Episode 4 Additional Transcripts
Transcripts for Episode 4 Additional Materials
Introduction
People look at air and water pollution as leading causes of cancer, but in reality, smoking and diet are for more significant.Peter Greenwald, MD
Director of Cancer Prevention
National Cancer Institute
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GREENWALD
I suspect that people don't know that there are two main things that the average person can do. Don't smoke which I think that people do know, but they don't all follow it. And keep trim. I don't think people realize that 90,000 cancer deaths per year in the United States are related to obesity, that you should get a lot of physical activity and keep trim. On the other hand people tend to think that synthetic chemicals in our environment cause cancer much more than they do. They are only rare causes of cancer.
GREENWALD
Air and water pollution are not major factors in cancer spread, but we do live on a fragile planet. For a clean and safe environment, I think we should do all we can to minimize environmental combination and to keep our planet clean. But I cannot say, based on evidence, that this is contributing to a lot of the cancer today. It's the indoor air that is the biggest thing. There's second hand smoke, for example, is the main thing after smoking that contributes to lung cancer.Environmental Mutagens and Promoters that Cause Cancer
Promoters and mutagens can both increase the risk of cancer. What are they and how do they differ?Robert Weinberg, PhD
Daniel K. Ludwig Professor for Cancer Research
Massachusetts Institute of Technology
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WEINBERG
At one time we thought that all substances that cause cancer, we'll call them carcinogens, act through their ability to damage DNA. And in fact we know that many carcinogenic substances are mutagenic, i.e. they can mutate and thereby damage DNA molecules. But there are many human carcinogens that don't damage DNA molecules and which, instead, act to encourage the formation of cancer through their ability to irritate tissues, to inflame tissues, and to provoke uncontrolled cell proliferation which itself is a precondition for the development of cancer. And so, of cours,e this theory that all carcinogens are mutagens, DNA damaging substances, is a bit of a simplification. We now understand that many carcinogens act to promote the presence of cancers without damaging DNA and are called, therefore, promoters.WEINBERG
Cancer of the mouth and throat is really an excellent illustration of how mutagenic carcinogens that damage DNA can collaborate and conspire with non-mutagenic carcinogens to create human tumors. In the case of individuals who smoke many cigarettes and drink hard alcohol, we realize that the mutagenic tobacco tars they put in their mouth are able to damage and mutate cells lining their mouth and lining their throat. That, on it's own, isn't sufficient enough for a cancer. Instead, when they drink hard alcohol. the alcohol acts as an irritant and induces cell proliferation in the mouth and the throat. Indeed, it induces the proliferation of cells that have already been mutated by the tobacco tars and as a consequence this leads to the appearance of these very unpleasant cancers.Colon Cancer Screening and Prevention
Colon cancer is one of the most common cancers, and screening can help prevent it.Lynn Butterly, MD
Dartmouth-Hitchcock Medical Center
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BUTTERLY
Colon cancer is a big problem. First of all, I think it's useful to know that it's the second most common cause of death from cancer in this country. The only cancer that causes death more frequently in men and women is lung cancer, so if people didn't smoke, colon cancer would be the most common cause of death from cancer in this country. So it's a big problem in that sense. There are about 150 thousand people or so who develop colon cancer every year and about 60 thousand people every year who are dying of colon cancer in the United States. Since it's a largely preventable disease, that's something that we'd like to change.Fortunately we have enough medical evidence that's been accumulated over the past, particularly the past 5 to 10 years, but for the past 30 years, that shows that colon cancer screening is in fact very effective, and for that reason it is one of the forms of screening that is advocated by all the societies, including the US preventive task force, which uses evidence from clinical trials to make its recommendation. So colon cancer screening is now universally recommended, and that's because studies have shown us that it's effective.
Smoking
Related Links: http://www.tobaccofreekids.org
http://www.cancer.org
http://www.lungusa.org/
Tobacco causes many cancers besides lung cancer.
