A Trial of Calcium and Vitamin D for the Prevention of Colorectal Adenomas

2017 update on the relationship between diabetes and colorectal cancer: epidemiology, potential molecular mechanisms and therapeutic implications

Worldwide deaths from diabetes mellitus (DM) and colorectal cancer increased by 90% and 57%, respectively, over the past 20 years. The risk of colorectal cancer was estimated to be 27% higher in patients with type 2 DM than in non-diabetic controls. However, there are potential confounders, information from lower income countries is scarce, across the globe there is no correlation between DM prevalence and colorectal cancer incidence and the association has evolved over time, suggesting the impact of additional environmental factors. The clinical relevance of these associations depends on understanding the mechanism involved. Although evidence is limited, insulin use has been associated with increased and metformin with decreased incidence of colorectal cancer. In addition, colorectal cancer shares some cellular and molecular pathways with diabetes target organ damage, exemplified by diabetic kidney disease. These include epithelial cell injury, activation of inflammation and Wnt/β-catenin pathways and iron homeostasis defects, among others. Indeed, some drugs have undergone clinical trials for both cancer and diabetic kidney disease. Genome-wide association studies have identified diabetes-associated genes (e.g. TCF7L2) that may also contribute to colorectal cancer. We review the epidemiological evidence, potential pathophysiological mechanisms and therapeutic implications of the association between DM and colorectal cancer. Further studies should clarify the worldwide association between DM and colorectal cancer, strengthen the biological plausibility of a cause-and-effect relationship through characterization of the molecular pathways involved, search for specific molecular signatures of colorectal cancer under diabetic conditions, and eventually explore DM-specific strategies to prevent or treat colorectal cancer.

LOWER SERUM 25-HYDROXYVITAMIN D IS ASSOCIATED WITH OBESITY BUT NOT COMMON CHRONIC CONDITIONS: AN OBSERVATIONAL STUDY OF AFRICAN AMERICAN AND CAUCASIAN MALE VETERANS

OBJECTIVE

The study examined whether vitamin D insufficiency is a predictor of prevalent and/or incident common chronic conditions in African American men (AAM) and Caucasian American men (CAM).

METHODS

A total of 1,017 men were recruited at an urban VA medical center and followed prospectively for a mean of 5.4 years. Prevalent and incident chronic conditions evaluated were: obesity, type 2 diabetes, cancer, depression, dementia, and cardiovascular disease (CVD, including coronary artery disease [CAD], cerebrovascular accident [CVA], and congestive heart failure [CHF]). Univariate and multivariate regressions were performed to examine the association between 25-hydroxyvitamin D (25[OH]D) and these chronic illnesses.

RESULTS

This analysis was limited to 955 men (65.5% AAM, 27.2% CAM, 6.4% Hispanic) who had at least 1 year of follow-up (range, 1.0 to 7.1 years). Univariate analysis of the entire group showed that 25(OH)D correlated negatively with body mass index (BMI). There was no correlation between 25(OH)D and prevalent CVD (including separate analyses for CAD, CVA, and CHF), cancer, depression, dementia, all-cause mortality, or incident cancer, CAD, or CVA. Independent predictors of prevalent common conditions included increasing age, BMI, smoking, alcohol and polysubstance use, but not 25(OH)D levels.

CONCLUSION

The study does not support previously suggested associations of low vitamin D levels with prevalent common chronic conditions or increased risk for cancer, CAD, and CVA in a population of men with high burden of chronic disease. The finding that smoking and alcohol and polysubstance use are predictors of chronic conditions is an important reminder for addressing these risks during patient encounters.

ABBREVIATIONS

AAM = African American men BMI = body mass index CAD = coronary artery disease CAM = Caucasian American men CHF = congestive heart failure CI = confidence interval CVA = cerebrovascular accident CVD = cardiovascular disease HTN = hypertension OR = odds ratio T2DM = type 2 diabetes mellitus VAMC = Veteran Administration Medical Center 25(OH)D = 25-hydroxyvitamin D.

Dietary Inflammatory Index and Risk of Colorectal Adenoma Recurrence: A Pooled Analysis

No studies have evaluated the association between the dietary inflammatory index (DII) and colorectal adenoma recurrence. DII scores were calculated from a baseline food frequency questionnaire. Participants (n = 1727) were 40-80 years of age, enrolled in two Phase III clinical trials, who had ≥1 colorectal adenoma(s) removed within 6 months of study registration, and a follow-up colonoscopy during the trial. Multiple logistic regression was used to estimate odds ratios (ORs) and 95% confidence intervals (95% CIs). No statistically significant associations were found between DII and odds of colorectal adenoma recurrence [ORs (95% CIs) = 0.93 (0.73, 1.18) and 0.95 (0.73, 1.22)] for subjects in the second and third DII tertiles, respectively, compared to those in the lowest tertile (Ptrend = 0.72). No associations were found for recurrent colorectal adenoma characteristics, including advanced recurrent adenomas, large size, villous histology, or anatomic location. While our study did not support an association between a proinflammatory diet and colorectal adenoma recurrence, future studies are warranted to elucidate the role of a proinflammatory diet on the early stages of colorectal carcinogenesis.

Greater Adherence to Cancer Prevention Guidelines Is Associated with Higher Circulating Concentrations of Vitamin D Metabolites in a Cross-Sectional Analysis of Pooled Participants from 2 Chemoprevention Trials

