Thanks to medical research, there's new hope for fighting cancer. Promising drug therapies, and even a vaccine, are available that not only lower the risk of cancer but in some cases stop cells from growing. “Chemoprevention” is just one of the cancer-fighting strategies addressed in a new book, "The Answer to Cancer." Dr. Carolyn Runowicz, one of the authors, was invited on the “Today” show to discuss the cutting-edge treatments covered in the book. Here’s an excerpt:
The Cancer Problem
Cancer scares us, and for good reason. It kills more people between ages 45 and 64 than anything else. Experts estimate that it soon will surpass heart disease as the number one cause of death in the United States.
It scares us, too, because it often comes without warning. Although cancer typically develops over many years, we may not discover it until it causes symptoms. By then, the window of opportunity for cure is closing fast.
Even when we detect cancer early on, it has the power to frighten us. Treatments can be harsh, and the threat of a recurrence hangs like a cloud of uncertainty over the future.
Finally, cancer scares us because the risk factors seem to be everywhere. Cancer-causing agents lurk in the air we breathe, in the food we eat — even within our own bodies, in the genes we inherit.
Maybe because it’s so frightening, some of us prefer to put the possibility of cancer out of our minds, crossing our fingers that it never touches us or those we love. We’d be smart to change our strategy. Yes, cancer is a formidable foe, but it is not invulnerable. We can do more than simply hope to avoid it. We can take action to lower our risk.
The more we learn about the process that sets the stage for cancer, the more we learn about methods that can alter its course. Since this process usually occurs over many years, we have many opportunities to disrupt it. Scientists are making great strides in determining how we can stop cancer before it gets a foothold in the body.
In medical terms, an action that switches off cancer formation or eliminates a precancer is known as an intervention. Some of the most exciting cancer research going on today is showing that interventions work. For instance, women who have undergone treatment for breast cancer can take a drug to block the hormonal signals that could stimulate a recurrence. For men, a drug commonly prescribed to relieve benign prostate enlargement also can lower prostate cancer risk. And a topical cream that clears up actinic keratoses — brown spots caused by the sun — helps prevent skin cancer as well. (For that matter, so does removing the spots surgically.)
Since the passage of the National Cancer Act in 1971, there has been a government-backed nationwide movement to control cancer. But the impetus to focus on prevention really got going in 1981, with the publication of a landmark study whose authors concluded that most cancers affecting Americans are avoidable. According to the authors, Sir Richard Doll and Sir Richard Peto, about one-third of cancers result from smoking, one-third from diet, and one-third from environmental and occupational causes.
A few years before Doll and Peto’s famous paper, Michael B. Sporn, M.D., conducted a study on the use of vitamin A and its derivatives to slow the cancer process. His work with these particular substances, which he called retinoids, gave birth to a whole new concept: chemoprevention.
Nearly two decades later, scientific proof that drugs could prevent cancer in humans was mounting rapidly. In the late 1990s, researchers found that a vaccine against hepatitis B dramatically reduced the incidence of liver cancer in Asia, where the disease had been very prevalent. In 1998, a study of tamoxifen — already found to head off recurrences in breast-cancer survivors — showed that the drug could reduce risk by 40 percent in women especially susceptible to the disease. Retinoids, the vitamin A derivatives that led Dr. Sporn to shape the concept of chemoprevention, proved effective in getting rid of oral precancers. And nonsteroidal anti-inflammatory drugs, or NSAIDs, were useful in keeping colon polyps — which can turn cancerous — from coming back.
To date, the FDA has approved a few drugs that help prevent cancer by treating precancers. Among them are BCG, for recurrent bladder tumors; topical fluorouracil, for actinic keratoses; tamoxifen, for women with ductal carcinoma in situ (abnormal cells that have not yet spread beyond the lining of the breast duct); and celecoxib, for colon polyps.
Finding other drugs that could prevent cancer has become a very active area of study. In 1998, the National Cancer Institute established the Chemoprevention Implementation Group to set research priorities. This group, in turn, created the Rapid Access to Preventive Intervention Development (RAPID) program, whose mission is to speed the process of bringing research from the laboratory to clinical trial, and to recommend other strategies for identifying and testing preventive agents.
