Cancers in Australia in 2010 attributable to modifiable factors: summary and conclusions

High-Grade Serous Ovarian Cancer: Basic Sciences, Clinical and Therapeutic Standpoints

Among a litany of malignancies affecting the female reproductive tract, that of the ovary is the most frequently fatal. Moreover, while the steady pace of scientific discovery has fuelled recent ameliorations in the outcomes of many other cancers, the rates of mortality for ovarian cancer have been stagnant since around 1980. Yet despite the grim outlook, progress is being made towards better understanding the fundamental biology of this disease and how its biology in turn influences clinical behaviour. It has long been evident that ovarian cancer is not a unitary disease but rather a multiplicity of distinct malignancies that share a common anatomical site upon presentation. Of these, the high-grade serous subtype predominates in the clinical setting and is responsible for a disproportionate share of the fatalities from all forms of ovarian cancer. This review aims to provide a detailed overview of the clinical-pathological features of ovarian cancer with a particular focus on the high-grade serous subtype. Along with a description of the relevant clinical aspects of this disease, including novel trends in treatment strategies, this text will inform the reader of recent updates to the scientific literature regarding the origin, aetiology and molecular-genetic basis of high-grade serous ovarian cancer (HGSOC).

High-Grade Serous Ovarian Cancer: Basic Sciences, Clinical and Therapeutic Standpoints

Among a litany of malignancies affecting the female reproductive tract, that of the ovary is the most frequently fatal. Moreover, while the steady pace of scientific discovery has fuelled recent ameliorations in the outcomes of many other cancers, the rates of mortality for ovarian cancer have been stagnant since around 1980. Yet despite the grim outlook, progress is being made towards better understanding the fundamental biology of this disease and how its biology in turn influences clinical behaviour. It has long been evident that ovarian cancer is not a unitary disease but rather a multiplicity of distinct malignancies that share a common anatomical site upon presentation. Of these, the high-grade serous subtype predominates in the clinical setting and is responsible for a disproportionate share of the fatalities from all forms of ovarian cancer. This review aims to provide a detailed overview of the clinical-pathological features of ovarian cancer with a particular focus on the high-grade serous subtype. Along with a description of the relevant clinical aspects of this disease, including novel trends in treatment strategies, this text will inform the reader of recent updates to the scientific literature regarding the origin, aetiology and molecular-genetic basis of high-grade serous ovarian cancer (HGSOC).

Proportion of cancer cases and deaths attributable to lifestyle risk factors in Brazil

BACKGROUND

Lifestyle risk factors (tobacco smoking, alcohol consumption, overweight and obesity, unhealthy diet, and lack of physical activity) have been associated with increased risk of at least 20 types of cancer. We estimated the proportion of cancer cases and deaths that could be potentially avoided by eliminating or reducing lifestyle risk factors in Brazil.

METHODS

We obtained the distribution of lifestyle risk factors by sex and age groups from recent representative health surveys in Brazil; relative risks from pooled analyses of prospective studies and meta-analyses; and cancer cases and deaths in 2012 from GLOBOCAN.

RESULTS

We found that 26.5% (114,497 cases) of all cancer cases and 33.6% (63,371 deaths) of all cancer deaths could be potentially avoided by eliminating lifestyle risk factors in Brazil. Plausible reductions in these exposures based on policy targets and cancer prevention recommendations could have potentially avoided 4.5% (19,731 cases) and 6.1% (11,480 deaths) of all cancer cases and deaths, respectively. Tobacco smoking accounted for most of the preventable cancer cases and deaths, followed by high body mass index and alcohol consumption. Larynx, lung, oropharynx, esophagus and colorectum cancer cases and deaths could be at least halved by eliminating these lifestyle risk factors.

CONCLUSION

Findings from this study may be useful to inform strategies for cancer prevention and control across Brazil.

Use of aspirin, other nonsteroidal anti-inflammatory drugs and acetaminophen and risk of endometrial cancer: the Epidemiology of Endometrial Cancer Consortium

BACKGROUND

Regular use of aspirin has been associated with a reduced risk of cancer at several sites but the data for endometrial cancer are conflicting. Evidence regarding use of other analgesics is limited.

PATIENTS AND METHODS

We pooled individual-level data from seven cohort and five case-control studies participating in the Epidemiology of Endometrial Cancer Consortium including 7120 women with endometrial cancer and 16 069 controls. For overall analyses, study-specific odds ratios (ORs) and 95% confidence intervals (CI) were estimated using logistic regression and combined using random-effects meta-analysis; for stratified analyses, we used mixed-effects logistic regression with study as a random effect.

RESULTS

At least weekly use of aspirin and non-aspirin nonsteroidal anti-inflammatory drugs (NSAIDs) was associated with an approximately 15% reduced risk of endometrial cancer among both overweight and obese women (OR = 0.86 [95% CI 0.76-0.98] and 0.86 [95% CI 0.76-0.97], respectively, for aspirin; 0.87 [95% CI 0.76-1.00] and 0.84 [0.74-0.96], respectively, for non-aspirin NSAIDs). There was no association among women of normal weight (body mass index < 25 kg/m2, Pheterogeneity = 0.04 for aspirin, Pheterogeneity = 0.003 for NSAIDs). Among overweight and obese women, the inverse association with aspirin was stronger for use 2-6 times/week (OR = 0.81, 95% CI 0.68-0.96) than for daily use (0.91, 0.80-1.03), possibly because a high proportion of daily users use low-dose formulations. There was no clear association with use of acetaminophen.

CONCLUSION

Our pooled analysis provides further evidence that use of standard-dose aspirin or other NSAIDs may reduce risk of endometrial cancer among overweight and obese women.

Trends in Colon and Rectal Cancer Incidence in Australia from 1982 to 2014: Analysis of Data on Over 375,000 Cases

BACKGROUND

Colorectal cancer is the third most commonly diagnosed cancer in Australia. Emerging evidence from several countries suggests increasing incidence in people aged <50 years.

