Occupational risk factors for small bowel carcinoid tumor: a European population-based case-control study

Appendiceal Neuroendocrine Neoplasms: A Comprehensive Review

ABSTRACT

Appendiceal neuroendocrine neoplasm (NEN) is the most common adult appendiceal malignant tumor, constituting 16% of gastrointestinal NENs. They are versatile tumors with varying morphology, immunohistochemistry, secretory properties, and cancer genomics. They are slow growing and clinically silent, to begin with, or present with features of nonspecific vague abdominal pain. Most acute presentations are attributed clinically to appendicitis, with most cases detected incidentally on pathology after an appendectomy. Approximately 40% of them present clinically with features of hormonal excess, which is likened to the functional secretory nature of their parent cell of origin. The symptoms of carcinoid syndrome render their presence clinically evident. However, slow growing and symptomatically silent in its initial stages, high-grade neuroendocrine tumors and neuroendocrine carcinomas of the appendix are aggressive and usually have hepatic and lymph node metastasis at presentation. This review article focuses on imaging characteristics, World Health Organization histopathological classification and grading, American Joint Committee on Cancer/Union or International Cancer Control, European Neuroendocrine Tumor Society staging, European Neuroendocrine Tumor Society standardized guidelines for reporting, data interpretation, early-stage management protocols, and advanced-stage appendiceal NENs. Guidelines are also set for the follow-up and reassessment. The role of targeted radiotherapy, chemotherapy, and high-dose somatostatin analogs in treating advanced disease are discussed, along with types of ablative therapies and liver transplantation for tumor recurrence. The search for newer location-specific biomarkers in NEN is also summarized. Regarding the varying aggressiveness of the tumor, there is a scope for research in the field, with plenty of data yet to be discovered.

Understanding the increasing incidence of neuroendocrine tumors

INTRODUCTION

Neuroendocrine tumors (NETs) are a diverse group of tumors with origins from different primary sites such as gastro-entero-pancreatic, lung and endocrine tissue. Worldwide, their incidence has increased in recent decades. Advances in imaging and better clinical awareness are traditionally attributed to this trend; however, other factors such as genetic and environmental contributors are appreciated as well.

AREAS COVERED

The purpose of this article is to review the worldwide epidemiologic trends in incidence of NET through the decades and discuss the various factors potentially contributing to the observed changes in incidence trends.

EXPERT OPINION

Overall, the incidence of NET has increased across the globe over the last few decades. Although multiple genetics and environmental factors have been proposed, the majority of this increase in incidence is secondary to earlier detection. Future studies will help in more accurate assessments and an improved understanding of disease incidence among patients with different grades and differentiation.

Lifetime Exposure to Welding Fumes and Risk of Some Rare Cancers

We investigated the association between exposure to welding fumes and the risk of biliary tract, male breast, bone, and thymus cancer, as well as cancer of the small intestine, eye melanoma, and mycosis fungoides, among men in a European, multicenter case-control study. From 1995-1997, 644 cases and 1,959 control subjects from 7 countries were studied with respect to information on welding and potential confounders. We linked the welding histories of the participants with a measurement-based exposure matrix to calculate lifetime exposure to welding fumes. Odds ratios (ORs) and 95% confidence intervals (CIs) were estimated using logistic regression models, conditional on country and 5-year age groups, and adjusted for education and relevant confounders. Regular welding was associated with an increased risk of cancer of the small intestine (OR = 2.30, 95% CI: 1.17, 4.50). Lifetime exposure to welding fumes above the median of exposed controls was associated with an increased risk of cancer of the small intestine (OR = 2.00, 95% CI: 1.07, 3.72) and male breast (OR = 2.07, 95% CI: 1.14, 3.77), and some elevation in risk was apparent for bone cancer (OR = 1.92, 95% CI: 0.85, 4.34) with increasing lifetime exposure to welding fumes. Welding fumes could contribute to an increased risk of some rare cancers.

