What does it mean to understand a risk? Evaluating risk comprehension

Risk communications are frequently intended to help people understand hazards they face, with the hope that this understanding will help them make better decisions about the need for action or help them choose among alternative actions. To evaluate the success of such communications, a definition of "understanding" is needed. This paper suggests that decisions about personal risks require, at a minimum, information about the nature and likelihood of potential ill effects, information about the risk factors that modify one's susceptibility, and information about the ease or difficulty of avoiding harm. Even if these attributes are accepted as essential criteria for understanding, research on risk perceptions suggests that assessing what people know or believe is sometimes quite difficult. The focus of the paper is on the several dimensions of risk comprehension. Examples of how each can be assessed are drawn from research on public perceptions of the risks from smoking. These examples demonstrate that the public has only a limited understanding of smoking risks.     

Implications for improving risk communication through various channels: a discussion

The news media need to improve their coverage of new and old cancer risks, avoiding sensational reporting of minor risks and underreporting of major ones. However, efforts to communicate about cancer risk to the general public need to go far beyond the traditional print and broadcast outlets into more innovative, personalized channels that can better educate individuals about the risks they face and what they can do about them.     

Human Carcinogens So Far Identified

The massive exploitation of natural resources, of which tobacco and asbestos are two conspicuous, though very different examples, and the synthesis of industrial chemicals have generated new hazards and new carcinogens which have been added to older ones. The majority of the over 50 agents that have been firmly identified so far as being human carcinogens belong to the relatively new hazards, that is environmental chemicals or chemical mixtures to which humans have been exposed only during the last century and a half. They are of more importance for cancer occurring in men than in women, and there is no evidence so far that they are related to cancers occurring at some of the most common target sites in either sex. It would be mistaken to believe that complete cancer prevention could be achieved solely by controlling these new, or relatively new, carcinogenic agents, but it would be similarly wrong to deny the importance of trying to control them and of continuing to do so. The experimental approach for the identification of carcinogens has an irreplaceable role to play in preventing the dispersal into our environment of new hazards and in identifying among the chemicals already in use, those that are carcinogenic. That a closer integration between the epidemiological and the experimental approaches may succeed in substantially reducing the size of the unknown region within the spectrum of cancer-causing factors, is today's hope that awaits confirmation. At the same time, advances in the understanding of the mechanisms underlying the different steps of the process leading to the clinical manifestation of cancer may help in the uncovering of agents and risk factors that the approaches used, at least in the way they have been used until now, may not have been apt to identify.     

Human carcinogens so far identified

The massive exploitation of natural resources, of which tobacco and asbestos are two conspicuous, though very different examples, and the synthesis of industrial chemicals have generated new hazards and new carcinogens which have been added to older ones. The majority of the over 50 agents that have been firmly identified so far as being human carcinogens belong to the relatively new hazards, that is environmental chemicals or chemical mixtures to which humans have been exposed only during the last century and a half. They are of more importance for cancer occurring in men than in women, and there is no evidence so far that they are related to cancers occurring at some of the most common target sites in either sex. It would be mistaken to believe that complete cancer prevention could be achieved solely by controlling these new, or relatively new, carcinogenic agents, but it would be similarly wrong to deny the importance of trying to control them and of continuing to do so. The experimental approach for the identification of carcinogens has an irreplaceable role to play in preventing the dispersal into our environment of new hazards and in identifying among the chemicals already in use, those that are carcinogenic. That a closer integration between the epidemiological and the experimental approaches may succeed in substantially reducing the size of the unknown region within the spectrum of cancer-causing factors, is today's hope that awaits confirmation. At the same time, advances in the understanding of the mechanisms underlying the different steps of the process leading to the clinical manifestation of cancer may help in the uncovering of agents and risk factors that the approaches used, at least in the way they have been used until now, may not have been apt to identify.     

Nicotine and smokeless tobacco

The following may be concluded about nicotine and smokeless tobacco use: Systemic absorption and levels of nicotine are similar in users of smokeless tobacco and cigarette smokers. Data from the few studies performed to date suggest that smokeless tobacco users develop a dependency similar to that for cigarette smokers. Effective treatment strategies to help smokeless tobacco users quit need to be developed. Smokeless tobacco use in young people also poses a concern for later development of dependence on cigarettes. The health hazards known to be caused by cigarette smoking and suspected to be related to chronic nicotine exposure are expected to be a hazard of habitual use of smokeless tobacco. A major concern in young males is accelerated coronary artery disease. Information about the potential health hazards of nicotine, as well as oral pathology, may be incorporated into educational programs to help discourage the use of smokeless tobacco, with a resultant decrease in the associated cancer risk.     

