NCI Cancer Bulletin: A Trusted Source for Cancer Research News
NCI Cancer Bulletin: A Trusted Source for Cancer Research News
May 15, 2007 • Volume 4 / Number 17 E-Mail This Document  |  Download PDF  |  Bulletin Archive/Search  |  Subscribe

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Cancer Research HighlightsCancer Research Highlights

Recent Drop in Mammography Rates Causes Concern

The drop in mammography rates in the United States in recent years is cause for concern because it could contribute to a future rise in breast cancer deaths, according to an analysis of data from representative national surveys published early online in Cancer.

Scientists from NCI's Division of Cancer Control and Population Sciences (DCCPS), led by Dr. Nancy Breen, examined data from the Centers for Disease Control and Prevention's National Health Interview Surveys (NHIS) and found a decline in mammography screening in 2005 compared with 2000 - from 70 percent to 66 percent. After many years of increases in mammography use, "[t]his report establishes for the nation what has already been observed in some local data. It confirms that use of mammography may be falling. Although small, this decline is cause for concern, as it signals a change in direction."

Mammography screening rates were lower in 2005 than in 2000 for nearly all the groups of women examined. "The largest significant declines were among women who have traditionally used mammography at high rates, including the 50-64 age group, those with higher incomes, and women aged 40-64 with private, non-HMO insurance coverage," the DCCPS investigators noted.

When screening rates drop, women with breast cancer will be diagnosed later, resulting in a short-term drop in incidence, they add. "Consequently, we are concerned that some of the observed decline in incidence may be due in part to the leveling off and reduction in mammography rates." The trend "may presage a future increase in mortality from breast cancer" from later detection of more advanced disease. "If future NHIS data continue to show a decline in mammography use, then we as a nation need to be prepared to address it," the NCI scientists concluded.

The recent decline in breast cancer incidence rates was examined in a separate study published May 3 in Breast Cancer Research. Scientists from the American Cancer Society, led by Dr. Ahmedin Jemal, examined data from NCI's Surveillance, Epidemiology, and End Results (SEER) program.

"Two distinct patterns are observed in breast cancer trends," they reported. The downturn in incidence rates in all age groups above 45 years coincides with a plateau in mammography use, which typically reduces incidence rates "due to a reduced pool of undiagnosed cases." The sharp decrease in incidence from 2002 to 2003 that occurred in women 50 to 69 years old who predominantly, but not exclusively, had ER-positive tumors may reflect the early benefit of the reduced use of hormone replacement therapy. A number of investigators within NCI-funded initiatives are now examining the contribution of recent changes in screening and hormone therapy to breast cancer trends.

HPV a Risk Factor for Oropharyngeal Cancer

A new epidemiological study led by researchers from Johns Hopkins University implicates human papillomavirus (HPV) exposure and infection as strong risk factors for oropharyngeal cancer. The results from the case-control study, published in the May 10 New England Journal of Medicine, show that HPV exposure and infection increase the risk of oropharyngeal squamous cell cancer independently of tobacco and alcohol use, two other important risk factors for the disease.

The investigators enrolled 100 patients with newly diagnosed oropharyngeal squamous cell carcinoma and 200 control patients in the study. Oral-mucosal and serum samples were colleted from all patients. Tumor samples were also collected from case patients. The investigators analyzed all collected samples for presence of HPV DNA or antibodies that would indicate prior exposure. Personal and medical history information collected included oral hygiene history, sexual history, and lifetime use of marijuana, tobacco, and alcohol.

Researchers found that "the presence of an oral HPV 16 infection was strongly associated with oropharyngeal cancer." HPV 16 is one of the two strains of HPV most often associated with cervical cancer. Past exposure to HPV 16, as measured by presence of antibodies to the virus in serum samples, was also strongly associated with oropharyngeal cancer. Antibodies against HPV 16 were found in 64 percent of case patients but only 4 percent of control patients. Data collected on sexual history "suggest that oral HPV infection is sexually acquired…but we cannot rule out transmission through direct mouth-to-mouth contact or other means," said the authors.

A history of heavy tobacco and alcohol use remained a strong risk factor, but "combined exposure to HPV and heavy tobacco and alcohol use was not additive," they explained. "It is important for health care providers to know that people without the traditional risk factors of tobacco and alcohol use can nevertheless be at risk for oropharyngeal cancer," stated first author Dr. Gypsyamber D'Souza in an accompanying press release.

New Data from HPV Vaccine Trials Available

Results from an average of 3 years of follow-up from the FUTURE I and FUTURE II clinical trials of Gardasil, a vaccine that protects against the two types of human papillomavirus (HPV) that are responsible for 70 percent of all cases of cervical cancer, have been published in the May 10 New England Journal of Medicine. Earlier data from the FUTURE II trial led to the FDA approval of Gardasil in June of 2006.

