BMC Cancer 2BR2M0e0Cs2eC,aanrccerh article x Male gynecomastia and risk for malignant tumours – a cohort study H Olsson*1,2, A Bladstrom2 and P Alm3 Address: 1Department of Oncology, University Hospital, Lund, Sweden, 2Department of Cancer Epidemiology and South Swedish Regional Tumour Registry, Lund, Sweden and 3Department of Pathology, University Hospital, Lund, Sweden E-mail: H Olsson* - hakan.olsson@onk.lu.se; A Bladstrom - anna.bladstrom@skane.se; P Alm - per.alm@pat.lu.se *Corresponding author BioMed Central Open Access Published: 16 October 2002 BMC Cancer 2002, 2:26 This article is available from: http://www.biomedcentral.com/1471-2407/2/26 Received: 5 July 2002 Accepted: 16 October 2002 © 2002 Olsson et al; licensee BioMed Central Ltd. This article is published in Open Access: verbatim copying and redistribution of this article are permitted in all media for any purpose, provided this notice is preserved along with the article's original URL. Keywords: male gynecomastia, malignancy Abstract Background: Men with gynecomastia may suffer from absolute or relative estrogen excess and their risk of different malignancies may be increased. We tested whether men with gynecomastia were at greater risk of developing cancer. Methods: A cohort was formed of all the men having a histopathological diagnosis of gynecomastia at the Department of Pathology, University of Lund, following an operation for either uni- or bilateral breast enlargement between 1970–1979. All possible causes of gynecomastia were accepted, such as endogenous or exogenous hormonal exposure as well as cases of unknown etiology. Prior to diagnosis of gynecomastia eight men had a diagnosis of prostate carcinoma, two men a diagnosis of unilateral breast cancer and one had Hodgkin's disease. These patients were included in the analyses. The final cohort of 446 men was matched to the Swedish Cancer Registry, Death Registry and General Population Registry. Results: At the end of the follow up in December 1999, the cohort constituted 8375.2 person years of follow-up time. A total of 68 malignancies versus 66.07 expected were observed; SIR = 1.03 (95% CI 0.80–1.30). A significantly increased risk for testicular cancer; SIR = 5.82 (95% CI 1.20–17.00) and squamous cell carcinoma of the skin; SIR = 3.21 (95% CI 1.71–5.48) were noted. The increased risk appeared after 2 years of follow-up. A non-significantly increased risk for esophageal cancer was also seen while no new cases of male breast cancer were observed. However, in the prospective cohort, diagnostic operations for gynecomastia may substantially have reduced this risk Conclusions: There is a significant increased risk of testicular cancer and squamous cell carcinoma of the skin in men who have been operated on for gynecomastia. Background Gynecomastia is a benign condition appearing both uni- and bilaterally. It is more common during some time pe- riods in life, such as early puberty and late adulthood [1]. Beside an endogenous hormonal imbalance in estrogen/ androgen ratio, drugs having estrogenic effects or diseases associated with injuries to gonads or liver affecting the es- trogen/androgen ratio may predispose to gynecomastia [2–4]. Also, many anti-psychotic drugs may induce hyper- prolactinemia and thus gynecomastia. It has been claimed Page 1 of 6 (page number not for citation purposes)