Background: Several lifestyle factors targeted by the American Cancer Society (ACS) Nutrition and Physical Activity Cancer Prevention Guidelines are also associated with circulating concentrations of vitamin D metabolites. This suggests that greater adherence to the ACS guidelines may be related to better vitamin D status.Objective: We examined the relation between adherence to the ACS guidelines and circulating concentrations of 2 vitamin D metabolites, 25-hydroxycholecalciferol [25(OH)D] and 1α,25-dihydroxyvitamin D [1,25(OH)₂D].Methods: We conducted cross-sectional analyses of pooled participants from the Wheat Bran Fiber (n = 503) and Ursodeoxycholic Acid (n = 854) trials. A cumulative adherence score was constructed with the use of baseline data on body size, diet, physical activity, and alcohol consumption. Continuous vitamin D metabolite concentrations and clinically relevant categories were evaluated with the use of multiple linear and logistic regression models, respectively.Results: The most adherent participants were more likely to be older, white, and nonsmokers than were the least adherent. A statistically significant association was observed between guideline adherence and concentrations of circulating 25(OH)D (means ± SEs-high adherence: 32.0 ± 0.8 ng/mL; low adherence: 26.4 ± 0.7 ng/mL; P-trend < 0.001). For 1,25(OH)₂D concentrations, high adherence was again significantly related to greater metabolite concentrations, with mean ± SE concentrations of 36.3 ± 1.3 pg/mL and 31.9 ± 1.0 pg/mL for high- and low-adherers, respectively (P-trend = 0.008). Furthermore, the odds of attaining a sufficient 25(OH)D status were 4.37 times higher for those most adherent than for those least adherent (95% CI: 2.47, 7.71 times).Conclusion: These findings demonstrate that greater adherence to the ACS guidelines is associated with higher circulating concentrations of both of 25(OH)D and 1,25(OH)₂D.

Vitamin D and Physical Activity in Patients With Colorectal Cancer: Epidemiological Evidence and Therapeutic Implications

Colorectal cancer (CRC) is a leading cause of cancer incidence and mortality in the United States. Notwithstanding major improvements in the early detection and treatment of CRC, an important proportion of patients who received a diagnosis of localized disease ultimately have a recurrence and die, underscoring the need of new therapeutic approaches. Vitamin D and physical activity (PA) have emerged as 2 potential interventions for both prevention and treatment of CRC. Plausible biological mechanisms have been described for the antineoplastic effects of vitamin D and PA, and a wealth of epidemiological evidence indicates that 25(OH)D (the main circulating form of vitamin D) and PA levels are inversely associated with CRC risk. Recent efforts have now focused on the role of vitamin D and PA as adjunct treatments after a CRC diagnosis. Observational studies evaluating prediagnosis and postdiagnosis circulating 25(OH)D levels among patients with CRC of all stages have found that subjects with levels in the highest quantiles have improved overall and CRC-specific survival compared with those with levels in the lowest quantiles. Similarly, prospective studies of PA have found that higher levels of postdiagnosis PA are associated with lower overall and CRC-specific mortality in patients with nonmetastatic CRC. Meta-analyses of the observational studies of 25(OH)D and postdiagnosis PA have confirmed significant protective associations against overall and CRC-specific mortality, as well as significant dose-response relationships. No randomized controlled trial of vitamin D or PA using survival outcomes as endpoints has been completed to date. Two randomized, placebo-controlled trials of vitamin D in patients with metastatic CRC assessing patient survival as an endpoint are underway: the first is a phase II trial comparing high-dose vitamin D3 (8000 IU/d for 2 weeks followed by 4000 IU/d) versus standard dose (400 IU/d), and the second is a phase I-II trial comparing customized oral doses of vitamin D3 titrated to raise serum 25(OH)D levels to 80 to 100 ng/mL versus 2000 IU/d. For PA, the ongoing phase III CHALLENGE (Colon Health and Life-Long Exercise Change) study is the first randomized controlled trial using survival as an endpoint among patients with stage II-III colon cancer. The results of these trials will pave the way to more conclusive phase III trials that will provide more definitive answers about the role of these interventions in the treatment of CRC. Lastly, the advent of genomic technologies will allow identifying molecular signatures in CRC associated with improved response to vitamin D and PA and will usher in a precision medicine approach to these therapies.

Plasma 25-Hydroxyvitamin D3 Levels in Colorectal Cancer Patients and Associations with Physical Activity

Physical activity (PA) and vitamin D are thought to affect colorectal cancer prognosis. The present study investigates associations between 25(OH)D₃ and PA in prospectively followed colorectal cancer patients in the ColoCare study. At 6, 12, and 24 mo after surgery, patients donated a blood sample, wore an accelerometer for 10 consecutive days, and completed a PA questionnaire. Plasma 25-hydroxyvitamin D₃ (25(OH)D₃) levels were measured by high-performance liquid chromatography. We tested associations using partial correlations and multivariate linear regression analysis, adjusted for season, age, and body mass index. A total of 137 assessments of 25(OH)D₃ levels and PA were conducted (58 at 6 mo, 51 at 12 mo, and 28 at 24 mo). More than 60% of the patients were vitamin D-deficient (25(OH)D₃ ≤20 ng/ml), independent of study time point. At 6-mo follow-up, accelerometry-based vigorous and moderate-to-vigorous PAs were positively associated with 25(OH)D₃ levels (P = 0.04; P = 0.006,). PA together with season was a significant predictor of elevated 25(OH)D₃ levels. Our results suggest that the majority of colorectal cancer patients may suffer from vitamin D deficiency. Engaging in PA may be an effective approach to increase their 25(OH)D₃ levels.

Chemoprevention of colorectal cancer in individuals with previous colorectal neoplasia: systematic review and network meta-analysis

OBJECTIVE

 To assess the comparative efficacy and safety of candidate agents (low and high dose aspirin, non-aspirin non-steroidal anti-inflammatory drugs (NSAIDs), calcium, vitamin D, folic acid, alone or in combination) for prevention of advanced metachronous neoplasia (that is, occurring at different times after resection of initial neoplasia) in individuals with previous colorectal neoplasia, through a systematic review and network meta-analysis.

DATA SOURCES

 Medline, Embase, Web of Science, from inception to 15 October 2015; clinical trial registries.

STUDY SELECTION

 Randomized controlled trials in adults with previous colorectal neoplasia, treated with candidate chemoprevention agents, and compared with placebo or another candidate agent. Primary efficacy outcome was risk of advanced metachronous neoplasia; safety outcome was serious adverse events.

DATA EXTRACTION

 Two investigators identified studies and abstracted data. A Bayesian network meta-analysis was performed and relative ranking of agents was assessed with surface under the cumulative ranking (SUCRA) probabilities (ranging from 1, indicating that the treatment has a high likelihood to be best, to 0, indicating the treatment has a high likelihood to be worst). Quality of evidence was appraised with GRADE criteria.