METHODS

We assessed colon and rectal cancer incidence trends in people aged 20+ in Australia from 1982 to 2014. We used data on 375,008 incident cases (248,162 colon and 126,846 rectal). We quantified the annual percentage change (APC) in rates by age group using Joinpoint regression.

RESULTS

For people aged <50 years, colon cancer rates increased from the mid-2000s, with the increase in APCs ranging from 1.7% to 9.3% per annum (depending on specific age group); rectal cancer rates increased from the early 1990s, with APCs ranging from 0.9% to 7.1% per annum. For people aged 50 to 69 years, colon and rectal cancer rates decreased from the mid-1990s, with the decrease in APCs in specific age groups ranging from 0.8% to 4.8% per annum (except for colon cancer in those ages 65 to 69 years, where similar rate decreases were observed from 2007). An overall reduction in older persons (>70 years) was estimated at 1.9% to 4.9% per annum for colon cancer from 2010 onward and 1.1% to 1.8% per annum in rectal cancer from the early 2000s onward.

CONCLUSIONS

Colon and rectal cancer incidence has increased in people aged <50 years in Australia over the last two decades. However, colon and rectal cancer rates decreased in people aged 50+, likely due to de facto and organized bowel cancer screening.

IMPACT

Further research is needed to examine the cause of the increase and to quantify the impact of future trends on the cost-effectiveness of population-based screening for those <50 years.

Cancers related to lifestyle and environmental factors in France in 2015

BACKGROUND

Cancer is a major cause of premature illness and death in France. To quantify how cancer prevention could reduce the burden, we present estimates of the contribution of lifestyle and environmental risk factors to cancer incidence in France in 2015, comparing these with other high-income countries.

METHOD

Prevalences of, and relative risks for tobacco smoking, alcohol consumption, inadequate diet, overweight and obesity, physical inactivity, exogenous hormones, suboptimal breastfeeding, infectious agents, ionising radiation, air pollution, ultraviolet exposure, occupational exposures, arsenic in drinking water and indoor benzene were obtained to estimate the population attributable fraction (PAF) and the number of attributable cancers by the cancer site and sex.

RESULTS

In 2015, 41% (or 142,000 of 346,000) of all new cancers diagnosed in France could be attributed to the aforementioned risk factors. The numbers and PAF were slightly higher in men than in women (84,000 versus 58,000 cases and 44% versus 37%, respectively). Smoking (PAF: 20%), alcohol consumption (PAF: 8%), dietary factors (PAF: 5%) and excess weight (PAF: 5%) were the most important factors. Infections and occupational exposures each contributed to an additional 4% of the cancer cases in 2015.

CONCLUSION

Today, two-fifths of cancers in France are attributable to preventable risk factors. The variations in the key amenable factors responsible in France relative to other economically similar countries highlight the need for tailored approaches to cancer education and prevention. Reducing smoking and alcohol consumption and the adoption of healthier diet and body weight remain important targets to reduce the increasing number of new cancer patients in France in the decades to follow.

The future burden of lung cancer attributable to current modifiable behaviours: a pooled study of seven Australian cohorts

Background

Knowledge of preventable disease and differences in disease burden can inform public health action to improve health and health equity. We quantified the future lung cancer burden preventable by behavioural modifications across Australia.

Methods

We pooled seven Australian cohort studies (n = 367 058) and linked them to national registries to identify lung cancers and deaths. We estimated population attributable fractions and their 95% confidence intervals (CIs) for modifiable risk factors, using risk estimates from the cohort data and risk factor exposure distribution from contemporary national health surveys.

Results

During the first 10-year follow-up, there were 2025 incident lung cancers and 20 349 deaths. Stopping current smoking could prevent 53.7% (95% CI, 50.0-57.2%) of lung cancers over 40 years and 18.3% (11.0-25.1%) in 10 years. The smoking-attributable burden is highest in males, those who smoke <20 cigarettes per day, are <75 years of age, unmarried, of lower educational attainment, live in remote areas or are healthy weight. Increasing physical activity and fruit consumption, if causal, could prevent 15.6% (6.9-23.4%) and 7.5% (1.3-13.3%) of the lung cancer burden, respectively. Jointly, the three behaviour modifications could prevent up to 63.0% (58.0-67.5%) of lung cancers in 40 years, and 31.2% (20.9-40.1%) or 43 300 cancers in 10 years. The preventable burden is highest among those with multiple risk factors.

Conclusions

Smoking remains responsible for the highest burden of lung cancer in Australia. The uneven burden distribution distinguishes subgroups that could benefit the most from activities to control the world's deadliest cancer.

Hepatocellular carcinoma over three decades in Victoria, Australia: epidemiology, diagnosis and trends, 1984-2013

BACKGROUND

Liver cancer continues to be a health priority in Australia, with the majority attributable to preventable causes, and certain populations at higher risk.

AIMS

Epidemiological assessment of incidence, trends and distribution to inform prevention, and reassessment of data in light of recent changes to registry case definitions.

METHODS

Reported cases of hepatocellular carcinoma (HCC) in Victoria, Australia, 1984-2013, were obtained from the Victorian Cancer Registry. Demographic characteristics were examined, incidence and survival assessed using Poisson and Cox regression, and geographic distribution mapped. Incidence was compared before and after inclusion of non-histologically confirmed cases in Registry data to assess impacts on incidence trends.

RESULTS

Diagnoses of HCC rose substantially between 1984 and 2013, increasing sixfold from 0.9 to 5.9 per 100 000. The rate of increase per year accelerated from 5.3% between 1984 and 2003 to 9.5% between 2004 and 2013. Cases were disproportionately male (80%), median age at diagnosis was 66 years and 53% were born overseas. Even during 2004-2013, 5-year survival was only 16%, although higher among younger people, metropolitan residents and people born overseas. Incidence showed strong geographic clustering. The proportion of cases diagnosed clinically increased from 1% during 1984-2004 to 43% in 2009-2013. The revised case definition added 993 cases (27.3% of total).

