Cancer Prevention | Cancer.Net

Transcript: Cancer Prevention Chat with Bernard Levin, MD
Friday, April 11, 2003, 2:00 - 3:00 PM ET

Moderator: On behalf of the American Society of Clinical Oncology (ASCO), welcome to the Cancer.Net chat on cancer prevention, a live question-and-answer session hosted by Bernard Levin, MD. During this hour, Dr. Levin will answer as many questions as time permits. Some questions may be adapted so that Dr. Levin's answers can help as many people as possible. Dr. Levin will take questions from 2:00 - 3:00 PM ET. As you prepare your questions, please keep in mind that Dr. Levin is unable to give individual medical advice in this setting. In answering questions about specific drugs, Dr. Levin's comments will focus on the state of current research and clinical trials. This chat is governed by all terms and conditions of the Cancer.Net website.

Good afternoon and welcome. Thank you for joining us. Dr. Levin will now begin taking questions.

Dr. Levin is Vice President of Cancer Prevention at The University of Texas M.D. Anderson Cancer Center, and Chair of ASCO's Cancer Prevention Committee. He is also Chair of the American Cancer Society's National Advisory Task Force on Colorectal Cancer and the National Colorectal Cancer Roundtable. He is a member of the Medical Advisory Board of the National Colorectal Cancer Research Alliance and is an Advisory Board Member of the Cancer Research and Prevention Foundation. His research interests include seeking molecular markers for detection of colorectal cancer, drug therapy for preventing colorectal cancer, and better methods for enhancing public awareness of colorectal cancer prevention.

Dr. Levin, thank you for taking the time to join us today. Please begin by telling us your thoughts about cancer prevention.

Dr. Levin: The most important cause of preventable cancer is tobacco. And, it is estimated that one third of all cancer deaths could be prevented by not having people smoke. Sun exposure is another very important, preventable lifestyle.

Another very important method of preventing cancer is identifying polyps within the colon and removing them before they can become malignant. We also realize that screening for cervical cancer identifies individuals with abnormalities that, once treated, can prevent progression to cancer.

Marcus: My dad smokes, and none of his smoker friends have gotten lung cancer so he thinks he won't. What can I tell him?

Dr. Levin: You should tell him that the longer he smokes, the more likely he is to increase his risk for developing lung cancer, as well as all the other cancers associated with tobacco, including head and neck, esophagus, pancreas, and bladder cancer, as well as lung disease and heart disease. The fact that his friends don't have obvious lung cancer doesn't mean they aren't going to get it or aren't at risk for other serious medical conditions.

Kelly: Are there specific dietary practices that may decrease cancer risk, like soy or garlic?

Dr. Levin: The best advice is to enjoy the benefits of a diet rich in vegetables, fruit, and with reduced intake of red and processed meats and a low intake of alcohol. Specific foods such as soy and/or garlic may have some beneficial effects, but should not be relied on as a primary source of dietary prevention.

Sharon: Should I get a full-body computed tomography (CT) scan to see if I have cancer?

Dr. Levin: The answer is emphatically no and why is that the answer? Wherever possible, we should rely on objective evidence to guide choices regarding cancer screening, which is the detection of disease in individuals without symptoms.

There is no evidence that whole-body CT scans will result in a beneficial outcome. Furthermore, many minor abnormalities are likely to be detected that may result in further tests that can cause serious harm and incur major expense for that individual and society.

PaulaH: I visit a tanning salon every week. Is that bad?

Dr. Levin: The answer is yes. Rates of melanoma and skin cancer continue to increase because of exposure to sun and tanning salons. Damage to the skin incurred by such exposure is serious and should be avoided.

Joan: Should I take aspirin to prevent cancer?

Dr. Levin: It is not possible to provide an individual answer to this question, as there are several complex issues involved. Certainly there is evidence from epidemiologic studies that regular intake of aspirin and other nonsteroidal anti-inflammatory drugs (NSAIDs) is associated with a decreased risk for a number of common cancers. Also, recent studies have shown some reduction in the incidence of colorectal polyps in those who took aspirin regularly in a trial.

However, there are risks associated with aspirin including gastrointestinal bleeding and hemorrhagic stroke that need to be considered in a discussion with your personal physician.