RESULTS

 15 randomized controlled trials (12 234 patients) comparing 10 different strategies were included. Compared with placebo, non-aspirin NSAIDs were ranked best for preventing advanced metachronous neoplasia (odds ratio 0.37, 95% credible interval 0.24 to 0.53; SUCRA=0.98; high quality evidence), followed by low-dose aspirin (0.71, 0.41 to 1.23; SUCRA=0.67; low quality evidence). Low dose aspirin, however, was ranked the safest among chemoprevention agents (0.78, 0.43 to 1.38; SUCRA=0.84), whereas non-aspirin NSAIDs (1.23, 0.95 to 1.64; SUCRA=0.26) were ranked low for safety. High dose aspirin was comparable with low dose aspirin in efficacy (1.12, 0.59 to 2.10; SUCRA=0.58) but had an inferior safety profile (SUCRA=0.51). Efficacy of agents for reducing metachronous colorectal cancer could not be estimated.

CONCLUSIONS

 Among individuals with previous colorectal neoplasia, non-aspirin NSAIDs are the most effective agents for the prevention of advanced metachronous neoplasia, whereas low dose aspirin has the most favorable risk:benefit profile.

REGISTRATION

 PROSPERO (CRD42015029598).

An update on vitamin D for clinicians

PURPOSE OF REVIEW

The clinical benefits of vitamin D therapy have received substantial attention over the past decade. Recently, several trials looked to clarify the optimal vitamin D dose or serum level needed to promote human health. The purpose of this review is to highlight selected studies published since January 2015.

RECENT FINDINGS

Several recent trials challenge whether serum vitamin D levels at least 30 ng/ml promote human health. In postmenopausal women with 25-hydroxyvitamin D [25(OH)D] levels 21 ± 3 ng/ml, high-dose vitamin D for 1 year increased calcium absorption by 1%, without changes in bone mineral density, physical function, or falls when compared with low-dose vitamin D and placebo. High-dose vitamin D increased risk of falling in 200 adults 78 ± 5 years old with baseline 25(OH)D levels of ∼19 ± 9 ng/ml. High-dose vitamin D in adults increased the number and duration of upper respiratory tract infections compared with placebo. Asthma patients achieving 25(OH)D levels more than 30 ng/ml during a trial experienced more respiratory infections than those not achieving such levels.

SUMMARY

Recent studies are congruent with the Institute of Medicine's conclusion that humans are vitamin D replete when their serum 25(OH)D levels are at least 20 ng/ml. Higher levels seem to promote falls and respiratory infections.

Endoscopic ultrasound-guided transmural stenting for gallbladder drainage in high-risk patients with acute cholecystitis: a systematic review and pooled analysis

BACKGROUND

Endoscopic ultrasound-guided transmural stenting for gallbladder drainage is an emerging alternative for the treatment of acute cholecystitis in high-risk surgical patients. A variety of stents have been described, including plastic stents, self-expandable metal stents (SEMSs), and lumen-apposing metal stents (LAMSs). LAMSs represent the only specifically designed stent for transmural gallbladder drainage. A systematic review was performed to evaluate the feasibility and efficacy of EUS-guided drainage (EUS-GBD) in acute cholecystitis using different types of stents.

METHODS

A computer-assisted literature search up to September 2015 was performed using two electronic databases, MEDLINE and EMBASE. Search terms included MeSH and non-MeSH terms relating to acute cholecystitis, gallbladder drainage, endoscopic gallbladder drainage, endoscopic ultrasound gallbladder drainage, alone or in combination. Additional articles were retrieved by hand-searching from references of relevant studies. Pooled technical success, clinical success, and adverse event rates were calculated.

RESULTS

Twenty-one studies met the inclusion criteria, and the eligible cases were 166. The overall technical success rate, clinical success rate, and frequency of adverse events were 95.8, 93.4, and 12.0 %, respectively. The technical success rate was 100 % using plastic stents, 98.6 % using SEMSs, and 91.5 % using LAMSs. The clinical success rate was 100, 94.4, and 90.1 % after the deployment of plastic stents, SEMSs, and LAMSs, respectively. The frequency of adverse events was 18.2 % using plastic stents, 12.3 % using SEMSs, and 9.9 % using LAMSs.

CONCLUSIONS

Among the different drainage approaches in the non-surgical management of acute cholecystitis, EUS-guided transmural stenting for gallbladder drainage appears to be feasible, safe, and effective. LAMSs seem to have high potentials in terms of efficacy and safety, although further prospective studies are needed.

Evaluating Digital Health Interventions: Key Questions and Approaches

Digital health interventions have enormous potential as scalable tools to improve health and healthcare delivery by improving effectiveness, efficiency, accessibility, safety, and personalization. Achieving these improvements requires a cumulative knowledge base to inform development and deployment of digital health interventions. However, evaluations of digital health interventions present special challenges. This paper aims to examine these challenges and outline an evaluation strategy in terms of the research questions needed to appraise such interventions. As they are at the intersection of biomedical, behavioral, computing, and engineering research, methods drawn from all of these disciplines are required. Relevant research questions include defining the problem and the likely benefit of the digital health intervention, which in turn requires establishing the likely reach and uptake of the intervention, the causal model describing how the intervention will achieve its intended benefit, key components, and how they interact with one another, and estimating overall benefit in terms of effectiveness, cost effectiveness, and harms. Although RCTs are important for evaluation of effectiveness and cost effectiveness, they are best undertaken only when: (1) the intervention and its delivery package are stable; (2) these can be implemented with high fidelity; and (3) there is a reasonable likelihood that the overall benefits will be clinically meaningful (improved outcomes or equivalent outcomes at lower cost). Broadening the portfolio of research questions and evaluation methods will help with developing the necessary knowledge base to inform decisions on policy, practice, and research.

Lifestyle and Other Factors Explain One-Half of the Variability in the Serum 25-Hydroxyvitamin D Response to Cholecalciferol Supplementation in Healthy Adults

BACKGROUND

Many factors have been associated with serum 25-hydroxyvitamin D [25(OH)D] concentrations in observational studies, with variable consistency. However, less information is available on factors affecting the magnitude of changes in serum 25(OH)D resulting from vitamin D supplementation.

