ncologist Greg Smith, M.D., is a cancer specialist practicing at St. Helena Hospital in Deer Park, California, the oldest continuously operating Adventist hospital in the world. Because of his cancer research Dr. Smith was invited to act as medical adviser for the cancer chapters of the newly released book Medical Breakthroughs of 2001 (Reader's Digest), in which he directed, supervised, and reviewed the work of scientific writers about the most recent developments in cancer research. (Here Lynn McDowell interviews Dr. Smith.)

So what's the good word in cancer research?
Lots of positive things are happening. Some of the most exciting developments have been in genetic research, in new combinations of modalities or tools for treatment, and in some of the prevention studies.

Let's begin with the genetic research.
We can now identify some of the genes that carry tendencies toward specific cancers, such as the BRCA1 and BRCA2 forms of breast cancer. What's exciting to me is using some of the new modalities to turn off cancer cell growth. I think we're going to see a tremendous amount of advancement in cancer treatment soon. It's going to be through genetic manipulation or stopping blood vessel growth to the cancer by using antiangiogenesis factors such as thalidomide, which has been effective in stopping blood vessel formation in tumors. It's going to be through knowing the mechanisms that turn cancers on and finding out how to turn them off. These breakthroughs will combine with the standard treatments such as chemotherapy, radiation, and surgery.

What do you mean by "new combinations"
of modalities/tools for treatment?
Since there is no cure for metastasized cancer and because everything in this area changes every three months, you have to keep looking for the next "best" thing. That's why I like to offer participation in clinical trials to patients, because there is no "correct answer." If you have breast cancer, there's not one right thing to do. So if there's a selection of things to do, we might as well find out what's best for the next person through recording what we find by using different approaches, rather than just picking a program off the shelf.

In treating patients, I'm interested in taking drugs that we know work and finding new combinations, or drugs that we know work but may not be approved yet, and finding a place for them in our cancer treatment--Phase III research protocols [Phase I and II use more experimental drugs]. Or testing one standard treatment against other standard treatments. The way I do that is by being associated with a big national investigational group like the Southwest Oncology Group (SWOG). All their trials are national trials with strict protocols and oversight to protect patients.

There seems to be a strong link between the good news you've cited and the way you approach cancer treatment, and that's research. Is that why you've invested in establishing an endowment for cancer research at St. Helena Hospital?
I don't think you can treat cancer patients without doing research. Sometimes finding the new "best" treatment involves using things other than chemotherapy, such as combinations of radiation and surgery, or vitamins, or diet, or adding different types of immune system stimulants. Effective cancer treatment is, and will continue to be, a combination of things.

Including preventive strategies?
Yes. We see cancer patients, but we also see their families, who can do things to alter their lifestyles to prevent cancer. That may include simple things like losing weight, exercising, stopping smoking, limiting exposure to toxins, or taking medicine to prevent potential development of cancer.

What prevention-focused research carries good news?
It's hard to say that there are certain things in the diet that definitely cause or prevent cancer. There are prospective studies [more reliable than retrospective studies in which people try to remember what they ate and did years ago] looking at cancer prevention with diet. But it's so hard to do the [prospective] population studies. You have to have a dedicated population, and you have to have the people to follow them. And there has to be money to pay the people to follow the people in the study. But there have been some interesting findings.

A big study looked at nurses who reported what they ate, how much alcohol they used, and how much caffeine they had. It followed them for 10 years. One of the conclusions was that more than one glass of wine per day increased the risk of breast cancer. That hasn't been shown in all studies. The interrelationship of alcohol and breast cancer has been shown in a lot of studies but not all studies. We do know that alcoholics have a higher incidence of esophageal and head and neck cancers. These are usually people who drink hard liquors, and that's definitely associated with those cancers.

Also, we know that if you take a same population [a population with the same genetic pool] in different countries they have different risks of cancer. Japanese women in Japan have a relatively low risk of breast cancer. If you take Japanese women in Hawaii, their risk of breast cancer goes up, and Japanese-American women have a much higher risk of breast cancer. From what we can tell, it has to do with fat intake and also lean body massCthe women in Japan tend to be leaner than those women living in the United States. Does dietary fat cause breast cancer? Probably not, but there's a link there, so the general recommendation has been low-fat diets.

There's also a dietary link between high-fat diets and colon cancer, and it seems there's something [preventive] in having a diet high in fiber. If you take people in Africa--who have very low- fat diets and get a lot of roughage in their dietCthey have a very low incidence of colon cancer. You come to the United States, with its high-fat, high-protein, high-fried-food diet, and there's a high incidence of colon cancer. It looks like it has to do with the amount of fat in the diet, the amount of roughage in the diet, and it may also have to do with the amount of calcium in the diet. In populations with high calcium intake, they have a tendency toward lower colon cancer rates.

Guidelines for Cancer Prevention Choose a diet rich in a variety of plant-based foods. Eat plenty of vegetables and fruits. Maintain a healthy weight and be physically active. Drink alcohol in moderation, if at all. Select foods low in fat and salt. Prepare and store foods safely. And always remember: Do not smoke or use tobacco in any form. Source: The American Institute for Cancer Research (AICR), www.aicr.org.

A retrospective study of vegetarian Seventh-day Adventists looked at the calcium intake in colon cancer. It showed that Adventists had a decrease in colon cancer over the general population. Two hypotheses are increased roughage and increased calcium intake, and possibly a low-fat diet. But Adventists definitely have a lower incidence of colon cancer.

The information on vitamins is confusing. We know that some of the vitamin A and E derivatives can decrease precancerous lesions in the mouth, but a similar study of lung cancer patients who were still smoking found that patients who had extra vitamins A and E had a higher risk of developing lung cancer again. Then studies on gastric and esophageal cancers in China found a decreased risk of those cancers in patients who took supplemental vitamin A and E.

Researchers are now looking at levels of exercise for women in terms of risk for breast cancer. Athletic young women tend to have a lower incidence of breast cancer, perhaps for a couple reasons: lower body fat and later onset of menses, which is linked to low estrogen levels. Breast cancer risk is directly related to the amount of uninterrupted time that a woman has regular menstrual cycles. Late onset of cycles, multiple pregnancies, and early menopause translate into a shorter time of hormone stimulation and lower risk of breast cancer.

One of the bright spots in breast cancer prevention is the phytoestrogens, or plant estrogens, in soy. Plant estrogens have varying degrees of ability to stimulate the estrogen receptor. They bind to the estrogen receptor but don't have some of the effects that estrogen does. Some of [these plant estrogens] have some of the positive effects of estrogen, such as preventing osteoporosis, but may not have the ability to stimulate the cells to grow, like estrogen does. In some ways they act like the antiestrogen medication tamoxifen.

So the plant estrogens in soy may help
prevent breast cancer and osteoporosis?
Yes.

Do you believe that someday cancer will be beaten?
Yes. I think we're going to see a lot of advancement in terms of knowing the genetics of cancer. Cancer may end up becoming a chronic disease that we control, rather than cure, through keeping the growth stimulus turned off.

With your background and reputation, why did you choose
to join St. Helena Hospital--an Adventist Health hospital?
There was a need, and I think it has excellent medical staff and an excellent reputation. And you can't beat the view!

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Lynn Neumann McDowell is director of planned and major gifts at St. Helena Hospital in California's Napa Valley.