Guest17: Although colorectal screening isn't recommended until a person reaches age 50, there have been cases of people under that age diagnosed with colon cancer. What symptoms should we watch for?

Dr. Levin: Symptoms of colorectal cancer include bleeding, change in bowel habit, persistent constipation or diarrhea, rectal or abdominal pain, or weakness. In general, we hope to have tests for colorectal cancer that would detect both polyps that can lead to cancer and cancer at a stage before symptoms develop; these could be applied in the future to people under age 50.

Nevertheless, a family history of colorectal cancer or polyps should direct one to discuss screening with your physician, even before the age of 50.

Toby: Is there anything that can be done to prevent prostate cancer?

Dr. Levin: Those individuals with a family history may benefit from early screening, but for the general population, there are no specific measures. Dietary advice such as a balanced diet rich in vegetables and fruit and lower in red and processed meat may also be helpful in a nonspecific way.

Tenet: I have recently begun smoking cigars, no more than two per week. Does that put me at a significantly higher risk of developing cancers of the mouth and throat area?

Dr. Levin:Yes. I would encourage you to satisfy oral urges in other ways, such as chewing gum.

Daughters: My mother and aunt both have breast cancer. Knowing that there is a genetic link, should my sisters and I do anything to help prevent us from getting it too? What about genetic testing?

Dr. Levin: This is a very important and complex question. I would urge you to seek the advice of an expert in inherited breast cancer and consider genetic counseling and possibly genetic testing. In some instances, based on expert opinion, prophylactic mastectomy may be advised. Sometimes, for women at high risk, tamoxifen therapy may be advantageous.

Guest158: Can you please explain chemoprevention?

Dr. Levin: Chemoprevention is the treatment of premalignancy. Essentially, it involves the use of chemical substances to reduce the risk of progression to a more invasive stage of a lesion.

John: Do you believe the hormones and other chemicals given to animals raised for meat contribute to cancer in humans?

Dr. Levin: I do not know, but I believe that it is reasonable whenever possible to minimize the use of such chemicals and to minimize their intake.

Guest56: What about the use of herbs and vitamin supplements to lower cancer risk?

Dr. Levin: This is becoming a very important area because we recognize that many healthy individuals, as well as those who may have been diagnosed with cancer, are seeking ways to reduce the risk of ever getting cancer or a recurrence. It is impossible to make a blanket statement about the impact of herbal therapies without considering both potential risks and harms of such interventions.

Multivitamins containing folic acid may be helpful in preventing colorectal polyps and cancers. Beta carotene, a form of vitamin A, actually can cause harm in those who smoke and drink alcohol by increasing the risk of lung cancer.

Guest110: Do you know of any clinical studies that deal with preventing cancer?

Dr. Levin: There are many clinical studies that deal with preventing cancer. These can be accessed through the National Cancer Institute. In addition, your local comprehensive cancer center is likely to have a range of studies aimed at both prevention and screening.

CuriousG: Is there any progress on catching ovarian cancer early? My wife only got diagnosed by accident.

Dr. Levin: There are promising leads in this field as we learn more and more about its genetics and its cellular biology. Recently researchers at the National Cancer Institute and other centers used a new technology to identify protein patterns in the blood "serum" of women that may have promise for such early identification. This area of research is highly promising.

Maggie: My grandmother died of breast cancer. Should I not take oral contraceptives?

Dr. Levin: There is not a simple answer to this question. It will depend on the risk-benefit ratio involved in your need to use contraceptives, and you should discuss the specifics with your own physician. Without a stronger family history, there may not be an increased risk, but there are many other considerations.

Guest181: What are your thoughts on obesity increasing the risk of cancer?

Dr. Levin: The evidence is becoming stronger that being overweight is a risk factor. In many instances, it is now expressed as having an abnormal body mass index (BMI), and you may encounter this term. In some individuals, obesity is associated with other habits that predispose to the development of cancer, such as low expenditure of physical activity or dietary factors.

Guest56: What are the recommended screening guidelines for men 50 years and older?

