0
Communications to the Editor |

On Perception, Perspicuity, and PrecisionResponseResponse FREE TO VIEW

William K. C. Morgan, MD, FCCP
Author and Funding Information

Affiliations: University Hospital London, Ontario, Canada ,  Finnish Institute of Occupational Health Tampere, Finland ,  Chief, Pulmonary Medicine Catholic Medical Center Professor of Clinical Medicine Albert Einstein School of Medicine Clinical Professor of Community Medicine Mount Sinai Medical School, NY



Chest. 1999;115(1):303-305. doi:10.1378/chest.115.1.303-a
Text Size: A A A
Published online

Ralph Waldo Emerson wrote, “Next to the originator of a good sentence is the first quoter of it,” but he seems to have said nothing about a misquoter! What I wrote in 1974 was, “It is often assumed that the interpretation of films for pneumoconiosis requires profound knowledge and perspicacity and that the ideal interpreter is an happy blend of Sherlock Holmes, Albrecht Dürer, and Socrates. The interpretation of a film for pneumoconiosis is a glorified guess or estimate of the number of dots present on it.”1 Miller,2 like the character in Byron’s Don Juan, is blessed “with just enough of learning to misquote.” After reading a further 25,000 plus films for pneumoconiosis, I now know that image perception, patience, and resilience are essential. Dürer certainly had the former, while Socrates and Holmes probably had both the latter qualities.

Miller makes a number of points with which I agree. It is high time the International Labour Office revised the 1980 classification and I would gratuitously add that National Institute for Occupational Safety and Health by now should have realized that several of the films they use in the B reader recertification examination, which in 1980 were thought to show pleural thickening, in reality show axillary and pleural fat pads. Miller mentions that “the diagnosis of asbestosis does not reside in the reading 1/0 rather than 0/1.” Perhaps the same could be said of 1/1, as well as 1/0. The problem in this regard is confounded by smoking and the fact that many smokers show the presence of scanty irregular opacities. When one is trying to decide whether a subject has asbestosis, the chest x-ray alone is insufficient, as was suggested in the American Thoracic Society statement, “The Diagnosis of Nonmalignant Diseases Related to Asbestos.”3

Oksa and colleagues, the authors of the paper that Miller critiques, state that it is difficult to attribute the progression of the radiographs to cigarette smoking;4 however, the reader is not given any information as to whether the smoking histories were taken at both interviews or whether any of the ex-smokers at the first interview had resumed smoking at the second interview. It is well known that more than two thirds of those who give up smoking resume at a later date. Similarly, the radiographs should have been interpreted completely independently, without a second film being present.1 The authors are mistaken if they believe that seeing paired films in random order excludes bias. It is often easy to identify the earlier film. Apart from wear and tear on the older film and aside from the technique that was used, certain features on the radiograph will sometimes permit recognition of the company’s product. Joint decisions tend to introduce bias, with the most opinionated reader insisting on having his way.

Much is also made in Miller’s editorial of the reduced FVC in the Mount Sinai studies of those exposed to asbestos. The FVC is difficult to measure accurately and many patients terminate their FVC maneuver prematurely. Modern spirometers contribute to this by displaying the time vs volume curve for only 10 s, with the result that a plateau is not achieved unless the technician is looking at the oscilloscope particularly carefully. In the same context, it is inappropriate to suggest restrictive impairment unless both the FVC and FEV1 are both decreased proportionately.

I find myself in agreement with many of Miller’s other statements. With some due deference, I would point out to him that there is now a third edition of the Morgan and Seaton textbook which, we hope, contains much in the way of useful new information, especially in regard to the interpretation of chest films for pneumoconiosis.1

Correspondence to: William K. C. Morgan, MD, FCCP, University Hospital, Chest Disease Unit, 339 Windemere Road, London, Ontario, Canada

Morgan, WKC (1974) Epidemiology and occupational lung disease. Morgan, WKC Seaton, A eds.Occupational lung diseases,29-38 WB Saunders. Philadelphia, PA:
 
Miller A., Sherlock Holmes, Albrecht Durer, and Socrates: the International Labour Office radiographic Classification of Pneumoconioses reassessed for asbestosis. Chest 1998; 113:1439–1442.
 
