University of Iowa finds no evidence of cancer cluster at Hudson Schools, admits investigation was limited

CEDAR RAPIDS, Iowa (KCRG) -The University of Iowa has wrapped up an investigation at Hudson Schools after 12 teachers were diagnosed with breast cancer within a decade.

For the last few months, the Iowa Cancer Registry has been working to determine if there’s a breast cancer cluster associated with the school. They did not find any evidence of a breast cancer cluster among school staff in Hudson. But the University says the investigation did have some shortfalls, and proved more difficult than most.

The Iowa Cancer Registry keeps track of each and every cancer case in the state to help with research, including potentially pinpointing causes.

“We have complete cases back to 1974 through present time,” explained Mary Charlton, Director of the Iowa Cancer Registry.

They did what’s called a cancer cluster investigation at Hudson Schools which typically involves a geographical area, but this situation was different.

“This was more of a work site one so people don’t all live in Hudson. You know 2/3 of the people in the Hudson staff in the file they gave us didn’t live in Hudson,” said Charlton.

The hope was to find a similar school district to compare to, but when that didn’t work out the University compared Hudson staff to the areas of Hudson, Dike and Cedar Falls.

“They did not have a higher mix or a higher proportion of breast cancer among their cancer cases than those other comparison populations,” Charlton explained.

But she says a cluster couldn’t be completely be ruled out as they were lacking information along the way.

“It was basically what’s available in their directory. So we did not have things like date of birth which would have made our linkage to our database much more precise and we’d be much more confident that we are linking the right people,” said Charlton.

Hudson Superintendent Dr. Tony Voss sent a statement saying, “We are grateful for the work of the University of Iowa Cancer Registry, and we understand there were some limitations to the study due to the district not being able to release some of the requested personal employee data. We knew this going in, and we also knew that getting a completely definitive answer would be challenging. This is why the district took the preemptive step of contracting with a third-party environmental testing firm.

As for the data that could not be released, the district worked diligently with legal counsel on this issue. We requested that our legal counsel consult with other firms to find a way to release the data. Ultimately, legal counsel recommended we not release this data due to possible legal exposure for the district.

It’s also important for our community to understand exactly what data was being requested for release. This data included social security numbers, middle initials, home addresses, and dates of birth for more than 1,300 current and former employees, without their consent. We worked with the Registry over the course of several months to find a way to get them as much data as we could, at one point meeting their request to release zip code information.

The follow-up question, however, was impossible to answer: Can you confirm whether or not this is a current zip code or the zip code of the employee at the time of their employment? The district had no way to confirm this information, as the database query went back decades.

The district provided as much information as possible to the Iowa Cancer Registry. Even with the limitations, we believe the report provided gives us valuable data and insights into the concerns expressed by some members of our school district community.”

Diane Anderson is a former Hudson teacher who had breast cancer. She wishes more could have been done to help the investigation.

“I was a little bit disappointed that the district couldn’t provide all of the needed information to maybe make the results a little bit more accurate,” Anderson said.

Still, she’s grateful there was an investigation and hopes it makes people aware of their health and the possible connections to their surroundings.

“I hope that it’s raised awareness for people because that was really our intent. We didn’t want a cluster to be found. We wanted it to be researched and ruled out,” said Anderson.

“We collect a lot of information about the cancer types that people have including the tissue features of the cancer and if there was one common source that was causing this among the teachers we would have expected them to have all similar features of their cancer,” Charlton said.

That was not the case at Hudson Schools , adding to the confidence that there isn’t a cluster there.

While doing this investigation the University did have one unexpected finding. There’s a higher amount of prostate cancer among men in Hudson than in Cedar Falls. However, that finding was not enough to warrant any additional investigation by the CDC and is not considered a cluster.

You can read the full investigation report here.

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