CONCLUSION

Cases of HCC are becoming increasingly common, and revised incidence estimates highlight the impact of case definitions in the context of changing diagnostic approaches. The ongoing burden, disproportionate population distribution and low survival emphasise the importance of prevention and early detection as a public health imperative.

Cancers Due to Smoking and High Alcohol Consumption

BACKGROUND

Tobacco and alcohol consumption are known causes of cancer. We set out to estimate the absolute numbers and proportions of cancer attributable to smoking and high alcohol consumption in Germany in 2018.

METHODS

Numbers and proportions (population-attributable fractions, PAF) were calculated by sex and age group for ages 35 to 84 years based on population projections, national cancer incidence and exposure data, and published relative risks.

RESULTS

For the year 2018 we estimated the smoking-attributable cancer burden to be 85 072 cases (men 58 760, women 26 312), corresponding to 19% of all incident cancers. The highest PAF was seen for lung cancer: 89% of male and 83% of female lung cancer cases are attributable to smoking. The cancer burden attributable to high alcohol consumption was estimated to be 9588 (men 8117, women 1471) cases (2% of all incident cancers). The highest PAF were observed for cancer of the oral cavity and pharynx (men 34%, women 6%) and squamous cell carcinoma of the esophagus (men 30%; women 5%).

CONCLUSIONS

A considerable proportion of cancer cases are attributable to smoking and high alcohol consumption. More rigorous prevention efforts are required to achieve significant reductions in the prevalence of these risk factors and the attributable cancer burden.

Leitzmann M, Brenner*2 H, Mons*2 U. Cancers Due to Excess Weight, Low Physical Activity, and Unhealthy Diet

BACKGROUND

Excess weight, low physical activity, low intakes of dietary fiber, fruits, and vegetables, and high meat and salt intake increase cancer risk.

METHODS

Numbers and proportions (population-attributable fractions, PAF) of incident cancer cases in Germany in 2018 attributable to these factors were estimated by sex and age groups for ages 35 to 84 years using population projections, national cancer incidence and exposure data, and published risk estimates.

RESULTS

Estimated numbers (percentages) of attributable cancers were 30 567 (7%) for excess weight, 27 081 (6%) for low physical activity, 14 474 (3%) for low dietary fiber intake, 9447 (2%) for low fruit and vegetable consumption, 9454 (2%) and 1687 (0.4%) for processed meat and high red meat consumption, respectively, and 1204 (0.3%) for high salt intake. Excess weight substantially contributed to endometrial, renal, and liver cancer (PAF = 24 to 35%). Low physical activity contributed to endometrial, renal, and lung cancer (PAF = 15 to 19%), and dietary factors mainly contributed to colorectal, breast, and lung cancer (PAF = 9 to 16%).

CONCLUSION

A considerable proportion of cancer cases are attributable to excess weight, physical inactivity, and unhealthy dietary habits. Major prevention efforts are needed to reduce the cancer incidence attributable to these avoidable factors.

Main and interactive effects of physical activity, fitness and body mass in the prevention of cancer from the Copenhagen Male Study

Little knowledge exists about the role of cardiorespiratory fitness (CRF) or its interaction with excess adiposity determined by body mass index (BMI) in cancer prevention. A total of 5,128 middle-aged men, without a history of cancer at baseline in 1970–71, were examined for subsequent incidence and mortality of several cancer types. Participants’ data were linked with cancer registration and mortality data to March 2017. During 47 years of follow-up, a total of 1,920 incident cases and 1,638 cancer-related deaths were ascertained. BMI, particularly obesity, was associated with (i) incidence and (ii) mortality from respiratory/thoracic cancers; and (iii) all cancer-cause mortality. The respective adjusted hazard ratios (HRs) were: (i) 0.51 (95%CI:0.32–0.79), (ii) 0.48 (95%CI:0.30–0.75) and (iii) 0.73 (95%CI:0.59–0.89) when compared obese men (BMI ≥30 kg/m²) to men with healthy-BMI (<25 kg/m²). Increasing CRF was inversely associated with incidence and mortality of respiratory/thoracic cancers, HRs 0.78 (95%CI:0.67–0.90) and 0.73 (95%CI:0.63–0.84) respectively; and all cancer-cause incidence 0.92 (95%CI:0.86–0.98) and mortality 0.85 (95%CI:0.79–0.91). Physical activity (PA) was not associated with most outcomes. We found no evidence of interactions between CRF or PA and BMI on cancer risk. This evidence suggests that midlife CRF is associated with lowered risk of cancer incidence and mortality with no evidence of cancer risk modification by BMI.

The Future Colorectal Cancer Burden Attributable to Modifiable Behaviors: A Pooled Cohort Study

BACKGROUND

Previous estimates of the colorectal cancer (CRC) burden attributed to behaviors have not considered joint effects, competing risk, or population subgroup differences.

METHODS

We pooled data from seven prospective Australian cohort studies (n = 367 058) and linked them to national registries to identify CRCs and deaths. We estimated the strength of the associations between behaviors and CRC risk using a parametric piecewise constant hazards model, adjusting for age, sex, study, and other behaviors. Exposure prevalence was estimated from contemporary National Health Surveys. We calculated population attributable fractions for CRC preventable by changes to current behaviors, accounting for competing risk of death and risk factor interdependence. Statistical tests were two-sided.