Cancer Incidence Rates in the Kurdistan Region/Iraq from 2007-2009

Cancer is a disease of gradual increase in incidence overall the world. Kurdistan Region in Iraq has beenexposed to several carcinogenic hazards. There are few reports about the increased risk of cancer in different citiesin Iraq. These reports did not cover Kurdistan region. The aim of this paper was to study cancer incidence and toidentify possible risks of cancer in this region. Cancer registries from 9 hospitals in three cities of Kurdistan wereused as a source of data. Information on these cases was subjected to careful verification regarding repetition,place of residence and other possible errors. Overall registered cases in 2007, 2008 and 2009 were 1444, 2081,2356 respectively. 49% of registered cases were males and 51% were female. The Age Standardized Rate ofcancer was 89.83/100 000 among male and 83.93/100 000 among female. The results showed major variationin incidence rates of different types of cancer in the three governorates of Kurdistan. Furthermore, there wasevidence of increased risks of cancer in Kurdistan Region in Iraq. Hematological malignancies were the mostcommon cancer among male (21.13% of all cancer in males) and second most common in female (18.8% of allcancer in female), only exceeded by breast cancer. To reach sound conclusions about extent and determinantsof cancer in Kurdistan, enormous multi-spectrum efforts are now needed.     

Infertility and pregnancy after breast cancer: current knowledge and future perspectives

Fertility impairment induced by adjuvant treatments and potential risk associated with pregnancy, are major concerns of young pre-menopausal patients with early breast cancer. Although current evidences suggest that pregnancy does not negatively affect prognosis, a low rate (3-8%) of pregnancy after breast cancer has been reported. Among the potential causes of such a low rate there are a high chance of spontaneous abortions (25%) as well as the fertility impairment induced by adjuvant treatments. No standard strategy to preserve fertility in breast cancer patients is available so far. Experimental approaches include cryopreservation strategies, and use of gonadotropin-releasing hormone (GnRH) agonists to render germinal epithelium quiescent and less sensitive to the chemotherapy cytotoxicity. Here, we reviewed current knowledge about incidence and risks of pregnancy after breast cancer, risks of ovarian failure after adjuvant treatments and experimental strategies aiming to preserve ovarian function and fertility in young breast cancer patients.     

Health Council of the Netherlands and evaluation of the fifth generation, 5G,for wireless communication and cancer risks

Currently the fifth generation, 5G, for wireless communication is about to be rolled out worldwide. Many persons are concerned about potential health risks from radiofrequency radiation. In September 2017, a letter was sent to the European Union asking for a moratorium on the deployment until scientific evaluation has been made on potential health risks (http://www.5Gappeal.eu). This appeal has had little success. The Health Council of the Netherlands released on September 2, 2020 their evaluation on 5G and health. It was largely based on a World Health Organization draft and report by the Swedish Radiation Safety Authority, both criticized for not being impartial. The guidelines by the International Commission on Non-Ionizing Radiation Protection were recommended to be used, although they have been considered to be insufficient to protect against health hazards (http://www.emfscientist.org). The Health Council Committee recommended not to use the 26 GHz frequency band until health risks have been studied. For lower frequencies, the International Commission on Non-Ionizing Radiation Protection guidelines were recommended. The conclusion that there is no reason to stop the use of lower frequencies for 5G is not justified by current evidence on cancer risks as commented in this article. A moratorium is urgently needed on the implementation of 5G for wireless communication.     

Risk of colon cancer associated with a family history of cancer or colorectal polyps: The Diet,Activity, and Reproduction in Colon Cancer Study

The Diet, Activity, and Reproduction in Colon Cancer (DARCC) study is a large, multi-center case-control study of colon cancer. We examined family histories of cancer among first-degree relatives obtained by computer-assisted in-person interviews from the DARCC to study the impact of family histories of several cancers and colorectal polyps on colon cancer risk. We examined familial cancer risks both by treating a family history of polyps or cancer as a covariate in a logistic regression model, and by comparing cancer or polyp incidence among relatives of cases to incidence among relatives of controls in a proportional hazards model. There were few differences between the odds ratios (OR) or confidence intervals (CI) generated from logistic regression models and the hazard rate ratios (HRR) generated from the proportional hazards models. Overall, the OR of colon cancer among subjects with a family history of colorectal cancer was 1.77. There were only minor differences in risk by sex, age and subsite. A family history of colorectal polyps also increased risk by about the same amount as a family history of colorectal cancer. The increased risk associated with a family history of polyps did not appear to decrease with age. Int. J. Cancer 78:157–160, 1998.© 1998 Wiley-Liss, Inc.     

