Every year the American Cancer Society, along with the Centers for Disease Control, the National Cancer Institute and the North American Association of Central Cancer Registries provides a report to the nation on the status of our efforts to reduce the burden and suffering from cancer.
For the past several years, as discussed previously in this blog, the news has been good: we have seen a sustained and durable reduction in deaths from cancer, especially in those cancers that affect the most folks in this country.
This year, the progress continued.
But, not all the news is good and that trend has continued this year as well.
Sometimes, we find some surprises in the data. And this year was also no exception in that regard.
The key message remains: We could be doing much better with respect to many types of cancer if we applied the knowledge we already possess.
First, the good news: death rates from cancer continue to decline, maintaining a trend that has been evident for many years. All races and both sexes have experienced this decline, although men have benefited more than women. In men, the annual percentage decrease in deaths from cancer is 1.6% a year, and for women the number is 0.8% per year.
At first glance, that doesn’t seem like much. But you need to take into account that over the past decade, that means there are 16% fewer deaths from cancer in men today than 10 years ago, and 8% fewer deaths from cancer in women over the same time period.
That decrease in death rates has occurred in the face of an aging population, which is the single greatest risk factor for developing cancer. This country also has a population that is becoming more overweight and obese, another factor which a couple of years ago was linked to significantly increased risks of developing several cancers.
For the most part, the reasons for the decline in death rates are well known: we do a better job of screening for certain common cancers; we smoke less now than we did in the past which in turn affects the incidence of several forms of cancer; our treatments are more effective.
We still don’t do as well as we would like at preventing many forms of cancer and our screening efforts are not as robust as they should be.
We have seen, and continue to see, a rise in the number of cases of prostate cancer. This may in part be explained by the fact that over the past decade more men are getting the PSA test, and therefore many more prostate cancers can be found. Fortunately, death rates from prostate cancer continue to decline.
The inexorable climb in the incidence of breast cancer has finally started to decline. For the most recent period analyzed in the report (from 2000-2003), the incidence of invasive breast cancer decreased 4.8% per year. Why that has happened is uncertain, and may be related to the significant decrease in the use of hormone replacement therapy following the report of the Women’s Health Initiative in 2001.
(Actually, why the media hasn’t been focusing on this as much as they have on the increase in thyroid cancer discussed below is a surprise to me. It is true that we need to follow this in future years to be certain it is a trend, but an annual decrease of this magnitude is of no small consequence.)
One concern that cannot be addressed by this study with regard to the decreasing incidence of breast cancer is whether or not this is a real decline. We won’t know this until we have data for more years in the future.
The decrease could reflect other factors, such as the possibility that we are diagnosing fewer breast cancer because of problems with access to mammography, or because women are becoming complacent and not getting their annual mammograms in accordance with the American Cancer Society guidelines.
Another somewhat distressing trend is the observation that the rate of lung cancer diagnoses in women has not yet begun to decrease to a significant degree.
This probably is related to the fact that women were slower than men to understand the harms of smoking, and any change in that behavior takes 15-20 years until it has a real impact on the number of deaths from that disease.
(Although some would like to read a gender issue into this—namely that more women non-smokers develop lung cancer than men non-smokers--a recent study showed that that is simply not the case. The bottom line is that the rates of lung cancer in non-smoking women have remained stable for many years. There are more women non-smokers than men who are non-smokers, so the number of lung cancers in non-smoking women appears greater.)
For men, the rate of lung cancer continues to decline, reflecting a trend that has been present since the 1980’s.
Lung cancer remains particularly problematic for black men, who have the highest rate of the disease. The good news here is that their rate of deaths from lung cancer has dropped an average of 2.7% a year from 1995 through 2003.
What has received a lot of attention in the media is the marked increase in the incidence of thyroid cancer diagnoses in women from 2000 through 2003, at an average of 9.1% a year. That means that thyroid cancer is on a trend to double in incidence in women over the eight year period from 2000 through 2008 unless this abates. For men, the average annual rate of increase in the incidence of thyroid cancer from 1995 through 2003 was 5.4%.
We don’t know why this is happening. A number of years ago there was substantial concern about the delayed risks of people who were treated with radiation for their enlarged tonsils around the late 1940s and early 1950s. I can still recall the doctor offering my parents that very choice when I was about four years old. Fortunately, they opted for surgery which was much more commonly done then than it is today for that condition.
But there may be other explanations, such as improved diagnostic and biopsy techniques. And of course there have been other concerns about environmental radiation exposure that have been raised periodically in the past, especially in the era of above ground nuclear testing in the United States and elsewhere (I suspect that a good number of my readers aren’t familiar with the pictures of service men watching the mushroom cloud rise over the Nevada desert after a nuclear test explosion. Little did we understand the harm of those tests. And little did we understand about the impact of other countries’ nuclear testing as radiation clouds encircled the globe).
