211 literature to the most efficient method of performing liver biopsy. We have reviewed over 300 laparotomies performed by one of us (J.C.G.) between October, 1969, and October, 1977. When the liver biopsy is done at laparotomy, we take four quadrant Menghini needle-biopsy specimens (two from each lobe) and one wedge-biopsy specimen from the liver edge. Of the 203 patients with Hodgkin’s disease who had laparotomy, 15 patients had histological evidence of liver involvement (7.4%). The liver was macroscopically normal in all cases. The wedge-biopsy specimen was positive in 14 of the 15 patients, while the needle-biopsy specimens were positive in only 8 of the 15 patients. In only 1 patient was the wedgebiopsy specimen negative while needle-biopsy specimens were

positive. We conclude that the histology of a single wedge-biopsy specimen is more effective in determining liver involvement than the cumulative histology of four quadrant Menghini needle-biopsy specimens. Despite this we recommend that both methods of biopsy are performed at each laparotomy.

population symmetrical around the smelter or were they only taken in the direction of the prevailing winds? To compare mortalities in geographical areas directly we need to know the lung-cancer rates in each area rather than merely the numbers of cases. Finally, since there is a large non-smoking Mormon population in Utah, it would be useful to know if there are differences in the relative number of Mormons in the areas studied. An increased lung-cancer rate in an area heavily populated with non-smokers would be of great interest, especially since non-smoking smelter workers seem to be at greater risk of arsenic-related lung cancer than are workers who smoke. 12 Division of Occupational Health and Toxicology, American Health Foundation, JEANNE M. STELLMAN New York, N.Y. 10019, U.S.A. GEOFFREY C. KABAT V This letter has been shown whose reply follows.-ED. L.

to

Dr

Lyon and his colleagues,

areas which we used to define the around the smelter were symmetrical. However, the smelter is on the western edge of both the Salt Lake Valley and Salt Lake County. Immediately to the north-west of the smelter is the Great Salt Lake, and the areas west and southwest are sparsely populated desert. The prevailing winds are to the south and south-east. The valley is also subject to almost daily air inversions in winter (November to March), and the smelter effluent was the single largest contributor to the resulting air pollution during the time of the study, and for decades before. Epidemiologists prefer to work with rates as descriptors of disease risk in a population. However, when the disease is rare, age-adjusted rates for the smallest feasible geographical areas for which age-specific populations are available are highly unstable, due to the small numbers of cases and/or to shifts in the underlying populations. Both these conditions applied, particularly, in the areas closest to the smelter. We therefore chose a different method, analogous to the case-control approach. Population data which would give a distribution of Mormons and non-Mormons within each geographical area do not exist. However, of the 975 smelter workers, 72% were Mormons and the proportion of smokers among them was 38.6%, compared with a smoking-rate of 51.4% in the non-Mormons. Most of these workers live in the areas nearest the smelter, and would, if the association of increased lung-cancer risk among non-smoking smelter workers held, be at double risk, due to a work and home exposure. Thus they should produce an increase of lung cancer cases near the smelter, yet this was not found. JOSEPH L. LYON Department of Family and Community Medicine, JEFF FILLMORE of Utah Medical Center, University Salt Lake City, Utah 84132, U.S.A. THOMAS J. SMITH

SIR,-The geographical

areas

J. P. GLEES M. THOMAS W. H. REDDING M. HEFNEY J. C. GAZET

Royal Marsden Hospital, Sutton SM2 5PT

ARSENICAL AIR POLLUTION AND LUNG CANCER ;’!R)—L)r Lyon ana nis colleagues- icuna no association between lung-cancer mortality and residence near a copper smelter in Salt Lake County, Utah. This report was prompted in part by a study by Blot and Fraumeni2 suggesting a possible causal relationship between excess lung-cancer mortality and residence in counties with smelters. We believe that the apparent contradiction between these two reports can be resolved. Blot and Fraumeni drew up a table giving the standardised mortality ratios for male and female residents of eighteen counties with copper smelters/refiners, but Dr Blot tells us that, in the interests of space, this table was omitted from the paper. Salt Lake County residents experienced the most favourable mortality ratios, 75 for males and 58 for females, of all the counties tabulated. In fact Salt Lake County was the only county in which an S-M.R. below 100 was obtained for both males and females. The mean value for the S.M.R. for all the arsenic smelter-refiner counties was 124 for males and 111 for females. The medians were 117 and 109, respectively. We are carrying out an extensive health assessment of the effects of arsenic for the U.S. Environment Protection Agency, and have found nine reports of a connection between lung cancer and arsenic exposure.3-11 To help elucidate the important environmental question of the effects of arsenic exposure, publication of the complete Blot and Fraumeni data would be

helpful. Since Salt Lake County lung-cancer mortality experience be atypical of the experience in other arsenic smelter counties, further data should be provided by Lyon et al. When the smelter stack was used as the origin for determining distance from the smelter, were the geographical areas defining seems to

1. Lyon,J. L., Fillmore,J. L. Klauber, M. R. Lancet, 1977, ii, 869. 2. Blot, W. J., Fraumeni, J. F. Jr. ibid. 1975, ii, 142. 3. Lee, A. M., Fraumeni, J. F., Jr. J. natn. Cancer Inst. 1969, 42, 1045. 4. Milham, S. Jr., Strong, T. Environ. Res. 1974, 7, 176. 5. Karatsune, M., Tokudome, S., Shirakusa, T., Yoshida, M., Tokumitsu, Hayano, T., Seita, M. Int. J. Cancer, 1974, 13, 552.

Y.,

6. Newman, J. A., Saccomanno, G., Auerbach, O., Archer, V., Kushner, M.,

Grondahl, R., Wilson, J. Ann. N. Y. Acad. Sci. 1976, 271, 160. 7. Tokudome, S., Karatsune, M. Int. J. Cancer, 1976, 17, 310. 8 Rencher, A. C., Carter, M. W. J. occup. Med. 1977, 19, 754. 9. Pinto, S. S., Enterline,

P.

E., Henderson, V., Varner, M. O. Envir. Hlth

LATE EFFECTS OF FEMALE STERILISATION

SIR,-We agree with Margaret McCann and Dr Kessel (Jan. 7, p. 37) that women who have been sterilised may have a significant increase or decrease in menstrual loss. In our paper’ we failed to emphasise that in 10% of women menstrual loss decreased, but, being gynaecologists, we were concerned by the numbers who returned with menstrual problems and subsequently have had to have hysterectomies.2 This is particularly important because many more women are being sterilised and at a younger age. Our follow-up period was between one and three years and the response-rate to our questionnaires was 75%. The women in McCann and Kessel’s study have been examined at one year only, and only 30% were contacted. Their case would be

Perspect. 1977, 19, 27. 10. Milham, S., Jr. Paper presented at international conference on Cancer and Environment, held in Oct. 13, 1977. 11. Pershagen, G., Elinder, C. G., Bolander, A. M. Envir. Hlth Perspect. 1977, 19, 133.

12. Pinto, S. S., Enterline, P. E. Archs envir. Hlth (in the press). 1. Neil, J. R., Hammond, G. T., Noble, A. D., Rushton, L., Letchworth, Lancet, 1975, ii, 699. 2. Letchworth, A. T., Noble, A. D. ibid. 1977, ii, 768.

A. T.,

Arsenical air pollution and lung cancer.

211 literature to the most efficient method of performing liver biopsy. We have reviewed over 300 laparotomies performed by one of us (J.C.G.) between...
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