Diagnosis of digestive system tumours

The WHO Classification of Tumours provides the international standards for the classification and diagnosis of tumours. It enables direct comparisons to be made between different countries. In the new fifth edition, the series has gone digital with the launch of a website as well as a series of books, known widely as the WHO Blue Books. The first volume to be produced is on the classification of Digestive System tumours, replacing the successful 2010 version. It has been rewritten and updated accordingly. This article summarises the major diagnostic innovations that have occurred over the last decade and that have now been incorporated in the classification. As an example, it incorporates the recently proposed classification of neuroendocrine tumours, based on the recognition that neuroendocrine tumours and carcinomas differ substantially in the genetic abnormalities that drive their growth, findings relevant to treatment selection and outcome prediction. Several themes have emerged during the production process. One is the importance of the progression from hyperplasia to dysplasia to carcinoma in the evolution of the malignant process. Advances in imaging techniques and endoscopy have resulted in enhanced access to precancerous lesions in the gastrointestinal and biliary tract, necessitating both changes in classification schema and clinical practice. Diagnosis of tumours is no longer the sole purview of pathologists, and some patients now receive treatment before tissue is obtained, based on clinical, radiological and liquid biopsy results. This makes the classification relevant to many disciplines involved in the care of patients with tumours of the digestive system.

Rare cancers of unknown etiology: lessons learned from a European multi-center case-control study

Rare cancers together constitute one fourth of cancers. As some rare cancers are caused by occupational exposures, a systematic search for further associations might contribute to future prevention. We undertook a European, multi-center case–control study of occupational risks for cancers of small intestine, bone sarcoma, uveal melanoma, mycosis fungoides, thymus, male biliary tract and breast. Incident cases aged 35–69 years and sex-and age-matched population/colon cancer controls were interviewed, including a complete list of jobs. Associations between occupational exposure and cancer were assessed with unconditional logistic regression controlled for sex, age, country, and known confounders, and reported as odds ratios (OR) with 95% confidence intervals (CI). Interviewed were 1053 cases, 2062 population, and 1084 colon cancer controls. Male biliary tract cancer was associated with exposure to oils with polychlorinated biphenyls; OR 2.8 (95% CI 1.3–5.9); male breast cancer with exposure to trichloroethylene; OR 1.9 (95% CI 1.1–3.3); bone sarcoma with job as a carpenter/joiner; OR 4.3 (95% CI 1.7–10.5); and uveal melanoma with job as a welder/sheet metal worker; OR 1.95 (95% CI 1.08–3.52); and cook; OR 2.4 (95% CI 1.4–4.3). A confirmatory study of printers enhanced suspicion of 1,2-dichloropropane as a risk for biliary tract cancer. Results contributed to evidence for classification of welding and 1,2-dichloropronane as human carcinogens. However, despite efforts across nine countries, for some cancer sites only about 100 cases were interviewed. The Rare Cancer Study illustrated both the strengths and limitations of explorative studies for identification of etiological leads.

Prevalence of Small Intestine Carcinoid Tumors: A US Population-Based Study 2012-2017

BACKGROUND AND AIMS

Most carcinoid tumors of the gastrointestinal tract are located in the small bowel (SB). Epidemiological studies of these tumors have been limited by small sample sizes. Our aim was to evaluate the epidemiology of SB carcinoids (SBCs) using a large database.

METHODS

We queried a commercial database (Explorys), an aggregate of electronic health data from 26 US healthcare systems. We identified patients with SBCs between 2012 and 2017. We evaluated the epidemiology of SBC and identified possible risk factors.

RESULTS

Of the 35,798,290 individuals in the database between 2012 and 2017, we identified 3280 patients with SBCs, with a prevalence of 9.2/100,000. Prevalence was higher in men [odds ratio (OR) 1.23, 95% confidence interval (CI) 1.153-1.322, p < 0.0001], whites [OR 2.031, 95% CI 1.872-2.203, p < 0.0001], and elderly (aged > 65) [OR 4.856, 95% CI 4.533-5.203, p < 0.0001]. Patients with SBCs were more likely to have a history of smoking [OR 2.749, 95% CI 2.549-2.970, p < 0.0001], alcohol use [OR 2.031, 95% CI 1.864-2.21, p < 0.0001], obesity (BMI > 30) [OR 3.476, 95% CI 3.213-3.761, p < 0.0001], diabetes mellitus [OR 4.198, 95% CI 3.900-4.519, p < 0.0001], and a family history of cancer [OR 5.902, 95% CI 5.396-6.456, p < 0.0001].