Understanding population and individual risk assessment: the case of polychlorinated biphenyls.

Decisions about how to improve or protect the public health can be, and sometimes necessarily are, made on imprecise science. The regulation of potential human carcinogens in the environment entails a population-risk assessment process intended to reduce risks to less than one additional cancer in 100,000 or 1,000,000 persons. These risk assessment processes, however, may be miscommunicated or misinterpreted in the context of individual cancer risks by scientists, regulators, the lay media, and the public. This commentary will review methods for establishing a causal relationship between carcinogen exposures and cancer risk. It will use the case of polychlorinated biphenyls (PCB) as an example of how to place scientific data into the context of human exposure and cancer risk. PCBs are widespread environmental contaminants and most people have detectable levels of PCBs in their bodies. The primary source for exposure in the general population is through the diet. PCBs are carcinogens in experimental animal models, but how this information can be extrapolated to human risk remains uncertain. PCB experimental studies provide data that are used to regulate and control human exposure, although the epidemiologic evidence fails to establish PCBs as human carcinogens. Thus, what is used for population-risk assessment may not be appropriate for individual-risk assessment or concluding that a causal relationship exists between PCB exposure and cancer risk. The hazards from a carcinogen designated by regulatory and review agencies as a "probable" human carcinogen is often misunderstood out of context about the magnitude of the risk and in what settings. How scientists communicate their results in scientific articles can strongly influence how others interpret their data. Misunderstandings from both the use of regulatory and review-agency opinions and the conclusions espoused by scientists occur in the media, among private physicians counseling their patients about cancer risk, and in the legal settings where plaintiffs seek compensation for exposure and alleged harm (or future harm). This can lead to false conclusions about what caused a cancer in a specific patient, undue anxiety about future cancer risk, inappropriate cancer screening, and attendant increased morbidity due to increased uses of the medical system and complication rates from medical procedures. The communication of research findings by scientists must be presented with caution, resisting the temptation to extrapolate, inappropriately, research data to the general population.     

Projecting individualized probabilities of developing breast cancer for white females who are being examined annually

To assist in medical counseling, we present a method to estimate the chance that a woman with given age and risk factors will develop breast cancer over a specified interval. The risk factors used were age at menarche, age at first live birth, number of previous biopsies, and number of first-degree relatives with breast cancer. A model of relative risks for various combinations of these factors was developed from case-control data from the Breast Cancer Detection Demonstration Project (BCDDP). The model allowed for the fact that relative risks associated with previous breast biopsies were smaller for women aged 50 or more than for younger women. Thus, the proportional hazards models for those under age 50 and for those of age 50 or more. The baseline age-specific hazard rate, which is the rate for a patient without identified risk factors, is computed as the product of the observed age-specific composite hazard rate times the quantity 1 minus the attributable risk. We calculated individualized breast cancer probabilities from information on relative risks and the baseline hazard rate. These calculations take competing risks and the interval of risk into account. Our data were derived from women who participated in the BCDDP and who tended to return for periodic examinations. For this reason, the risk projections given are probably most reliable for counseling women who plan to be examined about once a year.     

Long-term nicotine replacement therapy: cancer risk in context

Nicotine replacement therapy (NRT) for up to 12 weeks is well established, safe and efficacious for fostering smoking cessation. Some smokers at a high risk of relapse may benefit from long-term use, and so long-term NRT safety and efficacy have become a paramount question for the FDA and others. Laboratory studies have indicated a carcinogenic potential of nicotine. Animal model studies reported in this issue of the journal by Maier and colleagues (beginning on page 1743) and Murphy and colleagues (beginning on page 1752), however, provide additional reassurance that NRT does not promote lung cancer. Very long-term studies of NRT effects do not yet exist and would be needed to definitively answer the question about NRT efficacy and cancer risk and some decision making will need to be made based on limited human data and experimental studies. The overall NRT safety question is complex and requires consideration of three contexts and comparator groups (long-term NRT/abstinence vs. smoking, long-term intermittent NRT/reduced smoking vs. smoking, and long-term NRT/abstinence vs. abstinence without long-term NRT). Although the data on these issues are insufficient, the first comparison seems intuitive and may be compelling enough to allow the FDA to approve a long-term indication for NRT. An important public health goal is to help smokers and their health care providers understand the implications of potential long-term NRT risks in the context of its potential benefits and the far greater risks of continued smoking.     

