patients with FAP or MUTYH and other polyposis as well as in patients with Lynch syndrome. The main conclusions of the few available guidelines in these situations are also discussed.

Salicylate induces AMPK and inhibits c-MYC to activate a NRF2/ARE/miR-34a/b/c cascade resulting in suppression of colorectal cancer metastasis

Aspirin and its active metabolite salicylate have emerged as promising agents for the chemoprevention of colorectal cancer (CRC). Moreover, aspirin suppresses the progression of established CRCs. However, the underlying molecular mechanisms are not completely understood. Here we found that salicylate induces the expression of the miR-34a and miR-34b/c genes, which encode tumor suppressive microRNAs, in a p53-independent manner. Salicylate activated AMPK, thereby activating NRF2, which directly induced miR-34a/b/c expression via ARE motifs. In addition, salicylate suppressed c-MYC, a known repressor of NRF2-mediated transactivation, via activating AMPK. The suppression of c-MYC by salicylate was necessary for NRF2-mediated activation of miR-34a/b/c. Inactivation of miR-34a/b/c largely abrogated the inhibitory effects of salicylate on migration, invasion and metastasis formation by CRC cells. In the future, aspirin and its derivates may be used therapeutically to activate miR-34a and miR-34b/c in tumors that have lost p53.

Naproxen chemoprevention induces proliferation of cytotoxic lymphocytes in Lynch Syndrome colorectal mucosa

Background

Recent clinical trial data from Lynch Syndrome (LS) carriers demonstrated that naproxen administered for 6-months is a safe primary chemoprevention that promotes activation of different resident immune cell types without increasing lymphoid cellularity. While intriguing, the precise immune cell types enriched by naproxen remained unanswered. Here, we have utilized cutting-edge technology to elucidate the immune cell types activated by naproxen in mucosal tissue of LS patients.

Methods

Normal colorectal mucosa samples (pre- and post-treatment) from a subset of patients enrolled in the randomized and placebo-controlled 'Naproxen Study' were obtained and subjected to a tissue microarray for image mass cytometry (IMC) analysis. IMC data was processed using tissue segmentation and functional markers to ascertain cell type abundance. Computational outputs were then used to quantitatively compare immune cell abundance in pre- and post-naproxen specimens.

Results

Using data-driven exploration, unsupervised clustering identified four populations of immune cell types with statistically significant changes between treatment and control groups. These four populations collectively describe a unique cell population of proliferating lymphocytes within mucosal samples from LS patients exposed to naproxen.

Conclusions

Our findings show that daily exposure of naproxen promotes T-cell proliferation in the colonic mucosa, which paves way for developing combination of immunoprevention strategies including naproxen for LS patients.

Dietary fibre and health: the story so far

The present paper reviews progress in research on dietary fibre and human health over the past five decades. There is now convincing evidence from prospective cohort studies that diets low in dietary fibre are associated with increased risk of common non-communicable diseases including CVD, type 2 diabetes and colorectal cancer. These findings provide strong support for hypotheses proposed by Denis Burkitt 50 years ago, based on very limited evidence but with considerable imagination and insight. For the first two to three decades of this period, research on dietary fibre was hampered by the lack of consensus about the definition, and measurement, of this complex and diverse dietary component and by the lack of appropriate tools for investigating the gut microbiome that is central to understanding mechanisms of action. Recent technical and scientific advances in microbiome research (based on fast, low-cost, DNA sequencing) are facilitating investigation of the associations between dietary fibre, the gut microbiome and human health. Current challenges include the need for agreement about the characteristics of a healthy gut microbiome. Although the health benefits attributed to higher dietary fibre intake are likely to be shared with most types of dietary fibre, one should anticipate that different sources of dietary fibre and the other components (resistant starch and non-digestible oligosaccharides) that make up dietary fibre will have characteristically different effects on human physiology and disease risk. In conclusion, population-level intakes of dietary fibre are low and there is a public health priority to develop and implement more effective interventions to increase intake.

Colorectal Cancer Chemoprevention: A Dream Coming True?

Colorectal cancer (CRC) is one of the deadliest forms of cancer worldwide. CRC development occurs mainly through the adenoma-carcinoma sequence, which can last decades, giving the opportunity for primary prevention and early detection. CRC prevention involves different approaches, ranging from fecal occult blood testing and colonoscopy screening to chemoprevention. In this review, we discuss the main findings gathered in the field of CRC chemoprevention, focusing on different target populations and on various precancerous lesions that can be used as efficacy evaluation endpoints for chemoprevention. The ideal chemopreventive agent should be well tolerated and easy to administer, with low side effects. Moreover, it should be readily available at a low cost. These properties are crucial because these compounds are meant to be used for a long time in populations with different CRC risk profiles. Several agents have been investigated so far, some of which are currently used in clinical practice. However, further investigation is needed to devise a comprehensive and effective chemoprevention strategy for CRC.

Genetic Predisposition to Colorectal Cancer: How Many and Which Genes to Test?

Colorectal cancer is one of the most common tumors, and genetic predisposition is one of the key risk factors in the development of this malignancy. Lynch syndrome and familial adenomatous polyposis are the best-known genetic diseases associated with hereditary colorectal cancer. However, some other genetic disorders confer an increased risk of colorectal cancer, such as Li-Fraumeni syndrome (TP53 gene), MUTYH-associated polyposis (MUTYH gene), Peutz-Jeghers syndrome (STK11 gene), Cowden syndrome (PTEN gene), and juvenile polyposis syndrome (BMPR1A and SMAD4 genes). Moreover, the recent advances in molecular techniques, in particular Next-Generation Sequencing, have led to the identification of many new genes involved in the predisposition to colorectal cancers, such as RPS20, POLE, POLD1, AXIN2, NTHL1, MSH3, RNF43 and GREM1. In this review, we summarized the past and more recent findings in the field of cancer predisposition genes, with insights into the role of the encoded proteins and into the associated genetic disorders. Furthermore, we discussed the possible clinical utility of genetic testing in terms of prevention protocols and therapeutic approaches.

Fifty years with aspirin and platelets

In 2021, we reached the 50th anniversary of the publication of Sir John Vane's seminal paper in Nature New Biology describing the experiments supporting his mechanistic hypothesis that inhibition of prostaglandin synthesis might explain the main pharmacological effects of aspirin and aspirin-like drugs, that is, reduction in pain, fever and inflammation. Bengt Samuelsson's subsequent discoveries elucidating the cyclooxygenase pathway of platelet arachidonic acid metabolism motivated my research interest towards measuring platelet thromboxane A₂ biosynthesis as a tool to investigate the clinical pharmacology of cyclooxygenase inhibition by aspirin in health and disease. What followed was a long, winding road of clinical research leading to the characterization of low-dose aspirin as a life-saving antiplatelet drug that still represents the cornerstone of antithrombotic therapy. Having witnessed and participated in these 50 years of aspirin research, I thought of providing a personal testimony of how things developed and eventually led to a remarkable success story of independent research.

