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Mesothelioma: Has Patient Had Contact With Even Small Amount of Asbestos?
MESOTHELIOMA, primarily an asbestos-related cancer, has traditionally been tracked through the incidence rate in workers handling asbestos directly. Now, epidemiologists are recording
cases of the tumor in persons who have
worked with materials containing even small quantities of asbestos.
"It is a very important new phenomenon," says Irving J. Selikoff, MD, professor emeritus, Mount Sinai School of Medicine, City University of New York. "Physicians must now begin taking histories with questions directed to [learning if patients ever have been]
construction workers."
Electricians, plumbers, steamfitters, laborers, carpenters, boilermakers, and their supervisors all have worked around asbestos. Brake-lining repairpersons, workers in chemical plants, refineries, powerhouses, and factories, and building maintenance personnel all are at risk, just as were the much\x=req-\ studied shipbuilders of the 1940s.
Until recently, the basic implements
used in these trades contained the friable fibers. Some still do. Asbestos has
been used in pipes, concrete, plastics, paints, asphalt, and shingles. The list
goes on.
Robert Spirtas, MD, biostatistician, National Cancer Institute, Bethesda, Md, points to two trends that arose during the 1950s as asbestos use was introduced in the construction industry: more material was being used, and more people were being exposed with less intensity.
The lower concentrations of asbestos
were thought by many to have mini mized the susceptibility of workers to
mesothelioma. But as cases of the ma
lignant tumor appeared in tradesmen, epidemiologists began to suspect that
the concentration level of the fibers was
not the prime concern.
Further studies showed that one fiber
of a certain length can lodge in the pleura of the lung, and 40 years later, the patient will exhibit signs of dysp nea, chest pain, or both (Clin Chest Med 1985;6[1]:127-140). To date, there has
been no threshold level defined for as
bestos-induced mesothelioma (Mt Sinai
JMed (NY) 1986;53[6]:409-415).
Risk assessment tables have been
attempted by Hans Weill, MD, profes sor of pulmonary medicine, Tulane Uni versity School of Medicine, New Or leans (Am Rev Respir Dis 1986;133: 5-13); the Health and Safety Commis sion, London (Doll R and Peto J: Effects on health of exposure to asbestos, London, HM Stationery Office, 1985); and the Royal Commission on Matters of Health and Safety, Canada (Report on matters of health and safety arising from the use of asbestos in Ontario, Toronto: Ontario Ministry of Govern ment Services, 1984). Much of the evi
dence for these assessments relies on
the studies of heavily exposed workers. The construction industry poses
problems for epidemiologists. The tran sient nature of the work force, the con stantly changing locales of the workplace, and the very large number of firms involved (many with just a few employees) hamper research (Am J Pub Health 1986;176[12]:1392-1395).
Selikoff's studies in the 1960s of ship
builders and asbestos workers alerted
the medical community to the hazards of the asbestos fibers (JAMA 1964;188: 22-26). Later studies suggested that the
number of deaths from mesothelioma
would continue to rise throughout the
1980s. This expectation was based on two factors: that the highest exposure rates occurred around 1943 as ships were built for the war effort, and that the 30- to 40-year latency period would end by the early 1980s (Yale J Bio & Med 1986;59[4]:435-451).
Further studies have led Selikoff to
suggest that the incidence of mesotheli
oma will reach its peak around 1990 and then gradually decline. This estimate is
based on the idea that exposure to as
bestos would stop by 1980. Since asbestos still is being used to
day, the number of deaths occurring
from mesothelioma may be underesti mated. The Bureau of Mines cites the
1985 US consumption of asbestos at
162 000 metric tons, down from the 1973
high of 800 000 metric tons. Consump tion has not stopped, but it has dimin
ished.
In June, the Occupational Safety and
Health Administration lowered the allowable rate of exposure in the work
place from <2 fibers per cc of air to <.01
fibers per cc of air. The Environmental
Protection Agency is holding hearings
now to determine if a total ban on the
use of asbestos is warranted. A decision
is expected within the year.
