A recent article in the New York Times (New York Times) suggests that we are winning the war against cardiovascular disease, but losing the war on cancer. The article leads in by citing President Richard Nixon’s 1971 announcement of his goal to cure cancer by 1976, in time for the Nation’s bicentennial celebration. After more than a hundred billion of dollars of research invested in cancer biology, prevention, and treatment between 1950 and 2005, the article continues, the death rate for cancer has decreased by a paltry 5 percent while, during the same period, the death rate for cardiovascular disease has dropped 64 percent, and death rates due to flu and pneumonia have declined by nearly 60 percent. The author of this article then goes on to cite the case of an unfortunate woman who, despite living a very healthy lifestyle, still contracted breast cancer, which went on to metastasize to her lungs.
This New York Times piece concludes that the promise of cancer prevention through lifestyle modification, and our overall progress in improving survival through the development of more effective cancer treatments, has been greatly overstated. In an interview with a nationally renowned colorectal cancer specialist, in the same article, incremental improvements in survival among patients with advanced cancers are portrayed as essentially insignificant. By the time one reads to the end of this New York Times article, it is easy to come to the conclusion that we have utterly failed, despite having invested more than a hundred billion dollars in cancer research over the past 5 or 6 decades, in our war against a disease that most experts believe has already supplanted heart disease as the number one cause of premature death in the United States, and throughout much of the world. However, as is often the case, the big picture is rather more complex than what was presented in this brief newspaper article.
Unlike cardiovascular disease, which results from increasingly well understood and relatively straightforward biological and genetic processes, cancer arises from a staggering number of biological and genetic processes gone awry. In fact, the very term “cancer,” when used in its usual context to infer a single disease entity, is, in fact, a collection of approximately 150 separate and distinct diseases which share a few common biological traits. These cancer-specific traits include the ability of malignant cells to endlessly divide until they form tumors, or masses, composed of cancer cells; and the capability of these cancer cells to break away from their parent tumors and spread, or metastasize, to distant sites throughout the body. Aside from these few critical similarities in biological behavior, however, individual types of cancer can vary from other types of cancer in their underlying cellular biology by about as much as heart disease varies from appendicitis (even within a single patient, diverse populations of genetically different cancer cells frequently coexist). Although inflammation plays a critical role in both heart disease and appendicitis, the underlying mechanisms that give rise to these two very different diseases are not the same at all. The treatments for heart disease and appendicitis are, needless to say, also quite different. Finally, the prognosis associated with heart disease is dramatically different than for appendicitis, as well. Thus, simplistic commentaries about a lack of progress in reaching the goal of curing all 150 types of cancer is, on its face, tantamount to engaging in profound na´vetÚ and incorrect thinking, in my view.
It is true, however, as the New York Times article points out, that as we have deepened our understanding of the molecular processes by which normal and cancer cells sustain themselves and reproduce, we have had to concede that the biological and genetic processes underlying cancer development and progression are infinitely more complex, varied, and bewildering than was appreciated back in the 1970s, when confident predictions about a “cure for cancer” were loosely bandied about. It is also true that we have recently entered the “molecular era” of cancer treatment, whereby incredibly expensive “targeted therapies” are increasingly being used to extend the lives of individual cancer patients by, in many cases, only a few weeks, or, at best, by only a few months.
But is all of this nihilism justified when it comes to the cumulative progress that has been made, thus far, in understanding cancer biology (which is the fundamental key to developing more effective cancer therapies), and in developing more effective cancer treatments? As a Surgical Oncologist, when I look back over the past 20 years since I began my medical training, I see stunning advances in our understanding of cancer biology, in the effectiveness of our cancer prevention programs, and in the efficacy (and reduced toxicity) of our primary cancer treatments. However, rather than focusing purely upon anecdotal clinical experiences, it is very important to review some important epidemiological data that, I believe, offers a more balanced overview of the strides that we have made in cancer prevention and treatment over the past few decades.
