Incidence rises with age, and nearly 70% of men autopsied at age 80–89 had cancer in their prostates. Autopsies of men who died at various ages have shown cancer in the prostates of more than 40% of men over age 50. Less commonly, tumors have aberrant activation of the Wnt signaling pathway via disruption of members APC (9% of tumors) or CTNNB1 (4% of tumors); or dysregulation of the PI3K pathway via PI3KCA/PI3KCB mutations (6% of tumors) or AKT1 (2% of tumors). Similarly, deletions of the tumor suppressor PTEN are harbored by 12–17% of castrate-sensitive tumors, but more than 40% of castrate-resistant tumors. Many of these mutations are in genes that protect from DNA damage, such as p53 (mutated in 8% of localized tumors, more than 27% of metastatic ones) and RB1 (1% of localized tumors, more than 5% of metastatic ones). As the tumor grows, its cells accumulate more mutations, allowing it to stimulate the growth of new blood vessels to support further growth. With these processes dysregulated, some cells replicate abnormally, forming a clump of cells called a tumor. The prostate is the only male accessory gland that occurs in cetaceans, consisting of diffuse urethral glands surrounded by a very powerful compressor muscle. In some marsupial species, the size of the prostate gland changes seasonally. The structure of the prostate varies, ranging from tubuloalveolar (as in humans) to branched tubular. The presence of a functional prostate in monotremes is controversial, and if monotremes do possess functional prostates, they may not make the same contribution to semen as in other mammals. This was improved upon by Patrick C. Walsh's 1983 description of a retropubic prostatectomy approach that avoided damage to the nerves near the prostate, preserving erectile function. In 1945, Terence Millin described a retropubic prostatectomy approach, which provided easier access to pelvic lymph nodes to assist in staging the extent of disease, and was easier for surgeons to learn. In 1931 a new surgical method, transurethral resection of the prostate, became available, replacing perineal prostatectomy for symptomatic relief of obstruction. Perineal prostatectomy was first performed in 1904 by Hugh H. Young at Johns Hopkins Hospital. Around the turn of the 19th century, prostate surgery to relieve urinary obstruction became more common, allowing surgeons and pathologists to examine the removed prostate tissue. In only 1 study was testosterone given orally,24 and that study included 3 intervention groups and 1 control group. Possible performance bias from inappropriate blinding of participants and personnel might be present in 6 studies, and 1 study did not clearly state the blinding process; thus, 53.3% (8/15) of studies had low performance bias (blinding of participants and personnel), and 40.0% (6/15) of studies had high performance bias. Characteristics of the 15 studies included in the meta-analysis are summarized in Table 1, and outcomes are summarized in Table 2. Subsequently, 66 were excluded and 15 studies were included in the systematic review and meta-analysis (Table 1). If cancer is present, the pathologist assigns a Gleason score; a higher score represents a more dangerous tumor. However, significantly elevated PSA levels or rapidly rising PSA levels would warrant further investigation and may preclude TRT until the underlying cause is determined. Monitoring PSA levels during TRT helps to detect any potential issues early on. As discussed, the key issue is the potential to accelerate the growth of existing cancer, not to induce the formation of new cancerous cells. However, because PSA levels increase with age, some doctors apply a higher cutoff (such as 5 ng/ml) for older men and a lower cutoff ( such as 2.5 ng/mL) for younger men (1). In general, a PSA level above 4.0 ng/mL is considered abnormal and may result in a recommendation for prostate biopsy. Most organizations now recommend that individuals who are considering PSA screening first discuss the risks and benefits with their doctors before making a decision. Secondary outcomes were elevated PSA level after treatment, and the number of patients who developed prostate cancer. Testosterone replacement therapy is used for the treatment of age-related male hypogonadism, and prostate-specific antigen (PSA) is a primary screening tool for prostate cancer. Because testosterone levels change with age and time, a prospective study with long-term testosterone monitoring is required to find a relationship between testosterone and prostate cancer. Only a known prostate cancer predictor, PSAD, showed a significant difference between patients with and those without prostate cancer, even in high-risk patients with a PSA level of 10 ng/ml or higher. Subsequent increases in serum testosterone levels beyond that concentration did not stimulate the prostate because the binding capacity of the intra-prostatic androgen receptors had been saturated.