Attributable and absolute risk of lung cancer death by smoking status: findings from the Japan Collaborative Cohort Study

Estimating the proportion of lung cancer deaths that can be avoided is important in assessing the potential impact of antismoking efforts on the reduction of lung cancer deaths. We calculated the population attributable risk (PAR) and absolute risk of lung cancer death according to smoking status based on the Japan Collaborative Cohort (JACC) Study. The analytic cohort included 45,010 males and 55,724 females aged 40-79 years. Cox proportional hazards model was used to determine age-adjusted relative risks and PAR according to smoking status. We also computed lung cancer mortality according to age and smoking status. In males, 52.2% and 14.8% of lung cancer deaths were attributable to current and former cigarette smoking, respectively. In females, the corresponding figures were 11.8% and 2.8%. Among current male smokers, the relative risk was strongly correlated with the intensity and duration of cigarette smoking. In contrast, the PAR was associated with an intermediate level of smoking except for the years of smoking: the largest PARs were observed in those with 20-29 cigarettes per day, 40-59 pack-years and 20-22 years old at starting smoking. Absolute risks were estimated to increase with age and duration of smoking and not to decrease even after cessation. These findings suggest that avoidable lung cancer deaths are primarily among light to moderate smokers who are considered amenable to population-based antismoking strategies. For all current smokers, immediate cessation is encouraged because it offers the only realistic way to avoid a substantial increase in lung cancer mortality brought about by further continuation of smoking.     

Toward precision medicine for preserving fertility in cancer patients: existing and emerging fertility preservation options for women

As the number of young cancer survivors increases, quality of life after cancer treatment is becoming an ever more important consideration. According to a report from the American Cancer Society, approximately 810,170 women were diagnosed with cancer in 2015 in the United States. Among female cancer survivors, 1 in 250 are of reproductive age. Anticancer therapies can result in infertility or sterility and can have long-term negative effects on bone health, cardiovascular health as a result of reproductive endocrine function. Fertility preservation has been identified by many young patients diagnosed with cancer as second only to survival in terms of importance. The development of fertility preservation technologies aims to help patients diagnosed with cancer to preserve or protect their fertility prior to exposure to chemo- or radiation therapy, thus improving their chances of having a family and enhancing their quality of life as a cancer survivor. Currently, sperm, egg, and embryo banking are standard of care for preserving fertility for reproductive-age cancer patients; ovarian tissue cryopreservation is still considered experimental. Adoption and surrogate may also need to be considered. All patients should receive information about the fertility risks associated with their cancer treatment and the fertility preservation options available in a timely manner, whether or not they decide to ultimately pursue fertility preservation. Because of the ever expanding number of options for treating cancer and preserving fertility, there is now an opportunity to take a precision medicine approach to informing patients about the fertility risks associated with their cancer treatment and the fertility preservation options that are available to them.     

Influence of dose and duration of smoking on lung cancer rates

Lung cancer risks depend far more strongly on the duration than on the daily dose-rate of cigarette smoking. For example, a three-fold increase in the daily dose-rate may produce only about a three-fold increase in effect, while a three-fold increase in duration might produce about a 100-fold increase in effect. Hence, a few decades after cigarette smoking becomes widespread, national lung cancer rates may remain very misleadingly low, even though they will eventually become extremely high.     

Intention to quit smoking and concerns about household environmental risks: findings from the Health in Common Study in low-income housing

Purpose

To assess the association between intention to quit smoking and perceptions of household environmental risks among racially/ethnically diverse residents of low-income housing.

Methods

Baseline data were collected from 2007 to 2009 for the Health in Common Study, which assessed social and physical determinants of cancer risk-related behaviors among residents of 20 low-income housing developments in the Greater Boston metropolitan area. Participants were surveyed about their tobacco use and concerns about household exposures. Household environmental inspections were also conducted to identify conditions associated with increased risk of exposure to indoor environmental agents, including pesticides, mold, and cleaning products.

Results

Intention to quit smoking was associated with a greater degree of concern about exposures in the home, yet not with the actual presence of household hazards, as identified by home inspections and survey findings.

Conclusions

An ecological approach targeting multiple levels of influence may help to highlight the importance of both quitting tobacco and reducing potential household environmental exposures as part of comprehensive efforts to promote individual and household health.     