Dietary Intervention for Preventing Colorectal Cancer: A Practical Guide for Physicians

Colorectal cancer (CRC) is a disease with high prevalence and mortality. Estimated preventability for CRC is approximately 50%, indicating that altering modifiable factors, including diet and body weight, can reduce CRC risk. There is strong evidence that dietary factors including whole grains, high-fiber, red and processed meat, and alcohol can affect the risk of CRC. An alternative strategy for preventing CRC is use of a chemopreventive supplement that provides higher individual exposure to nutrients than what can be obtained from the diet. These include calcium, vitamin D, folate, n-3 polyunsaturated fatty acids, and phytochemicals. Several intervention trials have shown that these dietary chemopreventives have positive protective effects on development and progression CRC. Research on chemoprevention with phytochemicals that possess anti-inflammatory and/or, anti-oxidative properties is still in the preclinical phase. Intentional weight loss by bariatric surgery has not been effective in decreasing long-term CRC risk. Physicians should perform dietary education for patients who are at high risk of cancer for changing their dietary habits and behaviour. An increased understanding of the role of individual nutrients linked to the intestinal micro-environment and stages of carcinogenesis would facilitate the development of the best nutritional formulations for preventing CRC.

Cancer Prevention with Resistant Starch in Lynch Syndrome Patients in the CAPP2-Randomized Placebo Controlled Trial: Planned 10-Year Follow-up

ABSTRACT

The CAPP2 trial investigated the long-term effects of aspirin and resistant starch on cancer incidence in patients with Lynch syndrome (LS). Participants with LS were randomized double-blind to 30 g resistant starch (RS) daily or placebo for up to 4 years. We present long-term cancer outcomes based on the planned 10-year follow-up from recruitment, supplemented by National Cancer Registry data to 20 years in England, Wales, and Finland. Overall, 463 participants received RS and 455 participants received placebo. After up to 20 years follow-up, there was no difference in colorectal cancer incidence (n = 52 diagnosed with colorectal cancer among those randomized to RS against n = 53 on placebo) but fewer participants had non-colorectal LS cancers in those randomized to RS (n = 27) compared with placebo (n = 48); intention-to-treat (ITT) analysis [HR, 0.54; 95% confidence interval (CI), 0.33-0.86; P = 0.010]. In ITT analysis, allowing for multiple primary cancer diagnoses among participants by calculating incidence rate ratios (IRR) confirmed the protective effect of RS against non-colorectal cancer LS cancers (IRR, 0.52; 95% CI, 0.32-0.84; P = 0.0075). These effects are particularly pronounced for cancers of the upper GI tract; 5 diagnoses in those on RS versus 21 diagnoses on placebo. The reduction in non-colorectal cancer LS cancers was detectable in the first 10 years and continued in the next decade. For colorectal cancer, ITT analysis showed no effect of RS on colorectal cancer risk (HR, 0.92; 95% CI, 0.62-1.34; P = 0.63). There was no interaction between aspirin and RS treatments. In conclusion, 30 g daily RS appears to have a substantial protective effect against non-colorectal cancer cancers for patients with LS.

PREVENTION RELEVANCE

Regular bowel screening and aspirin reduce colorectal cancer among patients with LS but extracolonic cancers are difficult to detect and manage. This study suggests that RS reduces morbidity associated with extracolonic cancers. See related Spotlight, p. 557.

The efficacy of chemopreventive agents on the incidence of colorectal adenomas: A systematic review and network meta-analysis

Colorectal cancer (CRC) is the fourth most common cancer and third leading cause of cancer-related death worldwide. Use of chemopreventive agents (CPAs) to reduce the incidence of precursor colorectal adenomas could lower the future burden of CRC. Many classes of potential CPAs have been investigated. To identify the most effective CPAs, we conducted a systematic review and a network meta-analysis (NMA). An electronic search was performed through August 2020 to identify all randomized controlled trials (RCTs) assessing the efficacy of CPAs in reducing the incidence of colorectal adenomas at the time of surveillance colonoscopy among patients who had previously undergone polypectomy during an index colonoscopy. In total, 33 RCTs were included in the NMA, which was conducted under a Bayesian inference framework. Random effects models were used with adjustment for follow-up length and control group event rates to yield relative risks (RRs) and 95% credible intervals (CrIs). Our full network consisted of 13 interventions in addition to a placebo arm. Of 20,925 included patients, 7766 had an adenoma. Compared to placebo, the combination of difluoromethylornithine (DFMO) + Sulindac (RR 0.24, CrI 0.10-0.55) demonstrated a protective effect, while aspirin had a RR of 0.77 (CrI 0.60-1.00), celecoxib 800 mg had a RR of 0.56 (CrI 0.31-1.01) and metformin had a RR of 0.56 (CrI 0.22-1.39). Our results suggest that select CPAs may be efficacious in preventing the development of adenomas. Further studies are needed to identify those patients most likely to benefit and the minimum effective dosages of CPAs.

Can a Banana a Day Keep the Cancer Away in Patients with Lynch Syndrome?

The CAPP2 investigators report on the long-term effects of resistant starch (RS) on the incidence of colorectal cancer and other Lynch syndrome–related tumors in the trial population of the CAPP-2 study. RS has no effect on colorectal cancer incidence, but it reduced the numbers of other Lynch syndrome–related tumors, mainly driven by upper gastrointestinal cancers. Although the study has limitations related to secondary analysis, it fills an important void in the field of cancer interception of non–colorectal Lynch syndrome–related tumors and should form the basis for future trials of RS in Lynch syndrome.

See related article, p. 623

Lynch Syndrome: From Carcinogenesis to Prevention Interventions

Simple Summary

Promoting proper preventive interventions to reduce morbidity and mortality is one of the most important challenges pertaining to inherited conditions. Lynch syndrome (LS) is an inherited disorder that predisposes to several kinds of tumor and is responsible for a relevant proportion of human colorectal and endometrial cancers. Recent knowledge has allowed for a better understanding of the genetic cause, pathogenesis, underlying immunological mechanisms, epidemiological distribution, and prevalence of this disease. This opens up unpredictable perspectives of translating such knowledge into validated programs for prevention and surveillance, in order to reduce the health impact of this disease through medical interventions before cancer development. In our review, we summarize the updated guidelines of the screening, surveillance, and risk-reducing strategies for LS patients. Moreover, we present novel opportunities in the treatment and prevention of LS patients through harnessing the immune system using immunocheckpoint inhibitors and vaccines.

