A new study examining data on incidence trends, mortality rates and survival rates from the National Cancer Institute's Surveillance Epidemiology and End Results (SEER) cancer registries indicates that the incidence of liver cancer in the United States tripled between 1975 and 2005.
Researchers also found for the first time that one- through five-year survival rates improved significantly for patients diagnosed with liver cancer between 1992 and 2005, in part because more patients were diagnosed at earlier stages, when treatment is more effective. Earlier diagnosis may be due to increasing awareness and screening to detect localized disease in patients at risk for liver cancer.
"Although the study could not determine why liver incidence rates are increasing, these trends may be partially attributable to an increase in chronic hepatitis C, which together with hepatitis B is a major risk factor for liver cancer," said Dr. Sean Altekruse, an Epidemiologist with the NCI's SEER Program and the study's lead author. "Additional research into the factors related to this increase in incidence will be vital to preventing these rates from rising further." Dr. Altekruse noted that heavy alcohol consumption, fatty liver disease, obesity, diabetes mellitus and iron storage diseases may also contribute to the increasing incidence of liver cancer.
The study found that between 1975 and 2005, liver cancer rates tripled, from 1.6 cases per 100,000 people to 4.9 per 100,000. From 1992 to 2005, liver cancer incidence trends increased significantly:
• African-Americans and Hispanics both experienced an approximately 67 percent increase in liver cancer incidence between 1992 and 2005 (4.2 to 7.0/100,000 and 4.8 to 8.0/100,000, respectively), and whites experienced an approximately 50 percent increase in incidence (2.6 to 3.9/100,000) during this time period.
• Between 2000 and 2005, incidence rates increased most markedly among African-American men (42 percent, 28.7 to 40.8/100,000), Hispanic men (43 percent, 23 to 32.8/100,000), and white men (43 percent, (11.5 to 16.5/100,000) 50 to 59 years of age. These increases may be partially due to an epidemic of hepatitis C infection that began in the 1960s, when men in this age range were young adults.
• From 1992 to 2005, liver cancer incidence rates among Asians and Pacific Islanders were the highest of all racial groups overall; however, rates increased by a relatively modest 17 percent (10.0 to 11.7/100,000) in this time period. Researchers attribute a substantial portion of liver cancer cases in Asians and Pacific Islanders to higher rates of hepatitis B among some Asian subgroups.
One-year survival rates nearly doubled between 1992 and 2005, rising from 25 percent of patients to 47 percent. Dr. Altekruse points out that while the increasing survival rates are encouraging, further improvement is still needed, noting that one-year survival rates are still below 50 percent.
Source: American Society of Clinical Oncology
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