The positive news continues: cancer death rates have continued to fall in the United States, for men and women, maintaining a trend that began in the early 1990's. That's the essence of a report released today by the American Cancer Society, the National Cancer Institute, the Centers for Disease Control and Prevention and the North American Association of Central Cancer Registries in the Journal of the National Cancer Institute.
The report, titled in part "Annual Report to the Nation on the Status of Cancer, 1975-2009" also features a special section on the burden and trends in Human Papilloma virus (HPV) associated cancers and HPV vaccination coverage levels. Unlike the continuing decline in cancer deaths in the United States, we could be doing a much better job of getting young folks vaccinated against HPV and reducing the incidence and death rates from several HPV-associated cancers, according to the authors of the report and an editorial that accompanied the report.
This report comes out every year. It is a summation of what we know about the trends in incidence rates for the most common cancers in the United States among both men and women as well as the trends in death rates from those cancers that lead to the highest mortality in the general population as well as specific ethnic groups. It is in a real sense a report card on our progress, which in large part is good but in a number of cancers, not so good.
The good news is what we have come to expect: since the year 2000, the overall cancer death rates have continued to decline 1.8% per year in men, 1.4% in women and 0.6% per year in children. That may not sound like much, but when you consider the fact that this is an average change seen every year, those numbers begin to add up.
Overall cancer incidence rates during that same time frame decreased 0.6% a year among men, and remained stable in women. Unfortunately, the incidence rates for childhood cancer increased 0.6% a year from 2000 through 2009.
When it comes to incidence, we continue to see certain cancers diagnosed less frequently. In men, 5 out of 17 of the most common cancers-including prostate cancer, lung cancer, colorectal cancer and stomach cancer-were diagnosed less often. Unfortunately, in men, other cancers increased in frequency including cancers of the kidney, pancreas, liver, thyroid, melanoma, and myeloma.
For women, cancers of the lung, colon and rectum, bladder, cervix, oral cavity and pharynx, ovary and stomach declined in incidence while thyroid, melanoma, kidney, pancreas, leukemia, liver and uterus increased.
When considering deaths from cancer from 2000-2009 in men, several of the most common cancers saw continued decreases in death rates. These included lung, prostate, colon and rectum among others while increases were seen in death rates for pancreatic, liver, soft tissue cancers and melanoma.
In women 15 out of 18 cancers experienced a decrease in death rates, most prominently among them breast cancer, lung cancer, colon and rectum cancer, and ovarian cancer. On the other hand, death rates increased for cancer of the pancreas, liver and uterus.
It is always a challenge to answer the question why we see these shifts over time. There are so many factors that go into making cancers more or less prevalent or cancer deaths more or less frequent. There are, however, a number of trends that can contribute to these observations. Increased awareness and better ways to take pictures of the body (think x-ray, ultrasound, CT scans, MRI for example) can lead to finding more cancers, including those we didn't suspect in the first place. It is no longer uncommon for an imaging study of a part of the body to be done, and quite unexpectedly find a cancer such as in the thyroid or the kidney.
But better imaging and awareness doesn't explain every situation. For example, there is a widespread belief that many thyroid cancers are found incidentally and may never have caused someone harm during their lifetime had they not been diagnosed. On the other hand, as noted in the report, not all experts agree that that is the entire explanation and there might be other reasons-such as environmental factors-that have contributed to this truly significant increase in thyroid cancer in this country.
For cancers of the pancreas, uterus and kidney-among others-overweight and obesity could explain some of the problem. But, again, being overweight and obese doesn't answer the entire question. And we aren't even certain at this point precisely how being overweight or obese leads to increased cancer risk.
It's a bit easier to explain why we see fewer lung cancers, or cervical cancers, or colorectal cancers. For lung and other tobacco-related cancers, the significant decrease in incidence and death is directly related to the fact that we have experienced a significant decline in smoking in this country. Screening for colorectal cancer and especially for cervical cancers has made a significant impact on the number of actual cancers of those organs that we diagnose today. But with prostate cancer screening so widespread, why are we seeing a sustained decline in the number of prostate cancers diagnosed each year since 2000 through 2009? Could it be some other factor that has led to a change in the frequency of certain cancers? The answer to that question is almost certainly "yes."
The sad part of this story is that certain cancers continue to increase in incidence and mortality despite our improved diagnostic techniques and treatments. Liver cancer and pancreatic cancer come to mind, possibly related to the obesity epidemic and probably to uncertain factors. In the case of liver cancer, there is increasing concern about the impact of hepatitis C virus, for which the Centers for Disease Control now recommends routine screening among certain age groups given that we now have effective treatments which can reduce the risk of serious damage to the liver from this virus.
As noted above, every year the annual report covers a topic of special interest. This year that topic is the burden of human papilloma virus, or HPV.
The good news is that we now have a vaccine which is effective in providing protection against the 2 types of HPV viruses that cause a majority of HPV-related cancers, including cervical, oral, anal, vaginal and vulvar cancers. The not-so-good news is that compared to other countries, we in the United States are not as good at getting appropriate people vaccinated at the right time to prevent long-term infection with HPV. This becomes a more concerning topic as we see an increase in both oral and anal HPV-related cancers, caused in no small part by sexual practices.
It doesn't have to be this way, according to the report's authors. There are a number of ways we could increase HPV immunization, ranging from improved communication between doctors' offices and their patients and better coverage for the cost of the vaccine. Hopefully, improved access to health insurance and medical care for more people at risk will help reverse this trend and increase the population-based immunity to HPV.
I was asked today whether I found this report encouraging. My response was yes, with some cautionary notes.
Who cannot be pleased that we are seeing significant declines in cancer deaths in this country, especially for the most common cancers? But we must not forget that there are still too many people who die from cancer in this country every year. This happens for many reasons, some of which we can do something about, and some over which we have no control.
Making cancer care more universally available is one major step. Getting people access to effective screening and prompt and appropriate treatment if they are diagnosed with cancer is another. We could do better at getting the "lifestyle" messages out to the population and creating an environment of health that will make it easier to adopt and implement healthy behaviors, such as maintaining a normal body weight, exercising, and eating a healthy diet. We have made great strides in reducing tobacco consumption, as reflected in the decline in lung cancer incidence in men and women, but we still have about 20% of our population smoking-and that has been a steady number for many years.
We still have major gaps that we are not closing: the increasing risk of pancreatic cancer diagnoses and deaths being but one example. We could do much better in treating this disease and others such as advanced lung and ovarian cancer and sarcomas to name but a few.
And let's not forget the researchers, who are pressing forward rapidly with new discoveries, many centered on the new understanding of the human genome and our ability to decode the genetic code of an individual's cancer.
So the bottom line is that we are making progress, and that should be applauded. But we also have failures, which must be addressed. If we do not engage the obesity epidemic we are at risk in the opinion of some experts of moving backwards from the gains we are discussing today. If we don't make access to cancer detection and treatment easily available we may see our progress slow substantially. If we don't take into account the quality of life of cancer survivors and their caregivers we will make the burden of diagnosis and treatment of cancer even greater that it already is.
So let's be optimistic, while at the same time leavening our optimism with the sobering reality that we still have much progress to make. Let it be our hope and prayer that these annual reports for years to come will show continued success in reducing the burden and devastation of cancer, and unwelcome loss of life.
If we concentrate our attention and our resources, we can make that dream a reality for many years to come.