Κυριακή, 20 Μαρτίου 2016

USA ANNUAL CANCER REPORT

UPDATED March 16, 2016 // Death rates from 1975 to 2012 continued to decline for all common cancers in the United States (such as breast, prostate, and lung), with one exception: liver cancer.
In the Annual Report to the Nation on the Status of Cancer, 1975-2012published online by the National Cancer Institute (NCI), the overall cancer death rates for men and women of all major racial and ethnic populations decreased by 1.5% per year from 2003 to 2012. Incidence rates -- new cancer cases diagnosed per 100,000 people -- decreased among men and remained stable among women during that period.
Among men, overall cancer death rates decreased by an average of 1.8% per year; among women, they decreased by an average of 1.4% per year; and for children and adolescents aged 0 to 19 years, they decreased by an average of 2% per year.
However, deaths from liver cancer went against this trend.
According to the report, liver cancer deaths increased 2.8% per year in men and 2.2% per year in women from 2003 to 2012.
During the period 2008 to 2012, the incident rate of liver cancer was nearly three times higher in men than in women. For men, the incidence rate was 11.5%, and for women, it was 3.9%.
In 2012, the most recent year for which data are available, 28,012 people were diagnosed with liver cancer in the United States. Of these, 20,207 were men, and 7805 were women.
Deaths from liver cancer in 2012 were almost twofold greater in men than in women: 15,563 in men vs 7409 in women.
The NCI report did not consider pancreatic cancer to be among the common cancers, said Harvey Risch, MD, PhD, an epidemiologist at the Yale School of Medicine in New Haven, Connecticut, who was not involved with the report.
"Pancreatic cancer mortality is appreciably greater than liver cancer mortality, has been increasing and is continuing to increase, and will exceed liver cancer mortality for at least a decade," he told Medscape Medical News.
Hepatitis C Virus Infection a Major Risk Factor
The report states that a major risk factor for liver cancer is hepatitis C virus (HCV) infection. The incidence of new HCV infections peaked from the 1960s through 1980s before the virus was discovered and preventive measures could be taken.
The report found that liver cancer incidence rates were higher among baby boomers (people born from 1945 to 1965) than among those born in other periods because of higher rates of HCV infection in that birth cohort.
Another cause of liver cancer listed in the report is cirrhosis of the liver. Risk factors for cirrhosis include heavy alcohol consumption, obesity, and type 2 diabetes.
Hepatitis B virus (HBV) infection also increases the risk for liver cancer. HBV is a common risk factor for liver cancer among Asian/Pacific Islander populations, especially among Asians not born in the United States. Fortunately, rates of HBV infection are declining worldwide, owing to increases in hepatitis B vaccination of children beginning at birth, according to the report.
HCV Meds Too Expensive?
"At least half of liver cancer in the US is associated with infection by hepatitis C virus; thus, treatment as early as possible is thought to reduce the risk of liver cancer," Dr Risch explained.
"However, current costs of the treatment medication are very expensive, upwards of $30,000 to $40,000. At these prices, it is unlikely that substantial reduction in incidence of liver cancer will be accomplished," he said.
Srinevas Reddy, MD, from the Roswell Park Cancer Institute, Buffalo, New York, agreed that the prohibitive cost of HCV medication is a factor in the increase in liver cancer deaths.
"Liver cancer incidence is increasing, and this is due to a high prevalence of hepatitis C and the inability of many people to have access to the new drugs that are used to treat it, so even though we have these new treatments for hepatitis C, it is not expected that the prevalence of the disease will drop until 2025," Dr Reddy told Medscape Medical News.
"The second issue is, we are rapidly discovering that, in fact, the most common liver disease in the US and the rest of the world is fatty liver disease. Soon, maybe even in the next 5 to 10 years, this will actually be the most common cause of primary liver cancer and the most common cause of cirrhosis," he said.
Fatty liver disease is the manifestation of the metabolic syndrome in the liver, Dr Reddy said.
"Just as other elements of the metabolic syndrome, like obesity and diabetes, fatty liver disease shows no prospects of declining, and actually it will continue to increase in the future. There is a small percentage of patients who can develop fatty inflammation of the liver, and this is what can lead to cirrhosis and primary liver cancer," he said.
The final issue is the lack of good treatment options for liver cancer, Dr Reddy said.
"Unlike colon cancer and breast cancer, for example, we do not have very good chemotherapy treatment options, and so the only shot at long-term cure for these patients is surgery. The problem is that many times, the disease is caught too late, when surgery is not possible. Many times, there are no early symptoms from liver cancer. The liver is a very resilient organ, that is the benefit and curse of the liver. So on one hand, the liver can compensate for a large mass without causing any symptoms of liver insufficiency or failure, but on the other hand, that means that many times, these masses may keep on growing unbeknownst to the patient until it is too late to do anything about it from a surgical standpoint," he said.
"So taken together, all of these factors -- the inaccessibility of many HCV-infected individuals to drugs to treat the disease, the increase in fatty liver disease, the fact that we have no good chemotherapy for liver cancer, and the fact that once liver cancer manifests, it is often too late to treat it -- all are contributing to the increase in liver cancer deaths," Dr Reddy concluded.
Dr Risch and Dr Reddy report no relevant financial relationships.
National Cancer Institute. Annual Report to the Nation on the Status of Cancer, 1975-2012

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