A normal prostate is about the size of a walnut. It is a small, squishy gland located under the bladder (see figure 1). The urethra runs straight through the prostate. Just above the prostate, the seminal vesicles can be found. These two little glands secrete about 60% of the substances that make up the semen.
Figure 1: Location of the prostate gland.
While the prostate is not essential for survival, it is quite important for reproduction. It supplies several substances that facilitate fertilization, sperm transit and sperm survival.
The prostate is divided into several anatomic regions. Most prostate cancers develop in the peripheral zone (see figure 2), near the rectum, which is why the digital rectal exam is a useful screening test.
Figure 2: The difference between a normal prostate and a prostate with cancer.
After prostate cancer has been diagnosed, tests are performed to find out in which stage the cancer is. During this staging process, it will be researched if the cancer has spread to other parts of the body or has remained inside the prostate. There are two main staging systems that are used to identify the stages of prostate cancer. The numeral system has four stages, which take in account the size of the tumor, the location and the distribution of cancer cells:
- Stage I: The tumor is very small and located completely inside the prostate gland, which feels normal during an examination.
- Stage II: The tumor is still inside the prostate, but it is larger and can be felt as a lump or hard area during examination.
- Stage III: The cancer has spread through the covering of the prostate and may have grown into the tubes which carry semen.
- Stage IV: The cancer has spread to the bladder, rectum, lymph nodes or other parts of the body, such as the bones, lungs or liver.
Another staging system is called the TNM system, which separately assesses the tumor (T), lymph nodes (N) and secondary cancer or metastases (M).
The tumor staging:
- T1: Tumor is too small to be noticed during an examination.
- T2: Tumor is completely inside the prostate gland. This stage is divided into three sub stages (2a, b and c, depending on the size of the tumor).
- T3: Tumor has broken through the prostate gland.
- T4: Tumor has spread into other body organs.
The lymph node staging:
- N0: No cancer cells found in any lymph nodes.
- N1: Cancer in one lymph node smaller than 2cm.
- N2: Cancer in more than one lymph node, or in one node 2 – 5cm.
- N3: Cancer in any lymph node larger than 5cm.
The metastases staging:
- M0: No cancer outside the pelvic area.
- M1: Cancer outside the pelvic area.
The rate of survival (overall survival is 81%) depends on two main factors: stage and age.
- Stage: If the prostate cancer is organ confined (stage I and II, or T1 and 2, N0 and M0), the survival rate is very high at 98.6%. However, if the cancer is metastasized (Stage III and IV, or T3 and 4, N1 – 3 and M1), the survival rate drops to 32.6%.
- Age: Men in their sixties have the highest probability of survival. They have a higher survival than younger men because they are examined more often, and a higher survival than older men because they are in relatively better health.
Since the difference in survival rate is very dependent on the stages of prostate cancer, it is certainly recommended to get your prostate checked regularly from a certain age (most doctors would say around 50).
- Figure 1: https://www.topnews.in/health/diseases/prostate-cancer
- Figure 2: https://www.healthhype.com/tag/prostate-cancer
- Cancer Research UK: https://www.cancerhelp.org.uk/type/prostate-cancer/treatment/the-stages-of-prostate-cancer
- National Cancer Institute: https://www.cancer.gov/cancertopics/pdq/treatment/prostate/Patient/page2
- Prostate Cancer Foundation: https://www.pcf.org/site/c.leJRIROrEpH/b.5699537/k.BEF4/Home.htm
- South West Public Health Observatory: https://www.swpho.nhs.uk/resource/item.aspx?RID=41287