EXCESS DEATHS OF LUNG CANCER DUE TO ASBESTOS, 1977-2017
Total 4368 5055 5472 5497 5259
4693 3921
2987
2108
CONSTRUCTION
X. SHIPYARDS INSULATORS
1997
YEAR
2002
PROJECTED DEATHS OF MESOTHELIOMA, 1977-2017
Total 1425 1775 2398 2748 2969 3060 2999 2661
2028
CONSTRUCTION
Because the extent of asbestos expo sure is wide and the risk levels are still
undetermined, emphasis must be placed on the screening, testing, and
education of workers.
According to Selikoff, the construc tion unions are becoming very sophisti cated about asbestos problems. They are beginning screening processes for
workers associated with the material.
The American Federation of Labor-
Congress of Industrial Organizations (AFL-CIO) has lawyers working on the legal problems, but the unions see edu cation as the key. Selikoff has recently compiled a booklet for the AFL-CIO
aimed at workers who have been ex
posed to asbestos. The nine-page man-
ual provides facts for "at risk" persons, describing the types of diseases that can
occur, the symptoms, the tests that can
be expected, and the type (specialty) of physician who should be seen.
Mesothelioma is still a relatively
young disease. The first incidence of the asbestos-related tumors was recorded
only 40 years ago. Knowledge is increas ing, but inadequate record keeping, lax reporting of case histories (many times, due to the long time lapse between exposure and symptoms, patients can not remember working around asbes tos), and poor health education among workers have hindered epidemiologists (Am J Pub Health 1986;176[12]:
1392-1395).
According to Weill, the rates of meso thelioma in men are still going up and are expected to continue to do so. Be cause information in the tumor regis tries cannot be retrieved by job classi fication, he says, it is difficult to tell if the construction industry and other
trades are accountable for the increase.
Spirtas says: "It is difficult to predict
future trends in mesothelioma. How ever, the current levels of incidence are
clearly of substantial enough magnitude to justify greater scientific as well as public health and economic concerns" (Am J Ind Med 1986;9:397-407). -by Katherine Garrahan, winter graduate journalism fellow (Medill School ofJournalism, Northwestern University, Ev-
anston, Ill)
Friable Asbestos in Schools Must Be Found
by May 1988, Removal Plan Must Start by 1989
FOR 20 YEARS, from the 1950s to the 1970s, asbestos was used as a fireproofing agent in America's school systems. Today, the presence of the potentially cancer-causing material is igniting fires
of concern across the country.
Parental anxiety, boycotting of classes, and the closing of school buildings in many communities forced the Environmental Protection Agency to mandate the inspection of all elementary and secondary public and private institutions for asbestos-containing materials. By federal law, the inspections must be carried out by May 9,1988, and the implementation of management plans for the removal of any friable asbCehsitldosremn'susetxbpeogsuinrebtyoJauslbye9s,to1s9i8n9.the schools naturally is of special concern to pediatricians. Higher activity and
breathing rates, more time spent close to the floor where fibers accumulate, and natural curiosity or mischievous-
ness may lead children to seek contact
with deteriorating surfaces in school buildings. The American Academy of
Pediatrics (AAP) has issued a state-
ment urging physicians to work with school boards to promote the cleanup of such potentially hazardous situations.
Philip Landrigan, MD, Mount Sinai School of Medicine, City University of New York, chair of the AAP's commit tee on environmental hazards, says: "The most important factor is that each situation must be judged on its own merits." Landrigan points to two crucial elements that physicians should empha size when dealing with the presence of asbestos in schools: individual inspec tions must be made at each site, and if
friable asbestos is found, contractors experienced in asbestos removal must
be hired to rid the site of the fibers.
"It is certainly possible to remove the
material with proper work and proper
protection," says William Nicholson, PhD, professor of community medicine, Mount Sinai School of Medicine, City University of New York. He advocates
removal to prevent any asbestos expo sure, but admits sealing the material is
sufficient in many cases.
Presently, 15 states require asbestos
abatement contractors to be licensed.
Ten other states have legislation pend ing, and the EPA is developing a model accreditation plan for persons who in spect, develop management plans, and remove the asbestos from buildings.