OBJECTIVE

This study aimed to identify factors associated with the serum 25(OH)D response to supplementation with 1000 IU cholecalciferol/d during the first year of a large, multicenter, randomized, placebo-controlled colorectal adenoma chemoprevention trial.

METHODS

Eligible older adults who were not vitamin D-deficient [serum 25(OH)D ≥12 ng/mL] were randomly assigned in a modified 2 × 2 factorial design to 1 of 4 groups: daily 1000 IU cholecalciferol, 1200 mg Ca as carbonate, both, or placebo. Women could elect 2-group (calcium ± cholecalciferol) random assignment. In secondary analyses, we used multivariable models to assess factors associated with serum 25(OH)D concentrations in all enrollees (n = 2753) and with relative changes in serum 25(OH)D after 1 y cholecalciferol supplementation among those randomly assigned (n = 2187).

RESULTS

In multivariable models, 8 factors accounted for 50% of the variability of proportional change in serum 25(OH)D after cholecalciferol supplementation. Larger increases were associated with being female (34.5% compared with 20.5%; P < 0.001) and with lower baseline serum 25(OH)D (P < 0.0001), optimal adherence to study pill intake (P = 0.0002), wearing long pants and sleeves during sun exposure (P = 0.0002), moderate activity level (P = 0.01), use of extra vitamin D-containing supplements during the trial (P = 0.03), and seasons of blood draw (P ≤ 0.002). Several genetic polymorphisms were associated with baseline serum 25(OH)D and/or serum response, but these did not substantially increase the models' R² values. Other factors, including body mass index, were associated with serum 25(OH)D at baseline but not with its response to supplemental cholecalciferol.

CONCLUSIONS

The factors that most affected changes in serum 25(OH)D concentrations in response to cholecalciferol supplementation included sex, baseline serum 25(OH)D, supplement intake adherence, skin-covering clothes, physical activity, and season. Genetic factors did not play a major role. This trial was registered at www.clinicaltrials.gov as NCT00153816.

Effect of 1,25(OH)2D3 on transdifferentiation of rat renal tubular epithelial cells induced by high glucose

Deficiency in vitamin D and its active metabolite is a characteristic of chronic kidney diseases (CKDs). Previous studies have reported that 1α,25-dihydroxyvitamin D₃ [1,25(OH)₂D₃], the active form of vitamin D, can attenuate renal interstitial fibrosis. The present study aimed to explore the effect of 1,25(OH)₂D₃ on the transdifferentiation of NRK-52E rat renal tubular epithelial cells (RTECs) induced by high glucose, as well as the expression of vitamin D receptor (VDR) and production of angiotensin (Ang) II. Western blot and reverse transcription-quantitative polymerase chain reaction (RT-qPCR) analyses were performed to detect the protein and mRNA expression of α-smooth muscle actin (α-SMA), E-cadherin and VDR. Furthermore, the production of Ang II was analyzed by enzyme-linked immunosorbent assay (ELISA). Treatment with high glucose decreased E-cadherin and VDR, while increasing α-SMA and Ang II, and of note, these changes were attenuated by 1,25(OH)₂D₃ in a dose-dependent manner. In conclusion, the present study revealed that 1,25(OH)₂D₃ inhibits high glucose-induced transdifferentiation of rat RTECs in a dose-dependent manner, which may be associated with the downregulation of Ang II and upregulation of VDR.

A Review of Outcomes for Colorectal Adenomas

OBJECTIVES

Using data from former reports, this study reviews and analyzes the outcomes of tumor recurrence, tumor progression, and tumor-specific survival of patients with colorectal adenomas.

METHODS

Data were collected from 32 longitudinal studies of outcomes after the first diagnosis of colorectal adenoma and collected as individual patient results, that is, as failure times from the first tumor to the three outcomes. Altogether, there were 45,286 patients, including 22,148 for the outcome of additional adenomas, 23,796 for the outcome of progression to invasive carcinoma, and 2,602 for the outcome of disease-specific survival (some patients were available for more than one outcome).

RESULTS

In these data, the mean time to additional adenomas was 6 years, the mean time to invasive carcinoma was 15.9 years, and the mean tumor-specific survival time was 21.9 years.

CONCLUSIONS

Although greater than 50% of those with colorectal adenomas will have additional adenomas, few progress to invasive tumor or die of colorectal cancer.

Vitamin D and cancer: does it really matter?

PURPOSE OF REVIEW

This article provides a background for an evidence-based decision regarding the prescription of vitamin D for cancer prevention and improvement of outcomes in oncology.

RECENT FINDINGS

In 2014, Feldman and colleagues published a review suggesting a beneficial role for vitamin D in cancer development. In the same year, a Cochrane meta-analysis that included 18 randomized clinical trials comparing vitamin D administration versus no intervention in healthy population found no difference regarding cancer incidence between the groups. One year later, a phase III trial published in the New England Journal of Medicine did not show any protective effect of vitamin D against adenoma development.

SUMMARY

Vitamin D is well known for its importance in calcium and phosphate homeostasis, being essential for bone mineralization. However, calcitriol, or 1,25-dyhydroxy-vitamin D3, is a multifunctional steroid hormone with many extra skeletal actions and may regulate signaling pathways related to cancer development and progression. In preclinical studies, it was shown that vitamin D can promote cell differentiation and inhibit proliferation, angiogenesis, and cell migration. Inconsistent results are found in epidemiological studies and early trials regarding clinical effects of vitamin D supplementation and cancer in terms of prevention and impact in cancer-related mortality.

