男性因素不孕症與睪丸癌風險有關

作者：Laurie Barclay, MD  
出處：WebMD醫學新聞

　　March 3, 2009 — 根據一項發表於2月23日內科學誌的研究結果顯示，有男性因素不孕症的男士們，發展成睪丸癌的風險比較高。
　　
　　舊金山加州大學Thomas J. Walsh醫師與其同事寫到，相較於一般大眾，尋求不孕症治療的男性，睪丸癌的風險被認為是較高的。這目前並未在美國大型群眾資料庫中進行確認。這項研究在美國一群群眾中探索男性不孕症與接下來發生睪丸癌風險之間的關係。
　　
　　這項研究共收納51,461對夫婦，他們於1967年到1998年間在加州15個不孕症中心接受不孕症評估，另外22,562位確認的男性伴侶與加州癌症註冊試驗相連結。透過監視流行病學與最終結果計畫，研究團隊將這群群眾中睪丸癌與年齡相仿的一般大眾進行比較。以Cox比例風險迴歸模式來確定有無男性因素不孕症男士發生睪丸癌的風險。
　　
　　男性因素不孕症以世界衛生組織精液分析異常結果臨床表徵來確認。
　　
　　總共有34件過去被診斷罹患不孕症的病理學確認男性睪丸癌病例。尋求不孕症治療的男性，之後發生睪丸癌的風險（標準化發生率比值[SIR]為1.3；95%信賴區間為0.9-1.9）是已知男性因素不孕症男士的近一倍（標準化發生率比值[SIR]為2.8；95%信賴區間為1.5-4.8）。
　　
　　多變項分析顯示，有男性因素不孕症的男士發生睪丸癌的風險幾乎是沒有此狀況男士的三倍（危險比值為2.8；95%信賴區間為1.3-6.0）。
　　
　　研究作者們寫到，有男性因素不孕症的男士接下來發生睪丸癌的風險上升，代表不孕症與睪丸癌之間存在著共同致病因素。
　　
　　這項研究的限制包括可能未評量的干擾因素，以及缺乏有關隱睪症相關的數據，這是另一個造成不孕症與睪丸癌的潛在原因。
　　
　　研究者們寫到，不孕症與睪丸癌之間的關連已經被證實是生物學上與臨床上可行的。更重要的，男性因素不孕症睪丸生殖細胞癌之間的關連應該刺激之後的研究，將重點放在這個族群生殖細胞健康不良的生物學。
　　
　　國家兒童健康機構與人類發展及加州泌尿學基金會贊助這項研究。研究作者們表示沒有相關資金上往來。

Male Factor Infertility Linked to Risk for Testicular Cancer

By Laurie Barclay, MD
Medscape Medical News

March 3, 2009 — Men with male factor infertility have an increased risk for the subsequent development of testicular cancer, according to the results of a study reported in the February 23 issue of the Archives of Internal Medicine.

"The risk of testicular cancer is thought to be higher among men seeking infertility treatment compared with the general population," write Thomas J. Walsh, MD, MS, from University of California–San Francisco and colleagues. "Confirmation of this risk in a large US cohort of at-risk patients is lacking. This study explored the association between male infertility and subsequent development of testicular cancer in a US-based cohort."

The study cohort consisted of 51,461 couples evaluated for infertility from 1967 to 1998 at 15?California infertility centers. Data from 22,562 identified male partners were linked to the California Cancer Registry. Using the Surveillance Epidemiology and End Results program, the investigators compared the incidence of testicular cancer in this cohort vs an age-matched, general-population sample. A Cox proportional hazards regression model allowed determination of the risk for testicular cancer in men with and without male factor infertility.

Male factor infertility was determined by the clinical presentation with abnormal semen analysis variables as defined by World Health Organization criteria.

There were 34 cases of histologically confirmed testicular cancer in men who had been previously diagnosed with infertility. The risk for the subsequent development of testicular cancer was increased in men seeking infertility treatment (standardized incidence ratio [SIR], 1.3; 95% confidence interval [CI], 0.9 - 1.9), with more than double the increased risk in men with known male factor infertility (SIR, 2.8; 95% CI, 1.5 - 4.8).

Multivariable analysis showed that men with male factor infertility were nearly 3 times more likely to have testicular cancer vs men without this condition (hazard ratio, 2.8; 95% CI, 1.3 - 6.0).

"Men with male factor infertility have an increased risk of subsequently developing testicular cancer, suggesting the existence of common etiologic factors for infertility and testicular cancer," the study authors write.

Limitations of this study include possible unmeasured confounding and lack of data concerning cryptorchidism, which is another potential cause of infertility and testicular cancer.

"The association between infertility and testicular cancer has been shown to be biologically and clinically feasible," the study authors write. "More importantly, the association between male infertility and testicular germ cell cancer should stimulate further research that focuses on the etiology of poor germ cell health in these populations."

The National Institute of Child Health and Human Development and the California Urology Foundation supported this study. The study authors have disclosed no relevant financial relationships.

Arch Intern Med. 2009;169:351-356.