Opinions vary as to the exposure risk
children encounter in the school envi-
acquired during their time as prisoners working on the Burma-Thai railway, 40 years previously.
Of the 150 veterans so far investi-
gated, 29 have had the typical clinical manifestations of episodic diarrhea, vague abdominal discomfort, eosinophilia, and rapidly advancing linear skin eruptions (larva currens).2 The remaining 121 patients were not consid ered to have strongyloidiasis and, in deed, this was supported by lack of eosinophilia and at least three negative
stool examinations and cultures. In the
group of 29 suspicious cases, however, S stercoralis was found in 25 (86%) on
stool examination.
Comment.--Thus, the typical clinical findings in this group of patients ex posed to infestation decades before seem quite reliable in predicting para site carriage. Examination of their past
medical records also indicated that
these features had been quite consistent over the years, with diagnoses of postdysenteric scarring and psychoneurosis being applied to explain the symptom atology. Several of the patients even had episodic larva currens rash while undergoing investigation.
We still consider the clinical manifes
tations of disseminated strongyloidia sis--although sometimes ill-defined-- to be helpful in suggesting the diagnosis and discriminating carriers from noncarriers, particularly in high-risk groups. A high index of suspicion must be maintained when dealing with veter ans of foreign wars, particularly if they have been prisoners of war, and also with immigrants from endemic areas.
Roger W. Byard, MB, BS University of Ottawa Nicholas W. J. Oliver, MB, BS
David J. Rowbottom
Repatriation General Hospital Hobart, Tasmania, Australia
1. Genta RM, Weesner R, Douce RW, et al: Strongyloidiasis
in US veterans of the Vietnam and other wars. JAMA 1987;258:49-52.
2. Grove DI: Strongyloidiasis in Allied ex-prisoners of war in Southeast Asia. Br MedJ1980;1:598-601.
In Reply.\p=m-\Weagree with Byard and colleagues that the clinical manifestations of disseminated strongyloidiasis are helpful in suggesting the diagnosis. However, our study was designed to evaluate the usefulness of serology for the detection of chronic, nondisseminated infections, which often remain undiagnosed for a long time precisely because of their few and nonspecific
manifestations.
The high prevalence of larva currens found in British,1 Australian,2 and American3 former prisoners of war who
worked on the Burma-Thai railroad contrasts with the virtual absence of this
dermatitis in patients with documented S stercoralis infections presumably acquired on the American continent.4 We have suggested that the existence of separate geographic strains of the parasite may account for this difference,5 but
further studies are needed to test this
hypothesis. Based on their Tasmanian experi-
ence, Byard and colleagues correctly stress the importance of maintaining a high index of suspicion when dealing with veterans of foreign wars and immi-
grants from endemic areas. It should be
emphasized, however, that S stercoralis
is also present in the southeastern
United States. Since the publication of our article, three new cases of dissemi nated strongyloidiasis have occurred in immunosuppressed patients in the Cin cinnati area: all patients were natives of eastern Kentucky and had no history of
overseas travel. In each case the serol-
ogy was highly positive, but no attempt to rule out strongyloidiasis had been made prior to the initiation of steroid therapy. Such occurrences further stress the importance of screening (by serology or repeated stool examina
tions) all candidates for immuno-
suppression who have a significant geographic history.
Robert M. Genta, MD Peter D. Walzer, MD Robert E. Weesner, MD
Veterans Administration Medical Center
Cincinnati
University of Cincinnati College of Medicine
1. Gill GV, Bell DR: Strongyloides stercoralis infection in former Far East prisoners of war. Br MedJ 1979;2:572-574. 2. Grove DI: Strongyloidiasis in Allied ex-prisoners of war in Southeast Asia. Br Med J 1980;1:598-601. 3. Pellettier LL: Chronic strongyloidiasis in World War II Far East ex-prisoners of war. Am J Trop Med Hyg
1984;33:55-61.