A Way Forward for Cancer Chemoprevention: Think Local

As cells progress through carcinogenesis, the associated exponential expansion of genetic and molecular aberrations and resultant heterogeneity make therapeutic success increasingly unattainable. Therapeutic intervention at early stages of carcinogenesis that occurs within the primary organ and in the face of a lower burden of molecular aberrations, constitutes a basic tenet of cancer chemoprevention, and provides a situation that favors a greater degree of therapeutic efficacy compared with that of advanced cancer. A longstanding barrier to chemoprevention relates to the requirement for essentially no systemic toxicity, and the fact that when large numbers of people are treated, the emergence of systemic toxicity is almost universal. A rational means to address this in fact relates to a second basic tenet of the chemopreventive strategy: the focus of therapeutic intervention is to disrupt a process that is in essence localized to a single organ. Based upon this consideration, a strategy which is based upon local delivery of therapeutics to an at-risk organ will achieve therapeutic efficacy while avoiding systemic delivery and its associated toxicity. This article will review the rationale for undertaking such an approach, describe successful clinical achievements based on this strategy, describe ongoing efforts to expand the impact of this approach, and together will highlight the high impact that this approach has already had on the field as well as its extremely high potential for future impact. Cancer Prev Res; 10(1); 14-35. ©2016 AACR.

Transforming Cancer Prevention through Precision Medicine and Immune-oncology

We have entered a transformative period in cancer prevention (including early detection). Remarkable progress in precision medicine and immune-oncology, driven by extraordinary recent advances in genome-wide sequencing, big-data analytics, blood-based technologies, and deep understanding of the tumor immune microenvironment (TME), has provided unprecedented possibilities to study the biology of premalignancy. The pace of research and discovery in precision medicine and immunoprevention has been astonishing and includes the following clinical firsts reported in 2015: driver mutations detected in circulating cell-free DNA in patients with premalignant lesions (lung); clonal hematopoiesis shown to be a premalignant state; molecular selection in chemoprevention randomized controlled trial (RCT; oral); striking efficacy in RCT of combination chemoprevention targeting signaling pathway alterations mechanistically linked to germline mutation (duodenum); molecular markers for early detection validated for lung cancer and showing promise for pancreatic, liver, and ovarian cancer. Identification of HPV as the essential cause of a major global cancer burden, including HPV16 as the single driver of an epidemic of oropharyngeal cancer in men, provides unique opportunities for the dissemination and implementation of public health interventions. Important to immunoprevention beyond viral vaccines, genetic drivers of premalignant progression were associated with increasing immunosuppressive TME; and Kras vaccine efficacy in pancreas genetically engineered mouse (GEM) model required an inhibitory adjuvant (Treg depletion). In addition to developing new (e.g., epigenetic) TME regulators, recent mechanistic studies of repurposed drugs (aspirin, metformin, and tamoxifen) have identified potent immune activity. Just as precision medicine and immune-oncology are revolutionizing cancer therapy, these approaches are transforming cancer prevention. Here, we set out a brief agenda for the immediate future of cancer prevention research (including a "Pre-Cancer Genome Atlas" or "PCGA"), which will involve the inter-related fields of precision medicine and immunoprevention - pivotal elements of a broader domain of personalized public health.

The UVB1 Vitamin D analogue inhibits colorectal carcinoma progression

Vitamin D has been shown to display a wide variety of antitumour effects, but their therapeutic use is limited by its severe side effects. We have designed and synthesized a Gemini vitamin D analogue of calcitriol (UVB1) which has shown to display antineoplastic effects on different cancer cell lines without causing hypercalcemia. The aim of this work has been to investigate, by employing in silico, in vitro, and in vivo assays, whether UVB1 inhibits human colorectal carcinoma progression. We demonstrated that UVB1 induces apoptotic cell death and retards cellular migration and invasion of HCT116 colorectal carcinoma cells. Moreover, the analogue reduced the tumour volume in vivo, and modulated the expression of Bax, E-cadherin and nuclear β-catenin in tumour animal tissues without producing toxic effects. In silico analysis showed that UVB1 exhibits greater affinity for the ligand binding domain of vitamin D receptor than calcitriol, and that several characteristics in the three-dimensional conformation of VDR may influence the biological effects. These results demonstrate that the Gemini vitamin D analogue affects the growth of the colorectal cancer and suggest that UVB1 is a potential chemotherapeutic agent for treatment of this disease.

Hypercalcemia, hypercalciuria, and kidney stones in long-term studies of vitamin D supplementation: a systematic review and meta-analysis

BACKGROUND

Vitamin D supplementation is increasingly being used in higher doses in randomized controlled trials (RCTs). However, adverse events from very large annual doses of vitamin D have been shown in 2 RCTs, whereas in a third RCT, low-dose vitamin D, with calcium supplements, was shown to increase kidney stone risk.

OBJECTIVE

We analyzed the side effects related to calcium metabolism in RCTs, specifically hypercalcemia, hypercalciuria, and kidney stones, in participants who were given vitamin D supplements for ≥24 wk compared with in subjects in the placebo arm.

DESIGN

The following 3 main online databases were searched: Ovid Medline (PubMed), EMBASE, and the Cochrane Library. Software was used for the meta-analysis.

RESULTS

A total of 48 studies with 19,833 participants were identified, which reported ≥1 of the following side effects: hypercalcemia, hypercalciuria, or kidney stones. Of these studies, kidney stones were reported in only 9 trials with a tendency for fewer subjects reporting stones in the vitamin D arm than in the placebo arm (RR: 0.66, 95% CI: 0.41, 1.09; P = 0.10). In 37 studies, hypercalcemia was shown with increased risk shown for the vitamin D group (RR: 1.54; 95% CI: 1.09, 2.18; P = 0.01). Similar increased risk of hypercalciuria was shown in 14 studies for the vitamin D group (RR: 1.64; 95% CI: 1.06, 2.53; P = 0.03). In subgroup analyses, it was shown that the effect of vitamin D supplementation on risk of hypercalcemia, hypercalciuria, or kidney stones was not modified by baseline 25-hydroxyvitamin D, vitamin D dose and duration, or calcium co-supplementation.

CONCLUSIONS

Long-term vitamin D supplementation resulted in increased risks of hypercalcemia and hypercalciuria, which were not dose related. However, vitamin D supplementation did not increase risk of kidney stones. Additional large RCTs of long-term vitamin D supplementation are required to confirm these findings.