CONCLUSIONS

This is one of the largest studies done on the prevalence of SBC. The prevalence of 9.2/100,000 individuals is higher than previously reported. Further genetic and environmental studies are needed to understand the potential mechanisms for the risk factors identified in this study.

Epidemiology of Cancers of the Small Intestine: Trends, Risk Factors, and Prevention

The latest data from the United States and Europe reveal that rare small intestine cancer is on the rise, with the number of cases having more than doubled over the past 40 years in the developed world. Mortality has grown at a slower pace, thanks to improvements in early diagnosis and treatment, as well as a shift in the etiology of neoplasms affecting the small intestine. Nevertheless, 5-year survival for small intestine adenocarcinomas has lingered at only 35%. Lifestyle in developed nations, including the rise in obesity and physical inactivity, consumption of alcohol, tobacco, and red and processed meats, and occupational exposures may be to blame for the proliferation of this rare cancer. Identification of hereditary and predisposing conditions, likely to blame for some 20% of cases, may help prevent and treat cancers of the small intestine. Studies of the neoplasm have been limited by small sample sizes due to the rarity of the disease, leaving many questions about prevention and treatment yet to be answered.

Occupational Class Groups as a Risk Factor for Gastrointestinal Cancer: A Case-Control Study

BACKGROUND

Cancer has a high mortality rate in both developing and developed countries. 11%-15% of cancers are attributable to occupational risk factors.

OBJECTIVE

To determine if specific occupational classes, based on the International Standard for Classification of Occupations 2008 (ISCO-08), are risk factors for gastrointestinal (GI) cancer.

METHODS

In this case-control study, 834 cancer patients were interviewed by a single physician. Cases included patients with GI cancer. Age-matched controls were selected from non-GI cancer patients. Each year of working, up until 5 years before the diagnosis, was questioned and categorized by the ISCO classification.

RESULTS

243 GI cancer cases and 243 non-GI cancer patients (486 in total) were studied. Working in ISCO class 8 (plant and machine operators, and assemblers) was significantly associated with higher risk of GI cancer (OR 1.63, 95% CI 1.05 to 2.52). Working in ISCO class 6 (skilled agricultural, forestry and fishery workers) and 9 (elementary occupations) were also associated with higher incidence of GI cancers.

CONCLUSION

Working in ISCO classes of 8, 6, and 9, which are usually associated with low socio-economic status, can be considered a risk factor for GI cancers.

Risk factors for neuroendocrine neoplasms: a systematic review and meta-analysis

BACKGROUND

Neuroendocrine neoplasms (NENs) are rare cancers mainly of lung and digestive tract. Little is known on risk factors. The aim of this work is to define the risk factors for NEN development by extensive review and meta-analysis of published data.

METHODS

The search was conducted on Medline, Scopus, and Web of Science following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses. The Newcastle-Ottawa scale was used for study quality. Meta-analyses were conducted by primary site. Odds ratio (OR), hazard ratio, risk ratio, standardized incidence ratio, and associated 95% confidence intervals (CIs) were abstracted. Data were combined and analyses carried out for risk factors considered by at least two studies. Random-effects model was adopted for study variation.

RESULTS

Of 1535 extracted articles, 24 were enrolled. Meta-analyses were possible for pancreas, small intestine, and rectum. Risk for NEN associated with: (i) family history of cancer at all investigated sites (lung, stomach, pancreas, small intestine, appendix, and colon; OR 2.12 [95% CI 1.40-3.22, I(2) = 0.0%, P = 0.681] at meta-analysis in pancreas); (ii) body mass index (BMI) or diabetes (stomach, pancreas, and small intestine; OR of 2.76 [95% CI 1.65-4.64, I(2) = 58.5%, P = 0.090] for diabetes at meta-analysis in pancreas); (iii) cigarette smoking (lung, stomach, pancreas, and small intestine; OR of 1.34 [95% CI 1.10-1.63, I(2) = 0.0%, P = 0.780] and of 1.59 [95% CI 1.07-2.37, I(2) = 32.9%, P = 0.225] for smokers versus never-smokers at meta-analysis for pancreas and small intestine); (iv) alcohol consumption (pancreas and rectum; OR of 2.44 [95% CI 1.07-5.59, I(2) = 65.8%, P = 0.054] and of 1.53 [95% CI 0.99-2.35, I(2) = 0.0%, P = 0.630] for heavy drinkers versus never-drinkers at meta-analysis for pancreas and rectum).

