Energy in and energy out: what matters for survivors of colorectal cancer?

The care of the colorectal cancer survivor

PURPOSE OF REVIEW

The gastroenterology literature emphasizes factors that increase colorectal cancer (CRC) incidence but presents little about management after initial CRC treatments. The purpose of this review is to describe the remarkably increasing numbers of CRC survivors in whom surveillance guidelines are often not followed and patient care is fragmented. The gastroenterologist can play an important role in this care to improve prognosis and overall health.

RECENT FINDINGS

Existing surveillance recommendations by specialty societies for CRC survivors are fairly consistent but implementation occurs in less than half. The gastroenterologist can help to coordinate care to ensure appropriate surveillance and also can help to diagnose and treat chemotherapy and radiotherapy complications in survivors which can affect the quality of life long after the initial treatment. The gastroenterologist also can focus on host factors, including management of obesity, exercise programs, and the diet and can introduce potential chemopreventive agents such as nonsteroidal anti-inflammatory drugs when positive prospective studies are forthcoming. Interested gastroenterologists also have a role in participating in such prospective studies.

SUMMARY

The gastroenterologist should enhance her/his role for coordinated management of CRC survivors to improve patient surveillance care, to treat posttherapy complications and encourage preventive measures to improve prognosis and quality of life.

Diet and lifestyle in survivors of colorectal cancer

Much research supports the association between diet and lifestyle in the development of colorectal cancer. Recent studies have demonstrated an association between various energy balance host factors (obesity, physical inactivity, and certain dietary factors) and outcomes. This review summarizes the impact of modifiable lifestyle factors, including prediagnosis and postdiagnosis adiposity, physical activity, and diet, on the prognosis of patients with colorectal cancer. The article focuses on associations of these factors in survivors of stage I to III colorectal cancer, and summarizes the possible mechanisms for the association between modifiable lifestyle factors and the prognosis of patients with colorectal cancer.

Proceedings of the second international molecular pathological epidemiology (MPE) meeting

Disease classification system increasingly incorporates information on pathogenic mechanisms to predict clinical outcomes and response to therapy and intervention. Technological advancements to interrogate omics (genomics, epigenomics, transcriptomics, proteomics, metabolomics, metagenomics, interactomics, etc.) provide widely open opportunities in population-based research. Molecular pathological epidemiology (MPE) represents integrative science of molecular pathology and epidemiology. This unified paradigm requires multidisciplinary collaboration between pathology, epidemiology, biostatistics, bioinformatics, and computational biology. Integration of these fields enables better understanding of etiologic heterogeneity, disease continuum, causal inference, and the impact of environment, diet, lifestyle, host factors (including genetics and immunity), and their interactions on disease evolution. Hence, the Second International MPE Meeting was held in Boston in December 2014, with aims to: (1) develop conceptual and practical frameworks; (2) cultivate and expand opportunities; (3) address challenges; and (4) initiate the effort of specifying guidelines for MPE. The meeting mainly consisted of presentations of method developments and recent data in various malignant neoplasms and tumors (breast, prostate, ovarian and colorectal cancers, renal cell carcinoma, lymphoma, and leukemia), followed by open discussion sessions on challenges and future plans. In particular, we recognized need for efforts to further develop statistical methodologies. This meeting provided an unprecedented opportunity for interdisciplinary collaboration, consistent with the purposes of the Big Data to Knowledge, Genetic Associations and Mechanisms in Oncology, and Precision Medicine Initiative of the US National Institute of Health. The MPE meeting series can help advance transdisciplinary population science and optimize training and education systems for twenty-first century medicine and public health.

Progress and opportunities in molecular pathological epidemiology of colorectal premalignant lesions

Molecular pathological epidemiology (MPE) is an integrative molecular and population health science that addresses the molecular pathogenesis and heterogeneity of disease processes. The MPE of colonic and rectal premalignant lesions (including hyperplastic polyps, tubular adenomas, tubulovillous adenomas, villous adenomas, traditional serrated adenomas, sessile serrated adenomas/sessile serrated polyps, and hamartomatous polyps) can provide unique opportunities for examining the influence of diet, lifestyle, and environmental exposures on specific pathways of carcinogenesis. Colorectal neoplasia can provide a practical model by which both malignant epithelial tumor (carcinoma) and its precursor are subjected to molecular pathological analyses. KRAS, BRAF, and PIK3CA oncogene mutations, microsatellite instability, CpG island methylator phenotype, and LINE-1 methylation are commonly examined tumor biomarkers. Future opportunities include interrogation of comprehensive genomic, epigenomic, or panomic datasets, and the adoption of in vivo pathology techniques. Considering the colorectal continuum hypothesis and emerging roles of gut microbiota and host immunity in tumorigenesis, detailed information on tumor location is important. There are unique strengths and caveats, especially with regard to case ascertainment by colonoscopy. The MPE of colorectal premalignant lesions can identify etiologic exposures associated with neoplastic initiation and progression, help us better understand colorectal carcinogenesis, and facilitate personalized prevention, screening, and therapy.

