Document jMQy8wyjxMMa9Xvp6LY2pmnQ

FILE NAME: Talc (TALC) DATE: 2006 Apr DOC#: TALC057 DOCUMENT DESCRIPTION: Journal Article - Carcinogenicity of Carbon Black, Titanium Dioxide, and Talc Policy Watch Carcinogenicity of carbon black, titanium dioxide, and talc In February, 2006, 19 scientists from eight countries met atthe International Agency for Research on Cancer (IARC), Lyon, France, to reassess the carcino genicity of carbon black, titanium dioxide, and non-asbestiform talc These assessments will be published as volume 93 of the IARC Monographs,1 and are the first assessments since the IARC Monograph preamble was amended.2 All three of the above agents are poorly soluble particles that are weakly toxic, and were chosen for assessment because evidence suggests that they cause cancer in the respiratory tract of rats through similar mechanismsafter exposure to high concentrations of these agents, deposition of particles onto the respiratory epithelium can lead to enhanced particle retention, impaired lung clearance, inflammatory response, production of reactive oxygen species, cell injury, cell proli feration, fibrosis, induction of mutations, and, ultimately, cancer Because many of these steps arise in people who work In dusty environ ments (eg, coal miners),34 data on cancer in animals obtained in conditions of impaired lung clearance could be relevant to human beings. Furthermore, impaired lung clearance and adverse effects in the lungs of rats that have been exposed to ultrafine particles (<100 nm) occur at much lower mass concentrations than in rats exposed to fine particles (<10 pm), increasing the potential relevance to human beings. Carbon black is a particulate form of elemental carbon. About 90% of carbon black is used in rubber products, mainly tyres. Carbon black is also used as a pigment in inks, paints and coatings, and in plastics. Exposure to carbon-black particles occurs mainly in the form of aggre gates (ie, particle size, 50 -6 0 0 nm) and agglomerates (227 pm). Most types of carbon black have small quantities (ie, <1%) of organic compounds, including polycyclic aromatic hydrocarbons, adsorbed onto their surface. The highest exposures to carbon black arise during its manufacturing. Exposure in industries that use carbon black is difficult to assess because data are scarce No substantial exposure to carbon black is thought to occur when it is bound to other materials such as rubber, printing ink, or paint. Workers who produced carbon black in Germany3and the UK5had an excess risk of lung cancer. Confoun ding by smoking was unlikely to explain the entire excess risk, but no clear dose-response relation between exposure to carbon black and lung cancer was noted A US study2 of workers in carbon black production found no excess risk of lung cancer, but no data according to level of exposure were reported. A study8 of workers in the rubber industry in Germany who were exposed to carbon black showed no significant excess risk of lung cancer after adjustment forpotentialconfounding by asbestos and talc. The working group concluded that the epide miological studies of carbon black provided inadequate evidence of carcinogenicity. Carbon black and its extracts have been tested in rats and mice by inhalation, intratracheal instillation, dermal application, and subcutaneous injection. The overall results provided sufficient evidence in laboratory animals for the carcinogenicity of carbon biackand carbon-black extracts. The working group classified carbon black as possibly carcinogenic to human beings (ie, group 2B). Titanium dioxide accounts for 70% of the total production volume of pigments worldwide. The primary particles are typically 200-300 nm in diameter, but larger aggregates and agglomerates are formed readily. Ultrafine grades of titanium dioxide (ie, 10-50 nm) are used in sunscreens and plastics to block ultraviolet light, and in catalysts. Highest exposures occur in titanium-dioxide production during packing, milling, site cleaning, and maintenance. Exposure data for industries that use titanium dioxide are scarce. The largest epidemiological cohort study5 considered included workers in the titanium dioxide production industry in six European countries, and showed a small but significant increase in risk of lung cancer compared with that for the general population; however, the data did not suggest an exposure-response relation. Two cohort studies under