CONCLUSIONS

Family history of cancer is the most relevant risk factor for NEN development at all investigated sites, followed by BMI and diabetes. Cigarette smoking and alcohol consumption are potential risk factors for selected anatomical sites.

Epidemiology of cancer of the small intestine

Cancer of the small intestine is very uncommon. There are 4 main histological subtypes: adenocarcinomas, carcinoid tumors, lymphoma and sarcoma. The incidence of small intestine cancer has increased over the past several decades with a four-fold increase for carcinoid tumors, less dramatic rises for adenocarcinoma and lymphoma and stable sarcoma rates. Very little is known about its etiology. An increased risk has been noted for individuals with Crohn’s disease, celiac disease, adenoma, familial adenomatous polyposis and Peutz-Jeghers syndrome. Several behavioral risk factors including consumption of red or smoked meat, saturated fat, obesity and smoking have been suggested. The prognosis for carcinomas of the small intestine cancer is poor (5 years relative survival < 30%), better for lymphomas and sarcomas, and best for carcinoid tumors. There has been no significant change in long-term survival rates for any of the 4 histological subtypes. Currently, with the possible exceptions of obesity and cigarette smoking, there are no established modifiable risk factors which might provide the foundation for a prevention program aimed at reducing the incidence and mortality of cancers of the small intestine. More research with better quality and sufficient statistical power is needed to get better understanding of the etiology and biology of this cancer. In addition, more studies should be done to assess not only exposures of interest, but also host susceptibility.

Risk factors associated with neuroendocrine tumors: A U.S.-based case-control study

Carcinoids are rare neuroendocrine tumors (NETs); however, their incidence has significantly increased in the United States over the past 30 years. Little is known about the epidemiology of these cancers and their associated risk factors. We evaluated the independent effects of multiple risk factors associated with NETs arising at 5 disease sites (small intestine, stomach, lung, pancreas and rectum). We conducted a retrospective, hospital-based, case-control study involving 740 patients with histologically confirmed NETs and 924 healthy controls. Information on different risk factors was collected, and unconditional logistic regression analysis was used to determine adjusted odds ratios (AORs) and 95% confidence interval (CI) by the maximum-likelihood method. Smoking and alcohol consumption were not associated with NETs development in either men or women. However, a family history of cancer was a significant risk factor for all NETs. A long-term history of diabetes mellitus was a significant risk factor for gastric NETs (AOR = 5.6; 95% CI, 2.1-14.5), particularly in women (AOR = 8.4; 95% CI, 1.9-38.1). Diabetes modified the risk among women with a positive family history of cancer for the development of gastric NETs (AOR = 52.2; 95% CI, 5.5-491.5). Our results suggest that the risk of NETs may mostly explained by genetic factors. The increased risk of gastric NETs in women with both diabetes and a positive family history of cancer suggest that women may have a greater genetic susceptibility to NETs than men.

Cancer risk among Finnish food industry workers

Occupational cancer risks suggested among food industry workers are inconclusive. The objective of our study was to assess associations between different cancers and working in the food industry in Finland. The carcinogenic exposures are mainly inhalatory, and we were therefore interested in respiratory cancers in particular. We followed up a cohort of all economically active Finns born between 1906 and 1945 for 30 million person-years during 1971-95. The 1970 Census data on occupations were linked with data on subsequent incident cancer cases. Standardized incidence ratios (SIR) and 95% confidence intervals (CI) were calculated for each occupation using the economically active population as the reference. A total of 2,526 incident cancer cases were observed. Elevated risks were observed among male food industry workers for pancreatic (SIR=1.50, CI=1.13-1.96) and kidney cancers (1.51, 1.16-1.94). With respect to specific occupations, there was an excess of lung cancer among female bakers (1.38, 1.01-1.85) and laryngeal cancer among male grain millers (2.60, 1.05-5.36). Occupational exposure is unlikely to be a major risk factor for cancer among Finnish workers employed in typical food industry occupations.

