The Prostate

Anatomy of the prostate

The prostate is a small gland in the male reproductive system. It is situated in front of the rectum, below the bladder, and surrounds the urethra, which is the tube through which urine flows out of the body. The main function of the chestnut-sized prostate is to secrete part of the seminal fluid that combines with sperm to form semen.

What is the normal prostate weight ?

A healthy adult prostate weighs around 20 to 25 grams and is approximately 4 cm wide, 3 cm high and 2 cm thick.

  1. Penis
  2. Urethra
  3. Testis
  4. Scrotum
  5. Bladder
  6. Seminal vesicle
  7. Prostate gland
  8. Anus
  9. Rectum

Size of the prostate

Prostate size remains the same until half of his life (around 40 years). Organ’s size can simply be described by words like “small”, “medium” or “big”. However, urologists use volume rather than weight to characterize it. Ultrasound are used to measure this data. Shaped as a chestnut, its common size is 3 cm high and 4 cm wide. Its common volume is 20 cm3 for around 20 grams. These data may change from one person to another.

What is the normal prostate size ?

A small prostate has a volume of 30 ml to 40 ml and a weight of 20 g to 70 g. A medium prostate has a volume of 40 ml to 80 ml and a weight of 20 g to 125g . A large prostate has a volume of 40ml to 100 ml and a weight of 40 g to 125 g.

Around age 40, prostate gland begins to grow. With a benign prostatic hyperplasia (a mild disease), gland’s size can increase by 4 to 5 times compared to its initial size.

Détection précoce du cancer de la prostate, Actualisation du référentiel de pratiques de l’examen périodique de santé (EPS), document PDF , HAS, mai 2013

Diseases of the prostate

Within the evolution, some disorders can affect the prostate: prostatitis is a prostate infection, prostate adenoma, also called Benign Prostatic Hyperplasia (BPH); is a prostate inflammation (abnormal magnification) and prostate cancer  (reproduction of abnormal and malignant cells).


The term prostatitis – or prostate infection – refers to a swelling of the prostate that usually occurs to men between 30 and 50 years old. As prostate is linked with urinary and genital tracts, a bacterial contamination of the urethra but also an infection of the entire urinary tract (bladder, urethra, kidneys) may cause prostatitis. In 2005, a study evaluated incidence of prostatitis at 1.26 cases per 1000 men / year. Most common symptoms are fever, urinary symptoms (frequent urge to urinate, burning sensation, intermittent urination, etc.), lower abdominal pain, muscle pain or a painful prostate during digital rectal examination. Prostatitis is treated with antibiotics.


Prostate adenoma or benign prostatic hypertrophy (BPH) is an abnormal increase of the volume of the prostate. It is benign and is often diagnosed when it causes urinary symptoms such as frequent urination, urinary leakage or sexual dysfunction. Adenoma is an enlargement of the prostate that will compress the urethra and cause symptoms. Half of the prostatitis screened will result in a medical treatment for Benign Prostatic Hypertrophy (BPH). On average, one in 10 men will require surgical treatment of their BPH. Disease’s incidence increases with age: BPH occurs in more than 80% of men over 80 years. But changes caused by the phenomenon will not be a problem for all men. In absence of complications (retention, infection, renal failure …), medical treatment is the first approach. In second intention, a surgery will restore a correct urination.

Prostate cancer

The human body is made up of cells that divide and reproduce throughout life. Sometimes the newly created cells are defective and will as well multiply, creating more and more abnormal and malignant cells, so called cancer. Majority of prostate cancers are adenocarcinomas; they develop from the prostate coating cells.

Prostate cancer is the most common cancer in men with more than 1 million new cases diagnosed each year worldwide  (according to the World Cancer Report 2014*: 1 111 689 cases identified in 2012). However, since prostate cancer is a slowly progressive disease affecting older men, mortality from the disease is moderate (6.6%, or 307,471 deaths in 2012 according to the same report *).

*: ©International Agency for Research on Cancer, 2014 – World Cancer Report

The risk for developing prostate cancer increases with age: after 45 years in case of family history and from 50 years for anyone else. It’s around 70 years old that the number of cases is the highest. All prostate cancers don’t have the same degree of severity: 80% are discovered at an early, localized stage. The disease progression is usually slow. Prostate cancer is generally not associated with any specific symptom: it can be detected during a recommended screening or during a prostate adenoma follow-up.

Prostate cancer screening includes several examinations such as PSA blood test, digital rectal examination, prostate biospies. The diagnosis must be refined by performing a series of imaging examinations for the staging assessment. The purpose of the staging assessment is to accurately determine whether the cancer is localized (i.e. wholly contained within the prostate gland) or has spread. Once the cancer diagnosed, the urologist will discuss the treatment strategy with the patient.

Prostate cancer risk factors

  • Age
  • Hereditary factors
  • Ethnic origin
  • Fatty diet
  • Other factors: sedentary lifestyle, obesity, etc.