Testicular cancer survivorship

Because of a rising incidence of, and declining mortality from, testicular cancer, there are an increasing number of survivors of testicular cancer. Given their young age at diagnosis, the survivors have many years of life ahead of them during which they may experience adverse consequences from cancer and its treatment. Over the past few decades and particularly in this century, research into the short- and long-term effects of treatments of testicular cancer has grown rapidly, and now there exist a much greater body of data to help us counsel patients about the risks and side effects of these treatments.     

Relationships among breast cancer perceived absolute risk, comparative risk, and worries.

When trying to predict breast cancer screening, it may be important to understand the relationships between perceived breast cancer risks and worries about getting breast cancer. This study examines the extent to which women's worries about breast cancer correlate with perceptions of both absolute (assessment of own) and comparative (self versus other) 10-year and lifetime risks. As part of a larger randomized intervention trial concerning hormone replacement therapy, 581 women participated in a telephone baseline survey to assess their perceptions of breast cancer risks and worries. Worries about getting breast cancer in the next 10 years and in one's lifetime were related positively to both absolute and comparative 10-year and lifetime risks. The magnitude of these relationships did not differ by time frame. Worry about breast cancer is a function of both how a woman views her own risk and how she compares her risk with that of other women. Some practitioners may encourage women to get screened for breast cancer by using emotional appeals, such as heightening women's worries about breast cancer by using risk information. Our data suggest that they should give careful consideration how best to combine, if at all, information about absolute and comparative risks. For example, if the motivation to screen is based on a sequential assessment of risk beginning with comparative and then absolute risk, creating communications that heighten perceived risk on both of these risk dimensions may be needed to evoke sufficient worry to initiate breast cancer screening.     

The Transformation of Adolescent and Young Adult Oncological and Supportive Care in Canada: A Mixed Methods Study

Background: Due to ongoing disparity in the specialized care available to adolescents and young adults (AYAs) with cancer, this study aimed to understand the gaps and barriers to accessing care and preferences on types of solutions at a national Canadian level. Methods: A mixed-methods study involving an online survey and focus groups (FGs) was conducted among AYAs residing in different regions of Canada. Results: There were a total of 174 survey respondents, of whom the majority were between 30–39 years of age (n = 125, 71.8%). Of the 174 respondents, 36 (20.7%) participated in one of seven FGs. Triangulation of the results illustrated that AYAs are not appropriately informed about the long-term health risks of being treated for cancer and where/how to seek support. These results culminated into three themes: (1) the need for AYA relevant and timely information about health risks; by (a) producing health risk-related content with the AYA life stage in mind; (b) providing a guided “map” to help AYAs anticipate what they may experience, and (c) providing checklists to help AYAs navigate their experience; (2) need for tailored and timely supportive care including (a) establishing ongoing check-ins and (b) receiving navigation support, and (3) need for enhanced connections by creating (a) a space to gather, connect and seek mentorship and (b) a hub to access information. Conclusion: AYAs continue to lack sufficient support both during and following cancer and mechanisms are required to ensure longitudinal support is provided across jurisdictions and in all stages of the cancer journey.     

Predictors of pancreatic cancer mortality among a large cohort of United States adults

Objectives: Cigarette smoking is considered an important risk factor for pancreatic cancer, but other purported risk factors are less well established. To learn more about the epidemiology of this important cause of mortality we examined associations with a variety of possible risk factors for death from pancreatic cancer in a large, prospective study of United States adults. Methods: We used proportional hazards models to obtain adjusted estimates of relative risks (hazards ratios). During 14 years of follow-up, 3751 persons died of pancreatic cancer in a cohort of 483,109 men and 619,199 women who had no reported history of cancer at enrollment in 1982. Results: Cigarette smoking at baseline was associated with fatal pancreatic cancer among men (multivariate relative risk [RR] = 2.1, 95% confidence interval [CI] 1.9–2.4) and among women (RR = 2.0, 95% CI 1.8–2.3). A trend in risk was observed with increasing number of cigarettes smoked per day among current smokers at baseline. With several variables included in separate models for men and women, we found additional factors to be predictive of pancreatic cancer mortality, including family history of pancreatic cancer, black race, diabetes, and increased body mass index. History of gallstones was predictive of pancreatic cancer among men. An inverse association with vegetable consumption was observed among men, that was not statistically significant. Conclusion: Our findings confirm that cigarette smoking is an important predictor of pancreatic cancer mortality, and identify several other factors that may contribute to increased risk.