Optimizing adjuvant therapy and survivorship care of stage III colon cancer

The MOSAIC trial demonstrated nearly a decade ago that the addition of oxaliplatin to 5-fluorouracil improves outcomes in the adjuvant treatment of colon cancer, but no new agents have been shown to be superior to standard FOLFOX therapy. Oncologists have refined the use of oxaliplatin containing regimens to optimize outcomes, improved patient selection for multi-agent chemotherapy and expanded survivorship care to meet the needs of the growing number of survivors. In this article, we review the historical contexts of current therapy, appropriate staging investigations, the importance of timely initiation of therapy and key survivorship issues. We also discuss exciting opportunities for change, including reduced duration of adjuvant chemotherapy and the use of circulating tumor cells and DNA in surveillance.

Calcium intake and colorectal cancer risk: Results from the nurses' health study and health professionals follow-up study

The relationship between calcium intake and colorectal cancer (CRC) risk remains inconclusive. We conducted this study to evaluate whether the association between calcium intake and CRC risk differs by anatomic subsite and determine the dose-response relationship for this association, as well as assess when in carcinogenesis calcium may play a role. We assessed calcium intake every 4 years and followed 88,509 women (1980-2012) in the Nurses' Health Study and 47,740 men (1986-2012) in the Health Professionals Follow-Up Study. We documented 3,078 incident CRC cases. Total calcium intake (≥1,400 vs. <600 mg/d) was associated with a statistically significant lower risk of colon cancer (multivariable relative risk: 0.78, 95%CI: 0.65-0.95). Similar results were observed by different sources of calcium (from all foods or dairy products only). The inverse association was linear and suggestively stronger for distal colon cancer (0.65, 0.43-0.99) than for proximal colon cancer (0.94, 0.72-1.22, p-common effects  = 0.14). Additionally, when comparing different latencies, the overall pattern suggested that the inverse association appeared to be stronger with increasing latency and was strongest for intakes 12-16 years before diagnosis. Comparing total calcium intakes of ≥1,400 vs. <600 mg/d for intake 12-16 y before diagnosis, the pooled RR (95% CIs) of CRC was 0.76 (0.64-0.91). Higher calcium intake was associated with a lower risk of developing colon cancer, especially for distal colon cancer. Overall inverse association was linear and did not differ by intake source. Additionally, calcium intake approximately 10 years before diagnosis appeared to be associated with a lower risk of CRC.

Prognostic role of 25-hydroxyvitamin D in patients with liver metastases from colorectal cancer treated with radiofrequency ablation

BACKGROUND AND AIM

Vitamin D is implicated in the etiology of several neoplastic diseases, but its relationship with colorectal cancer survival is still unclear. Aim of this study was to determine whether vitamin D levels influence survival outcomes in colorectal cancer liver metastases patients treated with percutaneous radiofrequency ablation.

METHODS

We measured 25-hydroxyvitamin D levels in 143 patients with 215 colorectal liver metastases who underwent radiofrequency ablation between 1999 and 2011 at our institution. The influence of 25-hydroxyvitamin D levels on overall survival and time to recurrence was evaluated in univariate and multivariate Cox analyses.

RESULTS

Median age was 68 years (range 41-85), and median number of nodules was 2 (1-3) with a median maximum diameter of 26 mm (10-48). Median survival was 44 months (36-62), and survival rate was 91.4%, 46.5%, and 42.2% at 1, 4, and 5 years in the whole cohort. Median survival was 65 months (52-74) if 25-hydroxyvitamin D >20 ng/mL and 34 months (24-41) if ≤20 ng/mL (P < 0.001). In the whole cohort, median time to recurrence was 34 months (26-47), 50 months (36-62) in the case of 25-hydroxyvitamin D >20 ng/mL and 24 months (20-32) if ≤20 ng/mL (P < 0.001). Nodule size and 25-hydroxyvitamin D resulted as significant predictors of both overall survival and time to recurrence in multivariate analysis.

CONCLUSIONS

Our study provides support for the use of 25-hydroxyvitamin D as a new predictor of outcome for colorectal liver metastases patients.

Randomized controlled trials: who fails run-in?

BACKGROUND

Early identification of participants at risk of run-in failure (RIF) may present opportunities to improve trial efficiency and generalizability.

METHODS

We conducted a partial factorial-design, randomized, controlled trial of calcium and vitamin D to prevent colorectal adenoma recurrence at 11 centers in the United States. At baseline, participants completed two self-administered questionnaires (SAQs) and a questionnaire administered by staff. Participants in the full factorial randomization (calcium, vitamin D, both, or neither) received a placebo during a 3-month single-blinded run-in; women electing to take calcium enrolled in a two-group randomization (calcium with vitamin D, or calcium alone) and received calcium during the run-in. Using logistic regression models, we examined baseline factors associated with RIF in three subgroups: men (N = 1606) and women (N = 301) in the full factorial randomization and women in the two-group randomization (N = 666).

RESULTS

Overall, 314/2573 (12 %) participants failed run-in; 211 (67 %) took fewer than 80 % of their tablets (poor adherence), and 103 (33 %) withdrew or were uncooperative. In multivariable models, 8- to 13-fold variation was seen by study center in odds of RIF risk in the two largest groups. In men, RIF decreased with age (adjusted odds ratio [OR] per 5 years 0.85 [95 % confidence interval, CI; 0.76-0.96]) and was associated with being single (OR 1.65 [95 % CI; 1.10-2.47]), not graduating from high school (OR 2.77 [95 % CI; 1.58-4.85]), and missing SAQ data (OR 1.97 [1.40-2.76]). Among women, RIF was associated primarily with health-related factors; RIF risk was lower with higher physical health score (OR 0.73 [95 % CI; 0.62-0.86]) and baseline multivitamin use (OR 0.44 [95 % CI; 0.26-0.75]). Women in the 5-year colonoscopy surveillance interval were at greater risk of RIF than those with 3-year follow-up (OR 1.91 [95 % CI; 1.08-3.37]), and the number of prescription medicines taken was also positively correlated with RIF (p = 0.03). Perceived toxicities during run-in were associated with 12- to 29-fold significantly increased odds of RIF.

CONCLUSIONS

There were few common baseline predictors of run-in failure in the three randomization groups. However, heterogeneity in run-in failure associated with study center, and missing SAQ data reflect potential opportunities for intervention to improve trial efficiency and retention.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT00153816 . Registered September 2005.

