Dr. Robin Herbert, co-director of the World Trade Center Medical Monitoring Program at Mount Sinai Medical Center, said researchers who have screened 20,000 of the estimated 40,000 ground zero workers are "most concerned" about lymphatic and blood cancer cases.
"We're worried about a third wave, which is the possibility of cancer down the road," Herbert said in an audiotaped interview posted on the New England Journal of Medicine's Web site.
"The kind of thing that worries us is that we know we have a handful of cases of multiple myeloma in very young individuals, and multiple myeloma is a condition that ... almost always presents later in life," she added. "That's the kind of odd, unusual and troubling finding that we're seeing already."
Doctors had previously said it was too soon to know whether any cancers can be linked to trade center dust exposure, although Mount Sinai published research last year that said about 70 percent of the workers they screened had respiratory illnesses.
An article published Thursday with Herbert's interview in the New England Journal of Medicine said that while workers did inhale cancer-causing chemicals, "an associated increased risk for respiratory tract cancer and most other types of cancer will not be apparent for decades."
The researchers from Johns Hopkins University and the University of Rochester suggested tracking diseases for at least two decades through a New York City-based health registry that plans to monitor residents' and workers' health for 20 years.
Herbert, who was not available for further comment Thursday, didn't say in her audiotaped interview how many blood cell cancer cases the Mount Sinai program was tracking. She said researchers are verifying all the cases that have been reported by members of the monitoring program.
An attorney representing thousands of workers and residents said that more than 100 of his clients have blood cell cancers. About eight have multiple myeloma, David Worby said. Most of his clients are in their 30s or 40s, and the youngest is 29, he said.
More than half of all cases of multiple myeloma, a plasma cell cancer that spreads throughout bone marrow, occur in people over 70, and about 1 percent of cases occur in people under 40, according to the Multiple Myeloma Research Foundation in Norwalk, Conn.
Herbert, referring to cancer as a possible third wave of disease, said the first was the chronic coughing and acute respiratory problems that workers got right after their post-Sept. 11 work.
Second, she said, are more serious chronic lung diseases such as sarcoidosis, which killed a New York woman who inhaled dust from the collapsing twin towers on Sept. 11, 2001. The city medical examiner last week added Felicia Dunn-Jones' 2002 death to the official list of Sept. 11 attack victims.
Mayor Michael Bloomberg said of Herbert's remarks on blood cell cancers: "The city's own doctors don't — they will not say there's no possibility — but they don't at the moment see this as the great threat."
Said Worby: "It's not a great threat to the general public, but to people who are already sick and have these blood cell cancers and who gave up their lives ... it's a great threat to them because a lot of them are going to die."