Abstract

Lynch syndrome (LS) is the most common inherited disorder responsible for an increased risk of developing cancers at different sites, most frequently in the gastrointestinal and genitourinary tracts, caused by a germline pathogenic variant affecting the DNA mismatch repair system. Surveillance and risk-reducing procedures are currently available and warranted for LS patients, depending on underlying germline mutation, and are focused on relevant targets for early cancer diagnosis or primary prevention. Although pharmacological approaches for preventing LS-associated cancer development were started many years ago, to date, aspirin remains the most studied drug intervention and the only one suggested by the main surveillance guidelines, despite the conflicting findings. Furthermore, we also note that remarkable advances in anticancer drug discovery have given a significant boost to the application of novel immunological strategies such as immunocheckpoint inhibitors and vaccines, not only for cancer treatment, but also in a preventive setting. In this review, we outline the clinical, biologic, genetic, and morphological features of LS as well as the recent three-pathways carcinogenesis model. Furthermore, we provide an update on the dedicated screening, surveillance, and risk-reducing strategies for LS patients and describe emerging opportunities of harnessing the immune system.

Aspirin Colorectal Cancer Prevention in Lynch Syndrome: Recommendations in the Era of Precision Medicine

Cancer prevention in the era of precision medicine has to consider integrated therapeutic approaches. Therapeutic cancer prevention should be offered to selected cohorts with increased cancer risk. Undoubtedly, carriers of hereditary cancer syndromes have a well-defined high cancer risk. Lynch Syndrome is one of the most frequent hereditary syndromes; it is mainly associated with colorectal cancer (CRC). Nonsteroidal anti-inflammatory drugs and, in particular, aspirin use, has been associated with reduced CRC risk in several studies, initially with contradictory results; however, longer follow-up confirmed a reduced CRC incidence and mortality. The CAPP2 study recruited 861 Lynch syndrome participants randomly assigned to 600 mg of aspirin versus placebo. Like sporadic CRCs, a significant CRC risk reduction was seen after an extended follow-up, with a median treatment time that was relatively short (2 years). The ongoing CAPP3 will address whether lower doses are equally effective. Based on pharmacology and clinical data on sporadic CRCs, the preventive effect should also be obtained with low-dose aspirin. The leading international guidelines suggest discussing with Lynch syndrome carriers the possibility of using low-dose aspirin for CRC prevention. We aim systematically promote this intervention with all Lynch syndrome carriers.

Chemoprevention Considerations in Patients with Hereditary Colorectal Cancer Syndromes

Secondary prevention of colorectal neoplasia with chemoprevention is long-studied area of research and clinical use in patients with the 2 most common hereditary colorectal cancer syndromes including Lynch syndrome and familial adenomatous polyposis. No medication is currently approved for use for the prevention of colorectal polyps or cancer in either the general population or individuals with the hereditary colorectal cancer syndromes. Emerging data in animal models and limited data in humans suggest vaccines may be the next breakthrough for neoplasia prevention in patients with hereditary colorectal cancer. Clinicians must acknowledge chemoprevention is an adjunct and does not supplant endoscopic surveillance.

Aspirin use for cancer prevention: A systematic review of public, patient and healthcare provider attitudes and adherence behaviours

We undertook a systematic review to synthesise the data on attitudes and behaviour towards the use of aspirin for cancer prevention, and healthcare providers' attitudes towards implementing aspirin in practice. Searches were carried out across 12 databases (e.g. MEDLINE, EMBASE). We used the Mixed Methods Appraisal Tool to evaluate study quality, and conducted a narrative synthesis of the data. The review was pre-registered (PROSPERO: CRD42018093453). Thirty-eight studies were identified. Uptake and adherence data were all from trials. Trials recruited healthy participants, those at higher risk of cancer, and those with cancer. Four studies reported moderate to high (40.9-77.7%) uptake to an aspirin trial among people who were eligible. Most trials (18/22) reported high day-to-day adherence (≥80%). Three trials observed no association between gender and adherence. One trial found no association between adherence and colorectal cancer risk. Three studies reported moderate to high (43.6-76.0%) hypothetical willingness to use aspirin. Two studies found that a high proportion of healthcare providers (72.0-76.0%) perceived aspirin to be a suitable cancer prevention option. No qualitative studies were identified. The likelihood that eligible users of aspirin would participate in a trial evaluating the use of aspirin for preventive therapy was moderate to high. Among participants in a trial, day-to-day adherence was high. Further research is needed to identify uptake and adherence rates in routine care, the factors affecting aspirin use, and the barriers to implementing aspirin into clinical care.

Aspirin Inhibition of Group VI Phospholipase A2 Induces Synthetic Lethality in AAM Pathway Down-Regulated Gingivobuccal Squamous Carcinoma

Background: To elucidate the role of iPLA2/PLA2G6 in gingivobuccal squamous cell carcinoma (GB-SCC) and to ascertain the synthetic lethality-based chemoprevention role of aspirin in arachidonic acid metabolism (AAM) pathway down-regulated GB-SCC. Methods: The in vitro efficacy of aspirin on GB-SCC cells (ITOC-03 and ITOC-04) was assessed by cell proliferation, colony formation, apoptosis, cell migration, cell cycle assay and RNA-seq, while inhibition of PLA2G6 and AAM pathway components was affirmed by qPCR, Western blot and immunofluorescence staining. The in vivo effect of aspirin was evaluated using NOD-SCID mice xenografts and immunohistochemical analysis. Results: We found that aspirin, which has been reported to act through the COX pathway, is inhibiting PLA2G6, and thereby the COX and LOX components of the AAM pathway. The findings were validated using PLA2G6 siRNA and immunohistochemical marker panel. Moreover, a pronounced effect in ITOC-04 cells and xenografts implied aspirin-induced synthetic lethality in the AAM pathway down-regulated GB-SCC. Conclusions: This study reveals that aspirin induces the anti-tumor effect by a previously unrecognized mechanism of PLA2G6 inhibition. In addition, the effect of aspirin is influenced by the baseline AAM pathway status and could guide precision prevention clinical trials of AAM pathway inhibitors.

The association of aspirin use with overall survival of patients with inoperable non-small cell lung cancer: a retrospective study

Background

Studies have indicated that individuals taking aspirin have a reduced risk of cancers and have also established chemo-preventive benefit of aspirin in colorectal cancer. However, research on the association between aspirin use and the survival in patients with lung cancer has revealed inconsistent results. In this study, we investigated the effect of aspirin use on the survival of inoperable non-small cell lung cancer (NSCLC) patients.

Methods

We identified a cohort of 38,842 patients diagnosed with NSCLC between 2000 and 2012 using the Taiwan’s National Health Insurance Research Database and used propensity score matching to reduce possible confounding factors. In total, 9864 patients (4932 matched pairs) were included in the matched cohort. Aspirin exposure was analyzed to identify a possible association with mortality in patients with inoperable NSCLC. Time-dependent Cox regression models were used to calculate the hazard ratios (HRs) and the 95% confidence intervals (95% CIs) that corresponded with aspirin exposure.