Separating Fact From Fiction
Just as there probably is no single drug or treatment that will cure cancer, there probably is no magic bullet that will prevent it, either. Each person has a unique genetic code, a unique lifestyle and environment, and a unique willingness to do what’s necessary to maintain his or her health. For this reason, everyone must look at their own situation and make their own decisions about what’s necessary to lower their cancer risk.
In this book, we hope to provide you with information to assess your own risk and make appropriate choices. We also hope to spare you the time, energy, and expense of trying things that have not proved helpful and that in fact may be harmful.
Sometimes it seems that every day brings a new headline about a nutrient, supplement, or drug that prevents cancer. A single study may add to the body of scientific evidence, but by itself, it is not proof. Several studies, including very large ones, are necessary to determine whether a particular intervention actually works.
Showing that certain foods and dietary habits are effective preventives can be especially challenging. Scientists struggle to maintain control over what their human subjects eat. And the people themselves don’t always remember what they eat, either.
Because the cancer process takes so long, evaluating the impact of certain nutrients also can be difficult. Thus far, studies that meet key scientific criteria are not too encouraging. In fact, two such trials found that rather than help to prevent cancer, extra doses of key nutrients encourage cancer growth or fail to inhibit precancers. For example, in a study evaluating vitamin E and beta-carotene, supplements of both nutrients promoted rather than prevented lung cancer in male smokers.
This is our objective — to provide a reality check about what you can and can’t do to lower your cancer risk. Along the way, we intend to clear up some common cancer-prevention myths. Perhaps most pervasive at the moment is the notion that all kinds of supplements have preventive powers. Patients routinely come to us with bags full of pills or long lists of supplements that they hope will protect them from a cancer diagnosis. Right now, we have only preliminary evidence to suggest that these products might do what they claim. What we do know for certain, with regard to nutrition and cancer prevention, is this: First, eating fruits and vegetables reduces risk; and second, being overweight — which often stems from poor dietary habits — increases risk.
In writing this book, we have made every effort to distinguish between what is proven to help prevent cancer, what no longer holds promise, and what shows promise but is not yet proven. Much remains to be discovered, and many studies are pointing in exciting new directions. But if you’re contemplating paying for certain tests, taking certain supplements or medications, or changing your diet or lifestyle, you should start with an accurate picture of the current “state of the science” in cancer prevention.
We want to stress again that assessing cancer risk is a very individualized task. You are a unique genetic package, and your risk factors are different from those of your neighbors, your friends, even your siblings. What’s important to remember is that while some risk factors (like your age, ethnicity, and family history) are beyond your control, others (like eating a high-fat diet or not exercising) are yours to change. Throughout this book, you’ll learn how to modify your risk profile and how to evaluate your risk for cancer in general, as well as for the nine most common forms of the disease.
The Key to Staying Cancer-Free
The study of how to modify the cancer process has snowballed in recent years. Today certain professional conferences and medical journals focus exclusively on prevention. It’s the new frontier of cancer research. Of course, developing new cancer treatments is an ongoing priority. But the most exciting and promising developments are in early detection and prevention.
For example, researchers have produced a vaccine to protect against infection with the virus that causes cervical cancer. They also have devised a method for catching early on the cellular changes that could lead to breast cancer. Various drugs excel in preventing breast, prostate, and colon cancers — and scores more are in the research pipeline.
Scientists the world over are scrutinizing different dietary components to determine why fruits, vegetables, soy products, and the polyphenols in green tea — among other foods and food-derived substances — are such potent cancer fighters. Perhaps they work best for people who are genetically programmed to respond to them. Maybe certain combinations are more beneficial than others. Or maybe they share a single, common substance that’s responsible for their cancer-fighting potential. As the answers come to light, the face of cancer prevention will transform.
We’re convinced that the solution to the cancer problem lies in detecting precancerous changes before they mushroom to full-blown cancer, and in stopping the cancer process from ever starting. With this two-pronged approach, you can do so much to dramatically lower your risk. And the more you learn about cancer prevention now, the better equipped you will be to take advantage of groundbreaking new measures that we suspect will be making headlines in the near future.
Excerpted from “The Answer to Cancer” by Carolyn Runowicz, Dianne Lange, Sheldon Cherry. Copyright © 2004 by Carolyn Runowicz, Dianne Lange, Sheldon Cherry. Published by Rodale. All rights reserved. No part of this excerpt can be used without permission of the publisher.