Prostate cancer is a common disease that affects men, usually in middle age or later. In this disorder, certain cells in the prostate become abnormal and multiply without control or order to form a tumor. The prostate is a gland that surrounds the male urethra and helps produce semen, the fluid that carries sperm.

Early prostate cancer usually does not cause pain, and most affected men exhibit no noticeable symptoms. Men are often diagnosed as the result of health screenings, such as a blood test for a substance called prostate specific antigen (PSA) or a medical procedure called a digital rectal exam. As the tumor grows larger, signs and symptoms can include difficulty starting or stopping the flow of urine, a feeling of not being able to empty the bladder completely, blood in the urine or semen, or pain with ejaculation. However, these changes can also occur with many other genitourinary conditions. Having one or more of these symptoms does not necessarily mean that a man has prostate cancer.

The severity and outcome of prostate cancer varies widely. Early-stage prostate cancer can usually be treated successfully, and some older men have prostate tumors that grow so slowly that they may never cause health problems during their lifetime, even without treatment. In other men, however, the cancer is much more aggressive; in these cases, prostate cancer can be life-threatening.

Some cancerous tumors can invade surrounding tissue and spread to other parts of the body. Tumors that begin at one site and then spread to other areas of the body are called metastatic cancers. The signs and symptoms of metastatic cancer depend on where the disease has spread.

A small percentage of all prostate cancers cluster in families. These hereditary cancers are associated with inherited gene mutations. Hereditary prostate cancers tend to develop earlier in life than non-inherited (sporadic) cases.

About 1 in 7 men will be diagnosed with prostate cancer at some time during their life. In addition, studies indicate that many older men have undiagnosed prostate cancer that is non-aggressive and unlikely to cause symptoms or affect their lifespan. While most men who are diagnosed with prostate cancer do not die from it, this common cancer is still the second leading cause of cancer death among men in the world.

More than 60 percent of prostate cancers are diagnosed after age 65, and the disorder is rare before age 40.

Cancers occur when genetic mutations build up in critical genes, specifically those that control cell growth and division or the repair of damaged DNA. These changes allow cells to grow and divide uncontrollably to form a tumor. In most cases of prostate cancer, these genetic changes are acquired during a man’s lifetime and are present only in certain cells in the prostate. These changes, which are called somatic mutations, are not inherited. Somatic mutations in many different genes have been found in prostate cancer cells. Less commonly, genetic changes present in essentially all of the body’s cells increase the risk of developing prostate cancer. These genetic changes, which are classified as germline mutations, are usually inherited from a parent. In people with germline mutations, changes in other genes, together with environmental and lifestyle factors, also influence whether a person will develop prostate cancer.

Inherited mutations in particular genes, such as BRCA1, BRCA2, and HOXB13, account for some cases of hereditary prostate cancer. Men with mutations in these genes have a high risk of developing prostate cancer and, in some cases, other cancers during their lifetimes. In addition, men with BRCA2 or HOXB13 gene mutations may have a higher risk of developing life-threatening forms of prostate cancer.

Inherited variations in dozens of other genes have been studied as possible risk factors for prostate cancer. Some of these genes provide instructions for making proteins that interact with the proteins produced from the BRCA1, BRCA2, or HOXB13 genes. Others act as tumor suppressors through different pathways. Changes in these genes probably make only a small contribution to overall prostate cancer risk. However, researchers suspect that the combined influence of variations in many of these genes may significantly impact a person’s risk of developing this form of cancer.

In addition to genetic changes, researchers have identified many personal and environmental factors that may contribute to a person’s risk of developing prostate cancer. These factors include a high-fat diet that includes an excess of meat and dairy and not enough vegetables, a largely inactive (sedentary) lifestyle, obesity, excessive alcohol use, or exposure to certain toxic chemicals. A history of prostate cancer in closely related family members is also an important risk factor, particularly if the cancer occurred at an early age.

Hereditary prostate cancer syndromes are conditions that impact other areas of an individual’s body in addition to increasing their risk for prostate cancer. A syndrome can be inherited in a dominant, de novo, or recessive manner. Two examples of hereditary prostate cancer syndromes are listed below:

Hereditary Breast and Ovarian Cancer (HBOC)

 Two genes, named BRCA1 and BRCA2, are common causes of hereditary breast cancer. Mutations in these two genes are also associated with a significant risk for breast and ovarian cancer, as well as prostate and pancreatic cancer. A mutation in BRCA2 also confers a higher risk for breast cancer in men, and melanoma for both men and women. Men with BRCA2 mutations who are diagnosed with prostate cancer tend to have more aggressive tumors and an earlier age of diagnosis than other men.

Lynch syndrome

Lynch syndrome, also known as Hereditary Non-Polyposis Colorectal Cancer (HNPCC), accounts for up to 15% of HOC cases. The condition is caused by a mutation in a gene whose job is to repair the DNA damage that normally occurs as cells grow and divide. People with Lynch syndrome are at an increased risk for different types of cancers, such as ovarian, gastric, prostate and brain. This is especially true for colon and endometrial cancer. Both men and women with this syndrome have up to an 80% risk to develop colon cancer by age 70 years. Women with Lynch syndrome have up to a 60% chance to develop endometrial cancer. Men with Lynch syndrome have a two to five-fold increased risk for prostate cancer compared to men without Lynch syndrome. Because of the high risk for cancer, people with Lynch syndrome require increased screening earlier than those without the condition.

Patients identified with hereditary prostate cancer can benefit from increased surveillance and preventative steps to better manage their risk for cancer. Also, your patient’s family members can be tested to help define their risk. If a pathogenic variant is identified in your patient, close relatives (children, siblings, parents) could have as high as a 50% risk to also be at increased risk.

What will genetic testing tell me?

POSITIVE +

 A positive result means that a genetic mutation causing an increased risk for prostate cancer was identified. Your risk for other cancers or health conditions may also be increased, depending on the gene involved. Your doctor can use this information to customize your care, which could include increased screening, preventative surgery, medication, and other steps. A positive result is also important for your family. Your parents, siblings, and children could have as high as a 50% chance to also have the mutation. As a result, sharing your genetic testing results with your relatives is important for their health.

NEGATIVE –

A negative result indicates that a genetic mutation was not identified. A negative result may indicate that there is not a cancer-risk gene mutation in you or your family. However, it can also mean that the gene increasing risk in you or your family was not included on the ordered test, or that it may not be currently known. Your doctor can use a negative result to continue your treatment and screening based on your clinical and family history, or they may consider another type of genetic testing.

 

VARIANT OF UNCERTAIN CLINICAL SIGNIFICANCE (VUS) ?

The third possible test result is called a Variant of Uncertain Clinical Significance. A gene variant is a genetic difference that could be disease-causing (mutation) or could be a normal finding (benign). More research is needed to determine whether the variant is important or not, and it should be treated as a negative result until more information is available.