Document B8vMVZ8KqYBJEQeb33bbg8B9j

19 Malignant Neoplasms of Urinary Organs. Although urinary tract tumors were not In excess, detailed data on the 8 deaths from this cause are shown in Table 22. Tumors of ['rain and Other Parts of Nervous System. Table 23 summarizes inform ation on the 28 deaths from tumors of other and unspecified sites, including 12 deaths from tumors of the brain, as opposed to 5.9 expected, giving an SNR of 203, significant at the 0.05 level. Of these, 4 are classified as glioblastoma multiforme, but only one of these 4 was definitely confirmed by autopsy, and in 2 cases, autopsy was certified as not performed. Five of the brain tumors were classified either as V "malignant brain tumors" or "carcinoma of the brain", but none of these diagnoses was definitely confirmed by autopsy, and in 3 cases the absence of autopsy was cert ified. Of the remaining 3 brain tumors, 2 were classified as astrocytoma, both confirm ed by autopsy, and one as "ependymoma of the 4th ventricle" confirmed by craniotomy. Of the 12 brain tumors, 7 occurred in workers from plants producing only PVC, 2 were in plants producing both PVC and VC (one of which also produced copolymers), 2 were in plants producing only homopolymers or copolymers, and one was in a plant producing only VC. There was no apparent relationship with maximum exposure or total integrated exposure: 6 deaths were in individuals whose maximum level of exposure was classified as "low", while 3 each occurred in-categories "medium" and "high". Five deaths were in men whose time-weighted dose was calculated as having been less than 100. It is difficult to interpret the significance of this finding of an apparent excess of brain tumors. In the absence of definite confirmation by either autopsy or cranio tomy in 8 of the 12 cases, it is quite possible that some might have been secondary brain tumors, with unrecognized primary sites, or other non-malignant space-occupying lesions in the cranial cavity. It is of interest to note that an excess of malignant brain tumors wjs also reported by Waxweiler.R.J. et al of NI0SH (Annals of the New York Acadeny of Science, 271:40-48, 1976) from a much smaller study (136 deaths and 12,720 person-years), confined to 4 plants with at least 15 years history of operation in the polymerization of VC. These authors reported an SMR of 329 based on only 3 deaths, all from glioblastoma multiforme, all histologically confirmed. In fact the NI0SH group claimed in this report to have identified altogether 9 histologically confirmed cases of glioblastoma multiforme in workers exposed to vinyl chloride in U.S. industry. It is difficult to say to what extent their study population overlaps that of the presently reported EEH study. In view of all the above, further investigation of the question of malignant brain tumors in workers exposed to vinyl chloride should be pursued. CUSAROSS 01823 VII. DISCUSSION 20 ']though the present study when compared with the first study reported in 1974 inc* cased the study size from 7,128 to 9,677 workers who were traced, the personyears of observation from 77,846 to 120,203, and the certified deaths available for iuulysis from 328 to 669, it did not strengthen any of the associations suggest ed i- the initial report. The successive additions to the population and the improved follow-up have been acco'panied by a rise in the overal1-cause Standardized Mortality Ratio from 75 to 89. Tiie ~ajor change has been in the SMR for major cardiovascular and renal disease, whir- was originally 80 and is now 95. There has been a concurrent downward shift in the SMR for "all malignancies", which is now 104 compared with 110 in the 1974 report. In the current study, the SMR's for malignancies of various specific sites are also lower than in the 1974 report. For example, the SMR for digestive tract cancer has changed from 94 to 75, that for respiratory tract cancer from 112 to 107, that for - nicer of other and unspecified sites from 155 to 147. The latter included 12 cancers of the brain as shown in Table 23 and discussed on the preceding page. No conclusion can be reached as to whether or not this apparent excess is related to occupational exposure to vinyl chloride, and further investigation is desirable. All SMR's based on more than five deaths were tested for statistical significance, and :Tree were found to be significantly lower than 100 ( see Table 5 ). In general, sine* the health of an employed population is better than that of the general United Slai-c population, these significantly small SMR's are not surprising. With the single exrc-ction of the brain tumors, already discussed above, none of the SMR's ( based on more Mian five deaths ) that exceeded 100 was significantly different from 100. Infererc CUSAROSS 01824 Tabic 5 Observed/Expected Deaths and Standardized Mortality Dotios for Selected Causes of Death in 9,677 Vinyl Chloride Workers , Cause of Death with ICD Number^3^ A 1 1 causes A 1 1 malignancies (140-205) Maliqnant neoplasms, buccal and pharynx (140-148) Malignant neoplasms, digestive cm gnus and peritoneum (150-159) Malignant neoplasms, respiratory system (160-164) Malignant neoplasms, genital organs (170-179) Malignant neoplasms, urinary organs (180-181) Malignant neoplasms, other and unspecified sites (190-199) Malignant neoplasms, brain and other parts of nervous system (193) leukemia and aleukemia (204) Lymphomas (200-203, 205) Major cardiovascu1ar and renal diseases (330-334, 400-468, 592-594) C i r i Losis of 1iver (581) A 1 1 '4hnr certified causes ; j' ii-.t m of wot kers Nun! ici of per son-years Obs./Exp. 707/795.02 139/141.39 5/ 5.19 29/ 40.02 45/ 44.29 4/ 7.17 8/ 6.85 28/ 20.18 12/ 5.90 9/ 6.65 11/ 10.36 347/385.24 14/ 26.45 169/241.95 9,6/7 120,203 SMR(b) 89* * 104 102 75 107 59 123 1 47 203 * 143 1 12 95 56* * 74** P i c i f i c numbers i n< 1 i i iM 11 onor i os in 1 ho 1955 ( /111 ) rev i s i on of 1 hi i 1 i '-na 1 C 1 ass i f i c.u t i on of Pi souses. ( <'!her than for All r miso-) act jus led for 38 doa1hs wi 1h no dca t h eet lit by l nr lor of 15.60?. * s ion if iront at the 0.05 level. 14 r i on i f i' 1 at' the 0.01 I1 . CUSAROSS 01825 /I and I 1i< >:' c w i I h 1 oni | (1 r <' x pr n; i1 re j x 11 i o< I:; . IliM.in tuiiiors were round Lo be in exer:,:;, twelve observed versus r> . h oxpcrl cd (:; i g n i I i re n I nl I lu- O.Oh level) l>ul I ho incidence was not related either: to duration of exposure nor to intensity of exposure to v.CM. This population should be studied again within the next r> years. Since the time of observation after first exposures will be longer, and more deaths will be available for analysis, it is possible that some of the questions about cancer in sites other than the liver may be resolved. CUSA*OSS 01^26