Results

A total of 4979 patients used aspirin at the time of diagnosis of NSCLC. The median overall survival (OS) of the aspirin users was 1.73 (interquartile range, 0.94–3.53) years compared with the 1.30 (interquartile range, 0.69–2.62) years of the non-aspirin users. The Cox proportional hazard model with the time-dependent covariate revealed that aspirin use was associated with a significantly longer OS (HR: 0.83, 95.0% CI: 0.80–0.86). After controlling the sociodemographic characteristics (age, sex, income, and level of urbanization) and lung cancer treatments by propensity score matching, the aspirin users still had a significantly longer OS than the non-aspirin users (HR: 0.79, 95.0% CI: 0.75–0.83).

Conclusion

Aspirin use is associated with a longer OS in patients with inoperable NSCLC, suggesting that aspirin has a potential anticancer effect. These results warrant further randomized clinical trials to evaluate the actual role of aspirin in the treatment of NSCLC patients.

Morphological predictors for microsatellite instability in urothelial carcinoma

Introduction

Microsatellite instability occurs due to a series of mutations in the DNA pairing error repair (Mismatch repair; MMR) genes, which can affect germ cells as occurs in Lynch syndrome, whose patients are at high risk of developing multiple cancers. The loss of MMR protein is commonly determined by immunohistochemical studies. Although the relation between microsatellite instability and urothelial carcinomas has been widely studied, its evaluation is not currently performed in the analysis of urothelial carcinomas.

Methods

In this study, the microsatellite status of 139 urothelial carcinomas was analyzed and their clinicopathological characteristics were evaluated. We identified that 10.3% (13 patients) of urothelial carcinomas had loss of MMR protein expression (9 MLH1; 5 MSH2; 2 PMS2; 2 PSH6; n = 139).

Results

Results suggest that these tumors occur more frequently in males, are more frequently located in the bladder or ureters, and present a high tumor grade with a papillary histological pattern that does not infiltrate the lamina propria or, in the case of infiltrating tumors, that grows into perivesical tissues.

Conclusions

We identified patients with the aforementioned tumor characteristics as patients with a high probability of presenting loss of MMR protein expression, and consider that only these patients should undergo further immunohistochemical and molecular techniques for proper diagnosis. Therefore, we propose that the clinicopathological characteristics found in the present study could become possible markers to determine which cases should undergo additional tests.

Screening and prevention of colorectal cancer

Mortality from colorectal cancer is reduced through screening and early detection; moreover, removal of neoplastic lesions can reduce cancer incidence. While understanding of the risk factors, pathogenesis, and precursor lesions of colorectal cancer has advanced, the cause of the recent increase in cancer among young adults is largely unknown. Multiple invasive, semi- and non-invasive screening modalities have emerged over the past decade. The current emphasis on quality of colonoscopy has improved the effectiveness of screening and prevention, and the role of new technologies in detection of neoplasia, such as artificial intelligence, is rapidly emerging. The overall screening rates in the US, however, are suboptimal, and few interventions have been shown to increase screening uptake. This review provides an overview of colorectal cancer, the current status of screening efforts, and the tools available to reduce mortality from colorectal cancer.

Influence of aspirin on prevention of colorectal cancer: an updated systematic review and meta-analysis of randomized controlled trials

PURPOSE

Colorectal cancer is the second most common cause of cancer death worldwide. Aspirin, due to its antineoplastic effects, has been suggested to have chemopreventive effects on colorectal cancer based on recent trials. We conducted this systematic review and meta-analysis to provide an updated evidence about the long-term efficacy of daily aspirin use in the prevention of colorectal cancer.

METHODS

We searched Medline/PubMed, Ovid, Web of Science, and Cochrane Library. We included randomized controlled trials (RCTs) that compared the efficacy of daily aspirin use to placebo in healthy individuals at the time of study entry. The desired outcomes of this review were the incidence of advanced lesions (i.e., adenomas with villous component, adenomas ≥1 cm in diameter, adenomas with high-grade dysplasia, and/or invasive cancer) and colorectal adenomas.

RESULTS

A total of 15 articles representing 11 RCTs were included. Overall, the results indicated that aspirin significantly reduced the risk of developing colorectal adenomas but not advanced lesions at 3 years (risk ratio (RR) = 0.84, P < 0.05 and risk ratio = 0.82, P = 0.10, respectively). At 5 years, the risk of advanced lesions but not adenomas was reduced by aspirin (RR = 0.68, P < 0.05 and RR = 0.87, P = 0.22, respectively). Aspirin was not found to have an effect on the risk of advanced lesions or adenomas beyond 5 years (hazard ratio (HR) = 0.82, P = 0.07 and HR = 0.99, P = 0.82, respectively).

CONCLUSION

Overall, aspirin (particularly high dose) only reduced the risk of advanced lesions up to 5 years.

Genetic variant of cyclooxygenase-2 in gastric cancer: More inflammation and susceptibility

Gastric cancer accounts for the majority cancer-related deaths worldwide. Although various methods have considerably improved the screening, diagnosis, and treatment of gastric cancer, its incidence is still high in Asia, and the 5-year survival rate of advanced gastric cancer patients is only 10%-20%. Therefore, more effective drugs and better screening strategies are needed for reducing the incidence and mortality of gastric cancer. Cyclooxygenase-2 (COX-2) is considered to be the key inducible enzyme in prostaglandins (PGs) synthesis, which is involved in multiple pathways in the inflammatory response. For example, inflammatory cytokines stimulate innate immune responses via Toll-like receptors and nuclear factor-kappa B to induce COX-2/PGE2 pathway. In these processes, the production of an inflammatory microenvironment promotes the occurrence of gastric cancer. Epidemiological studies have also indicated that non-steroidal anti-inflammatory drugs can reduce the risk of malignant tumors of the digestive system by blocking the effect of COX-2. However, clinical use of COX-2 inhibitors to prevent or treat gastric cancer may be limited because of potential side effects, especially in the cardiovascular system. Given these side effects and low treatment efficacy, new therapeutic approaches and early screening strategies are urgently needed. Some studies have shown that genetic variation in COX-2 also play an important role in carcinogenesis. However, the genetic variation analysis in these studies is incomplete and isolated, pointing out only a few single nucleotide polymorphisms (SNPs) and the risk of gastric cancer, and no comprehensive study covering the whole gene region has been carried out. In addition, copy number variation (CNV) is not mentioned. In this review, we summarize the SNPs in the whole COX-2 gene sequence, including exons, introns, and both the 5' and 3' untranslated regions. Results suggest that COX-2 does not increase its expression through the CNV and the SNPs in COX-2 may serve as the potential marker to establish risk stratification in the general population. This review synthesizes emerging insights of COX-2 as a biomarker in multiple studies, summarizes the association between whole COX-2 sequence variation and susceptibility to gastric cancer, and discusses the future prospect of therapeutic intervention, which will be helpful for early screening and further research to find new approaches to gastric cancer treatment.

Platelets: the point of interconnection among cancer, inflammation and cardiovascular diseases

INTRODUCTION

The association between thrombosis, cancer and inflammation is well-established. Platelets play a major role in atherosclerosis, inflammation and immune response. Furthermore, growing evidence suggests that they are also significantly involved in tumor development and progression so that anti-platelet agents may prevent cancer and improve outcomes in oncological patients. In this review, we aimed at analyzing the relationship between platelets, cardiovascular diseases and cancer. A comprehensive study in the main educational platforms was performed and high-quality original articles and reviews were included.