Dietary supplements and disease prevention - a global overview

Dietary supplements are widely used and offer the potential to improve health if appropriately targeted to those in need. Inadequate nutrition and micronutrient deficiencies are prevalent conditions that adversely affect global health. Although improvements in diet quality are essential to address these issues, dietary supplements and/or food fortification could help meet requirements for individuals at risk of deficiencies. For example, supplementation with vitamin A and iron in developing countries, where women of reproductive age, infants and children often have deficiencies; with folic acid among women of reproductive age and during pregnancy; with vitamin D among infants and children; and with calcium and vitamin D to ensure bone health among adults aged ≥65 years. Intense debate surrounds the benefits of individual high-dose micronutrient supplementation among well-nourished individuals because the alleged beneficial effects on chronic diseases are not consistently supported. Daily low-dose multivitamin supplementation has been linked to reductions in the incidence of cancer and cataracts, especially among men. Baseline nutrition is an important consideration in supplementation that is likely to modify its effects. Here, we provide a detailed summary of dietary supplements and health outcomes in both developing and developed countries to help guide decisions about dietary supplement recommendations.

Effects of supplemental calcium and vitamin D on the APC/β-catenin pathway in the normal colorectal mucosa of colorectal adenoma patients

APC/β-catenin pathway malfunction is a common and early event in colorectal carcinogenesis. To assess calcium and vitamin D effects on the APC/β-catenin pathway in the normal-appearing colorectal mucosa of sporadic colorectal adenoma patients, nested within a larger randomized, double-blind, placebo-controlled, partial 2 × 2 factorial chemoprevention clinical trial of supplemental calcium (1200 mg daily) and vitamin D (1000 IU daily), alone and in combination versus placebo, we assessed APC, β-catenin, and E-cadherin expression in colon crypts in normal-appearing rectal mucosa biopsies from 104 participants at baseline and 1-yr follow up using standardized, automated immunohistochemistry and quantitative image analysis. For vitamin D versus no vitamin D, the ratio of APC expression to β-catenin expression in the upper 40% (differentiation zone) of crypts (APC/β-catenin score) increased by 28% (P = 0.02), for calcium versus no calcium it increased by 1% (P = 0.88), and for vitamin D + calcium versus calcium by 35% (P = 0.01). Total E-cadherin expression increased by 7% (P = 0.35) for vitamin D versus no vitamin D, 8% (P = 0.31) for calcium versus no calcium, and 12% (P = 0.21) for vitamin D + calcium versus calcium. These results support (i) that vitamin D, alone or in combination with calcium, may modify APC, β-catenin, and E-cadherin expression in humans in directions hypothesized to reduce risk for colorectal neoplasms; (ii) vitamin D as a potential chemopreventive agent against colorectal neoplasms; and (iii) the potential of APC, β-catenin, and E-cadherin expression as treatable, pre-neoplastic risk biomarkers for colorectal neoplasms. © 2016 Wiley Periodicals, Inc.

Chemoprevention of hereditary colon cancers: time for new strategies

Colorectal cancer (CRC) is potentially preventable. Chemoprevention, a focus of research for the past three decades, aims to prevent or delay the onset of cancer through the regression or prevention of colonic adenomas. Ideal pharmacological agents for chemoprevention should be cheap and nontoxic. Although data indicate that aspirin can reduce the risk of CRC in the general population, the highest return from chemopreventive strategies would be expected in patients with the highest risk of developing the disease, particularly those with a defined hereditary predisposition. Despite compelling data showing that a large number of chemopreventive agents show promise in preclinical CRC models, clinical studies have yielded conflicting results. This Review provides a historical and methodological perspective of chemoprevention in familial adenomatous polyposis and Lynch syndrome, and summarizes the current status of CRC chemoprevention in humans. Our goal is to critically focus on important issues of trial design, with particular attention on the choice of appropriate trial end points, how such end points should be measured, and which patients are the ideal candidates to be included in a chemopreventive trial.

Plasma 25-Hydroxyvitamin D, Vitamin D Binding Protein, and Risk of Colorectal Cancer in the Nurses' Health Study

Total circulating 25-hydroxyvitamin D [25(OH)D)] has been associated with lower risk of colorectal cancer. The physiologic mechanism, however, may be more directly related to the free or bioavailable fraction of 25(OH)D, which is influenced by levels of vitamin D binding protein (VDBP). We assessed the association of prediagnosis total, free, and bioavailable 25(OH)D and VDBP with colorectal cancer risk among predominantly white women in the Nurses' Health Study (NHS) who provided a blood specimen in 1989-1990. We documented 378 cases of colorectal cancer through 2011 and matched them to 689 controls according to age and time of blood draw. We genotyped two common polymorphisms in the gene coding VDBP and calculated free and bioavailable 25(OH)D levels based on total 25(OH)D, VDBP, albumin, and their estimated genotype-specific binding affinities. Total 25(OH)D was associated with lower colorectal cancer risk (P for trend = 0.01). Compared with women in the lowest quintile of total 25(OH)D, those in the highest quintile had a multivariable-adjusted odds ratio (OR) for colorectal cancer of 0.54 [95% confidence interval (CI), 0.33-0.87]. Comparing extreme quintiles, we did not find any significant association with risk of colorectal cancer for VDBP (OR, 0.98; 95% CI, 0.65-1.47), free 25(OH)D (OR, 0.71; 95% CI, 0.46-1.10), or bioavailable 25(OH)D (OR, 0.92; 95% CI, 0.60-1.42). In conclusion, prediagnosis levels of total, but not free or bioavailable 25(OH)D, were associated with lower colorectal cancer risk. Although our findings support an inverse association of vitamin D with colorectal cancer, this association does not appear to be due to the unbound or bioavailable fraction of circulating vitamin D. Cancer Prev Res; 9(8); 664-72. ©2016 AACR.

Calcium supplementation for the prevention of colorectal adenomas: A systematic review and meta-analysis of randomized controlled trials

AIM: To determine the efficacy of calcium supplementation in reducing the recurrence of colorectal adenomas.

