http://www.expressnews.com/news/local/article/Agent-Orange-linked-to-doubled-cancer-risk-in-6497193.php
U.S. Air Force personnel who
conducted aerial spray missions of the Agent Orange herbicide during the
Vietnam War were twice as likely to have a disorder that can lead to a type of
blood cancer, says a new study published in JAMA Oncology online Sept. 3.
This is the first study to uncover
an association between exposure to Agent Orange and multiple myeloma among
Vietnam veterans.
Previous research showing an
association between similar herbicides and multiple myeloma examined
agricultural workers in the United States and Canada.
“We have, for the first time,
biological evidence of a connection between this particular cancer and exposure
to Agent Orange and its dioxin contaminant,” said Joel Michalek, a professor of
biostatistics at San Antonio’s University of Texas Health Science Center and an
author on the paper.
Multiple myeloma is a relatively
rare blood cancer that can damage the kidneys and other organs, weaken bones
and cause high calcium levels in the blood, the National Cancer Institute says.
Agent Orange has been linked to other cancers and diseases, including Type 2
diabetes.
U.S. Air Force personnel sprayed
Agent Orange from aircraft to destroy forests and foliage that provided enemy
cover in Vietnam from 1962 to 1971 as part of the Operation Ranch Hand program.
The study examined blood samples
collected and stored in 2002 from 479 Ranch Hand veterans and compared them to
blood samples from 479 veterans who served in Southeast Asia during the same
time period but weren’t involved in the aerial spray missions.
Researchers found a 2.4-fold
increased risk for a condition called monoclonal gammopathy of undetermined
significance, a precursor disease for multiple myeloma, in the Ranch Hand
veterans compared to the other veterans.
Of 479 Ranch Hand veterans, 34 of
them, or 7.1 percent, had the precursor for the cancer, compared to 15 of 479,
or 3.1 percent, in the other veterans.
The majority of people with the
multiple myeloma precursor do not develop the cancer, but previous research has
shown multiple myeloma is consistently preceded by that blood disorder, said
Dr. Ola Landgren, a hematologic oncologist at Memorial Sloan Kettering Cancer
Center in New York and the study’s lead author.
Agent Orange contains a contaminant
called TCDD, which the Environmental Protection Agency classifies as a probable
human carcinogen.
The study found the veterans who’d
been exposed to Agent Orange and had developed the precursor had significantly
higher levels of TCDD in their blood, making the results of the study “more
meaningful,” Dr. Nikhil C. Munshi, a physician with the Dana-Farber Cancer
Institute, wrote in an editorial accompanying the study. The risk
increases as the concentration of TCDD in the blood increases.
Not all Air Force personnel involved
in Operation Ranch Hand had the same level of exposure to Agent Orange,
Michalek said.
“The pilots were probably the least
exposed because they’re like the truck drivers,” Michalek explained. “The guys
who got it the worst were the enlisted ground crew who had to fill the tanks,
sit in the back of the plane, operate the spray equipment.”
Army ground troops in the jungles of
Vietnam, crew members on boats and ships and other service members also may
have been exposed.
“There’s a controversy going on even
now as to who was exposed in Vietnam and who wasn’t and by how much,” Michalek
said.
The research was conducted from 2013
to 2014 using specimens and exposure data collected by the Air Force Health
Study. That 25-year study, headquartered at the now-closed Brooks AFB, examined
the health effects of Agent Orange on Vietnam veterans and their children.
Michalek headed the study for about 10 years before it ended in 2005.
More than 80,000 biological
specimens from the study later were sent to Wright-Patterson AFB in Dayton,
Ohio, where researchers continue to have access to the materials.
Jack McManus, an Operation Ranch
Hand veteran who participated in the Air Force Health Study, wasn’t surprised
to learn about the association between Agent Orange and multiple myeloma. He
believes insufficient research has been conducted on the stored specimens.
“I think there are multiple more
diseases that we’re going to find,” said McManus, 69, who lives in North
Carolina and who works with the nonprofit Vietnam Veterans of America to
advocate for veterans exposed to Agent Orange. “I think what we’re going to get
is bits and pieces of information coming out for many, many years.”
Veterans exposed to Agent Orange
during military service may be eligible to receive disability compensation from
the Veterans Affairs Department for diseases associated
with that exposure, including multiple myeloma.
jbelasco@express-news.net