Neal L. Benowitz, MD
Professor, Medicine, Psychiatry, and Pharmacy
University of California at San Francisco
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BENOWITZ
There are a number of cancers that are caused by tobacco. In general, it's estimated that 30% of cancers are tobacco related. The one we hear most about and the most common one, of course, is lung cancer; and 90% of lung cancers occur because of tobacco. Before there was smoking, lung cancer used to be a rare cancer, and professors would call their students around because it was so rare. Now lung cancer is the most common cancer we see, and it is still one of the most lethal. It also causes cancer of the mouth and the throat and the esophagus. It causes liver cancer. It causes pancreatic cancer, kidney cancer, and bladder cancer; cervical cancer in women; and leukemia. So it causes cancers pretty much all over the body.Smoking: How tobacco causes cancer
Neal L. Benowitz, MD Professor, Medicine, Psychiatry, and Pharmacy
University of California at San Francisco
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BENOWITZ
What the carcinogens do is they damage the DNA, which is the control for the genetic messages that control body processes. And when you damage DNA, you disturb the process by which the body controls cell growth. There are genes that produce proteins that control cell growth and make sure that cells grow in a proper way. So if you get injured, you need to grow new skin cells; you grow them, but you don't grow too many of them. And the control of this is done by different genes controlling different proteins. When chemicals attach to DNA, they damage the DNA, and then the messages that get sent for protein generation get messed up; and then the proteins don't work properly. Cell growth is not controlled, and then uncontrolled cell growth means you develop tumors, and then it spreads, and you develop cancer. So the main thing that these chemicals are doing is damaging DNA.Smoking: Second Hand Smoke
Related Link: EPA: Secondhand Smoke Can Make Children Suffer Serious Health Risks
Neal L. Benowitz, MD
Professor, Medicine, Psychiatry, and Pharmacy
University of California at San Francisco
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BENOWITZ
It's pretty clear that if you are exposed to someone else's cigarette smoke, you are at risk for cancer. Now, of course, the absolute risk is low compared to being a smoker. If you're a nonsmoker and someone else smokes, you have a 30% increase of a risk. If you're an active smoker, you have more than a tenfold increased risk of lung cancer; and depending on how you smoke, it can be a fifty-fold increased risk.Smoking: Cessation
Related Link:SmokeFree.gov
Neal L. Benowitz, MD
Professor, Medicine, Psychiatry, and Pharmacy
University of California at San Francisco
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BENOWITZ
It is never too late to stop smoking. There is a lot of scientific research showing that, even if you're elderly, that your heart disease risk will drop. Your risk of a heart attack, for example, drops very quickly when you quit smoking. Your risk of infection drops, lung disease doesn't normalize; but lung disease gets progressively worse as you smoke, and as soon as you stop smoking, the progression of the lung disease stops, so you sort of stay where you are.Smoking: The global marketing of tobacco
Ross Hammond, EconomistRelated Link:
http://tobaccofreekids.org
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HAMMOND
My message is that the tobacco companies are getting away with things overseas that they would never be allowed to do here. They have cigarette girls walking around in shopping malls, they sponsor car races, they brand themselves on TV. They're involved in very, very aggressive marketing overseas in ways that are either illegal in the United States or that would just be considered beyond the pale.And the message that I say to people is, "We have a responsibility. These are companies that are from the United States. Philip Morris is the world's largest tobacco company. It's the largest purveyor of death and disease around the world, and we as Americans have a responsibility to do something about that."
Genetic Predisposition for Cancer
If your parents had cancer, it may increase your risk of cancer, but in most cancers, the heredity is not a major risk factor.Watch this video
Peter Greenwald, MD
Director of Cancer Prevention
National Cancer Institute
GREENWALD
Hereditary factors play a role in cancer, but there are only about maybe 10 or 15 percent of cancers where there's a fairly direct effect of specific known genes--dominant effective genes--, and even in those cases, you might be able to modify your risk through lifestyle changes, and there may be other ways we can intervene.Genetic Predisposition for Cancer
The presence of BRAC-1 AND BRAC-2 genes greatly increase a woman's risk of developing breast cancer. What action needs to be taken?Robert Smith, PhD
Director of Cancer Screening
National Office of the American Cancer Society
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SMITH
It is a very small group of women that we are talking about. We believe that these mutations on BRCA1 and BRCA2 as well as other genes account up to only 5 to 10% of all breast cancers. So in a sense you are talking about a population prevalence in these women in the one in eight hundred, nine hundred women.Some women may choose to make reproductive decisions based upon whether or not they are carrying the mutation BRCA1 or BRCA2. Some women may elect to go through prophylactic mastectomy which can measurable reduce the risk of breast cancer. Some women may wish to undergo prophylactic ovariectomy. Or just be in a program on heightened surveillance. A mutation on either one of these disease genes does not mean that you are going to develop this disease, but it means that you are at much higher risk of developing it than a woman without that mutation.
The important thing is that women in this particular case always undergo counseling prior to any decision about testing because there have been other issues associated with test results that have affected how they relate to the family members, affected there job, or there ability to get insurance. And it is very important that they have someone who is very skilled in this area to talk though the various issues.
Breast Cancer Screening
The American Cancer Societies advice on mammograms and self breast exams.Robert Smith, PhD
Director of Cancer Screening
National Office of the American Cancer Society
Related Link: http://breastscreening.cancer.gov/
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SMITH
Ideally, we want all breast cancers to be detected by mammography.For the small percentage that occur before the age of 40, we would hope that those would be picked up very early by women themselves in any way that they might, be it self-breast examination or just through very quick response to the signs and symptoms that they discover on their own. But increasingly the evidence is suggesting that in a population of heightened awareness, women do not really need to do breast self exams, and they shouldn't be made to feel guilty if they choose not to.
