Smokeless tobacco products, as used in Europe and North America, do not appear to increase cancer risk. A large meta-analysis, published in the open access journal BMC Medicine, has shown that snuff as used in Scandinavia has no discernible effect on the risk of various cancers. Products used in the past in the USA may have increased the risk, but any effect that exists now seems likely to be quite small.

Peter Lee and Jan Hamling, from P.N. Lee Statistics and Computing Ltd, carried out the analysis of 89 studies from the United States and Scandinavia. They found that, after adjustment for concurrent smoking, any effect of current US products or Scandinavian snuff seems very limited. According to Lee, “It is clear that any effect of smokeless tobacco on risk of cancer, if it exists at all, is quantitatively very much smaller than the known effects of smoking”.

In 2005 in US men aged 35 or over, there were a total of 142,205 deaths from seven cancers considered to be caused by smoking. If these people had never smoked, Lee and Hamling estimated that the numbers would have reduced by 104,737, with the reduction in lung cancer deaths, 79,195, being the major contributor. If smokeless tobacco was introduced to a similar population of never smokers, this meta-analysis shows that any increase in risk would be negligible compared to the lives saved by reducing cigarette use.

Lee said, “Our paper shows very clearly that, in marked contrast to smoking, smokeless tobacco use carries little or no risk of cancer. Concerns about possible effects of smokeless tobacco on oral cancer are answered by our analyses showing a lack of relationship based on the combined evidence from those 14 studies published since 1990 which allow adequate control for effects of smoking.”

Notes:
Systematic review of the relation between smokeless tobacco and cancer in Europe and North America
Peter N Lee and Jan S Hamling
BMC Medicine (in press)
http://www.biomedcentral.com/bmcmed/

Source:
Graeme Baldwin

BioMed Central

Researchers have devised a scheme for identifying genes in yeast that
could lead to the identification of new cancer genes in humans. The study
is
published online this week in the open-access journal PLoS Biology.

Cancers arise from the accumulation of mutations or genetic alterations
resulting in the uncontrolled proliferation of cells. However, the number
of
mutations accumulated during the evolution of cancerous cells is large,
making it difficult to identify which of the mutations are responsible for
the
cancer phenotypes. Identifying new genes that sustain cancerous growth is
a major challenge in the campaign against cancers.

Aneuploidy, an abnormality in chromosome number and structure, is a
hallmark of many cancer cells. One idea is that aneuploidy may cause
cancer by
changing the dosage or expression of oncogenes (cancer-causing genes).
After decades of research, only a handful of human oncogenes have been
identified, accounting for a tiny fraction of all cancers So methods of
identifying new oncogenes through their association with aneuploidy has
become an accepted strategy in the cancer field.

The Mcm4Chaos3 mutation causes a defect in an enzyme that unwinds DNA
during DNA replication and predisposes mice to mammary tumors. In this
study, a
team led by Bik Tye from Cornell University introduced the equivalent
mutation in yeast. Yeast with this mutation generate chromosomal
abnormalities
and yield faster growing progeny, a situation reminiscent of what happens
in tumors. Using the yeast genetics tools the researchers could show that
improved growth is not linked to aneuploidy, but to point mutations in
just a few genetic loci.

Pathways and genes that regulate proliferation rates are likely to be
conserved in all eukaryotes. So, by identifying mutations that give cells
a
growth advantage in yeast, the simplest of eukaryotes, will help guide
the search of cancer genes in humans.

Funding:
This work was supported by National Institutes of Health grant
GM072557 awarded to BKT. The funder had no role in study design, data
collection and analysis, decision to publish, or preparation of the
manuscript.

Competing interests statement:
The authors declare that no competing
interests exist.

Citation:
“Aneuploidy and Improved Growth Are Coincident but Not Causal in a Yeast Cancer Model.”
Li XC, Schimenti JC, Tye BK (2009)
PLoS Biol 7(7): e1000161. doi:10.1371/journal.pbio.1000161

Source
PLoS Biology

A new proposal from the Centers for Medicare and Medicaid Services (CMS) to cut payments for radiation therapy treatments would cause many cancer centers to close, stop accepting Medicare patients, lay off support staff and reduce services to cancer patients, according to a survey conducted by ASTRO, the American Society for Radiation Oncology.

