April 1, 2011 — Deaths from cancer are continuing to decline in the United States, and the overall incidence is decreasing slightly, according to the latest Annual Report to the Nation on the Status of Cancer. However, experts say that the progress being made is slow, and that there is still a long way to go.
The report is coauthored by researchers from the National Cancer Institute, the American Association of Central Cancer Registries, the Centers for Disease Control and Prevention, and the American Cancer Society.
It was published online March 31 and will appear in the May 14 print issue of the Journal of the National Cancer Institute.
This latest report covers the years from 2003 to 2007. The rate of death from all cancers for men and women continued to fall during that period, continuing a trend that began in the early 1990s.
Notably, there was a statistically significant decrease in the death rate from lung cancer in women — the first time this had been seen. This comes more than a decade after such a decline was seen in men and reflects the later uptake of cigarette smoking in women compared with men.
Overall cancer incidence rates decreased very slightly — by less than 1%. There was a statistically significant decline of 0.6% in women, but a nonsignificant decrease of 0.6% in men that was influenced by a recent (2005 - 2007) non–statistically significant increase in prostate cancer incidence.
When analyzed by different cancer types, there was a decrease in incidence for many cancers, but not for all cancer types.
There was an increase in the incidence of kidney and pancreas cancer, as well as melanoma of the skin in both sexes, and men have also seen an increase in liver cancer, whereas women have also seen an increase in thyroid cancer and leukemia.
"Of concern is the long-term increase in cancer incidence rates among children," note the authors, which may be a result of increases in the incidence rates for the lymphoid leukemias.
Commenting on the latest figures, National Cancer Institute Director Harold Varmus said: "It is gratifying to see the continued steady decline in overall cancer incidence and death rates in the United States."
This is the result of improved methods for preventing, detecting, and treating several types of cancer, he commented in a statement.
"But the full repertoire of numbers...also reflects the enormous complexity of cancer, with different trends for different kinds of cancer, important differences among our diverse people, and different capabilities to prevent, detect, and treat various cancers," Dr. Varmus said.
Reaction for Cancer Experts
"The incidence rates haven't declined that markedly — it's not impressive," Michael Caligiuri, MD, director of the Ohio State University Comprehensive Cancer Center and chief executive officer of the James Cancer Hospital & Solove Research Institute, Columbus, commented in an interview with Medscape Medical News.
It's not impressive.
One piece of good news is the decline in breast cancer seen after the fall in use of hormone replacement therapy, which was a result of research. This shows that "research can save lives: If we have the information, we can act quickly and change the course of a disease quite markedly," he said.
"The bad news is that we are not putting that sort of research, or sufficient research, into this field, and we could make an impact on prevalence and incidence of cancer if we did," he said.
"Specifically, we need to stop the stagnation of funding of cancer research," he continued. The level of funding has been flat in the United States for the last few years — with inflation, it has actually decreased in real terms — and failing to fuel research is slowing the progress being made against cancer.
There is now a better understanding of the heterogeneity of cancer, Dr. Caligiuri said. For instance, different cancer subtypes respond to different targeted therapies; for example, lung cancer and EGRF-inhibitors. "We have the technology, and we have this understanding, but we are not putting this into practice," he said.
Yet, putting this research into practice and using drugs more appropriately, and only in patients who would respond to them, would save money, spare other patients from unnecessary adverse effects, and "could ultimately save lives" he said.
"We are falling behind where science is telling us to go," Dr. Caligiuri said.
The rate of cancer deaths is falling, but not by a lot.
Another cancer expert, Edward Benz Jr, MD, president of the Dana Farber Cancer Institute in Boston, Massachusetts, said: "Overall, the rate of cancer deaths is falling, but not by a lot, not nearly enough."
"We still have a long way to go, and we have to redouble our efforts," Dr. Benz commented in a statement.
"But considering that the incidence of cancer continues to increase, while the number of deaths is flat or falling a little bit, it does suggest that efforts of prevention, early detection and better treatments are having a positive impact," he said.
One of the best ways to avoid dying of cancer is to prevent it in the first place.
However, he also emphasized that "one of the best ways to avoid dying of cancer is to prevent it in the first place."
In addition to participating in the screening that is offered, "this involves making lifestyle adjustments, such as not smoking, being careful about exposure to the sun, diet and exercise, and being careful about exposure to chemicals in the workplace," he said.
The point on smoking was also emphasized by Centers for Disease Control and Prevention Director Thomas Frieden, MD. Lung cancer still kills more people than any other type of cancer, he pointed out, but "it could become a rare disease if states support well-funded tobacco control programs."
Dr. Frieden predicted that the combination of aggressive antismoking campaigns, higher cigarette prices, and strong state laws that protect nonsmokers from secondhand smoke will "decrease the number of adult smokers and save lives."
New Insight Into Brain Tumors
A new finding to emerge from the report comes from data collected in a national brain tumor registry that was established in 2004.
"Our new data show that nonmalignant brain tumors are far more common than malignant brain tumors and affect different population groups," commented Betsy Kohler, executive director of the North American Association of Central Cancer Registries.
In adults, nonmalignant brain tumors were about twice as common as malignant tumors. Among the 213,500 patients recorded between 2004 and 2007, only about a third (35.8%) of the brain tumors diagnosed were malignant.
However, the ratio was directly opposite in children — here about two thirds of the brain tumors diagnosed were malignant.
The report notes that the relatively low variation in incidence and mortality rates during the past several decades for brain cancers suggest that external risk factors in the environment do not play a major role in this disease.
J Natl Cancer Inst. Published online March 31, 2011.
Tidak ada komentar:
Posting Komentar