Occupational factors and risk of adult bone sarcomas: a multicentric case-control study in Europe

We investigated the association between occupational factors and risk of bone sarcoma, a rare tumor with a largely unknown aetiology. A multicentric case-control study was conducted in 7 European countries in 1995-97. Ninety-six cases aged 35-69 years with a centrally reviewed diagnosis of bone sarcoma (68 chondrosarcomas and 28 osteosarcomas) were compared to 2,632 population (68%) or colon cancer (32%) controls. Subjects were interviewed to obtain information on occupational, medical and reproductive history, smoking and alcohol consumption and selected exposures including use of pesticides. Response proportions were 90% among cases and 66% among controls. Odds ratios (OR) and 95% confidence intervals (CI) were estimated for selected categories of job titles and branches of industry and for use of pesticides. We found an increased OR for bone sarcoma among blacksmiths, toolmakers, machine-tool operators (OR = 2.14, 95% CI 1.08-4.26), woodworkers (OR = 2.68, 95% CI 1.36-5.29) and construction workers (OR = 1.62, 95% CI 0.92-2.87). Ever users of pesticide had an OR of 2.33 (95% CI 1.31-4.13), with similar risks for exposure to insecticides and exposure to herbicides. Neither duration of employment in any of the analyzed occupational categories nor duration of use of pesticides showed an increasing trend in the risk of bone sarcoma. ORs of bone sarcoma were 1.03 (95% CI 0.23-4.57), 3.13 (95% CI 1.26-7.76) and 1.44 (95% CI 0.43-4.85) for the first, second and third tertile of days of use of pesticides. Our study suggests that novel and previously reported (woodworking) occupational factors play a role in the aetiology of bone sarcomas.

European multi-centre case-control study on risk factors for rare cancers of unknown aetiology

To search for occupational risk factors, we conducted a case-control study in nine European countries of cancers of the small intestine, male gall bladder, thymus, bone, male breast, melanoma of the eye, and mycosis fungoides. Recruitment was population based in Denmark, Latvia, France, Germany, Italy, and Sweden, from hospital areas in Spain and Portugal, and from one United Kingdom (UK) hospital. We recruited 1457 cases (84% interviewed). Numbers identified corresponded to those in the EUROCIM database for Denmark, but were below those observed for France, Italy and Sweden in the database. We recruited 3374 population (61% interviewed) and 1284 colon cancer controls (86% interviewed). It was possible to undertake this complicated study across Europe, but we encountered three main problems. It was difficult to ensure complete case ascertainment, for population controls, we found a clear divide in the response rate from 75% in the South to only 55% in the North, and a somewhat selective recruitment was noted for the colon cancer controls. The study showed there is a clear dose-response relationship between alcohol intake and the risk of male breast cancer, and an excess risk of mycosis fungoides among glass formers, pottery and ceramic workers. Further data are expected.

Epidemiology of neuroendocrine tumours

Neuroendocrine tumours account for only 0.5% of all malignancies. The incidence is approximately 2/100,000 with a female preponderance under the age of 50 years due to appendiceal location. The main primary sites are the gastrointestinal tract (62-67%) and the lung (22-27%). Presentation with metastatic disease accounts for 12-22%. In the last decades, the incidence has been rising. This might be due to more awareness, improved diagnostic tools or a change in definition. Most neuroendocrine tumours are mainly sporadic, but association with the multiple endocrine neoplasia type 1 syndrome and clustering within families is known. Also an increased risk of secondary cancers has been reported, but numbers are small. The 5-year survival is mainly associated with stage: 93% in local disease, 74% in regional disease and 19% in metastatic disease. In metastatic disease, survival increased since 1992, when treatment with octreotide became largely available in The Netherlands.