Scientists expect that being able to "read" these signatures—in other words, being able to compare the signatures of cells in their normal and cancerous states—will change cancer detection, diagnosis, and treatment in many exciting ways. Specifically, studying the exact sequence of molecular changes a cell undergoes during its transformation to a cancerous state will help scientists identify new molecular-level targets for prevention, detection, and treatment. One observation scientists have recently made is that cells surrounding an incipient tumor also may undergo changes that indicate that cancer is present. For example, early tobacco-induced molecular changes in the mouth may predict the risk of developing lung cancer, and cancers of the urinary tract may be signaled by molecularly altered cells that are shed in the urine. Reading the signatures of these easily accessed cells may enable scientists to develop simple, non-invasive tests that will allow early detection of cancerous or precancerous cells hidden deep within the body.
Reading such signatures will also enhance the specificity of cancer diagnosis by allowing scientists to differentiate among tumors at the molecular level. By assessing the meaning of individual changes in a cell's signature, scientists will be able to determine which cancers are most likely to progress and which are not—a dilemma that confronts doctors in the treatment of prostate cancer—thereby allowing patients to avoid the harmful consequences of unnecessary treatment.
Finally, molecular fingerprinting will allow researchers to develop new treatments specifically targeted at cellular subtypes of different cancers. Often, patients suffering from tumors that by traditional criteria are indistinguishable, nevertheless experience quite different outcomes despite having received the same treatment. Research indicates that these different outcomes sometimes are related to the presence or absence of particular gene products. In the future, such molecular characteristics likely will be used to identify patients who would benefit from one type of treatment as compared with another.
The ultimate goal of such work, of course, is to push back the detection and diagnosis of cancer to its earliest stages of development. For the first time in the history of humankind, scientists can now envision the day when medical intervention for cancer will become focused at identifying incipient disease and preventing its progression to overt disease, rather than treating the cancer after it is well established.
But what does this mean for society? The financial costs of cancer loom large, not only for the individual but also for the community. The NCI estimates overall annual costs for cancer at about $107 billion. This cost includes $37 billion for direct medical costs, $11 billion for morbidity costs (cost of lost productivity), and $59 billion for mortality costs. Interestingly, treatment for breast, lung, and prostate cancers account for more than one-half of the direct medical costs.
Although early detection and successful treatment can reduce cancer deaths, the most desirable way to reduce them is prevention. In fact, scientists estimate that as many as one-half of the deaths from cancer in the United States and Europe, two areas with closely tracked cancer rates, could theoretically be prevented.
Nevertheless, the widespread persistence of unhealthful habits suggests that many Americans remain unconvinced about the power of prevention as a defense against cancer. Part of the reason may be that the only data we have about factors related to cancer are drawn from whole populations. These data cannot tell us who will develop cancer. Nor can they tell us whether healthful choices prevented its appearance in a particular individual.
Unhealthful habits also may persist because of the long time that elapses between the exposures that trigger the development of cancer and its actual appearance as disease. Conversely, there is a time lag between the institution of a beneficial personal habit (such as quitting smoking) or public policy (such as banning use of a known carcinogen) and its positive impact on personal and public health.
In their article "Strategies for Minimizing Cancer Risk," Willett, Colditz, and Mueller propose four levels on which to focus cancer prevention efforts. The first level is that of the individual. These authors argue that because most of the actions that can prevent cancer must be taken by individuals, dissemination of accurate information directly to the American public, together with peer support for behavioral changes, is critical.
Figure 9 - A history of severe sunburns is strongly linked to the development of skin cancer later in life.
A second level is health care providers, who are in a position to provide both counseling and screening to individuals under their care. Here, dissemination of accurate and timely information also is key.
A third level of prevention is the national level, where government agencies can impose regulations that help minimize the public's exposure to known carcinogens and implement policies that improve public health. Examples include regulating industries to cease using potent carcinogens and providing community facilities for safe physical activity.
Finally, a fourth level of prevention is at the international level, where the actions of developed countries can affect the incidence of cancer worldwide. Unfortunate examples of this include promoting the exportation of tobacco products and moving hazardous manufacturing processes to unregulated developing countries.
How do we think about devising and implementing measures to improve personal and public health in a pluralist society? One way to address this question is by attending to the ethical and public policy issues raised by our understanding and treatment of cancer.
Ethics is the study of good and bad, right and wrong. It has to do with the actions and character of individuals, families, communities, institutions, and societies. During the last 2,500 years, Western philosophy has developed a variety of powerful methods and a reliable set of concepts and technical terms for studying and talking about the ethical life. Generally speaking, we apply the terms "right" and "good" to actions and qualities that foster the interests of individuals, families, communities, institutions, and society. Here, an "interest" refers to a participant's share in a situation. The terms "wrong" or "bad" apply to actions and qualities that impair interests. Often there are competing, well-reasoned answers to questions about what is right and wrong and good and bad about an individual's or a group's conduct or actions.
Ethical considerations are complex and multifaceted and raise many questions. In the United States, for example, we value protecting individuals from preventable harms. We support restrictions on who can purchase cigarettes and where smoking can occur. We inform pregnant women of the risks of drinking and smoking. However, we also value individual freedom and autonomy. We do not ban cigarettes outright; instead, we allow individuals over 18 years of age to take personal risks and be exposed to the related consequences. We permit pregnant women to buy and use liquor and cigarettes.