RESULTS

During the first 10 years of follow-up, there were 3471 incident CRCs. Overweight or obesity explained 11.1%, ever smoking explained 10.7% (current smoking 3.9%), and drinking more than two compared with two or fewer alcoholic drinks per day explained 5.8% of the CRC burden. Jointly, these factors were responsible for 24.9% (95% confidence interval [CI] = 19.7% to 29.9%) of the burden, higher for men (36.7%) than women (13.2%, P difference < .001). The burden attributed to these factors was also higher for those born in Australia (28.7%) than elsewhere (16.8%, P difference = .047). We observed modification of the smoking-attributable burden by alcohol consumption and educational attainment, and modification of the obesity-attributable burden by age group and birthplace.

CONCLUSIONS

We produced up-to-date estimates of the future CRC burden attributed to modifiable behaviors. We revealed novel differences between men and women, and other high-CRC burden subgroups that could potentially benefit most from programs that support behavioral change and early detection.

Environment, cancer and inequalities-The urgent need for prevention

The proportion of total deaths attributable to environmental factors is estimated to be 23% of global deaths and 22% of global disability-adjusted life years (DALYs) according to one review. These estimates encompass all environmental agents including infectious agents but excluding behavioural factors. The authors of the review also estimated that 16% (95% CI: 7-41%) of cancer deaths are attributable to environmental risk factors (and 36% [95% CI: 17-52%] for lung cancer). In this article, we focus on the reasons why epidemiology is often unable to account for the whole burden of environmental carcinogens. The experience of air pollution is particularly instructive. While in the 1970s and early 1980s, air pollution was considered as a relatively marginal exposure in terms of attributable risks, the most recent estimate is that it accounts for 7.6% of global deaths and 4.2% of global DALYs world-wide (with East and South Asia accounting for 59% of the total). According to a review, ambient fine particulate matter air pollution contributed to 17.1% of ischaemic heart disease, 14.2% of cerebrovascular disease, 16.5% of lung cancer, 24.7% of low respiratory infections, and 27.1% of COPD mortality in 2015. Estimates for cancer as a whole are not available. The change in appreciation of the role of air pollution has been mainly due to the refinement of exposure assessment methods and the new generations of longitudinal studies. Mechanistic evidence via omic technologies is now rapidly increasing, thus lending credibility to previous epidemiological ('black box') associations. Much less is known about other environmental contaminants, some of which are widespread and pervasive, thus suggesting the need for the same rigourous methods as those applied to air pollution. Finally, a crucial issue remains inequality across different population groups, with uneven exposure to hazards and acquired susceptibilities due to multiple concomitant exposures and poorer health status.

Novel Approaches To Undergraduate Oncology Education

With the increasing incidence of cancer and related survival, junior doctors are more commonly involved the management of oncology patients. A comprehensive oncology curriculum has been developed and adopted across medi-cal schools in Australia. However, it was not designed to inform how medical students should be taught, and whether curriculum content translates to knowledge and competency can depend on its implementation. We have conducted a literature review of PubMed, Embase and Cochrane databases to identify and summarise the evidence for novel approaches to delivering the undergraduate oncology curriculum. Numerous effective approaches have been developed across areas of prevention, clinical examination through simulation, the multidisciplinary team, psycho-oncology, palliative care and even research. There is growing focus on a holistic and multidisciplinary approach to cancer education although direct clinical exposure and interactions with cancer patients is still crucial. Medical schools may also have an under-recognised role in promoting positive health behaviour if their graduates are to convey these preventative measures to their patients. Application of such methods relies upon clinicians and medical educators to consider the practicability and relevance of specific implementation in their local context.

Low adherence to the western and high adherence to the mediterranean dietary patterns could prevent colorectal cancer

PURPOSE

To assess if the associations found between three previously identified dietary patterns with breast, prostate and gastric cancer are also observed for colorectal cancer (CRC).

METHODS

MCC-Spain is a multicase-control study that collected information of 1629 incident cases of CRC and 3509 population-based controls from 11 Spanish provinces. Western, Prudent and Mediterranean data-driven dietary patterns-derived in another Spanish case-control study-were reconstructed in MCC-Spain. Their association with CRC was assessed using mixed multivariable logistic regression models considering a possible interaction with sex. Risk by tumor site (proximal colon, distal colon, and rectum) was evaluated using multinomial regression models.

RESULTS

While no effect of the Prudent pattern on CRC risk was observed, a high adherence to the Western dietary pattern was associated with increased CRC risk for both males [OR_{fourth(Q4) vs. first(Q1)quartile} (95% CI): 1.45 (1.11;1.91)] and females [OR_{Q4 vs. Q1} (95% CI): 1.50 (1.07;2.09)] but seem to be confined to distal colon [OR_{fourth(Q4) vs. first(Q1)quartile} (95% CI): 2.02 (1.44;2.84)] and rectal [OR_{Q4 vs. Q1} (95% CI): 1.46 (1.05;2.01)] tumors. The protective effect of the Mediterranean dietary pattern against CRC was observed for both sexes [males: OR_{Q4 vs. Q1} (95% CI): 0.71 (0.55;0.92); females: OR_{Q4 vs. Q1} (95% CI): 0.56 (0.40;0.77)] and for all cancer sites: proximal colon [OR_{Q4 vs. Q1} (95% CI): 0.70 (0.51;0.97)], distal colon [OR_{Q4 vs. Q1} (95% CI): 0.65 (0.48;0.89)], and rectum (OR_{Q4 vs. Q1} (95% CI): 0.60 (0.45;0.81)].

CONCLUSION

Our results are consistent with most of the associations previously found between these patterns and breast, prostate and gastric cancer risk and indicate that consuming whole fruits, vegetables, legumes, olive oil, nuts, and fish and avoiding red and processed meat, refined grains, sweets, caloric drinks, juices, convenience food, and sauces might reduce CRC risk.