American Thoracic Society.. Medical Section of the American Lung Association: The diagnosis of nonmalignant diseases related to asbestos.Am Rev Respir Dis1986;134,363-368
 
Oksa, P, Klockars, M, Karjalainen, A, et al Progression of asbestosis predicts lung cancer.Chest1998;113,1517-1521
 
To the Editor:

Both Dr. Morgan in his letter and Dr. Miller in his editorial,1-1 discuss the International Labour Office (ILO) 1980 classification. We do agree with their criticism of the classification system.

The letter and editorial also contained some comments on our recently published paper.1-2 We used the ILO 1980 classification because it is the only widely accepted classification available. To minimize the influence of the weaknesses of the method, we used three readers and three different criteria to decide radiographic progression: (1) progression of small opacities, estimation side-by-side, (2) progression of asbestosis into a higher major category (4-point scale), and (3) progression of at least two minor categories (12-point scale). All the criteria gave the same result; radiographic progression appeared to predict lung cancer. When radiographs are read side-by-side, it may sometimes be possible to identify the one taken earlier. In our study, this possibility was unlikely to cause systematic bias, as the readers could not possibly know the future cancer status of the patients.

Although our cohort is a small one, the outcome is hard to neglect. Observations in small and well-defined cohorts often prove to be important. In fact, it is more difficult to interpret results from large cohorts with risk estimates close to 1.0 showing weak dose-response trends that are “statistically significant.”

For many cohorts, detailed smoking data are available, and our experience shows that a rather rough estimate gives roughly the same risk estimates as the most precise smoking index, including exact durations and grams of tobacco smoked daily.1-3 There are no reasons to believe that, for our cohort, the situation would be essentially different. We collected smoking data only once, at the beginning of the follow-up. Special attention was paid to promoting the cessation of smoking among the asbestosis patients. Such patients are highly motivated to stop, and according to our experience, it is rare that someone who quits would start again. There is little information on how fast and to what extent, if at all, the stopping of smoking and starting again affects ILO readings.

One purpose of publishing scientific reports is to stimulate discussion within the research community. It is, therefore, with some satisfaction that we notice these reactions to our article. As we pointed out in the discussion, our material is modest. Nevertheless, the results were interesting and seemed reliable enough to be reported as an observation. By no means do we consider our results conclusive. There should be large cohorts suitable for corroborating or refuting the suggested role of the progression of asbestosis in relation to the future development of cancer. As Dr. Miller in his editorial stated, we studied only patients with asbestosis, and the results do not contribute to the scientific discussion on the association between asbestos and lung cancer in the absence of fibrosis.1-4

Correspondence to: Panu Oksa, MD, Tampere Regional Institute of Occupational Health, PO Box 486, 33101 Tampere, Finland; e-mail: Panu.Oksa@occuphealth.fi

References
Miller, A Sherlock Holmes, Albrecht Durer, and Socrates: The International Labour Office radiographic classification of pneumoconioses reassessed for asbestosis.Chest1998;113,1439-1442
 
Oksa, P, Klockars, MLG, Karjalainen, A, et al Progression of asbestosis predicts lung cancer.Chest1998;113,1517-1521
 
Hakulinen T, Pukkala E, Puska P, et al. Various measures of smoking as predictors of cancer of different types in two Finnish cohorts. In: Colditz GA (ed). Proceedings of the Consensus Conference on Smoking and Prostate Cancer, Brisbane, Feb 12–14, 1996. Brisbane, Australia: Australian Government Publishing Service; 1996:58–70.
 
Henderson, DW, de Klerk, NH, Hammar, SP, et al Asbestos and lung cancer: is it attributable to asbestosis, or to asbestos fiber burden? Corrin, B eds.Tumors of the lung: contemporary issues1997,83-118 Churchill Livingstone. Edinburgh, Scotland:
 
To the Editor:

I appreciate Dr. Morgan’s agreement with “a number of points” which I made as well as his attribution to me of “just enough learning to misquote.” My quotation from his 1974 book was indeed verbatim and was intended to capture his wit and pungency as well as his meaning.