The inevitability of ethical tradeoffs is not simply a mark of the discussions in the United States. When considering differing health policy issues between and among countries, one cannot avoid encountering a pluralism of ethical considerations. Developing countries, whose health standards often differ from those in the United States, provide different cultural approaches to cancer and different standards for marketing and using tobacco and other known carcinogens. These different approaches raise a variety of ethical questions. For example, is there any legal and ethical way for people in the United States to prevent the widespread use of tobacco in other countries, a practice that contributes to the rise of lung cancer worldwide? Is there any legal and ethical way to govern other choices of individuals (for example, poor diet and lack of exercise) that contribute to cancer?
Typically, answers to such questions all involve an appeal to values. A value is something that has significance or worth in a given situation. One of the exciting events to witness in any discussion in ethics in a pluralist society is the varying ways in which the individuals involved assign value to things, persons, and states of affairs. Examples of values that students may appeal to in discussions of ethical issues include autonomy, freedom, privacy, sanctity of life, protecting another from harm, promoting another's good, justice, fairness, relationships, scientific knowledge, and technological progress.
Figure 10 - Where do we spend our money? A consequence of allowing unhealthful habits, such as smoking, is that public funds may be spent on cancer treatments instead of on other societal benefits, such as improved school facilities.
Acknowledging the complex, multifaceted nature of ethical discussions is not to suggest that "anything goes." Experts generally agree on the following features of ethics. First, ethics is a process of rational inquiry. It involves posing clearly formulated questions and seeking well-reasoned answers to those questions. Well-reasoned answers to ethical questions constitute arguments. Ethical analysis and argument, then, result from successful ethical inquiry.
Second, ethics requires a solid foundation of information and rigorous interpretation of that information. For example, one must have a solid understanding of cancer to discuss the ethics of requiring protective covering to be worn to prevent skin cancer. Ethics is not strictly a theoretical discipline but is concerned in vital ways with practical matters.
Third, because tradeoffs among interests are complex, constantly changing, and sometimes uncertain, there are often competing, well-reasoned answers to questions about what is right and wrong and good and bad. This is especially true in a pluralist society.
Public policy is a set of guidelines or rules that results from the actions or lack of actions of government entities. Government entities act by making laws. In the United States, laws can be made by each of the three branches of government: by legislatures (statutory law), by courts (case law), and by regulatory agencies (regulatory law).
Regulatory laws are written by the executive branch of the government, under authorization by the legislative branch. All three types of law are pertinent to how we respond to cancer. When laws exist to regulate behavior, public policy is called de jure public policy.
Whether one makes public policy involves at least the following five considerations:
For example, many argue that there is overwhelming evidence to support increased public policy restrictions on access to and use of cigarettes. Cigarette smoking is said to be linked to 85-90 percent of lung cancer cases. In 1998, 171,500 new cases of lung cancer were predicted. Of these, 160,100 were expected to end in death. Public policy prohibitions on cigarette use and access may be seen to satisfy four of the five considerations: (1) the cost of the policy would be minimal because cigarette access and use restrictions are in place, (2) the urgency of the situation is serious given the large number of deaths, (3) prohibiting purchase by minors and raising the prices (through taxation) are seen as effective, and (4) means are already in place for additional restrictions. The challenge in this era of high economic interest in cigarette production is the social, cultural, and political considerations (5).
It is important to recognize that sometimes the best public policy is not to enact a law in response to a controversy, but rather to allow individuals, families, communities, and societies to act in the manner they choose. Clearly, de jure public policy can only go so far in regulating people's behaviors. De jure public policy in the United States offers no match for the addictive power of nicotine and the marketing clout of the tobacco industry. In addition, any decline in cigarette use brought about by de jure public policy in the United States has been more than offset in recent years by a rapid increase of cigarette consumption elsewhere in the world.
When no laws exist to regulate behavior, public policy is called de facto (actual) public policy. With regard to lung cancer prevention programs, many think that other approaches are needed: improved general education and cultivation of an antismoking ethos. In any discussion of society's response to a social problem, it is important to think about other ways to address the problem.
We can conclude that science plays an important role in assisting individuals to make choices about enhancing personal and public welfare. Science provides evidence that can be used to support ways of understanding and treating human disease, illness, deformity, and dysfunction. But the relationships between scientific information and human choices, and between choices and behaviors, are not linear. Human choice allows individuals to choose against sound knowledge, and choice does not necessarily lead to particular actions.
Nevertheless, it is increasingly difficult for most of us to deny the claims of science. We are continually presented with great amounts of relevant scientific and medical knowledge that is publicly accessible. We are fortunate to have available a large amount of convincing data about the development, nature, and treatment of particular cancers. As a consequence, we might be encouraged to think about the relationships among knowledge, choice, behavior, and human welfare in the following ways:
knowledge (what is and is
not known) + choice = power
power + behavior = increased human welfare (that is, personal and public health)
One of the goals of this module is to encourage students to think in terms of these relationships, now and as they grow older.
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