Prostate Cancer
Whether or not to have a PSA test is up to you. The value of the test is still under study.Related Link:
About Prostate Cancer. Source: NCI.
Otis W. Brawley, MD
Professor of Hematology and Oncology
Emory University School of Medicine
Professor of Epidemiology
Emory Rollins School of Public Health
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BRAWLEY
The current state of affairs is that there are some individuals who believe that prostate cancer screening saves lives; they do not have scientific randomized clinical trials to demonstrate that that's true. There are some early indicators that screening saves lives. There are also, unfortunately, some early indicators that suggest that screening is harmful. And so there are a large number of people in the scientific community, experts in epidemiology and screening, who tend to side against the recommendation for prostate cancer screening.BRAWLEY
So treatment for prostate cancer is something that needs to be thought of very seriously before one undergoes it. I think screening needs to be thought of very seriously. I've endorsed the American Cancer Society's true screening recommendation, and that is that a man should be offered the test, should be explained the potential risks and the potential benefits, and then be encouraged to make an informed decision. Any man who wants to be screened I feel ought to be screened. Any man who doesn't want to be screened I don't think should ever be criticized for making that decision.Skin Cancer Screening and Prevention
Robert Smith, PhDDirector of Cancer Screening
National Office of the American Cancer Society
Martin A. Weinstock, MD, PhD
Chief of Dermatology, VA Medical Center
Providence, Rhode Island
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SMITH
Screening for skin cancer relies entirely on a visual inspection of the skin, which is time consuming and difficult to do in the primary care setting. We rely on people identifying changes in there skin and a mole--something is growing, changing shape and color. All the time when a patient sees his physician, sometimes the physician has an opportunity to examine the skin, but it is an enormous challenge to map those lesions and to map signs on the skin and to determine change over time.SMITH
And it is time consuming for primary care practitioners to do that so we rely very much on people identifying these themselves and bringing them to the attention to their doctors.WEINSTOCK
We recommend down and back exam. You start with the front of your body, you go down the front and then up the back. You use a hand mirror, and you have, maybe you have a wall mirror in the room where you are doing this, and so you can see every part of your body. You may want to enlist your husband or wife to help you with parts that are hard for you to see, like your low back for example, or some other relative might be able to help you. Doing that thorough skin self exam is a very important part of detecting melanoma early, and should be done once a month.WEINSTOCK
You are looking for any moles, or any spots on the skin that are changing--change in size, shape, or color, or any new spots or any sores that don't heal. Those are the main warning signs for melanoma. So if you see any of those, it doesn't necessarily mean you have a melanoma, but it means you should have it checked out. You're looking for changes in size, shape, or color, new spots, or sores that don't heal. And by change we mean change occurring over months or even a year or two. Changes that occur over days are insignificant from this point of view. It's changes that are progressive over at least a month or two, up to a year or two, that are more concerning.Diet and Exercise
Good food choices and exercise can help prevent cancer.
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Bruce Ames, PhD
Professor of Biochemistry and Molecular Biology
University of California, Berkeley
Otis W. Brawley , MD
Professor of Hematology and Oncology
Emory University School of Medicine
Professor of Epidemiology
Emory Rollins School of Public Health
Robert Smith, PhD
Director of Cancer Screening
National Office of the American Cancer Society
AMES
My interest for many years has been cancer prevention, prevention of disease. And it's clear that the gold is in nutrition because all the top epidemiologists think nutrition is just as important as smoking, if not more important; and all the numbers are coming in on obesity, and obesity's going to be worse than smoking - smoking leads to 400,000 premature deaths a year, and obesity is going to be more than that.BRAWLEY
One of the great problems with diet is we've no interventional studies as of yet that demonstrate that changing from a bad diet to a good diet decreases cancer risk. Theoretically, it should, and I believe that it does, and I encourage people to increase the amount of fiber in their diet, decrease the amount fat--red meat only once or twice a week. A vegetarian diet is absolutely wonderful [COVER CUT WITH DIP FADE] , and I can't even tolerate a vegetarian diet, so I'm being a little bit of a hypocrite when I advocate that; but the vegetarian diet is actually much more conducive to decreasing cancer risk. We have evidence, by the way, looking at Seventh Day Adventists, that a vegetarian diet lowers cancer rates overall.SMITH
There is really no certain path to prevent colorectal cancer or breast cancer. What epidemiology has told us is that people who have active life styles have lower incidences of disease. Somehow or another, as a result of being physically active, they have contributed to reducing risk to these diseases.What you and your community can do to help prevent cancer
Peter Greenwald, MDDirector of Cancer Prevention
National Cancer Institute
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