The fraction of cancer attributable to modifiable risk factors in England, Wales, Scotland, Northern Ireland, and the United Kingdom in 2015

BACKGROUND

Changing population-level exposure to modifiable risk factors is a key driver of changing cancer incidence. Understanding these changes is therefore vital when prioritising risk-reduction policies, in order to have the biggest impact on reducing cancer incidence. UK figures on the number of risk factor-attributable cancers are updated here to reflect changing behaviour as assessed in representative national surveys, and new epidemiological evidence. Figures are also presented by UK constituent country because prevalence of risk factor exposure varies between them.

METHODS

Population attributable fractions (PAFs) were calculated for combinations of risk factor and cancer type with sufficient/convincing evidence of a causal association. Relative risks (RRs) were drawn from meta-analyses of cohort studies where possible. Prevalence of exposure to risk factors was obtained from nationally representative population surveys. Cancer incidence data for 2015 were sourced from national data releases and, where needed, personal communications. PAF calculations were stratified by age, sex and risk factor exposure level and then combined to create summary PAFs by cancer type, sex and country.

RESULTS

Nearly four in ten (37.7%) cancer cases in 2015 in the UK were attributable to known risk factors. The proportion was around two percentage points higher in UK males (38.6%) than in UK females (36.8%). Comparing UK countries, the attributable proportion was highest in Scotland (41.5% for persons) and lowest in England (37.3% for persons). Tobacco smoking contributed by far the largest proportion of attributable cancer cases, followed by overweight/obesity, accounting for 15.1% and 6.3%, respectively, of all cases in the UK in 2015. For 10 cancer types, including two of the five most common cancer types in the UK (lung cancer and melanoma skin cancer), more than 70% of UK cancer cases were attributable to known risk factors.

CONCLUSION

Tobacco and overweight/obesity remain the top contributors of attributable cancer cases. Tobacco smoking has the highest PAF because it greatly increases cancer risk and has a large number of cancer types associated with it. Overweight/obesity has the second-highest PAF because it affects a high proportion of the UK population and is also linked with many cancer types. Public health policy may seek to mitigate the level of harm associated with exposure or reduce exposure levels-both approaches may effectively impact cancer incidence. Differences in PAFs between countries and sexes are primarily due to varying prevalence of exposure to risk factors and varying proportions of specific cancer types. This variation in turn is affected by socio-demographic differences which drive differences in exposure to theoretically avoidable 'lifestyle' factors. PAFs at UK country level have not been available previously and they should be used by policymakers in devolved nations. PAFs are estimates based on the best available data, limitations in those data would generally bias toward underestimation of PAFs. Regular collection of risk factor exposure prevalence data which corresponds with epidemiological evidence is vital for analyses like this and should remain a priority for the UK Government and devolved Administrations.

Environmental contributions to gastrointestinal and liver cancer in the Asia-Pacific region

In the Asia-Pacific region, gastric, colorectal, and hepatocellular (liver) cancer show substantial regional variation in incidence consistent with the presence of important environmental factors. For gastric cancer, global incidence is concentrated in Asia with substantially higher rates in East Asia than in South-East Asia and Australia. The differences in incidence rates for gastric cancer in the Asia-Pacific region may be due, in part, to differences in the prevalence of Helicobacter pylori infection and the prevalence of H. pylori virulence factors. Smoking is also correlated with gastric cancer risk and is responsible for the highest population attributable fraction among men in East Asia. Colorectal cancer has increased rapidly in incidence to become the third most common digestive cancer in Asia. According to cohort studies in Asia, smoking, alcohol use, obesity, and physical inactivity increase the risk of colorectal cancer. Unlike West Asia, East Asia and Australia have high incidence rates for colorectal cancer that correlates to a high Human Development Index and a high prevalence of alcohol consumption and obesity. Liver cancer is the second most common digestive cancer in Asia. The high incidence of liver cancer in East Asia and South-East Asia is concordant with the high prevalence of hepatitis B virus and hepatitis C virus infection. Other important risk factors include alcohol use, smoking, and diabetes. The identification of the earlier and other environmental factors (currently under investigation) is central to the development and implementation of effective cancer control programs for the region.

Evaluation of the Cancer Council NSW Eat It To Beat It Healthy Lunch Box Sessions: A short intervention to promote the intake of fruit and vegetables among families of primary school children in NSW Australia

ISSUE ADDRESSED

Children and adults in Australia are not eating the recommended amounts of fruits and vegetables. Our objective was to assess the effectiveness of a health promotion intervention to improve fruit and vegetable intake among primary school children and their families in NSW.

METHODS

The Cancer Council New South Wales Healthy Lunch Box sessions were a 25-minute session delivered to parents of primary school-aged children. The sessions provided information and resources about fruit and vegetables and healthy school lunch boxes. The evaluation is a quantitative uncontrolled pre-post design. Data were collected using three questionnaires, pre-intervention, 1 week post-intervention and 6 months post-intervention.

RESULTS

A total of 204 parents completed all three evaluation questionnaires to 6 months. Knowledge of recommended intakes and serving sizes of fruit and vegetables improved significantly after the intervention. There was an increase in parents reporting packing vegetables (often/always) in the child's lunch box at 1 week (47%) and 6 months post-intervention (40%) compared to pre-intervention (32%). The proportion of parents reporting that they were confident in packing a healthy lunch box increased from 45% pre-intervention to 62% after the intervention.

CONCLUSION

The Healthy Lunch Box sessions were effective in improving parental knowledge and practices related to fruit and vegetables and parental confidence with packing a healthy lunch box. SO WHAT?: This short intervention could be a useful component of a portfolio of interventions to support parents with knowledge and resources to pack a healthy lunch box for their children.

Smokers versus Smoking: Is There Detection Bias for Keratinocyte Carcinomas?