According to the American Cancer Society, nearly 1 in 2 men, and almost 1 of every 3 women, will be diagnosed with cancer at some point in their lifetimes. Nearly 1.5 million Americans will be diagnosed with a new cancer in 2009, and nearly 11 million Americans are now living with a current or previous diagnosis of cancer. Almost 600,000 people will die of their cancers in 2009, amounting to approximately 1,500 deaths per day. These are, to be sure, sobering public health figures, but, once again, taking a more balanced and holistic view, there are many glimmers of progress and hope to be found if one looks at recent cancer statistics in greater detail.
First of all, despite the dismal 5 percent improvement in cancer survival rates between 1950 and 2005 cited by the New York Times article, more recent data from the American Cancer Society and the Centers for Disease Control are, in fact, far more encouraging. If one compares overall 5-year cancer survival rates (which equates to a high likelihood of cure for most types of cancer) among patients diagnosed with cancer between 1975 and 1977 with the 5-year survival rates for patients who were diagnosed between 1996 and 2003, the improvement in average 5-year survival is actually rather astounding. The average 5-year survival rate for all patients diagnosed with cancer was only about 50 percent in the mid-1970s, while patients who were diagnosed with the same types of cancers between 1996 and 2003 experienced an average 5-year survival rate of 66 percent! In public health terms, this 15 percent improvement in survival is actually a dramatic and highly significant accomplishment, and speaks to the enormous (although incomplete) progress that we have made in cancer prevention, cancer screening, and cancer treatment. Moreover, there is every reason to believe that patients who have been diagnosed with cancer since 2003 will enjoy an even greater likelihood, on average, of remaining free of cancer 5 years after their diagnosis, as we continue to improve upon our ability to detect cancers at an earlier and more curable stage, and as our treatments for many types of cancer continue to incrementally improve as well.
Not only has the death rate due to cancer dropped significantly in recent years, but we are also doing a better job of preventing cancers as well (although we still have a long way to go in the area of cancer screening and prevention). In looking at recently published cancer incidence data collected between 2002 and 2005, we see, for the first time ever, a small but significant decrease in the incidence of new cancers in the United States, amounting to an average annual decrease of just under 1 percent. During this same period, the overall cancer death rate also decreased by almost 2 percent per year. (This data was reported in November of 2008 by the American Cancer Society, the National Cancer Institute, and the Centers for Disease Control.) These truly historic declines in cancer incidence and cancer death rates are the result of the same incremental but sustained improvements in cancer prevention, screening, and treatment that were largely disdained by the New York Times article. While these improvements in cancer incidence and cancer death rates may not seem enormous in absolute terms, in view of the prevalence of cancer in our society, the public health impact of these improving cancer trends cannot be understated, in my view. Still, not all of the news in this updated cancer incidence and survival report was favorable. Although death rates for 10 of the 15 most common causes of cancer-related death declined in the years between 2002 and 2005, cancer-related death rates actually increased for cancers of the esophagus, particularly in Caucasian men, as well as for cancers of the bladder, pancreas, and liver.
Even among some of the cancers where the overall death rates are declining, there is still some unfavorable news to be found. For example, lung cancer death rates have been slowly declining, overall, but when you look more carefully at the statistics for the number one cancer killer of both men and women in the United States, the data is a little bit more complicated. Deaths due to lung cancer have, indeed, been slowly falling among men since the 1990s, following years of declining smoking rates among men. During this same period, however, smoking rates among women have been rising, and the incidence of lung cancer-related deaths among women has continued to increase as well, not surprisingly. Because of the lag time between behaviors that cause cancer and the actual development of those cancers, we are only now beginning to see a leveling-off of the death rate due to lung cancer in women, although the incidence of new cases of lung cancer in women is still continuing to gradually increase (albeit at a slower rate than before).