Dr. Morgan raises the following points:

1. Is the chest x-ray alone “insufficient” for the decision whether a subject has asbestosis? I would consider this diagnosis well established in the absence of further findings with a reading greater than or equal to category 2, especially if bilateral pleural thickening confirms exposure to asbestos.

2. Can profusion > 1/0 or 1/1 be attributed to smoking? Dr. Morgan and coauthors, in a review article2-1 concluded that the irregular opacities attributable to cigarette smoking “are of scanty profusion ranging mostly from 0/1 to 1/1.” Blanc and Gamsu2-2 in their review concluded that “using the ILO[ International Labour Office] classification, cigarette smoking alone is not associated with radiographic opacities that would be mistaken for pneumoconiosis with sufficient frequency to be of any practical importance.” Many surveys of the general population especially in North America have yielded very low rates of readings ≥ 1/0, despite the inclusion of a high percentage of smokers.2-3,,2-4,,2-5,,2-6 Surveys of workers exposed to various dusts have shown similar findings. Of 28 workers exposed to acrylic dust who had profusions ≥ 0/1, 23 (82%) were 0/1, only two (7%) were 1/1, and none were higher.2-7 No perlite (noncrystalline silicate)2-8 and only 0.4% of carbon black-exposed workers2-9 were ≥ 1/0, even though smokers were more than 50% of each group.

3. Dr. Morgan does not cite a reference other than “well known” that more than two thirds of those who give up smoking resume at a later date. Key variables are how long the smoker discontinued his habit and his perception of his risks in not doing so. In interviewing many thousands of workers industrially exposed to asbestos, I have been struck by the far larger number of ex-smokers, defined as not smoking for at least 2 years (47%), than of continuing smokers (34%),2-10 a reversal of the numbers of 35 years earlier, before the synergistic risks of smoking and asbestos were appreciated.

4. Is the FVC difficult to measure accurately? From my experience of measuring FVC in so many workers, I concluded that it is a rugged and remarkably reproducible value, more so in surveys of workers than in hospital or clinic patients. I was not surprised that the FVC did indeed correlate with the ILO profusion score in 2,611 long-term asbestos insulators.2-10 Recent data from 1,512 workers with a variety of exposures to asbestos confirm the relationship between FVC and ILO profusion score and demonstrate a similar relationship for diffusing capacity, a measurement less influenced by patient effort (R Warshaw, MA, and J Segarra, MD; personal communication, March 3, 1998).

I hope one day to be able to quote from a fourth edition of Morgan and Seaton.

Correspondence to: Albert Miller, MD, FCCP, Catholic Medical Center, 88–25 153 Street, Jamaica, NY 11432; e-mail: amiller@CMCNY.com

References
Dick, JA, Morgan, WKC, Muir, DFC, et al The significance of irregular opacities on the chest roentgenogram.Chest1992;102,251-260
 
Blanc, PD, Gamsu, G The effect of cigarette smoking on the detection of small radiographic opacities in organic dust diseases.J Thorac Imaging1988;3,51-56
 
Meyer, JD, Islam, SS, Ducatman, AM, et al Prevalence of small lung opacities in populations unexposed to dusts: a literature analysis.Chest1997;111,404-410
 
Hilt, B, Hillendal, G, Lund-Larsen, PG, et al Asbestos-related radiographic changes by ILO classification of 10 × 10 cm chest x-rays in a screening of the general population.J Occ Environ Med1995;37,189-193
 
Castellan, RM, Sanderson, WT, Petersen, MR Prevalence of radiographic appearance of pneumoconiosis in an unexposed blue collar population.Am Rev Respir Dis1985;131,684-686
 
Kilburn, KH, Lilis, R, Anderson, HA Interaction of asbestos, age and cigarette smoking in producing radiographic evidence of diffuse pulmonary fibrosis.Am J Med1986;80,377-381
 
Weiss, W Cigarette smoking and small irregular opacities.Br J Industr Med1991;48,841-844
 
Cooper, WC, Sargent, EN Study of chest radiographs and pulmonary ventilatory functions in perlite workers.Occup Med1986;28,199-206
 
Crosible, WA Respiratory health of carbon black workers.Arch Environ Health1986;41,346-353
 