Dusingize et al. used a prospective observational cohort study to demonstrate a decreased risk of basal cell carcinoma and an increased risk of squamous cell carcinoma among smokers. This association disappeared after stratifying for skin screening visits, demonstrating the important role of detection bias. In the absence of randomized clinical trials, well-designed and critically analyzed observational studies can provide similarly valuable evidence.

Identification of cancer risk and associated behaviour: implications for social marketing campaigns for cancer prevention

BACKGROUND

Community misconception of what causes cancer is an important consideration when devising communication strategies around cancer prevention, while those initiating social marketing campaigns must decide whether to target the general population or to tailor messages for different audiences. This paper investigates the relationships between demographic characteristics, identification of selected cancer risk factors, and associated protective behaviours, to inform audience segmentation for cancer prevention social marketing.

METHODS

Data for this cross-sectional study (n = 3301) are derived from Cancer Council New South Wales' 2013 Cancer Prevention Survey. Descriptive statistics and logistic regression models were used to investigate the relationship between respondent demographic characteristics and identification of each of seven cancer risk factors; demographic characteristics and practice of the seven 'protective' behaviours associated with the seven cancer risk factors; and identification of cancer risk factors and practising the associated protective behaviours, controlling for demographic characteristics.

RESULTS

More than 90% of respondents across demographic groups identified sun exposure and smoking cigarettes as moderate or large cancer risk factors. Around 80% identified passive smoking as a moderate/large risk factor, and 40-60% identified being overweight or obese, drinking alcohol, not eating enough vegetables and not eating enough fruit. Women and older respondents were more likely to identify most cancer risk factors as moderate/large, and to practise associated protective behaviours. Education was correlated with identification of smoking as a moderate/large cancer risk factor, and with four of the seven protective behaviours. Location (metropolitan/regional) and country of birth (Australia/other) were weak predictors of identification and of protective behaviours. Identification of a cancer risk factor as moderate/large was a significant predictor for five out of seven associated cancer-protective behaviours, controlling for demographic characteristics.

CONCLUSIONS

These findings suggest a role for both audience segmentation and whole-of-population approaches in cancer-prevention social marketing campaigns. Targeted campaigns can address beliefs of younger people and men about cancer risk factors. Traditional population campaigns can enhance awareness of being overweight, alcohol consumption, and poor vegetable and fruit intake as cancer risk factors.

Exploring the provision of alcohol advice by clinicians to breast cancer patients

Interactions between clinicians and patients along the cancer trajectory provide an opportunity to deliver key messages regarding drinking behaviours and long-term health. This study aimed to explore the extent and nature of clinician-patient discussions regarding alcohol intake and cancer outcomes in the clinical breast cancer setting, using a qualitative research design involving semi-structured interviews. Purposive sampling was used to recruit 27 breast cancer clinicians (eight dietitians, nine breast care nurses, 10 oncologists) across Victoria, Australia. Interview data were analysed using descriptive statistics and a content analysis approach. Clinicians' knowledge of national alcohol recommendations was found to be inconsistent. Clinicians reported a lack of patient awareness of the link between alcohol and breast cancer. Current frameworks for assessing and advising on patient alcohol intake were felt to be impractical. The extent and nature of advice provided about alcohol was influenced by several patient and clinician factors. The provision of alcohol advice in the clinical breast cancer setting is not practiced systematically by any professional group. New approaches are needed to support patient education about alcohol intake and survivorship in the clinical oncology setting.

Cancer incidence attributable to lifestyle and environmental factors in Alberta in 2012: summary of results

BACKGROUND

Estimates of the proportion of cancer cases that can be attributed to modifiable risk factors are not available for Canada and, more specifically, Alberta. The purpose of this study was to estimate the total proportion of cancer cases in Alberta in 2012 that could be attributed to a set of 24 modifiable lifestyle and environmental risk factors.

METHODS

We estimated summary population attributable risk estimates for 24 risk factors (smoking [both passive and active], overweight and obesity, inadequate physical activity, diet [inadequate fruit and vegetable consumption, inadequate fibre intake, excess red and processed meat consumption, salt consumption, inadequate calcium and vitamin D intake], alcohol, hormones [oral contraceptives and hormone therapy], infections [Epstein-Barr virus, hepatitis B and C viruses, human papillomavirus, Helicobacter pylori], air pollution, natural and artificial ultraviolet radiation, radon and water disinfection by-products) by combining population attributable risk estimates for each of the 24 factors that had been previously estimated. To account for the possibility that individual cancer cases were the result of a combination of multiple risk factors, we subtracted the population attributable risk for the first factor from 100% and then applied the population attributable risk for the second factor to the remaining proportion that was not attributable to the first factor. We repeated this process in sequential order for all relevant exposures.

RESULTS

Overall, an estimated 40.8% of cancer cases in Alberta in 2012 were attributable to modifiable lifestyle and environmental risk factors. The largest proportion of cancers were estimated to be attributable to tobacco smoking, physical inactivity and excess body weight. The summary population attributable risk estimate was slightly higher among women (42.4%) than among men (38.7%).

INTERPRETATION

About 41% of cancer cases in Alberta may be attributable to known modifiable lifestyle and environmental risk factors. Reducing the prevalence of these factors in the Alberta population has the potential to substantially reduce the provincial cancer burden.

The burden of cancer attributable to modifiable risk factors: the Australian cancer-PAF cohort consortium

PURPOSE

To estimate the Australian cancer burden attributable to lifestyle-related risk factors and their combinations using a novel population attributable fraction (PAF) method that accounts for competing risk of death, risk factor interdependence and statistical uncertainty.

PARTICIPANTS

365 173 adults from seven Australian cohort studies. We linked pooled harmonised individual participant cohort data with population-based cancer and death registries to estimate exposure-cancer and exposure-death associations. Current Australian exposure prevalence was estimated from representative external sources. To illustrate the utility of the new PAF method, we calculated fractions of cancers causally related to body fatness or both tobacco and alcohol consumption avoidable in the next 10 years by risk factor modifications, comparing them with fractions produced by traditional PAF methods.