4. Milder JE, Walzer PD, Kilgore G, et al: Clinical features of Strongyloides stercoralis infection in an endemic area of the United States. Gastroenterology 1981;80:1481-1488. 5. Genta RM: Strongyloides stercoralis: Immunobiological considerations on an unusual worm. Parasitology Today 1986;2:241-246.
Incorrect Dosage. \p=m-\Anerror occurred in the COUNCIL REPORT entitled "In Vivo Diagnostic Testing and Immunotherapy for Allergy: Report I, Part II, of the Allergy Panel," published in the Sept 18 issue of The Journal (1987;258:1505-1508). On page 1507,
the second sentence in the first paragraph of the "Hymenoptera Venom Immunotherapy"
section should have read as follows: "Patients
should have clinical evidence of anaphylaxis from specific Hymenoptera sting, a positive skin test reaction with specific Hymenoptera venom and/or specific serum IgE antibody, and should receive injections according to
the recommended schedule to attain an effec-
tive dose of approximately 100 \g=m\g[not `100 mg'] of specific venom every month."
Incorrect Wording. \p=m-\Anerror occurred in
the Letter to the Editor entitled "Anabolic
Steroids and Sports," published in the Sept 25 issue of The Journal (1987;258:1608). On page 1608, the last complete sentence in
column 1 should have read as follows: "The
70th session of the Texas legislature recently passed a bill (Senate bill 1035) amending
Vernon's Texas Civil Statutes article 4476-14
and classifying [not `making'] 16 anabolic steroids and human growth hormone as dangerous drugs [not `controlled substances for which triplicate forms will have to be used to prescribe them']."
Incorrect Values. \p=m-\Severalerrors occurred in the Letter to the Editor entitled "Na-
proxen and Agranulocytosis," published in the April 3 issue of The Journal
(1987;257:1732). In the "Report of a Case" section, the third sentence should have
read as follows: "On admission he was noted to have a white blood cell count of
2300/mm3 (2.3X109/L) [not `0.0023 X 103/mm3 (0.0023 X109/L)'], with 16% (0.16) polymorphonuclear leukocytes (268/mm3 [0.368 X 109/L]) [not `0.000368 X 103/mm3 (0.000368 X109/L)'] and 0% (0.00) band forms." In that same paragraph, the eighth
sentence should have read as follows:
"His absolute granulocyte count dropped to 52/mm3 (0.052 X109/L) [not `0.00052 X 103/mm3 (0.00052 X109/L)'] while his white
blood cell count remained stable at
2600/mm3 (2.6 X 109/L) [not `0.0026 X 103/mm3
(0.0026 X 109/L)']." In the next paragraph, the
third sentence should have read as follows:
"His fever completely resolved within 72 hours of discontinuing the naproxen therapy,
and over the next week his white blood cell
count stabilized at 7600/mm3 (7.6xl07L) [not '0.0076 x 107mm3 (0.0076 x 107L)'] with 45% (0.45) polymorphonuclear leukocytes (3420/mm3 [3.42xl07L]) [not '0.00342 x 107mm3 (0.00342 X107L)'] and 10% (0.10)
band forms."
Incorrect Wording. \p=m-\An error occurred in
the SPECIAL COMMUNICATION entitled "Pa-
tient Dumping: Status, Implications, and Policy Recommendations," published in the March 20 issue of The Journal (1987;257: 1500-1502). On page 1501, the second sentence in the second full paragraph of column 1
should have read as follows: "The Hill-Burton
legislation's inadequacies include lack of a
definition of a medical emergency [not `Hil\x=req-\
Burton legislation includes community service of a medical emergency'] and no effective
means for enforcement.4"
Incorrect Value. \p=m-\Anerror occurred in the MEDICAL NEWS & PERSPECTIVES article entitled "Mesothelioma: Has Patient Had Contact With Even Small Amount of Asbestos?"
published in the March 27 issue of The Journal (1987;257:1569-1570). On page 1569, the first sentence of the third full paragraph
in column 3 should have read as follows: "In
June, the Occupational Safety and Health
Administration lowered the allowable rate of
exposure in the workplace from <2 fibers per
cc of air to <0.2 [not `<.01'] fibers per cc of
air."