Prostate Cancer: Everything You Need To Know

What is Prostate Cancer?

Prostate cancer is a tumor that forms in the tissues of the prostate gland, a urogenital organ found only in males.  Normally, a prostate gland is small about the size of a walnut.  It’s located deep in the pelvis under the bladder and sits directly in front of the rectum.

The prostate is an important organ of both reproduction and urinary control.  It is regulated by the hormone testosterone and produces seminal fluid, also known as semen.  Semen is the substance containing sperm that exits the urethra during ejaculation.  The prostate gland surrounds the urethra, the tube through which urine and semen flow.  Prostate tumors can therefore cause problems with reproduction and with urination; however, many people with prostate cancer have no symptoms, so it is important for men to discuss prostate cancer risk with their physician.  Reproductive problems include impotence and blood in semen; urinary problems include frequent need to urinate, a stream that’s slower than normal, and bleeding while urinating.  Pain and numbness can occur when the cancer has spread to other parts of the body such as the bones.

Prostate cancer usually occurs in older men.  It is the most common cancer and the second leading cause of cancer death among men in the United States.  It is very rarely seen in children and infants.  Virtually all prostate cancers are called carcinomas, with sarcoma of the prostate being very rare. 

Imaging is an important part of the evaluation of prostate cancer and helps to guide successful treatment and decision-making.

What are the latest Prostate Cancer Statistics?

Prostate Cancer is the most common cancer in men.  The older he gets, the higher the incidence of prostate cancer cells being present in a man’s prostate gland.  Approximately 80% of men who live to the age of 80 will have prostate cancer.  While one out of nine men will get prostate cancer, only one out of 39 will die of this disease.  Approximately 174,650 new cases of prostate cancer occurred in the United States in 2019, with approximately 31,620 deaths, making it the second leading cause of cancer death in men in the United States.  The number of prostate cancer deaths in the US continues to decline, but the death rate among black men is greater than twice the rate in white men.  Overall, approximately 98% of men with prostate cancer will survive at least 5 years.

What are the Risk Factors for Prostate Cancer?

There is no known cause for prostate cancer, but like all cancers, it could be caused by a number of things.

Being male and older are the primary risk factors for prostate cancer.  The risk of prostate cancer increases especially after age 50.

Race also is an important factor.  Black men have a higher risk of prostate cancer than white men and are more likely to develop prostate cancer at an earlier age with aggressive tumors that grow quickly.  Other risk factors include a family history of prostate cancer, and also hereditary breast and ovarian cancer (HBOC) syndrome or other genetic factors.

Diet may play a role.  More research is warranted to further solidify the involvement of diet in prostate cancer incidence and progression.  But, avoiding risk factors such as vitamin E alone, 1 mg supplements of folic acid, diet high in dairy foods and calcium, obesity, and increasing protective factors such quitting smoking and exercising may help prevent cancer.

Hormone such as testosterone may play a part in development of prostate cancer.

Agent Orange exposure has been linked to prostate cancer.  This was a chemical agent used during the Vietnam War.

What are the common symptoms of Prostate Cancer?

Early prostate cancer usually has no symptoms.  With more advanced disease, symptoms may include frequent urination, weak or interrupted urine flow, the need to strain to empty the bladder, blood in the urine, the urge to urinate frequently at night, discomfort when sitting, blood in the seminal fluid, and less commonly pain or burning during urination.  New onset of erectile dysfunction (ED) may also be a sign of prostate cancer.  These symptoms vary among patients.

How do you diagnose Prostate Cancer?

Prostate Cancer may present with or without symptoms.  Diagnosis is usually made by clinical history, physical exam (including a Digital Rectal Exam (DRE), laboratory data (the Prostate-Specific Antigen (PSA) level), various imaging tests, and tissue biopsy.  Biopsy is usually performed by a urologist, a specialist in male genitourinary disease.  Biopsy is guided by Transrectal Ultrasound (TRUS), which is when the urologist or radiologist uses a special ultrasound probe inserted in the rectum to image the prostate and guide prostate biopsy.  The biopsy is analyzed under a microscope by a pathologist in order to identify abnormal cells which may indicate the presence of cancer.

How is Prostate Cancer staged?

Staging defines where the cancer is located, if it has spread, and if it is affecting other areas of the body.  Most prostate cancers (81%) are found when disease is confined to the prostate and nearby organs.  When the disease has spread to distant organs like the bones, it is advanced.  Imaging is often used to determine whether the cancer has spread to other parts of the body.  When the cancer has spread to other parts of the body, it is called metastasis or metastatic disease. 

Prostate can also be categorized by how fast it grows aggressive (fast growing) or nonaggressive (slow growing). 

The staging process may include additional imaging tests such as:

1. PET/CT: PET/CT scans have emerged as a promising modality for both primary and recurrent prostate cancer with new tracers, such as Axumin (18F-Fluciclovine) or a new class of radio-tracers referred to as PSMA. These newer radio-tracers for PET scans have increased detection accuracies for smaller areas of disease. 
2. CT:  CT scans for prostate cancer are useful in demonstrating lymph node involvement or distant metastasis.  This gives detailed anatomical images and can be used to aid radiation therapy planning and to monitor treatment response.
3. MRI:  MRI scan for prostate cancer is currently the method of choice for local staging.  This test provides detailed images of tumor location (whether the tumor has spread outside of the prostate gland, such as extracapsular extension and seminal vesicle invasion).  MRI is also useful to restage disease.
4. Tc-99m Bone Scan: this test is used to detect prostate cancer that has spread to the bone, and usually is negative when the PSA level is less than 10 ng/mL.
5. Lab and pathology tests: this includes the PSA and Gleason scores.