AREAS COVERED

This review will focus on the role of platelets in cardiovascular disease and in cancer genesis and progression, analyzing their function as immune cells that link inflammation to thrombosis. Finally, it will examine the recent controversies on the use of anti-platelet agents as cancer medications, in particular the already known anti-tumor properties of aspirin, as well as the new perspectives regarding P2Y12 inhibitors.

EXPERT OPINION

Platelet-cancer crosstalk generates a vicious feed-back loop involving tumor cells and secreting molecules that activate platelets, which in turn promote cancer-associated inflammation, proliferation, spreading and immune system evasion. Therefore, platelets inhibition may represent an innovative therapeutical strategy offered to cancer patients, in the perspective of personalized medicine.

Immunology of Lynch Syndrome

PURPOSE OF REVIEW

Patients with Lynch syndrome have a high probability of developing colorectal and other carcinomas. This review provides a comprehensive assessment of the immunologic aspects of Lynch syndrome pathogenesis and provides an overview of potential immune interventions for patients with Lynch syndrome polyps and Lynch syndrome-associated carcinomas.

RECENT FINDINGS

Immunogenic properties of the majority of Lynch syndrome polyps and associated cancers include microsatellite instability leading to a high mutational burden and the development of novel frameshift peptides, i.e., neoantigens. In addition, patients with Lynch syndrome develop T cell responses in the periphery and in the tumor microenvironment (TME) to tumor-associated antigens, and a proinflammatory cytokine TME has also been identified. However, Lynch syndrome lesions also possess immunosuppressive entities such as alterations in MHC class I antigen presentation, TGFβ receptor mutations, regulatory T cells, and upregulation of PD-L1 on tumor-associated lymphocytes. The rich immune microenvironment of Lynch syndrome polyps and associated carcinomas provides an opportunity to employ the spectrum of immune-mediating agents now available to induce and enhance host immune responses and/or to also reduce immunosuppressive entities. These agents can be employed in the so-called prevention trials for the treatment of patients with Lynch syndrome polyps and for trials in patients with Lynch syndrome-associated cancers.

European guidelines from the EHTG and ESCP for Lynch syndrome: an updated third edition of the Mallorca guidelines based on gene and gender

BACKGROUND

Lynch syndrome is the most common genetic predisposition for hereditary cancer but remains underdiagnosed. Large prospective observational studies have recently increased understanding of the effectiveness of colonoscopic surveillance and the heterogeneity of cancer risk between genotypes. The need for gene- and gender-specific guidelines has been acknowledged.

METHODS

The European Hereditary Tumour Group (EHTG) and European Society of Coloproctology (ESCP) developed a multidisciplinary working group consisting of surgeons, clinical and molecular geneticists, pathologists, epidemiologists, gastroenterologists, and patient representation to conduct a graded evidence review. The previous Mallorca guideline format was used to revise the clinical guidance. Consensus for the guidance statements was acquired by three Delphi voting rounds.

RESULTS

Recommendations for clinical and molecular identification of Lynch syndrome, surgical and endoscopic management of Lynch syndrome-associated colorectal cancer, and preventive measures for cancer were produced. The emphasis was on surgical and gastroenterological aspects of the cancer spectrum. Manchester consensus guidelines for gynaecological management were endorsed. Executive and layperson summaries were provided.

CONCLUSION

The recommendations from the EHTG and ESCP for identification of patients with Lynch syndrome, colorectal surveillance, surgical management of colorectal cancer, lifestyle and chemoprevention in Lynch syndrome that reached a consensus (at least 80 per cent) are presented.

Aspirin reduces the incidence of metastasis in a pre-clinical study of Braf mutant serrated colorectal neoplasia

BACKGROUND

Aspirin reduces the incidence of conventional adenomas driven by APC mutation and thus colorectal cancer. The effect of aspirin on the ~20% of colorectal cancers arising via BRAF mutation is yet to be established.

METHODS

Braf^V637E/+;Villin-Cre^ERT2/+ mice were allocated to a control (n = 86) or aspirin-supplemented (n = 83) diet. After 14 months the incidence of murine serrated lesions, carcinoma and distant metastases were measured by histological examination. RNA was extracted from carcinomas from each cohort and subjected to sequencing to identify differentially expressed genes and molecular pathways.

RESULTS

Aspirin did not reduce the incidence of murine serrated lesions or carcinoma when compared to control, however, did significantly reduce lesion size (P = 0.0042). Among the mice with carcinoma there was a significant reduction in the incidence of distant metastasis with aspirin treatment (RR 0.69, 95% CI 0.48-0.90, P = 0.0134). Key pathways underlying metastasis of carcinoma cells include NOTCH, FGFR and PI3K signalling, were significantly downregulated in carcinomas sampled from mice on an aspirin-supplemented diet.

CONCLUSIONS

Aspirin reduces the incidence of metastatic Braf mutant carcinoma, although this is not due to a reduction in primary disease. The reduction in metastasis could be attributed to a delay or prevention of molecular changes within the primary site driving metastatic growth.

Aspirin at 120: Retiring, recombining, or repurposing?

During the past 20 years, we have witnessed the following trends in aspirin usage: (i) a "dropping" trend, characterized by the early discontinuation of low-dose aspirin from dual antiplatelet therapy or triple antithrombotic therapy (oral anticoagulation plus dual antiplatelet therapy in patients with atrial fibrillation) following an acute coronary syndrome or after percutaneous coronary intervention; (ii) a "combinatorial" trend, featuring the addition of a lower dose of a P2Y12 inhibitor or direct oral anticoagulant drug to low-dose aspirin for the long-term treatment of stable patients with atherosclerotic cardiovascular disease; and (iii) a "repurposing" trend, characterized by growing interest in the oncologic community to assess the chemopreventive effect of aspirin against certain types of cancers (particularly of the gastrointestinal tract), both as primary prevention and adjuvant therapy. The aim of this review is to present the mechanistic rationale underlying these trends, discuss the design and findings of trials testing novel treatments or new therapeutic applications of aspirin, and report on the ISTH Congress results on this topic.