Also, there are significant regional differences in cancer incidence and cancer-associated death trends in the United States. Once again, taking lung cancer as an example, we see that lung cancer death rates declined by almost 3 percent per year in California between 1996 and 2005, which is about twice the rate of decline that was observed among other states in the Midwest and the South. These discrepant results directly mirror the impact of anti-smoking ordinances enacted in California, and the absence of such public health policies and ordinances throughout much of the Midwest and the South. Statistics such as these demonstrate that lifestyle modifications really can dramatically impact upon the incidence of certain cancers, and (obviously) upon the death rates associated with these same cancers.
While the gradual overall decline in the death rate due to lung cancer is a direct result of decreasing smoking rates in our population, there are other examples of recent and significant reductions in cancer incidence due to changes in lifestyle, as well. For example, the recently observed decline in new breast cancer cases among postmenopausal women is now thought to be due to, in great part, a significant decrease in the number of women who are currently taking hormone replacement therapy for the symptoms of menopause. Colorectal cancer rates have also been declining for several years now, and most experts believe that this has occurred because more pre-cancerous colon and rectal polyps are being identified and removed during screening colonoscopy in patients who are compliant with colorectal cancer screening guidelines.
Therefore, I believe that we have been making sustained progress in cancer prevention, although not nearly enough progress when you consider that our best clinical estimates are that somewhere between 60 and 80 percent of new cancer cases can be prevented through behavioral, lifestyle, and dietary modifications. (Although our treatments for most types of cancers are gradually improving, an ounce of cancer prevention is still worth a ton of cancer cure.)
When one looks at the most common causes of cancer-related deaths in the United States (and in most other industrialized countries), the cancer survival picture, while far from ideal, looks much brighter than was portrayed in this recent New York Times piece. Significant declines in the death rates associated with three of the most common causes of cancer deaths, in both men and women, have been reported since the early 1990s for cancers of the colon and rectum, prostate, and breast, as well as for the number one cause of cancer death in men, lung cancer (hopefully, the death rate for lung cancer in women, which is also, by far, the most common cause of cancer-related death in women, will soon begin to fall as well). Contrary to the dismal picture painted in this brief and overly generalized New York Times article, survival rates even for patients with advanced cancers of the lung, colon, rectum, breast and prostate have actually continued to significantly, albeit incrementally, improve over the past two decades as our therapies have improved.
Yes, we still have much work left to accomplish in preventing and curing cancers. However, things are hardly as bleak as was described in this widely disseminated New York Times article when it comes to our sustained and ongoing improvements in cancer prevention, screening, and treatment. While the exponentially rising cost of cancer screening and new cancer treatments is a very serious issue, given our already grossly underfunded healthcare system in the United States, an overly nihilistic assessment of our progress in the war on cancer is, at the same time, unwarranted and unfair. The complexity of cancer, as a biological entity, has only recently come to be fully appreciated. As our understanding of the molecular underpinnings of cancer biology continues to grow, I predict that we will continue to make sizable gains in cancer prevention and cancer treatment outcomes. While a universal cure for all types of cancer is not likely to be achieved within my lifetime, I can honestly say that this is a wonderful and hope-filled era for cancer research and treatment, and for many cancer patients, and speaking more personally, for cancer physicians like me, as well.
In my forthcoming book, “A Cancer Prevention Guide for the Human Race,” I look forward to thoroughly reviewing a broad spectrum of clinical and scientific data regarding specific lifestyle and dietary factors that appear to be promising as cancer risk reduction strategies. At the same time, I will also discuss the growing body of research data that has recently called into question many of the popular dietary and other lifestyle approaches that have been marketed and hyped as cancer prevention strategies. Look for publication of this important new evidence-based approach to cancer prevention in early 2010.
Disclaimer: As always, my advice to readers is to seek the advice of your physician before making any significant changes in medications, diet, or level of physical activity
is an oncologic surgeon, a professor
of surgery, a widely published author, and the
Physician-in-Chief for Surgical
Oncology at the Kaiser Permanente healthcare system in Orange County,
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Robert A. Wascher, MD, FACS.
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