Determining whether prostate cancer has spread to lymph nodes or other parts of the body (e.g., bone) is critical for making accurate decisions on whether and how to treat the prostate cancer.  Imaging plays an important role in treatment planning for the oncologist. 

To learn more about imaging for prostate cancer click here.

Staging Info: https://www.cancer.net/cancer-types/prostate-cancer/stages-and-grades

What is the staging system for Prostate Cancer?

The American Joint Committee on Cancer (AJCC) uses the Tumor-Node-Metastasis (TNM) staging system- this is a standard way for the cancer care team to describe how far a cancer has spread.  The Grade of the tumor is known as the Gleason score and is a measure of how likely the cancer is to grow and spread quickly.  This is determined by the results of the prostate biopsy, or by surgery.

The Gleason score is the most common Prostate Cancer grading system used by cancer specialists.  Another less commonly used, but simplified grading system is called the Epstein Grading System.  The pathologist looks at how the prostate cancer cells are arranged in the prostate gland on a microscope and for each biopsy assigns a score on a scale of 1-5 in two separate random biopsy locations in the prostate gland.  The overall Gleason score ranges from 2-10, and is calculated by adding the most common grade and the second most common grade. This is a measure of how aggressive a tumor is (the higher the number, the more aggressive a tumor is).

While the grade of the tumor describes the degree of aggression of the prostate tumor, the Stage of prostate cancer is determined by 3 characteristics:

• Tumor, T: The size of the primary tumor and where it is located 

• Node, N: Whether the tumor spread to the lymph nodes 

• Metastasis, M: Whether the cancer has metastasized to other parts of the body

The specific use and order of testing is unique for each patient.  Guidelines for use of testing in specific cancers can be found at the National Comprehensive Cancer Network (NCCN) website: www.NCCN.org.

What are the treatment options for Prostate Cancer?

Treatment for prostate cancer depends on tumor location, grade and stage and the treatment plan is individualized to suit a patient’s particular needs and desires.  Optimal therapeutic approach varies widely including active surveillance, androgen ablation (chemical or surgical castration), hormone therapy, radical surgery, various forms of radiation therapy, chemotherapy, and immunotherapy.

Some general terms:

Localized: active surveillance, radical prostatectomy, external beam radiation therapy (EBRT) and brachytherapy:

Locally advanced: surgery, radiation therapy, hormone therapy 

Metastatic: hormone therapy, immunotherapy, chemotherapy (including bone directed treatment) 

Cancer specialists (urologists, radiation oncologists, surgeons) rely on consensus guidelines for help with diagnosis, staging and treatment. 

The National Comprehensive Cancer Network (NCCN) publishes evidence-based guidelines for all cancer subtypes:  www.NCCN.org/prostate cancer guidelines

What is PET/CT?

A PET/CT scan is a nuclear imaging test which measures metabolic activity in live tissue.  PET/CT helps the oncologist evaluate the tumor and treatment response.  Prostate cancer may have increased metabolic activity, so PET/CT scan can help to identify tumors of the prostate.  PET/CT scans come in many different forms, such as F-18 FDG, F-18 NaF, C-11 choline, F-18 fluciclovine (Axumin), and Prostate Specific membrane Antigen (PSMA PET scan).

What is the role of PET/CT in Prostate Cancer?

A PET scan helps to assess the response to treatment and guide management decisions.  PET/CT can play a critical role in staging advanced cancers and also in restaging prostate cancer.  Restaging refers to identifying cancer that has returned following treatment.  PET/CT is helpful for the physician to identify location of tumors and also helps in those cases where the cancer has recurred/returned.  New PET/CT tracers (radioactive material that help locate tumors) such as Axumin (F-18 Fluciclovine) and PSMA are now common tools for the doctor to identify biochemically recurrent prostate cancer.  These new tracers can be useful when traditional imaging studies cannot identify small tumors or recurrent disease.  This is especially helpful when the PSA level is rising again after treatment but the conventional tests like CT and MRI cannot detect the cancer. PET/CT allows for both anatomic and functional imaging that improves assessment of GTV (gross tumor volume), which is very important for newer radiation treatments.

Summary of PET/CT:

1. PET/CT is a powerful non-invasive diagnostic tool in oncology treatment.
2. New technology and radiological tracers show utility in detecting local and/or regional and distant recurrence.
3. Helpful in identifying hormone refractory aggressive tumors.
4. Indications for using PET/CT in prostate cancer patients include monitoring tumor response to chemotherapy or hormone therapy and evaluation for tumor recurrence:
   • Rising PSA with negative CT/MRI/SPECT, and Bone scan 
   • Radiation therapy planning
   • Staging of aggressive tumor types 

References 

▪www.americancancersociety.com 

▪www.NCCN.org; NCCN Guidelines 

▪www.cancer.gov/types/prostate 

▪www.cancer.net/cancer-types/prostate-cancer 

▪www.cdc.gov 

▪http://seer.cancer.gov/stat facts 

▪www.cancer.net/prostate-cancer/stages 

▪www.urologyhealth.org/prostate cancer grading and staging