taken in the USA did not report excess risks of lung cancer, neither did a Canadian population-based casecontrol study. Overall, the working group concluded that the epide miological studies on titanium dioxide provide inadequate evidence of carcinogenicity Pigment-grade titanium dioxide and ultrafine titanium dioxide have been tested in rats, mice, and hamsters by various routes of administration. Overall, results from studiesof inhalation and intratracheal instillation provided sufficient evid ence in animals for the carcino genicity of titanium dioxide. The working group classified titanium dioxide as possibly carcinogenic to human beings (ie, group 2B). Talc refers to both mineral talc and industrial products that contain 35% to >95% mineral talc. Mineral talc Upcoming meetings Jure 14-71,2006 ingest id nitrates and nitrites, and blue-green algae to>.<n$ mdud'ng muforystm-i R and node I inn Oct 10-17, 2005 indoo. air pollution from household combustion and heating http !, m onographs tan fr http //oncologythelancet tom Voi 7 A prii 2006 295 Policy Watch Monograph Working Group Members P A Demers, j Sienuatycki-Chair (Canada], J Olsen (Denmark;, U Heinrich, RSchins (Germany), H Tsoda (japan), E Weiderpass-Vaimo (Norway), IJ Yu (Republic of Korea), M vanTongeien (UK), V Antony, j A Bond, J S Brown, D Costa S Hankrnson, F D Kuempel, AG Wylie (USA) Conflicts of interest The working group declares no conflicts of interest invited Specialists l Levy (UK},TJunghans, SOlm (USA) Conflict s ofinterest LL is scientific advisor to the International Carbon Black Association, USA Representatives of health agenoes A Ullrich (WHO, Switzerland), CW Jameson (NIEHS, USA) Observers P Morfeid, K Mundt (International Carbon Black Association, USA), N jehan (University of Peshawar, Pakistan),] Hoskins (CFF1C, Belgium), JE Muscat, G Oberdorster (Industrial Minerals Association^of Europe, Beigrum, and of North America, USA), DB War heit i American Chemistry Council, USA) occurs naturally in a platy (flat) form, but also as asbestiform fibres. It is generally associated with other minerals, for instance, quartz and occasionally asbestos. Asbestiform talc should not be confused with talc that contains asbestos. Talc is used in agricultural products, ceramics, cosmetics, paint and other coatings, paper, pharmaceuticals, plastics, roofing materials, rubber, and for waste treatment Occupational exposure to talc arises during mining, milling, and industrial use. Consumers are exposed during the use of loose talc-based powders--eg, baby powders and body powders used by women on the perineum or genital area. Cohort studies from various countries of talc miners and millers were available for assessment. In US miners,10an excess risk of lung cancer was noted, but this risk could have been due to exposure to radon and quartz. The othet cohort studies did not report an increased cancer risk. A nested case-control study of cohorts in France and Austria" found no higher risk of lung cancer with increasing cumulative exposure to talc dust. A study" of women working In the Norwegian pulp and paper industry noted an Increased risk of ovarian cancer, but this risk was attributed to asbestos exposure. The working group concluded that the epidemiological studies provided inadequate evidence for the carcinogenicity of inhaled talc that does not contain asbestos or asbestiform fibres. Talc has been tested in rats, mice, and hamsters by various routes of administration A long-term inhalation study"' showed increased incidences of alveolar or bronchlolar carcinoma in female rats and adrenal pheochromocytoma in rats of both sexes This increase in incidence provided limited evidence for carcinogenicity in animals. Overall, the working group concluded that inhaled talc that does not contain asbestos or asbestiform fibres Is not classifiable as to its carcinogenicity (le, group 3). Particular attention was paid to 5 WellmannJ, W eilandSK, dertelei G, etai epidemiological data from a prospective cohort study14 and from Cancer m ortality in German carbon black workers 1 9 7 6 -1 9 9 8 Occ ip Environ Med 2006, published online Feb 23, )OI 10 1136/ 19 case-control studies on the oem 2006 026526 association between use of talc-based 6 Sorahan T, Hamilton (, van Tongeren M, et al A cohort mortality study j f UK carbon black body powder and risk of ovarian workers, 1 9 51 -19 9 6 Arr fin d Med 2001 cancer. Although the cohort