The epidemiology of laryngeal cancer in Brazil

Our plain-English summary of The epidemiology of laryngeal cancer in Brazil, by V. Wünsch Filho (São Paulo Medical Journal = Revista Paulista de Medicina, 2004).

The study

• Author: V. Wünsch Filho
• Journal: São Paulo Medical Journal = Revista Paulista de Medicina
• Published: 2004;122(5):188-94
• Type of article: Review
• Cited by: 39 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

The city of São Paulo exhibits one of the highest incidences of laryngeal cancer in world and Brazil presents remarkable occurrence, compared with other Latin American countries. Around 8,000 new cases and 3,000 deaths by laryngeal cancer occur annually in the Brazilian population. In the city of São Paulo, incidence rates for laryngeal cancer among males have been decreasing since the late 1980s while, among females, the rates have shown a stable trend. This phenomenon is probably the expression of changes in gender behavior related to tobacco smoking. Several risk factors are involved in the genesis of laryngeal cancer. The most important are tobacco smoking and alcohol intake, but occupational hazards have also been associated with the disease, such as asbestos, strong inorganic acids, cement dust and free crystalline silica. Additionally, salted meat and total fat intake have been linked to elevated risk of laryngeal cancer. Conversely, several studies have confirmed that fruits, raw leaf vegetables and legumes protect against this cancer. Some researchers have postulated a possible association between laryngeal squamous cell carcinoma and human papilloma virus (HPV), but this is not universally accepted. Gastroesophageal reflux disease is weakly, but consistently correlated with laryngeal cancer. Familial cancer clusters, particularly of head and neck tumors, seem to increase the risk of laryngeal cancer. Some genetic polymorphisms, such as of genes that code for xenobiotic-metabolizing enzymes, have shown elevated risk for laryngeal cancer according to recent studies. Public health policies regarding the control of tobacco smoking and alcohol consumption, and also surveillance of carcinogen exposure in occupational settings, could have an impact on laryngeal cancer. No proposals for screening have been recommended for laryngeal cancer, but one diagnostic goal should be to avoid treatment delay when suspected symptoms have been observed.

In plain English

This article was an invited review of the epidemiology of laryngeal cancer in Brazil. It drew on cancer registries, mortality statistics and earlier published studies. The review stated that Brazil had about 8,000 new cases of laryngeal cancer each year. It reported an incidence of 14.9 per 100,000 males in São Paulo in 1998. In São Paulo, incidence had declined among men since the late 1980s and stayed stable among women. The author named tobacco smoking and alcohol as the main risk factors. The review also summarized other researchers' studies of occupational exposures, including asbestos. It stated that asbestos has been treated as a risk factor for laryngeal cancer since the 1970s. In one case-control study by Shettigara and Morgan, asbestos was more strongly associated with the disease than smoking and alcohol. A study in Uruguay associated asbestos with increased risk. The author concluded that Brazil's high incidence requires policies to control smoking and alcohol and to reduce carcinogen exposure at work. The author noted that laryngeal cancer mortality data are hard to interpret because hypopharynx cancers may be recorded as laryngeal on death certificates.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: Narrative review (invited review) of the descriptive epidemiology and risk factors of laryngeal cancer, with emphasis on Brazil
• Who was studied: Laryngeal cancer in the Brazilian population, especially the city of São Paulo, compared with worldwide data from cancer registries and published studies
• Exposure: Risk factors for laryngeal cancer, chiefly tobacco and alcohol. Occupational exposures included asbestos (no fiber type specified), strong inorganic acid mists, cement dust, wood dust and free crystalline silica.
• Main results:
  • Laryngeal cancer incidence among males in São Paulo was 14.9 per 100,000 in 1998.
  • Incidence rates in the city of São Paulo declined for males since the late 1980s but were stable for females.
  • In Brazil, the highest laryngeal cancer mortality rates were registered in São Paulo: 6.2 per 100,000 for males and 0.6 per 100,000 for females.
  • Cited study: in a case-control study by Shettigara and Morgan, asbestos was more strongly associated with laryngeal cancer than smoking and alcohol. Other cited studies noted increased laryngeal cancer among asbestos-exposed workers.
  • Cited study: a case-control study in Uruguay (De Stefani et al.) found that asbestos, strong inorganic acid mists and pesticide exposure were associated with increased risk of laryngeal cancer.
  • Cited study: a São Paulo case-control study found an adjusted odds ratio of 7.5 for laryngeal cancer among heavy smokers.
  • Cited study: a cohort of rubber industry workers in São Paulo had four cases of laryngeal cancer. These were 6.0% of all cancers identified, three times higher than expected. Asbestos was listed among the agents considered as possible causes of cancer in the rubber industry.
• The authors' conclusion: The author concluded that the high incidence of laryngeal cancer in Brazil, particularly in the southeastern and southern regions, requires public health policies to control tobacco smoking and reduce alcohol consumption, and to reduce carcinogen exposure in occupational settings.
• Limitations the authors state:
  • Survival and mortality data for laryngeal cancer are difficult to interpret because cancers of the hypopharynx may be recorded as laryngeal cancer on death certificates.

Topics

The National Library of Medicine indexes this study under subjects our site covers: Throat and laryngeal cancer.

Medical terms in this study, explained in our Lexicon: Epidemiology, Laryngeal Cancer, Incidence, Crystalline, Squamous Cell Carcinoma.

Related studies

• The history, aetiology and epidemiology of laryngeal carcinoma — M.A. Rafferty, J.E. Fenton, et al. (2001)
• Laryngeal cancer and asbestos — G. Hillerdal, C.E. Lindholm (1980)
• Occupational asbestos exposure and risk of pleural mesothelioma, lung cancer, and laryngeal cancer in the prospective Netherlands cohort study — N.S. Offermans, R. Vermeulen, et al. (2014)
• Current theories for the development of nonsmoking and nondrinking laryngeal carcinoma — R. Wight, V. Paleri, et al. (2003)
• Asbestosis, laryngeal carcinoma, and malignant peritoneal mesothelioma in an insulation worker — A. Fischbein, J.C. Luo, et al. (1991)
• Asbestos, dental X-rays, tobacco, and alcohol in the epidemiology of laryngeal cancer — M.W. Hinds, D.B. Thomas, et al. (1979)

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