Obesity and colorectal cancer: Role of adipokines in tumor initiation and progression

Obesity-associated diseases account for a large portion of public health challenges. Among obesity-related disorders, a direct and independent relationship has been ascertained for colorectal cancer (CRC). The evidence that adipocyte hypertrophy and excessive adipose tissue accumulation (mainly visceral) can promote pathogenic adipocyte and adipose tissue-related diseases, has led to formulate the concept of “adiposopathy”, defined as adipocyte and adipose tissue dysfunction that contributes to metabolic syndrome. Adipose tissue can, indeed, be regarded as an important and highly active player of the innate immune response, in which cytokine/adipokine secretion is responsible for a paracrine loop between adipocytes and macrophages, thus contributing to the systemic chronic low-grade inflammation associated with visceral obesity, which represents a favorable niche for tumor development. The adipocyte itself participates as a central mediator of this inflammatory response in obese individuals by secreting hormones, growth factors and proinflammatory cytokines, which are of particular relevance for the pathogenesis of CRC. Among adipocyte-secreted hormones, the most relevant to colorectal tumorigenesis are adiponectin, leptin, resistin and ghrelin. All these molecules have been involved in cell growth and proliferation, as well as tumor angiogenesis and it has been demonstrated that their expression changes from normal colonic mucosa to adenoma and adenocarcinoma, suggesting their involvement in multistep colorectal carcinogenesis. These findings have led to the hypothesis that an unfavorable adipokine profile, with a reduction of those with an anti-inflammatory and anti-cancerous activity, might serve as a prognostic factor in CRC patients and that adipokines or their analogues/antagonists might become useful agents in the management or chemoprevention of CRC.

Impact of obesity on the survival of patients with early-stage squamous cell carcinoma of the oral tongue

BACKGROUND

Although obesity increases risk and negatively affects survival for many malignancies, the prognostic implications in squamous cell carcinoma (SCC) of the oral tongue, a disease often associated with prediagnosis weight loss, are unknown.

METHODS

Patients with T1-T2 oral tongue SCC underwent curative-intent resection in this single-institution study. All patients underwent nutritional assessment prior to surgery. Body mass index (BMI) was calculated from measured height and weight and categorized as obese (≥ 30 kg/m(2) ), overweight (25-29.9 kg/m(2) ), or normal (18.5-24.9 kg/m(2) ). Clinical outcomes, including disease-specific survival, recurrence-free survival, and overall survival, were compared by BMI group using Cox regression.

RESULTS

From 2000 to 2009, 155 patients (90 men, 65 women) of median age 57 years (range, 18-86 years) were included. Baseline characteristics were similar by BMI group. Obesity was significantly associated with adverse disease-specific survival compared with normal weight in univariable (hazard ratio [HR] = 2.65, 95% confidence interval [CI] = 1.07-6.59; P = .04) and multivariable analyses (HR = 5.01; 95% CI = 1.69-14.81; P = .004). A consistent association was seen between obesity and worse recurrence-free survival (HR = 1.87; 95% CI = 0.90-3.88) and between obesity and worse overall survival (HR = 2.03; 95% CI = 0.88-4.65) though without reaching statistical significance (P = .09 and P = .10, respectively) in multivariable analyses.

CONCLUSIONS

In this retrospective study, obesity was an adverse independent prognostic variable. This association may not have been previously appreciated due to confounding by multiple factors including prediagnosis weight loss.

Molecular pathological epidemiology of epigenetics: emerging integrative science to analyze environment, host, and disease

Epigenetics acts as an interface between environmental/exogenous factors, cellular responses, and pathological processes. Aberrant epigenetic signatures are a hallmark of complex multifactorial diseases (including neoplasms and malignancies such as leukemias, lymphomas, sarcomas, and breast, lung, prostate, liver, and colorectal cancers). Epigenetic signatures (DNA methylation, mRNA and microRNA expression, etc) may serve as biomarkers for risk stratification, early detection, and disease classification, as well as targets for therapy and chemoprevention. In particular, DNA methylation assays are widely applied to formalin-fixed, paraffin-embedded archival tissue specimens as clinical pathology tests. To better understand the interplay between etiological factors, cellular molecular characteristics, and disease evolution, the field of 'molecular pathological epidemiology (MPE)' has emerged as an interdisciplinary integration of 'molecular pathology' and 'epidemiology'. In contrast to traditional epidemiological research including genome-wide association studies (GWAS), MPE is founded on the unique disease principle, that is, each disease process results from unique profiles of exposomes, epigenomes, transcriptomes, proteomes, metabolomes, microbiomes, and interactomes in relation to the macroenvironment and tissue microenvironment. MPE may represent a logical evolution of GWAS, termed 'GWAS-MPE approach'. Although epigenome-wide association study attracts increasing attention, currently, it has a fundamental problem in that each cell within one individual has a unique, time-varying epigenome. Having a similar conceptual framework to systems biology, the holistic MPE approach enables us to link potential etiological factors to specific molecular pathology, and gain novel pathogenic insights on causality. The widespread application of epigenome (eg, methylome) analyses will enhance our understanding of disease heterogeneity, epigenotypes (CpG island methylator phenotype, LINE-1 (long interspersed nucleotide element-1; also called long interspersed nuclear element-1; long interspersed element-1; L1) hypomethylation, etc), and host-disease interactions. In this article, we illustrate increasing contribution of modern pathology to broader public health sciences, which attests pivotal roles of pathologists in the new integrated MPE science towards our ultimate goal of personalized medicine and prevention.