Aspects of colorectal cancer screening, methods, age and gender

Colorectal cancer (CRC) is, besides breast, prostate, lung and skin cancers, the most common cancer worldwide and is suitable for screening. The incidence of CRC varies considerably in different parts of the world: in well-developed countries, the incidence is between 30 and 70 per 100 000 inhabitants, whereas in less-developed countries such as sub-Saharan Africa, it is 10-20/100 000 inhabitants. Women have a lower incidence of CRC, which is usually one-third of total incidence. Several studies have shown that it is possible to decrease mortality from CRC with about 20%, which is evidenced through the data from countries with screening programmes. Though the method of choice to identify blood samples in faecal matter is under debate, the most feasible way is to perform colonoscopy. Other methods include more advanced faecal analyses, testing for mutations from CRC, sigmoidoscopy, CT colonoscopy or optical colonoscopy. Colonoscopy is in most countries not available in sufficient amount and has to be carried out with great accuracy; otherwise, lesions will be missed to identify, thus leading to complications. Gender is an issue in CRC screening, as women have about 20% fewer colorectal adenomas and CRCs, but they also have more right-sided lesions, which are more difficult to detect with tests for faecal blood since they create less blood in faeces. Thus, other strategies may have to be developed for women in order for screening to have the same effect. It is essential to introduce colorectal cancer screening in all countries together with other clinical pieces of advice such as information on smoking, obesity and exercise in order to reduce one of the most dangerous cancers.

Naproxen chemoprevention promotes immune activation in Lynch syndrome colorectal mucosa

OBJECTIVE

Patients with Lynch syndrome (LS) are at markedly increased risk for colorectal cancer. It is being increasingly recognised that the immune system plays an essential role in LS tumour development, thus making an ideal target for cancer prevention. Our objective was to evaluate the safety, assess the activity and discover novel molecular pathways involved in the activity of naproxen as primary and secondary chemoprevention in patients with LS.

DESIGN

We conducted a Phase Ib, placebo-controlled, randomised clinical trial of two dose levels of naproxen sodium (440 and 220 mg) administered daily for 6 months to 80 participants with LS, and a co-clinical trial using a genetically engineered mouse model of LS and patient-derived organoids (PDOs).

RESULTS

Overall, the total number of adverse events was not different across treatment arms with excellent tolerance of the intervention. The level of prostaglandin E2 in the colorectal mucosa was significantly decreased after treatment with naproxen when compared with placebo. Naproxen activated different resident immune cell types without any increase in lymphoid cellularity, and changed the expression patterns of the intestinal crypt towards epithelial differentiation and stem cell regulation. Naproxen demonstrated robust chemopreventive activity in a mouse co-clinical trial and gene expression profiles induced by naproxen in humans showed perfect discrimination of mice specimens with LS and PDOs treated with naproxen and control.

CONCLUSIONS

Naproxen is a promising strategy for immune interception in LS. We have discovered naproxen-induced gene expression profiles for their potential use as predictive biomarkers of drug activity.

TRIAL REGISTRATION NUMBER

gov Identifier: NCT02052908.

Updates in chemoprevention research for hereditary gastrointestinal and polyposis syndromes

PURPOSE OF REVIEW

To critically examine recently published research in the area of chemoprevention in hereditary polyposis and gastrointestinal cancers, and to briefly review several ongoing chemoprevention trials testing novel agents in this population.

RECENT FINDINGS

Four recent chemoprevention trials in patients with familial adenomatous polyposis (FAP) were identified and reviewed. In the FAPEST trial, the combination of erlotinib+sulindac (compared to placebo) met its primary outcome of decreased duodenal polyp burden. A secondary analysis of lower gastrointestinal tract outcomes also demonstrated significant benefits. Two randomized trials in FAP patients examining combination regimens (celecoxib+DFMO and sulindac+DFMO) failed to meet their primary endpoints. Benefits of further research into these combinations was suggested by efficacy signals seen in secondary and post-hoc analyses. Finally, a randomized trial found curcumin (vs placebo) to have no benefit in reducing colorectal polyp count or size in patients with FAP.

SUMMARY

Progress in developing new and more effective preventive options for patients with hereditary gastrointestinal syndromes continues to be made through the efforts of investigators conducting chemoprevention research.

Colorectal Cancer and Diet: Risk Versus Prevention, Is Diet an Intervention?

Colorectal cancer is the third most common cause of cancer in men and women in the world. Epidemiologic research approximates that half of colon cancer risk is preventable by modifiable risk factors, including diet. This article reviews prior studies involving certain food items and their relation to colorectal cancer, to elucidate whether diet can be a potential intervention.

Historical review of Lynch syndrome

Lynch syndrome was formerly known as Hereditary Nonpolyposis Colorectal Cancer. Currently, these two nomenclatures each have their unique definitions and are no longer used interchangeably. The history of hereditary nonpolyposis colorectal cancer was first recognized formally in the literature by Henry Lynch in 1967. With advances of molecular genetics, there has been a transformation from clinical phenotype to genotype diagnostics. This has led to the ability to diagnose affected patients before they manifest with cancer, and therefore allow preventative surveillance strategies. Genotype diagnostics has shown a difference in penetrance of different cancer risks dependent on the gene containing the mutation. Surgery is recommended as prevention for some cancers; for others they are reserved for once cancer is noted. Various surveillance strategies are recommended dependent on the relative risk of cancer and the ability to intervene with surgery to impact on survival. Risk reduction through aspirin has shown some recent promise, and continues to be studied.

Aspirin in the Prevention of Cardiovascular Disease and Cancer

More than a century after its synthesis, daily aspirin, given at a low dose, is a milestone treatment for the secondary prevention of cardiovascular disease (CVD). Its role in primary prevention of CVD is still debated. Older randomized controlled trials showed that aspirin reduced the low incidence of myocardial infarction but correspondingly increased the low incidence of serious gastrointestinal bleeds without altering mortality. More recent trials see the benefit attenuated, perhaps obscured by other cardioprotective practices, while the bleeding risk remains, especially in older patients. Indirect evidence, both preclinical and clinical, suggests that aspirin may protect against sporadic colorectal cancer and perhaps other cancers. However, further studies are still necessary to warrant the consumption of aspirin for primary prevention of CVD and cancer by apparently healthy individuals.

High Levels of Prebiotic Resistant Starch in Diet Modulate a Specific Pattern of miRNAs Expression Profile Associated to a Better Overall Survival in Pancreatic Cancer

Dietary patterns are well known risk factors involved in cancer initiation, progression, and in cancer protection. Previous in vitro and in vivo studies underline the link between a diet rich in resistant starch (RS) and slowing of tumor growth and gene expression in pancreatic cancer xenograft mice. The aim of this study was to investigate the impact of a diet rich in resistant starch on miRNAs and miRNAs-target genes expression profile and on biological processes and pathways, that play a critical role in pancreatic tumors of xenografted mice. miRNA expression profiles on tumor tissues displayed 19 miRNAs as dysregulated in mice fed with RS diet as compared to those fed with control diet and differentially expressed miRNA-target genes were predicted by integrating (our data) with a public human pancreatic cancer gene expression dataset (GSE16515). Functional and pathway enrichment analyses unveiled that miRNAs involved in RS diet are critical regulators of genes that control tumor growth and cell migration and metastasis, inflammatory response, and, as expected, synthesis of carbohydrate and glucose metabolism disorder. Mostly, overall survival analysis with clinical data from TCGA (n = 175) displayed that almost four miRNAs (miRNA-375, miRNA-148a-3p, miRNA-125a-5p, and miRNA-200a-3p) upregulated in tumors from mice fed with RS were a predictor of good prognosis for pancreatic cancer patients. These findings contribute to the understanding of the potential mechanisms through which resistant starch may affect cancer progression, suggesting also a possible integrative approach for enhancing the efficacy of existing cancer treatments.

