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Risk factors for cancers of unknown primary site: Results from the prospective EPIC cohort

Kaaks, Rudolf; Sookthai, Disorn; Hemminki, Kari LU ; Kraemer, Alwin; Boeing, Heiner; Wirfält, Elisabet LU ; Weiderpass, Elisabete; Overvad, Kim; Tjonneland, Anne and Olsen, Anja, et al. (2014) In International Journal of Cancer 135(10). p.2475-2481
Abstract
Cancer of unknown primary site (CUP) may be called an orphan disease, as it is diagnosed when metastases are detected while the primary tumor typically remains undetected, and because little research has been done on its primary causes. So far, few epidemiological studies, if any, have addressed possible risk factors for CUP. We analyzed data from the European Prospective Investigation into Cancer and Nutrition (EPIC) cohort (N=476,940). During prospective follow-up, a total of 651 cases of incident cases of CUP were detected (ICD-O-2 code C809). Proportional hazards models were conducted to examine the associations of lifetime history of smoking habits, alcohol consumption, levels of education and anthropometric indices of adiposity with... (More)
Cancer of unknown primary site (CUP) may be called an orphan disease, as it is diagnosed when metastases are detected while the primary tumor typically remains undetected, and because little research has been done on its primary causes. So far, few epidemiological studies, if any, have addressed possible risk factors for CUP. We analyzed data from the European Prospective Investigation into Cancer and Nutrition (EPIC) cohort (N=476,940). During prospective follow-up, a total of 651 cases of incident cases of CUP were detected (ICD-O-2 code C809). Proportional hazards models were conducted to examine the associations of lifetime history of smoking habits, alcohol consumption, levels of education and anthropometric indices of adiposity with risk of being diagnosed with CUP. Risk of being diagnosed with CUP was strongly related to smoking, with a relative risk of 3.66 [95% C.I., 2.24-5.97] for current, heavy smokers (26+ cigarettes/day) compared to never smokers (adjusted for alcohol consumption, body mass index, waist circumference and level of education) and a relative risk of 5.12 [3.09-8.47] for cases with CUP who died within 12 months. For alcohol consumption and level of education, weaker associations were observed but attenuated and no longer statistically significant after adjusting for smoking and indices of obesity. Finally, risk of CUP was increased by approximately 30 per cent for subjects in the highest versus lowest quartiles of waist circumference. Our analyses provide further documentation, in addition to autopsy studies, that a substantial proportion of cancers of unknown primary site may have their origin in smoking-related tumors, in particular. What's new? When cancer appears as metastatic disease but no primary tumor can be observed, it's called cancer of unknown primary site. Little is known about the risk factors for this type of cancer. This study analyzed data from a European cohort and discovered a strong association between smoking and these cancers. Other risk factors they identified were drinking alcohol and being fat. This is the first epidemiological study of these type of cancers, and it strengthens the observations from autopsy studies that many of these cancers of unknown primary site stem from smoking-related tumors. (Less)
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@article{c61e42f2-cf47-4ec3-a07e-0008d4cffc4c,
  abstract     = {Cancer of unknown primary site (CUP) may be called an orphan disease, as it is diagnosed when metastases are detected while the primary tumor typically remains undetected, and because little research has been done on its primary causes. So far, few epidemiological studies, if any, have addressed possible risk factors for CUP. We analyzed data from the European Prospective Investigation into Cancer and Nutrition (EPIC) cohort (N=476,940). During prospective follow-up, a total of 651 cases of incident cases of CUP were detected (ICD-O-2 code C809). Proportional hazards models were conducted to examine the associations of lifetime history of smoking habits, alcohol consumption, levels of education and anthropometric indices of adiposity with risk of being diagnosed with CUP. Risk of being diagnosed with CUP was strongly related to smoking, with a relative risk of 3.66 [95% C.I., 2.24-5.97] for current, heavy smokers (26+ cigarettes/day) compared to never smokers (adjusted for alcohol consumption, body mass index, waist circumference and level of education) and a relative risk of 5.12 [3.09-8.47] for cases with CUP who died within 12 months. For alcohol consumption and level of education, weaker associations were observed but attenuated and no longer statistically significant after adjusting for smoking and indices of obesity. Finally, risk of CUP was increased by approximately 30 per cent for subjects in the highest versus lowest quartiles of waist circumference. Our analyses provide further documentation, in addition to autopsy studies, that a substantial proportion of cancers of unknown primary site may have their origin in smoking-related tumors, in particular. What's new? When cancer appears as metastatic disease but no primary tumor can be observed, it's called cancer of unknown primary site. Little is known about the risk factors for this type of cancer. This study analyzed data from a European cohort and discovered a strong association between smoking and these cancers. Other risk factors they identified were drinking alcohol and being fat. This is the first epidemiological study of these type of cancers, and it strengthens the observations from autopsy studies that many of these cancers of unknown primary site stem from smoking-related tumors.},
  author       = {Kaaks, Rudolf and Sookthai, Disorn and Hemminki, Kari and Kraemer, Alwin and Boeing, Heiner and Wirfält, Elisabet and Weiderpass, Elisabete and Overvad, Kim and Tjonneland, Anne and Olsen, Anja and Peeters, Petra H. and Bueno-de-Mesquita, H. B. (As) and Panico, Salvatore and Pala, Valeria and Vineis, Paolo and Ramon Quiros, J. and Ardanaz, Eva and Sanchez, Maria-Jose and Chirlaque, Maria-Dolores and Larranaga, Nerea and Brennan, Paul and Trichopoulos, Dimitrios and Trichopoulou, Antonia and Lagiou, Pagona and Hallmans, Goeran and Khaw, Kay-Tee and Key, Timothy J. and Riboli, Elio and Canzian, Federico},
  issn         = {0020-7136},
  keyword      = {cancer of unknown primary site (CUP),prospective cohort study,smoking,alcohol,obesity,waist circumference},
  language     = {eng},
  number       = {10},
  pages        = {2475--2481},
  publisher    = {John Wiley & Sons},
  series       = {International Journal of Cancer},
  title        = {Risk factors for cancers of unknown primary site: Results from the prospective EPIC cohort},
  url          = {http://dx.doi.org/10.1002/ijc.28874},
  volume       = {135},
  year         = {2014},
}