Although there is certainly going to be an increased awareness of this increase in thyroid cancer as a result of these findings, as I write this we simply don’t know for certain why it has occurred. You can be assured that there will be researchers who will pursue the answer to that question.
Hopefully we will see this trend reverse, but we will have to wait to see what the data shows us over a longer period of time.
If there is any good news about this particular statistic, it is that deaths from thyroid cancer are uncommon in this country, which means the outlook for most patients with this illness is good. But that doesn’t negate the fact the this report suggests the incidence of thyroid cancer has been increasing significantly over the past several years, and now stands at a current estimated rate of 30,180 cases in 2006, of whom about 2/3 are women.
(The observation about the increase in thyroid cancer provides an opportunity to point out another weakness in our health care system, namely the delay in time it takes to get the information together for these reports. Note that the latest year for which the data has been analyzed is 2003. We are now in the last quarter of the year for 2006. How and when are we going to be able to effectively monitor our progress against cancer in real time when it takes so long to gather this information? Our surveillance systems are simply not able to keep pace with our need to have accurate information about the impacts of our various efforts to improve our prevention, early detection, diagnosis and treatment of cancer.)
As with every report to the nation, this one has a special section which examines a particular area in detail. This year’s report was no exception with its focus on the incidence of cancer in the Latino population who reside in the United States.
According to the report, 13% of the United States population identify themselves as Latino.
A point that is frequently overlooked when discussing this ethnic group, and that is made very clearly in this report, is that the Latino population is not homogeneous. It is in fact its own multicultural group.
As noted in the report, the predominant Latino groups in the United States are Mexican, Puerto Rican, Central American, South American, Cuban and Dominican. And each of these groups have there own specific demographic features, such as socioeconomic status, location of residence, and dietary habits among others.
As a group, Latinos had an overall lower incidence of cancers than the general United States population. However, they had higher rates of cancers of the stomach, liver and cervix as well as a greater incidence of myeloma in women. Latino children had a higher incidence of several childhood cancers. And, unfortunately—but not unexpectedly—cancers diagnosed in Latinos were more often at later stages, likely because of limited access to health care and cancer screenings. That translates into poorer outcomes for treatment of their cancers.
The interesting observation about several of the cancers noted to be of greater risk for this group--namely cervix, liver and stomach cancers—is that these are cancers which are known to be related to infections. We can immunize against the hepatitis virus, which causes liver cancer, and we now have a vaccine that will prevent many cases of cervical cancer. The infection that is linked to stomach cancer, called H. Pylori, can be successfully treated with antibiotics.
With improved access to care, all of these cancer rates would be decreased in the Latino population.
As the authors note in the report, “Affordable, culturally sensitive, linguistically appropriate and timely access to cancer information, prevention, screening, and treatment are important in Latino outreach and community networks.”
I would add that this advice applies to virtually every ethnic, socioeconomic and demographic group in this country.
How do I summarize the results of our efforts to reduce the burden and suffering from cancer, which is the core mission of the American Cancer Society and other respected organizations?
We are achieving successes in many cancers, and are not making progress in others.
Our country could do a better job of assuring that everyone has access to effective medical care, which also includes access to prevention strategies that have been proven to work.
As many of us have said many times, by applying the knowledge we have today—knowledge of prevention, early detection and effective treatment of cancer—we could rapidly decrease the death rates from many cancers.
The fruits of our research are providing tangible results in improving the quality and effectiveness of our cancer treatments. We are able to accomplish many things today that even 10 or 20 years ago were just dreams for many of us.
We have a tendency to forget the progress that we have made, and this report provides us a reminder that we have come a long way. Not far enough, mind you, but a long way nonetheless.
I am reminded even as a write this that we are at the beginning of another revolution in the diagnosis and treatment of cancer.
Several articles in just the past two weeks regarding the application of genetics to the diagnosis and treatment of cancer have only served to reinforce my sense that we are at the tipping point of applying this information in very practical and meaningful ways in our battle to conquer cancer.
I don’t know how long it will take until we see even greater and more substantial declines in cancer death rates beyond what has occurred over the past decade.
I am frequently asked when I think this will happen, and my answer is simply “I don’t know.” It could be five years, and I have heard some experts predict 10 years. The former director of the National Cancer Institute set a goal recently to significantly reduce deaths and suffering from cancer by 2015 through efforts to turn it into a chronic disease like diabetes or hypertension.
What I do know is that we could do better today by doing what we already know.
Couple that with our rapidly advancing knowledge on the research and treatment fronts, and you can begin to understand why I hold on to the hope and the promise that our annual reports will continue to show progress. And that progress means many lives will be saved every year for years to come.