AGENT ORANGE AND SOFT
TISSUE SARCOMAS
What are soft tissue sarcomas?
Soft tissue sarcomas are a group of different types of malignant tumors
which arise from body tissues such as muscle, fat, blood and lymph vessels
and connective tissues (that is, distinct from hard tissue such as bone
or cartilage). These tumors are relatively rare.
In regulations, VA has defined the term "soft tissue sarcoma"
to include adult fibrosarcoma; dermatofibrosarcoma protuberans, malignant
fibrous histiocytoma, liposarcoma; leiomyosarcoma; epithelioid leiomyosarcoma
(malignant leiomyoblastoma); rhabdomyosarcoma; ectomesenchymoma; angiosarcoma
(hemangiosarcoma and lymphangiosarcoma); proliferating (systemic) angioendotheliomatosis;
malignant glomus tumor; malignant hemangiopericytoma; synovial sarcoma
(malignant synovioma); malignant giant cell tumor of tendon sheath;
malignant schwannoma, including malignant schwannoma with rhabdomyoblastic
differentiation (malignant
Triton tumor), glandular and epithelioid malignant schwannomas; malignant
mesenchymoma; malignant granular cell tumor; alveolar soft part sarcoma;
epithelioid sarcoma; and clear cell sarcoma of tendons and aponeuroses.
(See 56 Fed. Reg. 51651, October 15, 1991).
Why are Vietnam veterans concerned about soft tissue sarcomas?
The possibility that exposure to phenoxy herbicides, such as Agent Orange,
may have caused rare forms of cancer in humans such as soft tissue sarcomas
was suggested in 1979 and 1981 by small scale studies conducted in Sweden.
These studies showed that persons reporting occupational exposure to
phenoxy herbicides may have a 5 to 6 fold higher risk of developing
soft tissue sarcomas as compared to persons without such exposure.
Have more recent research results supported or conflicted with the
Swedish studies finding regarding soft tissue sarcomas?
A number of scientific studies of soft tissue sarcomas among people
who may have been exposed to herbicides and/or dioxins have been published
in the past few years. Some studies suggested a possible association
between these exposures and an increased risk of some cancers, but none
showed an increased risk of soft tissue sarcomas of the magnitude cited
by the Swedish researchers, and the majority of these investigations
showed no association at all.
Mortality studies conducted by Massachusetts and West Virginia indicated
that there might be a link between service in Vietnam and soft tissue
sarcomas. However, the small number of deaths in the West Virginia study
makes it possible that these findings were the results of chance rather
than real association.
A New York State study showed that fewer Vietnam veterans died of soft
tissue sarcomas than Vietnam-era veterans who did not serve in Vietnam.
A study in New Zealand of soft tissue sarcomas and exposure to phenoxy
herbicides and chlorophenols, a National Cancer Institute study of agricultural
herbicide use and risk of lymphomas and soft tissue sarcomas in Kansas,
a western Washington State study, the Department of Veterans Affairs
(VA) Vietnam veterans mortality study, two VA studies of the relationship
between soft tissue sarcomas and military service in Vietnam, and the
Centers for Disease Control Selected Cancers Study have not supported
the findings of the Swedish researchers. The VA studies were published
in the Journal of Occupational Medicine in December 1986, and the Journal
of the National Cancer Institute in October 1987. Very few cases of
soft tissue sarcomas are appearing in the Agent Orange Registry. Research
on soft tissue sarcomas and other cancers is continuing.
What did the Veterans' Advisory Committee on Environmental Hazards
conclude about the relationship between herbicides and soft tissue sarcomas?
This VA committee, established by law, met on May 16-17, 1990, to review
scientific literature relating to whether there is a significant statistical
association between exposure to a dioxin-containing herbicide and subsequent
development of soft tissue sarcoma. After considering more than eighty
articles, the Advisory Committee concluded that it was as least as likely
as not that such an association existed.
Committee members noted that work done in Sweden was strongly compelling
for an association while studies done elsewhere not showing an association
were also very strong. Members observed that "positive" studies
tended to be confined to one geographic area of the world whereas studies
involving Vietnam veterans did not find such an association. Several
Committee members noted they did not believe that the scientific evidence
demonstrated a causal association.
How did VA respond to the Advisory Committee's finding?
The day after the meeting, Secretary Derwinski announced that VA would
recognize, as service- connected, soft tissue sarcomas based on exposure
to dioxin-containing herbicides.
Final rule implementing the Secretary's decision was published in the
Federal Register in October 1991. (See 56 Fed. Reg. 51651, October 15,
1991).
What did Public Law 102-4 due for Vietnam veterans who suffer with
soft tissue sarcomas?
To a large extent, Public Law 102-4, the Agent Orange Act of 1991, enacted
February 6, 1991, codified (established in law) the Secretary's decision.
However, since there are significant differences in the eligibility
requirements for service connection under the rule and the presumptions
of service connection established under Public Law 102-4, the rule implementing
the new statute was published separately in the Federal Register. (For
proposed rule, see 57 Fed. Reg. 30707, July 10, 1992; for final rule
see 58 Fed. Reg. 29107, May 19, 1993).
What did the National Academy of Sciences (NAS) conclude about soft
tissue sarcomas (STS) in its 1993 report, entitled Veterans and Agent
Orange Health Effects of Herbicides Used in Vietnam?
The 832-page NAS report contained the following statements:
The strongest evidence for an association
between STS and exposure to phenoxy herbicides come from a series
of case-control studies involving a total of 506 cases conducted by
Hardell and colleagues in Sweden that show an association between
STS and exposure to phenoxy herbicides, chloropenols, or both. Although
these studies have been criticized, the committee feels that there
is insufficient justification to discount the consistent pattern of
elevated risks, and the clearly described and sound methods employed.
These findings are supported by a significantly
increased risk in the NIOSH study for the production workers most
highly exposed to TCDD , and a similar increased risk in the IARC
cohort for deaths that occurred between 10 and 19 years after the
first exposure These are the two largest, as well as the most highly
exposed occupational cohorts.
Some studies in other occupational,
environmental, and veterans group showed an increased risk for STS,
but the results were commonly non-significant possibly because of
small sample sizes related to the relative rarity of STS in the population,
except for males in Zone R of Seveso. The risk of this group was significantly
elevated and is consistent with the findings supporting an association....
Evidence is sufficient to conclude
that there is a positive association between exposure to herbicides
(2,4-D; 2,4,5-T and its contaminant TCDD; cacodylic acid; and picloram)
and soft tissue sarcoma.
What did the NAS conclude regarding soft tissues sarcomas in its
1996 update?
In the 1996 update, the NAS commented that reports issued since the
publication of Veterans and Agent Orange provide "additional
evidence for an association" between exposure to herbicides and
soft tissue sarcomas.
Where can a veteran get additional information on this subject?
Information on soft tissue sarcomas and related matters can be obtained
at VA medical center libraries, from the Registry Physicians at every
VA medical center, or from the Environmental Agents Service (131), Department
of Veterans Affairs, 810 Vermont Avenue, N.W., Washington, DC 20420.
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