study1'1 did not lend supportto an association, 7 the case-control studies showed a high degree of consistency: the eight more-informative studies15"reported 8 39 158-70 Dell ID , Mundt KA Luipp )ld RS, et a! A cohort m ortality study of employees in the United States carbon black indus try j Occup Environ Med 2006 (in press) Straif K, Keif U, Jaeger D ,t al Exposure to mtrosammes, carbon blai k, asbestos, and talc a 30-60% increase in risk, and most of the other studies noted similar and m ortality from stom tch, lung and larygeai cancer in a co h o r o f rubber workers A m ) Epidemiol 7000,152 297-306 relative risks. Only two studies18" 9 Roffetta P, Soutar A, Chert le JW, et al Mortality suggested that women with the highest exposure had the highest among workers employed m the titanium dioxide production indus1ry in Europe Cancer Causes Control 2 0 04 ,1 5 : 6 9 7 -7 0 6 risk. The case-control studies could have been affected by recall bias, if women with ovarian cancer were 10 Selevan SG, Dement JM, Wagoner JK, Frames JR Mortality patterns am >ng miners and millers o f non-asbestiforr i talc preliminary report j Environ Pathol To col 1979, more likely to over-report bodypowder use. These powders generally contain quartz. Furthermore, low concentrations of asbestos were occasionally present In these powders 2: 273-84 11 W ild P Lung cancer risk and talc not containing asbestiform fibres a review of the epidemiological evidence Occup Environ Med 2006, 6 3 :4 -9 12 Langseth H, Kjaerheim K Ovarian cancer and occupational exposure ai long pulp and paper before the mid-1970s, but the available information is sparse and poorly reported, and analyses were employees in Norway Sir ndJ Work Environ Health 2004, 30: 3 5 6-6 1 13 US National Toxicology I5 ogram Toxicology and carcinogenesis studies of taic (CAS No often inadequate to Identify the fibres detected. After careful 14807-96-6 ) in F344/N rats and B6C3F mice (inhalation studies) Betr^sda National Institutes o f Health, 199 - assessment of the biases and possible confounding factors, the working group concluded that the epide 14 Gertig DM, HunterDJ,CramerDW, eta! Prospective study of talc 1 se and ovarian cancer j Natl Cancer Inst 2 9 0 0 ,9 2 :2 4 9 - 52 15 Chang S, Risch HA Perinealtalc exposure and miological studies provided limited evidence for the carcinogenicity of perineal use of talc-based body risk of ovarian carcinoma Cancer 1997, 79:2396-401 16 Cook IS , Kamh ML, Weiss NS Perineal powder exposure and the risk o f c vai tan cancer Am J powder, and classified this use as possibly carcinogenic to human beings (ie, group 2B). Epidemic/1 9 97 ,1 4 5 4 5 9 -6 5 17 Cramer DW, Welch WR, S l ully RE, W ojaechowski CA Qvai n cancer and talc a case-control Study C an te rl9 8 2 ,50: 372-- 6 The authors declare no conflicts o f interest 18 Cramer DW, I iberman Rf, 7 itus-Frnrtoff L, et al Genital talc exposure and risk o f ovarian 1 IARC (ARC m onographs on the evaluation of cancer IntJCanter 1999, 51:351-56 carcinogenic usks to humans Volum e 93 Carbon black, titanium dioxide, talc Lyon International Agency for Research on Cancer {n press). 2 ARC Preamble tothe ARC monographs on the evaluation o f carcinogenic risks to humans http.//monograph$ larcfr/monoeval/ preambSe-i tew-06 pdf (accessed March 6, 2006). 19 Harlow BL, Cramer DW, B ;ll DA, Welch WR Perineal exposure to ta lc. nd ovarian cancer risk Obsfet Gynecol 1992, 8 0 :1 9 -26 20 Mess RB, Gr.sso jA CottredU C, et al Factors related to inflam m ation c f the ovarian epithelium and risk o f ow nan cancer Epidemiology 20 0 0 ,1 1 :1 1 1 -1 7 21 Purdie D, Green A, DainC, et a! Repioductive and other factors and risk o f epithelial ovai ian 3 Kuempel ED, O'Flaherty EJ, Stayner LT, et al cancer an Australian case-contra! study IntJ A biom athem atical mode! o f particle clearance Cancer 1995, 62: 678-84 and retention in the lungs o f coal miners Regal 22 W hittemore AS, Wu ML, f affenbargerRS Jr, et al Personal and envirom ental characteristics Toxicol Pharmacol 2 0 0 1 ,3 4 :6 9 -8 7 related to epithelial ovai 1 m cancer !i 4 SoutarCA, HuileyJF, Miller BG, e tal Dust Exposuies to talcum powder, tobacco, alcohol, concentrations and respiratory risks m coal and coffee A m j Cpidenvoi 1988, miners key risk estim ates from the British pneum oconiosis fieid research Occup Environ 128:1228-40 Med 2 0 0 4 ,6l* 47 7-8 1 296 http//oncology theiancet cor ' Vol 7 A pril 2006