Perceptions of cancer risks, reality may be out of sync.

Byline: Marilynn Marchione

MILWAUKEE _ Kenneth Kilpela has some theories about what caused the throat cancer that cost him his voice box a decade ago.

"I worked three years in a steel mill. There was dirt, dust, smoke and a very difficult atmosphere," he said. He also was a carpenter and sometimes handled fiberglass insulation and sanded drywall.

It's understandable that he'd worry about conditions he found unpleasant at his jobs and whether they may have caused or contributed to his cancer.

But doctors are more likely to focus on something else in the 61-year-old Michigan man's past: 20 years of smoking.

While no one can say with certainty that any one person's cancer is due to any one risk factor, tobacco causes the vast majority of throat and oral cancers _ not just lung cancer, as Kilpela had thought, said his doctor, Bruce Campbell, interim director of the cancer center at Froedtert Memorial Lutheran Hospital and the Medical College of Wisconsin.

"We don't know everything about what causes cancer, but patients are quick to find things, to …