Harvard's Rosenthal, president of American Cancer Society, says two-thirds of cancers are preventable

People all over the University are buying daffodils to brighten their homes and offices and to contribute to the fight against cancer. But how are the battles going? Are fewer people dying from the disease? Is the incidence of breast, prostate, and lung cancers rising or falling? How is the money you spend on daffodils being used?

A man who knows the answers is David S. Rosenthal, president of the American Cancer Society, Henry K. Oliver Professor of Hygiene, and director of University Health Services. Gazette science writer William J. Cromie asked the questions.

Gazette : Are we winning or losing the war against cancer?

Rosenthal: We are winning. For the first time, cancer deaths are decreasing, as is the number of new cases. From 1991 to 1995, the nation's cancer death rate fell 2.6 percent, the first decline since we began keeping records in the 1930s. This year, the number of cancer deaths is expected to be 564,000.

The annual number of new cancer cases has also declined to an estimated 1.2 million, 11 percent lower than the estimate made in January 1997.

Now that a downward trend has begun, the American Cancer Society believes it will accelerate.

Gazette : What about the biggest killers -- breast, prostate, and lung cancers?

Rosenthal: Lung and bronchus cancer, the top killer, is down in men, but up in women. Prostate cancer deaths are decreasing, as are breast cancer deaths among women. Colon and rectal cancer mortality is declining among both men and women.

Smoking accounts for the lung cancer numbers. Men have been quitting for 10-20 years, while women in larger numbers started smoking later.

Between 1990 and 1994 prostate cancer deaths decreased 0.5 percent, or about 2,000, per year. In January 1997, the estimate for new prostate cancer cases reached 334,500; for 1998, the estimate is 184,500.

Death rates from breast cancer are in a striking decline, mostly due to earlier detection by mammograms. Five-year survival rates now reach 86 percent in white women, but only 70 percent in black women. Blacks have survival rates 10-to-15 percent lower than whites for the most frequently occurring cancers, except lung cancer. In the most startling example, blacks are twice as likely as whites to develop prostate cancer.

Gazette : What are the major causes of cancer and how can it be prevented?

Rosenthal: Most people don't realize that we currently have the knowledge to prevent up to two-thirds of all cancers.

Smoking accounts for one-third of all cancer deaths. It's the major cause of lung cancer, and it has been linked to stomach and oral cancers. That's why it's so important to prevent young people from starting to smoke.

Another one-third of cancers are probably diet- and nutrition-related. Colorectal cancer, the top killer of people 50 years and older, is likely affected by diet. Stomach cancer is also diet-related.

Many excellent studies at Harvard and elsewhere show that a diet high in fruits and vegetables and low in fat protects against many types of cancers. Controversy exists about the relative demerits of various fat types, so at this point it's best to cut down on all of them.

Federal recommendations call for five servings of fruits and vegetables daily. People are paying attention. Between 1989 and 1994, the average adult has gone from eating 3.6 to 4.4 servings a day. In the same period, however, children went from 3.5 to only 3.6 daily servings.

It's very easy to get the recommended five servings. I have a large glass of orange juice each morning; that's two servings. Then I have a piece of fruit or lettuce and tomato on my sandwich at lunch. Then I add vegetables or fruit juice at dinner.

We still don't know how fruits and vegetables protect us because it's not clear what causes cancer. Certainly the causes involve many factors, including smoking, diet, viruses, genes, and toxins in the environment.

We have a great deal to learn about these things. For example, some people are born with genes that make them more likely than others to get the disease when exposed to different risk factors, from tobacco smoke and alcohol to air and water pollutants. The absence of a tumor suppressor gene can make people more vulnerable; in other cases, such as breast cancer, it can be the presence of a particular gene. More research is needed to disentangle these relationships. And we need to better educate individuals, including physicians, about what they can do to reduce, to treat, and prevent cancer.

Gazette : Is that where Daffodil Day comes in?

Rosenthal: Exactly. We must raise money to support research and education efforts and to fight tobacco companies and polluters. Such funds will help the American Cancer Society achieve its goal of reducing cancer deaths 50 percent by the year 2015. At the same time, ACS wants to decrease the number of new cases annually and improve the quality of life for those with cancer.

There is increasing evidence that physical activity plays a role in cancer prevention. That idea needs more investigation. Also, we have targeted novel approaches for treating prostate cancer, and for dealing with health policy and psychological research related to breast and prostate cancer.

We'd like people to think about these things when they buy the daffodils and not just consider their purchase as just something they're asked to do each year.

Gazette : Where can people get more information about cancer in general, or have specific questions answered?

Rosenthal: The American Cancer Society has a home page at www.cancer.org that provides most of the things you might want to know about the disease. A link with the Massachusetts Department of Public Health, for example, gives the nicotine content of various regular, lite, and ultralite cigarette brands. If you look at that, you'd probably be surprised to learn that some lite and ultralite brands contain the same amount of nicotine as regular brands. In fact, people may get more nicotine and tars because they take deeper breaths and block filters with their fingers. That is leading, by the way, to cancers deeper in the lungs.

Those who have specific questions can contact our National Call Center at 1-800-ACS-2345. The calls are answered by real people, not machines.