Rare cancer follows state rail lines

Mesothelioma study tracks Montana cases

A new state study shows the majority of people diagnosed with a rare form of asbestos-related cancer over a 23-year period lived along Montana's railroad routes.

The study also indicated that Flathead and Missoula counties rank alongside Lincoln County - home to the former W.R. Grace vermiculite mine - in numbers of people with the rare cancer called mesothelioma.

Former state medical officer Michael Spence initiated the report that tracks mesothelioma in Montana from 1979 through 2002. The state Office of Vital Statistics, Central Tumor Registry and the Environment Public Health Tracking Project helped in the study.

Mesothelioma, a cancer of the tissue that covers the lungs and abdominal organs, is a deadly disease that typically kills people within a year after diagnosis. It has been clearly linked to asbestos exposure.

Spence said the link between the cancer and Montana's historic rail lines was somewhat of a surprise.

"It wasn't a preconceived notion that we'd have a high level of the disease on the rail lines," said Spence, who is now retired and lives near Somers.

But as statisticians began charting mesothelioma cases on a map, the relationship became clear.

"As we looked at it, we said, 'My gosh, look where these [rail] hubs are," Spence said. "Bingo, it fell into place."

The Libby mine produced more than 80 percent of the world's vermiculite at one point before it closed in 1990, and vermiculite ore was shipped by rail across Montana. Some of the ore was processed in Great Falls, and researchers assumed there would be a mesothelioma cluster there, Spence said.

From 1920 through 1990, 23,872 tons of vermiculite ore were received in Cascade County. Flathead County received only two tons.

But the study notes that data is insufficient to confirm a clear relationship between homes near a railroad and developing mesothelioma.

"Since most of the people in Montana live in these population centers, and along transportation routes, one would expect that many people affected with mesothelioma would live along these routes, whether or not the railroad contributed to the spread of the disease," the study stated.

People with mesothelioma may have been exposed to any number of asbestos sources at any time. Not all cases of mesothelioma came from vermiculite mining, according to the study data.

Construction, manufacturing, government jobs, agriculture and even homemaking were occupations of Montanans who contracted the disease.

The study combined information from both the state Central Tumor Registry and Death Registry to track 200 Montanans who were either diagnosed with or died of mesothelioma between 1979 and 2002.

During that time, Flathead County had 16 cases of the disease, Lincoln County had 12 and Cascade County (Great Falls) had 28. Lincoln, Cascade and Rosebud counties had more people diagnosed with mesothelioma than would be expected based on population.

Spence said he believes the state mesothelioma study is the first of its kind. New Jersey and New York also are researching the disease, interviewing patients and family members.

"We thought about getting involved with those studies, but we don't have the population," Spence said. "We have a million people in the state; they have a million people in a borough."

Montana's study documents that Libby isn't the only place where mesothelioma occurs, Spence pointed out. It also dispelled the notion that Libby's mesothelioma rate is extraordinarily higher than the national average. Some health experts had predicted Libby's cancer rate was up to 50 times higher than elsewhere in the country, but it's not nearly that high, Spence said.

On the other hand, any cases of mesothelioma are troublesome. Treatments to combat the cancer haven't been very successful.

"It's a bad one," Spence stated. "We tell people who have it that we'll do everything we can to make you comfortable, but you need to get your affairs in order."

The number of mesothelioma cases has risen dramatically through the years, from 15 cases documented from 1979 to 1982 to 55 cases reported from 1999 to 2002.

Like other asbestos-related diseases, mesothelioma turns up 20 to 30 years after the exposure, so the number of cases should decline significantly within the next five to 10 years, Spence said.

Features editor Lynnette Hintze may be reached at 758-4421 or by e-mail at lhintze@dailyinterlake.com