Κυριακή, 9 Απριλίου 2017

LIMITED PROGRESS IN USA CANCER MORTALITY

Cancer mortality related to smoking and obesity in the United States is on the upswing; progress on improving 5-year survival rates for pancreatic, liver, lung, and esophageal cancers remains "limited"; and racial disparities persist in many common cancers, according to the latest "Annual Report to the Nation on the Status of Cancer."
The report shows that overall, cancer mortality rates are decreasing in the United States, but it also shows an increase — between 2010 and 2014 — in mortality rates for cancers of the liver, pancreas, and brain in men and for liver and uterine cancers in women.
The good news is that improvements in prevention, early detection, and treatment are continuing to make a dent in overall cancer mortality rates in men, women, and children in the United States, say the authors, led by Ahmedin Jemal, DVM, PhD, vice president of Surveillance and Health Services Research for the American Cancer Society (ACS) in Atlanta, Georgia.
The report is published online March 31 in the Journal of the National Cancer Institute. It is a collaborative effort among the ACS, the Centers for Disease Control and Prevention (CDC), the National Cancer Institute (NCI), and the North American Association of Central Cancer Registries.

Overall Mortality Decreased 

Overall mortality decreased for 11 of the 16 most common cancer types (at a rate of 1.8% per year) in men and for 13 of the 18 most common cancer types (at a rate of 1.4% per year) in women; these included cancer of the lung, colorectum, breast, and prostate. Cancer mortality decreased by 1.6% per year in children.
Despite this, major risk factors need to be identified for colorectal, breast, and prostate cancer, and rising rates of uterine, breast, and pancreatic cancer need to be better understood, the authors emphasize.
"This report found that tobacco-related cancers have low survival rates, which underscores the importance of continuing to do what we know works to significantly reduce tobacco use," said Lisa C. Richardson, MD, MPH, director of CDC's Division of Cancer Prevention and Control, in a statement.
"In addition, every state in the nation has an adult obesity prevalence of 20 percent or more. With obesity as a risk factor for cancer, we need to continue to support communities and families in prevention approaches that can help reverse the nation's obesity epidemic. We need to come together to create interventions aimed at increasing the uptake of recommended, effective cancer screening tests, and access to timely cancer care."
For the report, data from 39 states covering 89% of the population were compiled from cases diagnosed from 1999 through 2013 as part of the National Program of Cancer Registries and/or the Surveillance, Epidemiology, and End Results program.

Overall Decrease in Cancer Mortality

Results show that between 1999 and 2013, the incidence of cancer decreased overall by 2.3% per year in men and stabilized in women. The largest decline was seen in prostate cancer, which decreased by an average of almost 8% per year from 2009 to 2013.
Results also show that survival varied by ethnicity and race. Compared with non-Hispanic whites, for instance, the adjusted relative risk for death for all cancers combined was 33% higher in non-Hispanic blacks and 51% higher in non-Hispanic American Indians and Alaska Natives.
Not only have racial disparities persisted for many common cancers, they may have increased for prostate cancer and female breast cancer, said Lynne T. Penberthy, MD, MPH, associate director of NCI's Surveillance Research Program, in a statement. "We still have a lot of work to do to understand the causes of these differences, but certainly differences in the kinds and timing of recommended treatments are likely to play a role."
Black women with breast cancer are less likely to receive and adhere to adjuvant chemotherapy and more likely to experience delayed initiation of such therapy, the authors suggest. "The risk of death in blacks compared with whites was higher overall (all sites) and for the most common cancers in stage-adjusted analyses," they say.
In addition, analysis showed that the risk for death in blacks compared with whites was higher overall as well as for the most common cancers.
For both early- and late-stage disease diagnosed in 2006 to 2012, there were significant improvements in 5-year survival compared with cancer diagnosed in 1975 to 1977 for all cancers, with the exception of cervical and uterine cancers. The highest relative 5-year survival rates were seen in thyroid cancer (98.3%), melanoma (93.2%), and female breast cancer (90.8%), with rate increases of 25% or more seen in cancers of the prostate (99.3%) and kidney, as well as in non-Hodgkin's lymphoma, myeloma, and leukemia.
In other cancers, "we are making progress, but it is very limited," said Dr Jemal in an
interview. "More than 80% of children with cancer are surviving more than 5 years but at the same time, only 8.5% of patients diagnosed with pancreatic cancer survive 5 years and 5-year survival for cancers of the liver, lung, and esophagus are between 18% and 20%." The report also shows 5-year survival rates of 31.1% for stomach cancer and 35.0% for brain and other neurologic cancers.
Most of the improvements in cancer survival are the result of prevention, Dr Jemal pointed out. During the past 40 to 50 years, the number of smokers in the United States has been cut by almost half, but about 40 million people still smoke — even though smoking contributes to about one third of all cancers and remains the leading cause of cancer death.
"If we want to make a major dent in reducing rates of cancer, there are known interventions that are effective," Dr Jemal said, suggesting that expansions for federal and state tobacco control programs with excise tax geared to inflation would be a step in the right direction, particularly given that "cigarettes are more affordable now than they were in the 1990s."
Obesity is also playing a significant role in cancer and is estimated to account for 49% of endometrial cancer cases in the United States as well as 28% of pancreatic cancer cases and 24% of kidney cancer cases.
Obesity may also be contributing to the continued increase in the incidence of liver cancer. The high prevalence of chronic hepatitis C virus infection resulting from intravenous drug use during the 1960s to 1980s is also thought to be playing a significant role in liver cancer in both men and women, as well as in pancreatic cancer in men.
Mortality associated with cancer of the oral cavity is also increasing as a result of human papillomavirus (HPV) infection, Dr Jemal noted. Although vaccination is recommended to protect against cervical and anogenital cancer, "there is no strong consensus that it is protective against HPV-related cancers of the oral cavity," he said.
Looking ahead, it is anticipated that advances in precision medicine and immunotherapy for late-stage cancers, such as melanoma and lung cancer, will markedly increase cancer survival. However, escalating costs associated with new treatments remain an important challenge in universal access and delivery of cancer care, the report authors point out.
"This report confirms a trend — ongoing for several decades now — that fewer people are dying from cancer than ever before," said Daniel Hayes, MD, president of the American Society of Clinical Oncology.
"In spite of these advances, far too many Americans continue to be diagnosed and die from cancer, including those cancers in which we have made great strides. Moreover, the fact that death rates for some hard-to-treat cancers and in certain populations are still increasing only serves to strengthen our commitment to ensure access to high quality care for anyone diagnosed with cancer," he commented in a statement.
This work was funded by the ACS, the CDC, the NCI, and the North American Association of Central Cancer Registries. The authors have disclosed no relevant financial relationships.
J Natl Cancer Inst. Published online March 31, 2017. Full text

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