OBJECTIVE: Cancer is more likely to be diagnosed in the left breast than the right, but the reasons are undetermined. Left-sided predominance has not been evaluated for some demographic groups or by tumor location. METHODS: Laterality was analyzed among 419,935 incident unilateral breast cancers from 26 population-based cancer registries covering 40% of the US population. Logistic regression assessed the independent contribution of race, ethnicity, age, histology, stage, and location to laterality. RESULTS: Breast cancer was about 5% more likely to be diagnosed in the left breast than the right, a finding that was generally consistent across demographic groups and tumor types. Left-sided predominance was evident among both younger (<45 years) and older women, and among men with either in situ or invasive disease. Among women, tumors in the upper-outer quadrant, where one-third of cancers are located, occurred with equal frequency in the left and right breast, while those in the lower quadrants were about 10% more likely to occur in the left breast. CONCLUSION: The observation that the left breast is at greater risk of cancer than the right may not apply to tumors arising in the upper-outer quadrant. The identification of physiologic, pathologic, or immunologic differences between the lower, but not upper, left and right breasts may assist in explaining breast cancer laterality.
OBJECTIVE:Cancer is more likely to be diagnosed in the left breast than the right, but the reasons are undetermined. Left-sided predominance has not been evaluated for some demographic groups or by tumor location. METHODS: Laterality was analyzed among 419,935 incident unilateral breast cancers from 26 population-based cancer registries covering 40% of the US population. Logistic regression assessed the independent contribution of race, ethnicity, age, histology, stage, and location to laterality. RESULTS:Breast cancer was about 5% more likely to be diagnosed in the left breast than the right, a finding that was generally consistent across demographic groups and tumor types. Left-sided predominance was evident among both younger (<45 years) and older women, and among men with either in situ or invasive disease. Among women, tumors in the upper-outer quadrant, where one-third of cancers are located, occurred with equal frequency in the left and right breast, while those in the lower quadrants were about 10% more likely to occur in the left breast. CONCLUSION: The observation that the left breast is at greater risk of cancer than the right may not apply to tumors arising in the upper-outer quadrant. The identification of physiologic, pathologic, or immunologic differences between the lower, but not upper, left and right breasts may assist in explaining breast cancer laterality.
Authors: Gretchen L Gierach; Berta M Geller; John A Shepherd; Deesha A Patel; Pamela M Vacek; Donald L Weaver; Rachael E Chicoine; Ruth M Pfeiffer; Bo Fan; Amir Pasha Mahmoudzadeh; Jeff Wang; Jason M Johnson; Sally D Herschorn; Louise A Brinton; Mark E Sherman Journal: Cancer Epidemiol Biomarkers Prev Date: 2014-08-19 Impact factor: 4.254
Authors: Emanuel M Campoy; Sergio R Laurito; María T Branham; Guillermo Urrutia; Angela Mathison; Francisco Gago; Javier Orozco; Raul Urrutia; Luis S Mayorga; María Roqué Journal: PLoS One Date: 2016-07-06 Impact factor: 3.240
Authors: Yunan Han; Justin Xavier Moore; Marvin Langston; Lindsay Fuzzell; Saira Khan; Marquita W Lewis; Graham A Colditz; Ying Liu Journal: Cancer Causes Control Date: 2019-08-27 Impact factor: 2.506
Authors: Jasmin Teresa Ney; Ingolf Juhasz-Boess; Frank Gruenhage; Stefan Graeber; Rainer Maria Bohle; Michael Pfreundschuh; Erich Franz Solomayer; Gunter Assmann Journal: BMC Cancer Date: 2013-01-31 Impact factor: 4.430
Authors: Sue M Hudson; Louise S Wilkinson; Rachel Denholm; Bianca L De Stavola; Isabel Dos-Santos-Silva Journal: Br J Radiol Date: 2019-11-04 Impact factor: 3.629