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Study Finds Increased Lung Cancer Risk Following Treatment for Hodgkin's Disease
I received this from another mailing list and thought I would pass it along.
-- John
John Jacobus, MS
Certified Health Physicist
3050 Traymore Lane
Bowie, MD 20715-2024
E-mail: jenday1@email.msn.com (H)
-----Original Message-----
. . .
The following press release was recently provided on
the National Institutes of Health's NCI Web site:
----------
Office of Communications/ Mass Media Branch/ Building
31, Room 10A19, Bethesda, MD 20892
National Institutes of Health:
NCI Press Office (301) 496-6641
EMBARGOED FOR RELEASE
4pm EST
Tuesday, February 5, 2002
Study Finds Increased Lung Cancer Risk Following
Treatment for Hodgkin's Disease
People with Hodgkin's disease (HD) who receive
chemotherapy, radiotherapy, or a combination of the two
treatments, are at higher risk of developing lung cancer,
according to a report in the Feb. 6, 2002, issue of the
Journal of the National Cancer Institute.* The study also
finds a higher risk for lung cancer among smokers treated
with both radiotherapy and chemotherapy.
"It was the combined effect of smoking and treatment that
accounted for the bulk of lung cancers in this study,
underscoring the importance of smoking cessation in the
management of patients with Hodgkin's disease," the
authors conclude. "It is clear that the tremendous
improvement in the treatment of HD far outweighs any
therapy-related risks of lung cancers, especially when
compared with the enormous burden imposed by tobacco,"
said Lois Travis, M.D., Sc.D., of the National Cancer
Institute's Division of Cancer Epidemiology and Genetics
in Bethesda, Md., and first author of the study.
While 7,000 people a year are diagnosed with HD in the
United States, it is among the more treatable and curable
types of cancer. Second cancers, which can arise after a
patient is diagnosed with HD, constitute the number one
cause of death in these patients. Lung cancer is the most
frequent solid tumor seen in this group. However, data on
the reasons behind the increased risk have been sparse
and inconsistent.
For this study, the researchers looked at many different
factors, but focused on three main measures: the type and
cumulative amount of chemotherapy drugs, the radiation
dose, and tobacco use. All three exposures contributed
significantly to elevated lung cancer risks. Tobacco use,
chemotherapy, and radiotherapy doses of five Gray (Gy) or
more were reported in 96 percent, 63 percent, and 53
percent of case subjects (those who developed lung
cancer), respectively, and in 70 percent, 52 percent, and
41 percent of patients who did not develop lung cancer.
Subjects who received either radiotherapy alone or
chemotherapy with drugs called alkylating agents
experienced a significantly increased risk of lung cancer.
And when researchers looked at the group of patients who
received both alkylating agents and radiotherapy, the
numbers showed risks that were additive.
"We found that chemotherapy for Hodgkin's
disease--specifically treatment with alkylating
agents--increases risk four-fold and radiation treatment
(radiotherapy) increases the risk of lung cancer almost
six-fold, said Travis. "When the number of cycles and
dose of either type of treatment increased, risk
increased again. When we examined the combined effects of
chemotherapy and radiotherapy, the risk was approximately
eight-fold, suggesting that combination therapy may
increase lung cancer risk in an additive fashion."
Researchers also demonstrated that lung cancer risk
increased with increasing total amounts of either
alkylating agents or radiotherapy dose.
In order to conduct the study, researchers from several
countries collaborated to assemble over 19,000 patients
diagnosed with HD between 1965 and 1994. This large group
of patients represents a unique cohort, comprising
information from seven cancer registries: two in the
United States, one in Canada, three in Scandinavia and
one in the Netherlands. Within this group, scientists
identified 222 case subjects who developed lung cancer
and 444 control subjects who did not develop lung cancer.
In order to better examine the risk factors for lung
cancer in HD patients, the researchers compared these two
groups to each other, in what is called a case-control
study.
Researchers also wanted to quantify the role of smoking
and tobacco use in the development of lung cancer in this
group. Of the lung cancers that were diagnosed,
researchers estimated that approximately 10 percent were
due to treatment alone, 63 percent were due to treatment
and smoking combination, 24 percent were due to smoking
alone, and 3 percent were cases in which neither smoking
nor therapy played a role.
In contrast to the effect of combined treatment, which
showed that risks were additive with combined therapy,
smoking appeared to multiply the risk of lung cancer.
The largest risks for lung cancer were seen in
individuals who were heavy smokers and received both
radiotherapy and alkylating agents.
While the findings are consistent with the established
role of tobacco in lung cancer, researchers warn that
the estimated risks for treatment-associated lung cancer
should be interpreted with caution. Radiotherapy and
chemotherapy information was readily available in the
reviewed records, but information on smoking habits was
not recorded in an optimal format for retrospective
studies. Additionally, because of the small number of
lung cancers in nonsmokers, the interaction of
chemotherapy and/or radiation with tobacco use could be
evaluated only by comparing moderate-to-heavy smokers
with all other patients combined.
The study also provides new information regarding the
time to development of lung cancer following treatment
for Hodgkin's disease. Researchers found that excess
lung cancers diagnosed after chemotherapy treatment
with alkylating agents occurred as early as one to four
years after the first treatment. In contrast, increases
in lung cancers diagnosed after radiotherapy were first
noted five years after treatment and persisted for over
20 years.
Researchers plan to continue to follow the study group,
since many questions remain unanswered. The way
alkylating agents, a cornerstone of current HD
treatment, contribute to the development of lung cancer
is not entirely clear. Although several possible
mechanisms were reviewed in the study, future research
should address this issue and also explore whether the
immunology associated with Hodgkin's disease might
also somehow contribute to secondary lung cancer, and
whether tissue damage and repair mechanisms seen after
radiotherapy may play a role, as well.
###
For more information about cancer, visit NCI's Web site
at[:] http://www.cancer.gov .
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The above may be viewed on the NIH Web site at URL:
http://newscenter.cancer.gov/pressreleases/hodgkinslung.html
. . .
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