Yu Xing-Fei, Yang Hong-Jian, Yu Yang, Zou De-Hong, Miao Lu-Lu
Department of Breast Tumor Surgery, Zhejiang Provincial Cancer Hospital, Hangzhou, Zhejiang Province, P.R. China.
Department of Medical Oncology, Zhejiang Provincial Cancer Hospital, Hangzhou, Zhejiang Province, P.R. China.
PLoS One. 2015 Aug 27;10(8):e0136670. doi: 10.1371/journal.pone.0136670. eCollection 2015.
Male breast cancer (MBC) is known to be rare compared with female breast cancer (FBC) and to account for only 1% of all breast cancers. To date, male patients diagnosed with breast cancer are normally treated based on the guidelines for FBC. Specifically, studies have found that diagnosing and treating MBC patients under the guidelines for the treatment of post-menopausal FBC are more favorable than are those of pre/peri-menopausal FBC from a physiological perspective because MBC and post-menopausal FBC patients show high estrogen receptor (ER) expression in the tumor and low estrogen expression in the body. In this medical study, we aimed to examine whether MBC actually has the same prognosis as post-menopausal FBC.
We identified MBC patients who were diagnosed as operable and who completed clinical treatment and we used follow-up data that were collected from January 2001 to January 2011. Each MBC patient was paired with four FBC patients who were diagnosed within the same period (two were pre/peri-menopausal, and two were post-menopausal). We compared disease-free survival (DFS) and overall survival (OS) among three groups, i.e., pre/peri-menopausal FBC (group A), post-menopausal FBC (group B) and MBC (group M), using the Kaplan-Meier method and a Cox proportional hazards regression model. We also evaluated the clinical characteristics of breast cancer patients using t-tests and chi-square tests. We used ten consecutive years of data that were collected at Zhejiang Provincial Cancer Hospital.
We identified 91 MBC cases for group M, 182 FBC cases for group A and 182 FBC cases for group B. The median follow-up period was 112 months. MBC cases were much more frequently ER positive than those of group A and group B (p<0.01); a similar trend was also found for progesterone (PR)-positive cases (p<0.01). The MBC group showed much lower human epidermal growth factor receptor-2 (HER2) expression than did the other groups (p<0.01). The 10-year OS rates were 79.1% for group M (72/91), 79.1% (144/182) for group A, and 87.9% (160/182) for group B, log-rank test indicated that group M had similar mean OS time as group A and group B (GourpM vs group A: p = 0.709; group M vs group B: p = 0.042). The Cox proportional hazards regression model indicated that pre/peri-menopausal FBC had similar DFS (hazard ratio (HR) = 0.706, p = 0.262) and OS (HR = 1.029, p = 0.941) values compared with MBC, whereas post-menopausal FBC had higher DFS (HR = 0.454, p = 0.004) and OS (HR = 0.353, p = 0.003) values than did MBC.
Based on this study, we can conclude that MBC displayed higher ER- and PR-positive expression and lower HER2-positive expression than both post-menopausal and pre/peri-menopausal FBC. However, the DFS and OS values of MBC were similar to those of pre/peri-menopausal FBC and were worse than were those of post-menopausal FBC.
与女性乳腺癌（FBC）相比，男性乳腺癌（MBC）较为罕见，仅占所有乳腺癌的1%。迄今为止，确诊为乳腺癌的男性患者通常根据FBC的指南进行治疗。具体而言，研究发现，从生理学角度来看，按照绝经后FBC的治疗指南诊断和治疗MBC患者比绝经前/围绝经期FBC更为有利，因为MBC和绝经后FBC患者肿瘤中雌激素受体（ER）表达高，而体内雌激素表达低。在这项医学研究中，我们旨在研究MBC的预后是否真的与绝经后FBC相同。
我们确定了诊断为可手术且完成临床治疗的MBC患者，并使用了2001年1月至2011年1月收集的随访数据。每位MBC患者与同期诊断的4名FBC患者配对（2名绝经前/围绝经期患者和2名绝经后患者）。我们使用Kaplan-Meier方法和Cox比例风险回归模型比较了三组患者的无病生存期（DFS）和总生存期（OS），即绝经前/围绝经期FBC（A组）、绝经后FBC（B组）和MBC（M组）。我们还使用t检验和卡方检验评估了乳腺癌患者的临床特征。我们使用了浙江省肿瘤医院连续十年收集的数据。
我们确定M组有91例MBC病例，A组有182例FBC病例，B组有182例FBC病例。中位随访期为112个月。MBC病例的ER阳性率远高于A组和B组（p<0.01）；孕激素（PR）阳性病例也有类似趋势（p<0.01）。MBC组的人表皮生长因子受体2（HER2）表达远低于其他组（p<0.01）。M组的10年OS率为79.1%（72/91），A组为79.1%（144/182），B组为87.9%（160/182），对数秩检验表明M组的平均OS时间与A组和B组相似（M组与A组：p = 0.709；M组与B组：p = 0.042）。Cox比例风险回归模型表明，与MBC相比，绝经前/围绝经期FBC的DFS（风险比（HR） = 0.706，p = 0.262）和OS（HR = 1.029，p = 0.941）值相似，而绝经后FBC的DFS（HR = 0.454，p = 0.004）和OS（HR = 0.353，p = 0.003）值高于MBC。
基于这项研究，我们可以得出结论，与绝经后和绝经前/围绝经期FBC相比，MBC的ER和PR阳性表达更高，HER2阳性表达更低。然而，MBC的DFS和OS值与绝经前/围绝经期FBC相似，且比绝经后FBC更差。