Non-Hodgkin's Lymphoma and Colorectal Carcinoma: Metachronous Occurrence in a Patient With Underlying DNA Mismatch Repair Syndrome

Constitutional mismatch repair deficiency (CMMRD) is an autosomal recessive disorder caused by biallelic mutations in DNA mismatch repair genes 1. These patients have clinical stigmata of neurofibromatosis 1 (NF-1) with childhood onset of hematological malignancies, high grade gliomas, and colorectal-cancers 2. We present a case of non-Hodgkin's lymphoma (NHL) who later on developed adenocarcinoma colon at an age of 11 years with significant family history of glioblastoma in elder brother and colonic cancer in mother. This is the first case of CMMRD in Pakistan who developed colonic neoplasm at the age of 11 years. Nearly 150 patients of CMMRD have been reported worldwide.

Mechanisms of Colorectal Cancer Prevention by Aspirin-A Literature Review and Perspective on the Role of COX-Dependent and -Independent Pathways

Aspirin, synthesized and marketed in 1897 by Bayer, is one of the most widely used drugs in the world. It has a well-recognized role in decreasing inflammation, pain and fever, and in the prevention of thrombotic cardiovascular diseases. Its anti-inflammatory and cardio-protective actions have been well studied and occur through inhibition of cyclooxygenases (COX). Interestingly, a vast amount of epidemiological, preclinical and clinical studies have revealed aspirin as a promising chemopreventive agent, particularly against colorectal cancers (CRC); however, the primary mechanism by which it decreases the occurrences of CRC has still not been established. Numerous mechanisms have been proposed for aspirin’s chemopreventive properties among which the inhibition of COX enzymes has been widely discussed. Despite the wide attention COX-inhibition has received as the most probable mechanism of cancer prevention by aspirin, it is clear that aspirin targets many other proteins and pathways, suggesting that these extra-COX targets may also be equally important in preventing CRC. In this review, we discuss the COX-dependent and -independent pathways described in literature for aspirin’s anti-cancer effects and highlight the strengths and limitations of the proposed mechanisms. Additionally, we emphasize the potential role of the metabolites of aspirin and salicylic acid (generated in the gut through microbial biotransformation) in contributing to aspirin’s chemopreventive actions. We suggest that the preferential chemopreventive effect of aspirin against CRC may be related to direct exposure of aspirin/salicylic acid or its metabolites to the colorectal tissues. Future investigations should shed light on the role of aspirin, its metabolites and the role of the gut microbiota in cancer prevention against CRC.

A comprehensive in vivo and mathematic modeling-based kinetic characterization for aspirin-induced chemoprevention in colorectal cancer

Accumulating evidence suggests that aspirin has anti-tumorigenic properties in colorectal cancer (CRC). Herein, we undertook a comprehensive and systematic series of in vivo animal experiments followed by 3D-mathematical modeling to determine the kinetics of aspirin's anti-cancer effects on CRC growth. In this study, CRC xenografts were generated using four CRC cell lines with and without PIK3CA mutations and microsatellite instability, and the animals were administered with various aspirin doses (0, 15, 50, and 100 mg/kg) for 2 weeks. Cell proliferation, apoptosis and protein expression were evaluated, followed by 3D-mathematical modeling analysis to estimate cellular division and death rates and their impact on aspirin-mediated changes on tumor growth. We observed that aspirin resulted in a dose-dependent decrease in the cell division rate, and a concomitant increase in the cell death rates in xenografts from all cell lines. Aspirin significantly inhibited cell proliferation as measured by Ki67 staining (P < 0.05-0.01). The negative effect of aspirin on the rate of tumor cell proliferation was more significant in xenograft tumors derived from PIK3CA mutant versus wild-type cells. A computational model of 3D-tumor growth suggests that the growth inhibitory effect of aspirin on the tumor growth kinetics is due to a reduction of tumor colony formation, and that this effect is sufficiently strong to be an important contributor to the reduction of CRC incidence in aspirin-treated patients. In conclusion, we provide a detailed kinetics of aspirin-mediated inhibition of tumor cell proliferation, which support the epidemiological data for the observed protective effect of aspirin in CRC patients.

A potential role for aspirin in the prevention and treatment of cholangiocarcinoma

Cholangiocarcinoma is the second most common primary hepatic cancer, with a rising incidence worldwide. Owing to late diagnosis and limited treatment options, the prognosis for cholangiocarcinoma remains dismal, compelling a search for new treatments. As aspirin exhibits a well-supported chemopreventive effect on common cancers, researchers have proposed using aspirin as a potential preventive and adjuvant agent for cholangiocarcinoma. In the present review of the literature, we provide a background on cholangiocarcinoma and potential mechanisms of action underlying the anticancer effect of aspirin. Although the exact mode of action remains unclear, multiple downstream effects of aspirin may interfere with cholangiocarcinogenesis, tumour growth and metastasis-including inhibiting the COX-2 pathway, preventing platelet aggregation and modulating certain proteins and signalling. This review also summarises evidence to support the chemopreventive effects of aspirin on common cancers, particularly colorectal cancer and discusses studies that report a positive outcome of aspirin in cholangiocarcinoma. Regular use of aspirin is associated with a reduced incidence of colorectal cancers as well as cholangiocarcinomas, and improved survival. Aspirin thus appears to play a role in the primary prevention and treatment of cholangiocarcinoma. However, further studies are needed to confirm these benefits and to establish a cause-and-effect relationship.

Aspirin in the Prevention of Colorectal Neoplasia

High-quality evidence indicates that regular use of aspirin is effective in reducing the risk for precancerous colorectal neoplasia and colorectal cancer (CRC). This has led to US and international guidelines recommending aspirin for the primary prevention of CRC in specific populations. In this review, we summarize key questions that require addressing prior to broader adoption of aspirin-based chemoprevention, review recent evidence related to the benefits and harms of aspirin use among specific populations, and offer a rationale for precision prevention approaches. We specifically consider the mechanistic implications of evidence showing differences in aspirin's effects according to age, the potential role of modifiable mechanistic biomarkers for personalizing prevention, and emerging evidence that the gut microbiota may offer novel aspirin-associated preventive targets to reduce high-risk neoplasia.