The FUTURE I study randomly assigned 5,455 women between the ages of 16 and 24 to receive either a 3-injection course of Gardasil vaccine or placebo. For women who had not previously been exposed to HPV 16 or 18, the efficacy of the vaccine was 100 percent in "preventing vaginal, vulvar, perineal, and perianal intraepithelial lesions or warts associated with the vaccine-type HPV."

In an intention-to-treat analysis, which included women who had previously been exposed to HPV 16 or 18, the vaccine efficacy was 73 percent against all grades of external anogenital or vaginal lesions and 55 percent against all grades of cervical lesions related to those HPV types.

The FUTURE II study randomly assigned 12,167 women between the ages of 15 and 26 to receive either a 3-injection course of Gardasil vaccine or placebo. For women who had not previously been exposed to HPV 16 or 18, the vaccine prevented 98 percent of high-grade cervical intraepithelial neoplasia related to those HPV types.

In an intention-to-treat analysis, which included women who had previously been exposed to HPV 16 or 18, vaccine efficacy was 44 percent against high-grade cervical disease caused by HPV types 16 or 18. As in the FUTURE I trial, "[v]accination did not appear to alter the course of cervical lesions related to HPV 16 or HPV 18 or of infection present at the time of randomization," explained the authors.

The vaccine reduced the rate of all cervical lesions in all patients regardless of prior HPV exposure, including lesions caused by HPV types not included in the vaccine, by 17 percent. "An interim analysis of vaccine trial data submitted to the FDA showed a disproportionate, but not statistically significant, number of cases of grade 2 or 3 cervical intraepithelial neoplasia related to nonvaccine HPV types among vaccinated women," stated Drs. George Sawaya and Karen Smith-McCune from the University of California, San Francisco, in an accompanying editorial. "Updated analyses of data from these ongoing trials will be important to determine the effect of vaccination on rates of preinvasive lesions caused by nonvaccine HPV types."

Additional reliable information from NCI about HPV vaccines and cervical cancer can be found at http://www.cancer.gov/cancertopics/hpv-vaccines.

Hepatitis C Increases Risk of NHL

A large, retrospective cohort study found that U.S. veterans infected with the hepatitis C virus (HCV) have an increased risk of developing certain lymphomas, according to study results published in the May 8 Journal of the American Medical Association.

Dr. Eric Engels of NCI's Division of Cancer Epidemiology and Genetics and colleagues looked at patient records collected from U.S. Veterans Affairs hospitals between 1997 and 2004. Researchers selected 146,394 patients who were diagnosed with HCV infection and 572,293 patients who were not. Researchers matched the two cohorts on age, sex, and baseline visit date and type - inpatient or outpatient.

Patients with HCV infection had a 20- to 30-percent increased risk of developing non-Hodgkin lymphoma (NHL) and a nearly threefold increased risk of developing Waldenström macroglobulinemia - a rare type of NHL. Patients with HCV infection also had an elevated risk of developing cryoglobulinemia - a condition marked by abnormal levels of certain proteins in the blood.

The researchers noted, "Although the clinical significance of these findings is unknown, it is possible that screening of individuals infected with HCV could identify early-stage lymphoproliferative conditions suitable for early intervention strategies, including chemoprevention trials on premalignant disease. Future epidemiological and pathophysiological studies are needed to further explore the relationship between HCV and NHL."

Study Measures Support Group Use by California Cancer Patients

Nearly one in four people diagnosed with cancer have participated in a support group at some time in their lives, NCI researchers report, though only about half of those did so for problems related to cancer. Nonetheless, cancer survivors' 23.7 percent participation rate was much higher than the 14.5 percent of patients with another chronic illness using a support group.

These results come from an NCI study appearing online May 14 in Cancer. Dr. Julia Rowland of NCI's Office of Cancer Survivorship and colleagues say they were surprised to find that only 10.2 percent of cancer patients using a support group were recommended by their physician to do so, given that 78.4 percent of those using such support reported receiving clear and positive benefits.

Both the use of support groups and their perceived benefit varied widely by cancer site. About 26 percent of breast cancer patients had group experience, 78 percent of whom perceived benefit. The highest rate of support group use, 41 percent, was by leukemia and Hodgkin lymphoma patients, with 93 percent of these patients perceiving benefit. Less than 1 percent of lung cancer patients used a group, and those with skin cancer reported the lowest rate of perceived benefit, 35 percent.

The study was conducted using telephone surveys with 9,187 people enrolled in the California Health Interview Survey Complementary and Alternative Medicine. There were 1,844 cancer patients in the survey and 4,951 participants with other chronic health problems.