New technology has allowed radiation oncologists to improve cancer cure rates while reducing side effects. However, on July 13, CMS announced proposed changes to the Medicare policies and payment rates for physician services, including radiation oncology, that would cut payments to radiation therapy services by nearly 20 percent. Community cancer centers, particularly those in rural and suburban areas, would be hardest hit. Running 2008 claims data from a sample of practices across the country showed overall impacts between 18 and 31 percent on the average practice, with some services receiving payment cuts by up to 44 percent. If approved, these cuts would take effect on January 1, 2010.

“Take, for example, Joyce Wittet from Ontario, Oregon, population 11,245. The 79-year-old retired teacher had breast cancer that was easily cured with radiation therapy. Fortunately, there is a cancer center 15 minutes away that accepts Medicare. If the cuts had caused her cancer center to close, she would have had to drive to a hospital nearly two hours away, roundtrip for six straight weeks. If faced with this option, Joyce might have had to choose between mastectomy or expensive travel costs to cure her cancer. Worse still, she might have even forgone treatment altogether until it was too late,” said Patricia Eifel, M.D., FASTRO, chairman of ASTRO and a radiation oncologist at M.D. Anderson Cancer Center in Houston. “We applaud Congress and the Obama Administration for their efforts to improve access to healthcare for more Americans. However, this CMS proposal would do just the opposite: limit access through longer waits to begin treatment, less time with doctors and longer, costlier drives to receive treatment.”

Five-hundred-fifteen individuals responded to ASTRO’s survey. For community-based practices, in the face of 30 percent cuts, two out of five say they would close their practice. Forty-seven percent of rural practices say they would close. Sixty percent of community practices with multiple locations will consolidate their practices. Among those community practices able to stay open, 54 percent say they will no longer accept Medicare patients and 68 percent say they will limit the number of Medicare patients they treat.

If the cuts force radiation oncologists to consolidate or close their practices, 43 percent said their cancer patients would be forced to travel more than 50 miles round-trip, for radiation therapy treatments. In rural areas, 81 percent reported that patients would have to travel more than 50 miles. Overall, 97 percent of community practices said the quality of care for cancer patients receiving radiation therapy would suffer due to the cuts.

“My center is not viable at greater than 20 percent cuts, and patients already drive an hour to us. They then would drive nearly two hours one-way to the next center. We are the primary service center for six rural counties and we are barely holding on as it is now in the recession. About four of 10 patients now have no insurance, and we treat them. With these Medicare cuts, we will be forced to close,” said a survey respondent from rural North Carolina.

Congressional leaders urge CMS to reconsider

ASTRO is running a series of ads on WTOP, Politico, Congressional Quarterly Today, Roll Call and in an AARP publication to raise public awareness of the proposed cuts and to encourage citizens to ask members of Congress to sign on to the bipartisan letter written by Reps. Lois Capps (Calif.), Parker Griffith, M.D. (Ala.), Sue Myrick (N.C.), and Mike Rogers (Mich.) urging CMS to reconsider. ASTRO praises the leadership of these representatives and more than 25 of their colleagues who’ve already committed to sign the letter.

“Radiation oncology is critical for the effective treatment of our nation’s cancer patients. While we need to work together to cut healthcare costs, lumping in radiation therapy with diagnostic imaging doesn’t serve our patients. We need to make sure that all cancer patients, including those who live in rural areas and depend on Medicare, have access to all the tools and resources they need to make a full recovery,” said Rep. Capps.

“As a radiation oncologist who practiced in the community setting, I am aware of how these severe cuts would limit access to life-saving radiation therapy for cancer patients. I am proud to be working on healthcare reform to expand access to high quality, effective care for cancer patients and all Americans, and I look forward to working with both parties as well as the administration to find a solution that averts these cuts and protects patient access to care,” said Rep. Griffith.

“Radiation therapy helped me survive breast cancer, as it has millions of other women. I believe CMS made a mistake by roping radiation therapy in with these diagnostic imaging changes. This doesn’t make sense if we’re trying to improve access to care. I’m honored to join my colleagues in protecting patient access to radiation therapy by asking Medicare to prevent these cuts,” Rep. Myrick said.

“Radiation oncology helps many people survive and even thrive after cancer diagnoses. There is no possible explanation for forcing cancer centers to close, stop seeing Medicare patients, lay off staff or use outdated equipment; doing so will certainly not help cancer patients. As a cancer survivor myself, I know how important it is to have access to every possible opportunity to fight for healing. Medicare patients should have the same opportunities to win their battle against cancer,” Rep. Rogers said.
Visit http://www.astro.org/medicarecuts/ for a copy of the survey and to see the bipartisan letter.

Source
American Society for Radiation Oncology