FINDINGS TO DATE

Over 10 years of follow-up, we observed 27 483 incident cancers and 22 078 deaths. Of cancers related to body fatness (n=9258), 13% (95% CI 11% to 16%) could be avoided if those currently overweight or obese had body mass index of 18.5-24.9 kg/m2. Of cancers causally related to both tobacco and alcohol (n=4283), current or former smoking explains 13% (11% to 16%) and consuming more than two alcoholic drinks per day explains 6% (5% to 8%). The two factors combined explain 16% (13% to 19%): 26% (21% to 30%) in men and 8% (4% to 11%) in women. Corresponding estimates using the traditional PAF method were 20%, 31% and 10%. Our PAF estimates translate to 74 000 avoidable body fatness-related cancers and 40 000 avoidable tobacco- and alcohol-related cancers in Australia over the next 10 years (2017-2026). Traditional PAF methods not accounting for competing risk of death and interdependence of risk factors may overestimate PAFs and avoidable cancers.

FUTURE PLANS

We will rank the most important causal factors and their combinations for a spectrum of cancers and inform cancer control activities.

Causality in cancer research: a journey through models in molecular epidemiology and their philosophical interpretation

In the last decades, Systems Biology (including cancer research) has been driven by technology, statistical modelling and bioinformatics. In this paper we try to bring biological and philosophical thinking back. We thus aim at making different traditions of thought compatible: (a) causality in epidemiology and in philosophical theorizing-notably, the "sufficient-component-cause framework" and the "mark transmission" approach; (b) new acquisitions about disease pathogenesis, e.g. the "branched model" in cancer, and the role of biomarkers in this process; (c) the burgeoning of omics research, with a large number of "signals" and of associations that need to be interpreted. In the paper we summarize first the current views on carcinogenesis, and then explore the relevance of current philosophical interpretations of "cancer causes". We try to offer a unifying framework to incorporate biomarkers and omic data into causal models, referring to a position called "evidential pluralism". According to this view, causal reasoning is based on both "evidence of difference-making" (e.g. associations) and on "evidence of underlying biological mechanisms". We conceptualize the way scientists detect and trace signals in terms of information transmission, which is a generalization of the mark transmission theory developed by philosopher Wesley Salmon. Our approach is capable of helping us conceptualize how heterogeneous factors such as micro and macro-biological and psycho-social-are causally linked. This is important not only to understand cancer etiology, but also to design public health policies that target the right causal factors at the macro-level.

Obesity as an Avoidable Cause of Cancer (Attributable Risks)

Excess body weight, commonly categorised as overweight (body mass index, BMI 25.0-29.9 kg/m2) and obesity (BMI ≥30 kg/m2) is an established risk factor for increased incidence of several adult cancers. As body weight is modifiable, there is a potential for cancer prevention. Calculation of attributable risk (here expressed at population attributable fraction, PAF) offers an estimate of the burden of excess cancers attributable to elevated BMI in populations, and thus an approximation of avoidable cases and the opportunity for prevention. Using counterfactual methods, the estimated PAF worldwide attributed to elevated BMI is 3.6 % or nearly half a million new cancer cases in adults (aged 30 years and older after a 10-year lag period). PAFs are higher in women compared with men (5.4 % vs. 1.9 %). Endometrial, post-menopausal breast, and colon cancers account for nearly two-thirds of cancers attributable to elevated BMI. Globally, excess body weight is the third commonest attributable risk factor for cancer (after smoking and infection); in western populations such as the UK, excess weight ranks as second commonest risk factor.

Precision in Setting Cancer Prevention Priorities: Synthesis of Data, Literature, and Expert Opinion

Cancer will continue to be a leading cause of ill health and death unless we can capitalize on the potential for 30-40% of these cancers to be prevented. In this light, cancer prevention represents an enormous opportunity for public health, potentially saving much of the pain, anguish, and cost associated with treating cancer. However, there is a challenge for governments, and the wider community, in prioritizing cancer prevention activities, especially given increasing financial constraints. This paper describes a method for identifying cancer prevention priorities. This method synthesizes detailed cancer statistics, expert opinion, and the published literature for the priority setting process. The process contains four steps: assessing the impact of cancer types; identifying cancers with the greatest impact; considering opportunities for prevention; and combining information on impact and preventability. The strength of our approach is that it is straightforward, transparent and reproducible for other settings. Applying this method in Western Australia produced a priority list of seven adult cancers which were identified as having not only the biggest impact on the community but also the best opportunities for prevention. Work conducted in an additional project phase went on to present data on these priority cancers to a public consultation and develop an agenda for action in cancer prevention.

Burden of Cancers Attributable to Infectious Agents in Nigeria: 2012-2014

Introduction

Infections by certain viruses, bacteria, and parasites have been identified as risk factors for some cancers. In Nigeria, like many other developing countries, infections remain a leading cause of morbidity and mortality. While there are data on the incidence of different cancers in Nigeria, there has been no study of cancers attributable to infections. This study was carried out to determine the burden of cancers attributable to infections using data from two population-based cancer registries (PBCRs) in Nigeria.

Methods

We obtained data on cancers associated with EBV, human papillomavirus (HPV), hepatitis B and C, HIV, HHV8, Helicobacter pylori, and Schistosoma spp. from the databases of Abuja and Enugu cancer registries in Nigeria. We used population-attributable fraction for infections-associated cancers in developing countries that are based on prevalence data and relative risk estimates from previous studies.