Effect of chemoprevention by low-dose aspirin of new or recurrent colorectal adenomas in patients with Lynch syndrome (AAS-Lynch): study protocol for a multicenter, double-blind, placebo-controlled randomized controlled trial

Abstract

Lynch syndrome (LS) is the most common cause of inherited colorectal cancer (CRC) and confers a high lifetime risk of CRC estimated to be up to 60%. Colonoscopy is recommended every 2 years in LS patients above the 20–25-year-old age bracket, and every year when colonic neoplasia has been detected. Efficient chemoprevention has the potential to represent a cost-effective intervention in these high-risk patients and could allow a delay in colonoscopy surveillance. Several epidemiological studies have shown that regular use of low dose aspirin is associated with a 20 to 30% reduction in the risk of sporadic colonic adenomas and colorectal cancer regardless of family risk. However, in recent large randomized trials in specific populations, aspirin use showed no protection for colorectal cancer. A prospective randomized CAPP-2 trial evaluated the effect of aspirin use in LS patients. The primary analysis of this trial showed no significant decrease in CRC in LS patients under daily aspirin. However, a preplanned secondary analysis after an extended follow-up showed a significant reduced risk of CRC in the aspirin group in the per-protocol analysis. The real effect and clinical benefit of aspirin are still to be consolidated in this population. The AAS-Lynch trial—a prospective, multicentric, double-blind, placebo-controlled, randomized clinical trial—was designed to investigate if daily aspirin therapy, at a dose of 100 or 300 mg, would decrease the occurrence or recurrence of colorectal adenomas in patients under 75 years of age, compared with placebo.

Trial registration

ClinicalTrials.gov NCT02813824. Registered on 27 June 2016. The trial was prospectively registered.

Aspirin and the chemoprevention of cancers: A mathematical and evolutionary dynamics perspective

Epidemiological data indicate that long-term low dose aspirin administration has a protective effect against the occurrence of colorectal cancer, both in sporadic and in hereditary forms of the disease. The mechanisms underlying this protective effect, however, are incompletely understood. The molecular events that lead to protection have been partly defined, but remain to be fully characterized. So far, however, approaches based on evolutionary dynamics have not been discussed much, but can potentially offer important insights. The aim of this review is to highlight this line of investigation and the results that have been obtained. A core observation in this respect is that aspirin has a direct negative impact on the growth dynamics of the cells, by influencing the kinetics of tumor cell division and death. We discuss the application of mathematical models to experimental data to quantify these parameter changes. We then describe further mathematical models that have been used to explore how these aspirin-mediated changes in kinetic parameters influence the probability of successful colony growth versus extinction, and how they affect the evolution of the tumor during aspirin administration. Finally, we discuss mathematical models that have been used to investigate the selective forces that can lead to the rise of mismatch-repair deficient cells in an inflammatory environment, and how this selection can be potentially altered through aspirin-mediated interventions. This article is categorized under: Models of Systems Properties and Processes > Mechanistic Models Analytical and Computational Methods > Analytical Methods Analytical and Computational Methods > Computational Methods.

Cancer prevention with aspirin in hereditary colorectal cancer (Lynch syndrome), 10-year follow-up and registry-based 20-year data in the CAPP2 study: a double-blind, randomised, placebo-controlled trial

BACKGROUND

Lynch syndrome is associated with an increased risk of colorectal cancer and with a broader spectrum of cancers, especially endometrial cancer. In 2011, our group reported long-term cancer outcomes (mean follow-up 55·7 months [SD 31·4]) for participants with Lynch syndrome enrolled into a randomised trial of daily aspirin versus placebo. This report completes the planned 10-year follow-up to allow a longer-term assessment of the effect of taking regular aspirin in this high-risk population.

METHODS

In the double-blind, randomised CAPP2 trial, 861 patients from 43 international centres worldwide (707 [82%] from Europe, 112 [13%] from Australasia, 38 [4%] from Africa, and four [<1%] from The Americas) with Lynch syndrome were randomly assigned to receive 600 mg aspirin daily or placebo. Cancer outcomes were monitored for at least 10 years from recruitment with English, Finnish, and Welsh participants being monitored for up to 20 years. The primary endpoint was development of colorectal cancer. Analysis was by intention to treat and per protocol. The trial is registered with the ISRCTN registry, number ISRCTN59521990.

FINDINGS

Between January, 1999, and March, 2005, 937 eligible patients with Lynch syndrome, mean age 45 years, commenced treatment, of whom 861 agreed to be randomly assigned to the aspirin group or placebo; 427 (50%) participants received aspirin and 434 (50%) placebo. Participants were followed for a mean of 10 years approximating 8500 person-years. 40 (9%) of 427 participants who received aspirin developed colorectal cancer compared with 58 (13%) of 434 who received placebo. Intention-to-treat Cox proportional hazards analysis revealed a significantly reduced hazard ratio (HR) of 0·65 (95% CI 0·43-0·97; p=0·035) for aspirin versus placebo. Negative binomial regression to account for multiple primary events gave an incidence rate ratio of 0·58 (0·39-0·87; p=0·0085). Per-protocol analyses restricted to 509 who achieved 2 years' intervention gave an HR of 0·56 (0·34-0·91; p=0·019) and an incidence rate ratio of 0·50 (0·31-0·82; p=0·0057). Non-colorectal Lynch syndrome cancers were reported in 36 participants who received aspirin and 36 participants who received placebo. Intention-to-treat and per-protocol analyses showed no effect. For all Lynch syndrome cancers combined, the intention-to-treat analysis did not reach significance but per-protocol analysis showed significantly reduced overall risk for the aspirin group (HR=0·63, 0·43-0·92; p=0·018). Adverse events during the intervention phase between aspirin and placebo groups were similar, and no significant difference in compliance between intervention groups was observed for participants with complete intervention phase data; details reported previously.

INTERPRETATION

The case for prevention of colorectal cancer with aspirin in Lynch syndrome is supported by our results.

FUNDING

Cancer Research UK, European Union, MRC, NIHR, Bayer Pharma AG, Barbour Foundation.

Non-Digestible Carbohydrate and the Risk of Colorectal Neoplasia: A Systematic Review

Non-digestible carbohydrate (NDC) is a fiber that can be fermented into short chain fatty acids (SCFAs) in gut, represented by resistant starch (RS) and inulin. Colorectal cancer (CRC) is one of the most common malignant cancer. Pre-clinical studies have reported that NDC can produce SCFAs to protect the gut epithelium, which is associated with prevention of CRC, but this role in clinical trails is controversial. In this review, we discusses whether RS and inulin should be offered to cancer/precancerous patients or healthy subjects to decrease their risk of CRC. A multiple database search was conducted for studies published on RS/inulin supplementation as a chemopreventive method from 1989 to 2019. The meta-analysis showed the total SCFAs and butyrate concentrations (P = 0.84; P = 0.79), and excretions (P = 0.55; P = 0.63) in feces did not increase significantly after RS/inulin supplementation. Only two studies reported that RS/inulin inhibit the proliferation of large bowel epithelial, whereas 15 studies showed that it does not decrease the risk of neoplasia. RS/inulin restored the promotion of tumor risk factors in two studies and did not in four studies. Notably, the other four studies showed that RS increases pro-tumorigenesis mechanisms. The clinical evidences consistently show that RS/inulin is ineffective for preventing colorectal neoplasia.