METHODS: We conducted a systematic review and meta-analysis of published studies. We searched PubMed, Scopus, the Cochrane Library, the WHO International Clinical Trials Registry Platform, and the ClinicalTrials.gov website, through December 2015. Randomized, placebo-controlled trials assessing supplemental calcium intake for the prevention of recurrence of adenomas were eligible for inclusion. Two reviewers independently selected studies based on predefined criteria, extracted data and outcomes (recurrence of colorectal adenomas, and advanced or “high-risk” adenomas), and rated each trial’s risk-of-bias. Between-study heterogeneity was assessed, and pooled risk ratio (RR) estimates with their 95% confidence intervals (95%CI) were calculated using fixed- and random-effects models. To express the treatment effect in clinical terms, we calculated the number needed to treat (NNT) to prevent one adenoma recurrence. We also assessed the quality of evidence using GRADE.

RESULTS: Four randomized, placebo-controlled trials met the eligibility criteria and were included. Daily doses of elemental calcium ranged from 1200 to 2000 mg, while the duration of treatment and follow-up of participants ranged from 36 to 60 mo. Synthesis of intention-to-treat data, for participants who had undergone follow-up colonoscopies, indicated a modest protective effect of calcium in prevention of adenomas (fixed-effects, RR = 0.89, 95%CI: 0.82-0.96; random-effects, RR = 0.87, 95%CI: 0.77-0.98; high quality of evidence). The NNT was 20 (95%CI: 12-61) to prevent one colorectal adenoma recurrence within a period of 3 to 5 years. On the other hand, the association between calcium treatment and advanced adenomas did not reach statistical significance (fixed-effects, RR = 0.92, 95%CI: 0.75-1.13; random-effects, RR = 0.92, 95%CI: 0.71-1.18; moderate quality of evidence).

CONCLUSION: Our results suggest a modest chemopreventive effect of calcium supplements against recurrent colorectal adenomas over a period of 36 to 60 mo. Further research is warranted.

The Use of 1α,25-Dihydroxyvitamin D₃ as an Anticancer Agent

The notion that vitamin D can influence the incidence of cancer arose from epidemiological studies. The major source of vitamin D in the organism is skin production upon exposure to ultra violet-B. The very first observation of an inverse correlation between exposure of individuals to the sun and the likelihood of cancer was reported as early as 1941. In 1980, Garland and Garland hypothesised, from findings from epidemiological studies of patients in the US with colon cancer, that vitamin D produced in response to sun exposure is protective against cancer as opposed to sunlight per se. Later studies revealed inverse correlations between sun exposure and the occurrence of prostate and breast cancers. These observations prompted laboratory investigation of whether or not vitamin D had an effect on cancer cells. Vitamin D is not active against cancer cells, but the most active metabolite 1α,25-dihydroxyvitamin D₃ (1,25D) has profound biological effects. Here, we review the anticancer action of 1,25D, clinical trials of 1,25D to date and the prospects of the future therapeutic use of new and low calcaemic analogues.

DNA Repair in Despair-Vitamin D Is Not Fair

The role of vitamin D as a treatment option for neoplastic diseases, once considered to have a bright future, remains controversial. The preclinical studies discussed herein show compelling evidence that Vitamin D Derivatives (VDDs) can convert some cancer and leukemia cells to a benign phenotype, by differentiation/maturation, cell cycle arrest, or induction of apoptosis. Furthermore, there is considerable, though still evolving, knowledge of the molecular mechanisms underlying these changes. However, the attempts to clearly document that the treatment outcomes of human neoplastic diseases can be positively influenced by VDDs have been, so far, disappointing. The clinical trials to date of VDDs, alone or combined with other agents, have not shown consistent results. It is our contention, shared by others, that there were limitations in the design or execution of these trials which have not yet been fully addressed. Based on the connection between upregulation of JNK by VDDs and DNA repair, we propose a new avenue of attack on cancer cells by increasing the toxicity of the current, only partially effective, cancer chemotherapeutic drugs by combining them with VDDs. This can impair DNA repair and thus kill the malignant cells, warranting a comprehensive study of this novel concept. J. Cell. Biochem. 117: 1733-1744, 2016. © 2016 Wiley Periodicals, Inc.

Calcium intake and mortality from all causes, cancer, and cardiovascular disease: the Cancer Prevention Study II Nutrition Cohort

BACKGROUND

Calcium intake may be important for bone health, but its effects on other outcomes, including cardiovascular disease (CVD) and cancer, remain unclear. Recent reports of adverse cardiovascular effects of supplemental calcium have raised concerns.

OBJECTIVE

We investigated associations of supplemental, dietary, and total calcium intakes with all-cause, CVD-specific, and cancer-specific mortality in a large, prospective cohort.

DESIGN

A total of 132,823 participants in the Cancer Prevention Study II Nutrition Cohort, who were followed from baseline (1992 or 1993) through 2012 for mortality outcomes, were included in the analysis. Dietary and supplemental calcium information was first collected at baseline and updated in 1999 and 2003. Multivariable-adjusted Cox proportional hazards models with cumulative updating of exposures were used to calculate RRs and 95% CIs for associations between calcium intake and mortality.

RESULTS

During a mean follow-up of 17.5 y, 43,186 deaths occurred. For men, supplemental calcium intake was overall not associated with mortality outcomes (P-trend > 0.05 for all), but men who were taking ≥1000 mg supplemental calcium/d had a higher risk of all-cause mortality (RR: 1.17; 95% CI: 1.03, 1.33), which was primarily attributed to borderline statistically significant higher risk of CVD-specific mortality (RR: 1.22; 95% CI: 0.99, 1.51). For women, supplemental calcium was inversely associated with mortality from all causes [RR (95% CI): 0.90 (0.87, 0.94), 0.84 (0.80, 0.88), and 0.93 (0.87, 0.99) for intakes of 0.1 to <500, 500 to <1000, and ≥1000 mg/d, respectively; P-trend < 0.01]. Total calcium intake was inversely associated with mortality in women (P-trend < 0.01) but not in men; dietary calcium was not associated with all-cause mortality in either sex.

CONCLUSIONS

In this cohort, associations of calcium intake and mortality varied by sex. For women, total and supplemental calcium intakes are associated with lower mortality, whereas for men, supplemental calcium intake ≥1000 mg/d may be associated with higher all-cause and CVD-specific mortality.