Results

The PBCRs reported 4,336 incident cancer cases [age standardized incidence rate (ASR) 113.9 per 100,000] from 2012 to 2014, of which 1,627 (37.5%) were in males and 2,709 (62.5%) were in females. Some 1,030 (23.8%) of these cancers were associated with infections (ASR 44.4 per 100,000), while 951 (22.0%) were attributable to infections (ASR 41.6 per 100,000). Cancers of the cervix (n = 392, ASR 28.3 per 100,000) and liver (n = 145, ASR 3.4 per 100,000); and non-Hodgkin’s lymphoma (n = 110, ASR 2.5 per 100,000) were the commonest infections-associated cancers overall. The commonest infectious agents associated with cancers in this population were HPV, EBV, hepatitis B and C, HIV, and HHV8.

Conclusion

Our results suggest that 23.8% of incident cancer cases in this population were associated with infections, while 22.0% were attributable to infections. The infections attributable cancers are potentially preventable with strategies, such as vaccination, risk factor modification, or anti-infective treatment.

Population Attributable and Preventable Fractions: Cancer Risk Factor Surveillance, and Cancer Policy Projection

The proportions of new cancer cases and deaths that are caused by exposure to risk factors and that could be prevented are key statistics for public health policy and planning. This paper summarizes the methodologies for estimating, challenges in the analysis of, and utility of, population attributable and preventable fractions for cancers caused by major risk factors such as tobacco smoking, dietary factors, high body fat, physical inactivity, alcohol consumption, infectious agents, occupational exposure, air pollution, sun exposure, and insufficient breastfeeding. For population attributable and preventable fractions, evidence of a causal relationship between a risk factor and cancer, outcome (such as incidence and mortality), exposure distribution, relative risk, theoretical-minimum-risk, and counterfactual scenarios need to be clearly defined and congruent. Despite limitations of the methodology and the data used for estimations, the population attributable and preventable fractions are a useful tool for public health policy and planning.

Designing a Healthy Food Partnership: lessons from the Australian Food and Health Dialogue

Background

Poor diets are a leading cause of disease burden worldwide. In Australia, the Federal Government established the Food and Health Dialogue (the Dialogue) in 2009 to address this issue, primarily through food reformulation. We evaluated the Dialogue’s performance over its 6 years of operation and used these findings to develop recommendations for the success of the new Healthy Food Partnership.

Methods

We used information from the Dialogue website, media releases, communiqués, e-newsletters, materials released under freedom-of-information, and Parliamentary Hansard to evaluate the Dialogue’s achievements from October 2013 to November 2015, using the RE-AIM (reach, efficacy, adoption, implementation and maintenance) framework. We also engaged closely with two former Dialogue members. Our findings update a prior assessment done in October 2013.

Results

Little data is available to evaluate the Dialogue’s recent achievements, with no information about progress against milestones released since October 2013. In the last 2 years, only one additional set of sodium reduction targets (cheese) was agreed and Quick Service Restaurant foods were added as an area for action. Some activity was identified in 12 of a possible 137 (9 %) areas of action within the Dialogue’s mandate. Independent evaluation found targets were partially achieved in some food categories, with substantial variation in success between companies. No effects on the knowledge, behaviours or nutrient intake of the Australian population or evidence of impact on diet-related disease could be identified.

Conclusions

The new Healthy Food Partnership has similar goals to the Dialogue. While highly laudable and recognised globally as cost-effective, the mechanism for delivery in Australia has been woefully inadequate. Strong government leadership, adequate funding, clear targets and timelines, management of conflict of interest, comprehensive monitoring and evaluation, and a plan for responsive regulation in the event of missed milestones will be required if the new Healthy Food Partnership is to achieve its urgent public health goals.

Cancers in Australia in 2010 attributable to modifiable factors: introduction and overview

OBJECTIVE

To describe the approach underpinning a national project to estimate the numbers and proportions of cancers occurring in Australia in 2010 that are attributable to modifiable causal factors.

METHODS

We estimated the population attributable fraction (PAF) (or prevented fraction) of cancers associated with exposure to causal (or preventive) factors using standard formulae. Where possible, we also estimated the potential impact on cancer incidence resulting from changes in prevalence of exposure. Analyses were restricted to factors declared causal by international agencies: tobacco smoke; alcohol; solar radiation; infectious agents; obesity; insufficient physical activity; insufficient intakes of fruits, vegetables and fibre; red and processed meat; menopausal hormone therapy (MHT); oral contraceptive pill (OCP); and insufficient breast feeding. Separately, we estimated numbers of cancers prevented by: aspirin; sunscreen; MHT; and OCP use. We discuss assumptions pertaining to latent periods between exposure and cancer onset, choices of prevalence data and risk estimates, and approaches to sensitivity analyses.

RESULTS

Numbers and population attributable fractions of cancer are presented in accompanying papers.

CONCLUSIONS

This is the first systematic assessment of population attributable fractions of cancer in Australia.

The Fraction of Cancer Attributable to Ways of Life, Infections, Occupation, and Environmental Agents in Brazil in 2020

Many human cancers develop as a result of exposure to risk factors related to the environment and ways of life. The aim of this study was to estimate attributable fractions of 25 types of cancers resulting from exposure to modifiable risk factors in Brazil. The prevalence of exposure to selected risk factors among adults was obtained from population-based surveys conducted from 2000 to 2008. Risk estimates were based on data drawn from meta-analyses or large, high quality studies. Population-attributable fractions (PAF) for a combination of risk factors, as well as the number of preventable deaths and cancer cases, were calculated for 2020. The known preventable risk factors studied will account for 34% of cancer cases among men and 35% among women in 2020, and for 46% and 39% deaths, respectively. The highest attributable fractions were estimated for tobacco smoking, infections, low consumption of fruits and vegetables, excess weight, reproductive factors, and physical inactivity. This is the first study to systematically estimate the fraction of cancer attributable to potentially modifiable risk factors in Brazil. Strategies for primary prevention of tobacco smoking and control of infection and the promotion of a healthy diet and physical activity should be the main priorities in policies for cancer prevention in the country.