Dr. Levin: The specific cancers to be screened for are colorectal cancer and this can be done by one of four methods: testing for hidden blood in the stool; flexible sigmoidoscopy, or a combination of those two; colonoscopy; or double contrast barium enema. Men over the age of 50 should discuss with their physicians the risks and benefits of screening for prostate cancer, usually using prostate-specific antigen (PSA) and a digital rectal examination.

Hakim: There are five people on my street with different kinds of cancer. We think this may be related to the power plant in our neighborhood. Any comments?

Dr. Levin: Clusters of cancer in neighborhoods are not uncommon. The local health authority would be the first point of contact to discuss this concern. Both state health authorities and in particular the Centers for Disease Control and Prevention (CDC) may need to do a careful analysis of the specifics before you can reach a conclusion about the relationship to this power plant.

Formyfriend: Where should the public go for cancer screening and prevention services?

Dr. Levin: The first approach is to become informed about the recommended age and gender specific screening guidelines. This information should be available from the American Cancer Society or from your personal physician. The evidence for both screening and prevention is also available from the National Cancer Institute.

Guest56: What are screening guidelines for women?

Dr. Levin: With regard to the Pap test, cervical cancer screening should begin approximately three years after beginning intercourse, but no later than 21 years of age. Screening should be done every year with conventional Pap tests or every two years using liquid-based Pap tests. At or after age 30, women who have had three normal results in a row may get screened every two to three years. Women 70 years of age and older who have had three or more normal Pap tests and no abnormal Pap tests in the last 10 years may choose to stop. And for breast cancer, a clinical breast exam every three years between ages 20 and 39, annually starting at age 40, and mammography starting at age 40.

Guest185: I read that asbestos can cause cancer. I worked with the stuff for 15 years. What am I at risk for and what can I do to stop myself from getting cancer?

Dr. Levin: The risk for asbestos-related cancer depends on the extent of your exposure and the particular type of asbestos. Asbestos has been associated with lung cancer, pleural-based cancer (mesothelioma), and kidney cancer. It is controversial whether ovarian cancer is related. I know of no specific ways to prevent the onset of cancer, but certainly would alert your personal physician to history of your exposure so that any symptoms or abnormal findings on tests may be interpreted appropriately.

PaulaH: I was diagnosed with colon cancer a few years ago and am worried about a recurrence. What can I do?

Dr. Levin: First, you should be under the care of a physician who is familiar with postoperative care, including endoscopic surveillance of your colon, which may need to be done periodically. Apart from monitoring the lining of your colon, it is also sometimes relevant to do blood tests and x-rays to determine if there been any spread. Dietary measures, such as a diet rich in vegetables, fruit, and calcium, and low in alcohol are also reasonable.

LaRue: What about children with leukemia or other cancers? Once our child is in remission, is he at higher risk for cancer later in life?

Dr. Levin: Such children do need to be monitored carefully throughout their lives because of the possibility of adverse effects of treatment. There may also be inherited factors that could predispose to the development of subsequent malignancy.

Guest56: My doctor put me on the nicotine patch to help me quit smoking. Is there anything else I can do?

Dr. Levin: Stopping smoking is a very important step to regaining good health. It is often difficult to do and requires expert assistance in many cases. This may include counseling, antidepressant medication, and avoidance of situations that trigger smoking as a behavior. Also, encouragement of family members to stop smoking is often crucial.

Moderator: The chat is now ending. Thank you for your thoughtful questions. We hope this discussion has been valuable, and we regret not being able to answer every question. Dr. Levin, thanks again for lending us your time and expertise.

TRANSCRIPTS: To receive a copy of the transcript by e-mail, please send a message to contactus@cancer.net.

SAVE THE DATE: Please join Cancer.Net on May 5, 2003, from 2:00 - 3:00 PM ET for a live chat about skin cancer and melanoma with Charles Balch, MD. Dr. Balch is the Executive Vice President and CEO of the American Society of Clinical Oncology and Professor of Surgery and Oncology at Johns Hopkins University School of Medicine.

The chat room is now closed. Thanks again for joining us.

For more information:

Prevention and Early Detection from the American Cancer Society

Cancer Prevention from the National Cancer Institute

Cancer Causes and Risk Factors from the National Cancer Institute