The Health Department calculated cancer rates several ways. One rate was for all cancers combined. Another looked at rates for each of the 25 most frequent types of cancer. The Department also examined the incidence of cancer in specific zip codes within each county.
No matter how they calculated the data, Dr. Alan Bender says, the result was pretty much the same. "Compared to what is going on both in the metro area and statewide, there is nothing abnormal in these communities or the counties."
Bender manages the Chronic Disease and Environmental Epidemiology Section at the Health Department. He oversaw the data review.
Bender found that in Washington County, for example, there were nearly 4,400 new cancers diagnosed among men. That was 3 percent lower than the more than 4,500 cancers officials would have expected to see among that group. Among women in the county, the cancer rate was nearly identical to what would be expected.
There were some noticeably higher rates of certain types of cancer. For example, liver cancers among women were higher than average in Dakota County. But there was also an unexpectedly low rate of larynx cancer among the county's male population.
Officials don't put too much stock in either of those rates because they are based on very small numbers of people.
Bender says what matters most is that there is no evidence to support some residents' claims that there is a cancer epidemic in the East Metro. "One of the problems that occurs is that people really don't understand how common cancer is in a lifetime perspective," says Bender. "Roughly 50 percent of people will develop cancer in their lifetime. So when you look out in a community you're going to see a lot of it. So the question is how do we compare and that's what we answered."
"Compared to what is going on both in the metro area and statewide, there is nothing abnormal in these communities or the counties."
Yet Bender is quick to point out that his agency only answered a very limited question. The review did not explore whether perfluorinated chemicals actually pose a cancer risk to people.
Cottage Grove resident Stephen Dailey says he's glad health officials are tracking cancer rates in his community. But he says his family is concerned about more than just cancer.
Dailey says he's aware of studies that have linked perfluorinated chemical exposure to developmental problems in newborn lab animals. "If my wife has any more children, there's a lot of chemicals out there that we don't know how they operate on fetuses and newborn babies," says Dailey. "If my wife does get pregnant, I'm sure we'll switch her to bottled water."
Dailey also questions whether the cancer data review is even applicable to today's situation in the East Metro. He says it's possible perfluorinated chemicals only recently reached the groundwater supply.
Or, he says, the chemicals might have affected a much smaller area during the 1980s and '90s than they do now. "Are the concentration of the chemicals... have they grown over the years? And so, yes, the cancer rates were low overall, but... in the future they might blossom up," says Dailey.
The chemicals are believed to be leaking from former landfills once used by 3M to dispose of waste from its Scotchgard and other PFC operations. The Health Department's John Linc Stine acknowledges that it is possible that PFC contamination happened in the years after the cancer data was collected. "We really don't know when they came to be present in the groundwater system in any of these communities," says Stine. "However given what we know about their nature, it's very likely that they were present."
Stine says his agency will continue to track cancer in the East Metro to see if the rates change unexpectedly in the years ahead.
Health officials are also looking at what other types of diseases might be linked to perfluorinated chemicals. The U.S. Environmental Protection Agency announced recently that it is examining whether PFCs are linked to developmental problems in babies, as well as thyroid and hormone problems.
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