It seems that patients have to choose from two diseases. Men taking testosterone-blocking drugs to cure prostate cancer have nearly twice the risk of developing Alzheimer's disease, according to researchers' study.

The treatment called Androgen-deprivation therapy, or also known as chemical castration, decreases the level of testosterone production and other male hormones that can drive the growth of prostate cancer. However, except its benefits on male reproduction system, the treatment is linked with cardiovascular disease, diabetes, loss of muscle mass and doubles the risk of prostate cancer.

 Several medical specialists also claimed that it does not improve the survival rates for men with localized prostate cancer. Moreover, many patients complained about memory loss and thinking problems.

"We observed a statistically significant increased risk of Alzheimer's disease with increasing duration of ADT (androgen deprivation therapy)," said Dr. Kevin Need from the University of Pennsylvania. He and his co-researchers from Stanford University wrote the large study about the risk of Androgen-deprivation therapy.

To arrive at their conclusions, they examined more than 16,000 patients with non-metastatic prostate cancer between 1994 and 2013. After a series of analysis, findings revealed that nearly 2,400 patients received  anti-androgen therapy, and they had more than 80% percent risk of being diagnosed with Alzheimer's disease.

Prostate cancer is one of the leading causes of death among American male adults. NBC News reported that 240,000 U.S. adults were diagnosed with the disease last year, and it kills about 30,000 a year.

Some of the treatments for prostate cancer include tumor surgery, radiation to destroy it, chemotherapy and taking radioactive beads to shrink the tumor. But Androgen-deprivation therapy is one of the oldest treatments for the disease.

The treatment has been used since the 1940s and it is given to more than 500,000 American male adults every year. The cure includes drugs such as flutamide and enzalutamide, which act against testosterone, and drugs called LHRH agonists that stop production of testosterone by interfering with other hormones.

As per Wall Street Journal report says, authors of the study noted that while the findings show that anti-androgen therapy is linked to Alzheimer's disease, testosterone has been shown to aid the growth of brain cells and control the rate of B-amyloid protein, a protein mostly found in neurons of Alzheimer's patients.

To know more about the latest findings, read the recent edition of the Journal of Clinical Oncology.

Records from the Centers for Disease Control and Prevention show that there were as many as 5 million Americans living with Alzheimer's disease in 2013. Moreover, the number of Americans with the disease doubles every 5 years. By 2050, the number of Alzheimer's patients will rise to 14 million, a nearly three-fold increase.