Trauma acumulativo

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Int. J. Cancer: 116, 331–339 (2005) ' 2005 Wiley-Liss, Inc.

MINI REVIEW Epidemiology of testicular cancer: an overview
Michael J. Garner1,2*, Michelle C. Turner1, Parviz Ghadirian1,3 and Daniel Krewski1 1 McLaughlin Center for Population Health Risk Assessment, Institute of Population Health, University of Ottawa, Ottawa, Canada 2 Carlington Community and Health Services, Ottawa, Canada 3  eUnit de recherche en epidmiologie, Centre de recherche du CHUM, Hotel-Dieu, Universit de Montral, e e e Montral, Canada e
Testicular cancer is a rare disease, accounting for 1.1% of all malignant neoplasms in Canadian males. Despite the low overall incidence of testicular cancer, it is the most common malignancy among young men. The incidence rate of testicular cancer has been increasingsince the middle of the 20th century in many western countries. However, the etiology of testicular cancer is not well understood. A search of the peer-reviewed literature was conducted to identify important articles for review and inclusion in this overview of the epidemiology of testicular cancer. Most of the established risk factors are related to early life events, including cryptorchidism,carcinoma in situ and in utero exposure to estrogens. Occupational, lifestyle, socioeconomic and other risk factors have demonstrated mixed associations with testicular cancer. Although there are few established risk factors for testicular cancer, some appear to be related to hormonal balance at various life stages. Lifestyle and occupational exposures occurring later in life may play a role inpromoting the disease, although they are not likely involved in cancer initiation. In addition to summarizing the current epidemiologic evidence on risk factors for testicular cancer, we suggest future research directions that may elucidate the etiology of testicular cancer. ' 2005 Wiley-Liss, Inc.

testicular cancer has been observed over the last 25 years.3 Testicular cancer accounts for 1.1% of allmalignant neoplasms in Canadian males; it occurs primarily in young males, and it represents an important source of morbidity for this age group.3 Mortality rates for testicular cancer are very low, with the 5-year survival rate increasing from about 63% to more than 90% during the last 30 years.12 Several factors have been associated with the increasing trends in testicular cancer incidence,including a strong birth cohort effect. A study in Norway found that males born in the 5-year intervals before (1935–39) or after (1945–49) the Nazi occupation (1940–1944) had an increased risk of testicular cancer when compared to those born during the occupation.5 A similar trend was also found in a study of Danish data from the same time period.13 The occupation of Norway caused many lifestylechanges, including decreased use of polluting vehicles, and an increase in physical activity and consumption of vegetables and dietary fiber.5 Etiology of testicular cancer Ninety-five percent of all tumors of the testis are germ-cell neoplasms.14 The International Agency for Research on Cancer (IARC) recognizes 4 specific types of germ-cell tumours: seminomas, embryonal carcinomas, malignant teratomasand choriocarcinomas.15 These lesions can be combined into 2 histologic groups: seminomas and nonseminomas. Approximately 50% of all germcell tumors are seminomas, with the remaining 50% being nonseminomas.16 Nonseminomas often represent tumors of mixed histology and may include a variety of seminoma or nonseminoma histologic subtypes. A recent study evaluating the histology of mixed germ-celltumors (MGCTs) reported a strong association between teratomas and yolk sac tumors.17 Further classification beyond the 2 main histologic categories (seminoma and nonseminoma) appears to have limited relevance in etiologic or clinical settings.18 Associations Cryptorchidism. The most established factor associated with testicular cancer is cryptorchidism (maldescendent testicle(s) or MDT).19–29 It...