Miller, A, Lilis, R, Godbold, J, et al Relationship of pulmonary function to radiographic interstitial fibrosis in 2,611 long term asbestos insulators: an assessment of the International Labour Office profusion score.Am Rev Respir Dis1992;145,263-270
 

Figures

Tables

References

Morgan, WKC (1974) Epidemiology and occupational lung disease. Morgan, WKC Seaton, A eds.Occupational lung diseases,29-38 WB Saunders. Philadelphia, PA:
 
Miller A., Sherlock Holmes, Albrecht Durer, and Socrates: the International Labour Office radiographic Classification of Pneumoconioses reassessed for asbestosis. Chest 1998; 113:1439–1442.
 
American Thoracic Society.. Medical Section of the American Lung Association: The diagnosis of nonmalignant diseases related to asbestos.Am Rev Respir Dis1986;134,363-368
 
Oksa, P, Klockars, M, Karjalainen, A, et al Progression of asbestosis predicts lung cancer.Chest1998;113,1517-1521
 
Miller, A Sherlock Holmes, Albrecht Durer, and Socrates: The International Labour Office radiographic classification of pneumoconioses reassessed for asbestosis.Chest1998;113,1439-1442
 
Oksa, P, Klockars, MLG, Karjalainen, A, et al Progression of asbestosis predicts lung cancer.Chest1998;113,1517-1521
 
Hakulinen T, Pukkala E, Puska P, et al. Various measures of smoking as predictors of cancer of different types in two Finnish cohorts. In: Colditz GA (ed). Proceedings of the Consensus Conference on Smoking and Prostate Cancer, Brisbane, Feb 12–14, 1996. Brisbane, Australia: Australian Government Publishing Service; 1996:58–70.
 
Henderson, DW, de Klerk, NH, Hammar, SP, et al Asbestos and lung cancer: is it attributable to asbestosis, or to asbestos fiber burden? Corrin, B eds.Tumors of the lung: contemporary issues1997,83-118 Churchill Livingstone. Edinburgh, Scotland:
 
Dick, JA, Morgan, WKC, Muir, DFC, et al The significance of irregular opacities on the chest roentgenogram.Chest1992;102,251-260
 
Blanc, PD, Gamsu, G The effect of cigarette smoking on the detection of small radiographic opacities in organic dust diseases.J Thorac Imaging1988;3,51-56
 
Meyer, JD, Islam, SS, Ducatman, AM, et al Prevalence of small lung opacities in populations unexposed to dusts: a literature analysis.Chest1997;111,404-410
 
Hilt, B, Hillendal, G, Lund-Larsen, PG, et al Asbestos-related radiographic changes by ILO classification of 10 × 10 cm chest x-rays in a screening of the general population.J Occ Environ Med1995;37,189-193
 
Castellan, RM, Sanderson, WT, Petersen, MR Prevalence of radiographic appearance of pneumoconiosis in an unexposed blue collar population.Am Rev Respir Dis1985;131,684-686
 
Kilburn, KH, Lilis, R, Anderson, HA Interaction of asbestos, age and cigarette smoking in producing radiographic evidence of diffuse pulmonary fibrosis.Am J Med1986;80,377-381
 
Weiss, W Cigarette smoking and small irregular opacities.Br J Industr Med1991;48,841-844
 
Cooper, WC, Sargent, EN Study of chest radiographs and pulmonary ventilatory functions in perlite workers.Occup Med1986;28,199-206
 
Crosible, WA Respiratory health of carbon black workers.Arch Environ Health1986;41,346-353
 
Miller, A, Lilis, R, Godbold, J, et al Relationship of pulmonary function to radiographic interstitial fibrosis in 2,611 long term asbestos insulators: an assessment of the International Labour Office profusion score.Am Rev Respir Dis1992;145,263-270
 
NOTE:
Citing articles are presented as examples only. In non-demo SCM6 implementation, integration with CrossRef’s "Cited By" API will populate this tab (http://www.crossref.org/citedby.html).

Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging & repositioning the boxes below.

  • CHEST Journal
    Print ISSN: 0012-3692
    Online ISSN: 1931-3543