Understanding and preventing prostate cancer
Find in this health file all the information you need to better understand and apprehend prostate cancer.
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I) Prostate cancer: definition and key figures
A) Key figures and facts
- Each year, 1.3 million prostate cancer cases are diagnosed worldwide [1].
- Worldwide, 10 million men have already been diagnosed and are living with the disease [1].
- In 2020, there will be 77,300 cases of prostate cancer in men in sub-Saharan Africa [2].
- In 40 sub-Saharan African countries, prostate cancer is the leading incident cancer in men [2].
B) Understanding the anatomy of the prostate
Image from : https://www.healthdirect.gov.au/male-reproductive-system
The male reproductive system is composed of various elements [4]:
- The penis, which is the external reproductive organ [4].
- The testicles, which are a pair of external reproductive organs, and are located under the penis [4]. The testicles produce sperm and secrete testosterone (male sex hormone)
- The urethra, which carries urine from the bladder and allows the ejaculation of sperm
- The seminal vesicles, which are two pouches connected to the prostate and located between the bladder and the rectal ampulla [4]. The seminal vesicles and prostate produce the fluid that nourishes sperm and accounts for most semen volume.
- The prostate is a gland in the male reproductive system. In young men, it is the size and shape of a chestnut and increases in size with age [3]. It is located below the bladder, in front of the rectum and surrounds the beginning of the urethra [3]. The prostate is surrounded by a capsule that separates it from the rest of the pelvic organs [3]. The prostate plays an important role in the male reproductive system as it produces the prostatic fluid that allows for the survival, maturation and mobility of spermatozoa as well as ejaculation.
C) The main forms of prostate cancer and the course of the disease
Prostate cancer refers to the occurrence of cancerous cells that grow from the cells of the prostate and multiply uncontrollably in the prostate [5]. In 90% of cases, prostate cancer is an adenocarcinoma and develops from the epithelial cells that make up the lining tissue of the prostate [4] These cells are sensitive to sex hormones (testosterone) and the resulting cancers are also sensitive to sex hormones. Therefore, drugs that block the action of testosterone are used to treat these hormone-sensitive cancers.
However, there are other, rarer forms of prostate cancer: carcinomas and sarcomas [4,5].
Prostate cancer has two stages of progression:
- In the first stage, the cancer cells are only present in the prostate. In this case, it is called localized or “intracapsular” cancer [4]. Prostate cancer usually progresses slowly (10 to 15 years) and remains localized for a long time [4].
- However, this cancer can evolve and become “extracapsular“. In this case, it will cross the capsule of the prostate. The cancer cells will then detach and pass into the blood or lymphatic vessels [4]. 4] The cancer cells will then invade the lymph nodes surrounding the prostate and other organs, mainly the bones, liver and lungs, and metastasize.
II) Risk factors
Although it is difficult to specifically identify the causes of cancers, their occurrence may be promoted by non-modifiable or behavioral risk factors.
A) Non modifiable risk factors
Prostate cancer can be the result of various non-modifiable factors:
– Age: This is the main risk factor for prostate cancers [4]. Men over 70 years of age are at risk and this risk increases with age [4,5]. Before the age of 40, prostate cancer is considered exceptional [5].
– Family history: Family history plays a role in the development of prostate cancer. It is estimated that 20% of prostate cancers are related to a familial form, i.e., at least two cases of prostate cancer have occurred in first-degree relatives (father, brother) or second-degree relatives (grandfather, uncle) [4] of the affected patient. On the other hand, 5% of prostate cancers are linked to a hereditary form [4]. This form is defined by the existence of at least 3 cases of prostate cancer in first- or second-degree relatives or in 2 family members diagnosed before the age of 55.
– Ethnicity: Men of African (Afro-Caribbean) descent are more likely to develop prostate cancer than Caucasian or Asian men [4].
B) Behavioral or lifestyle factors
Certain lifestyle habits could contribute to the occurrence of prostate cancer even if the link has not been fully established:
- Overweight and obesity [4].
- High consumption of dairy products or cold meats [5].
- Smoking [5].
III) Symptoms of prostate cancer
In general, prostate cancer is manifested by an increase in the volume of the prostate gland, but this increase can also be due to other pathologies such as benign prostatic hypertrophy [7].
Thus, in addition to an increase in the volume of the prostate, the appearance of several symptoms should alert the patient:
- Urinary disorders, particularly with the appearance of a frequent need to urinate, a low flow rate or difficulties in producing a constant stream [6]
- The feeling of not having completely emptied the bladder [7]
- Urinary leakage [7]
- Urinary tract infections (cystitis or prostatitis) [7]
- Blood in the urine or semen [6]
- Painful ejaculations with erectile dysfunction [6]
- Presence of pain in the pelvis, hips or upper thighs [6]
It is imperative that you see your doctor promptly if you experience any of these symptoms.
IV) Diagnosis and treatment of prostate cancer
A) Diagnosis
The diagnosis of prostate cancer is made in several steps.
First, the physician interviews the patient to determine his personal and family history and the existence of symptoms that may indicate the presence of prostate abnormalities [7]. The physician then performs a clinical examination by performing a digital rectal exam (DRE), which involves palpating the prostate by inserting the index finger into the rectum to check the volume, surface area and consistency of the prostate [7].
If the clinical examination reveals abnormalities, the physician may ask the patient to perform the following tests:
- Measurement of the blood level of PSA (Prostate Specific Antigen), which is a substance produced by the prostate gland and whose level may be indicative of cancer [8].
- Transrectal ultrasound: a probe is inserted into the patient’s rectum to allow the doctor to see all parts of the prostate [8].
- Prostate biopsy: This is used to determine if a cell is cancerous or not [7]. It consists of taking a minimum of 12 samples from different parts of the prostate wall under ultrasound guidance, under local anesthesia and transrectal access [7]. This examination allows to confirm the diagnosis of cancer and to give its characteristics.
B) Treatment
Based on the information gathered at diagnosis, the patient should be given a suitable treatment, considering the characteristics of his cancer, his age and the stage of the disease [9]. The treatment of prostate cancer requires multidisciplinary skills and involves at least 3 specialists: a urological surgeon, an oncologist and a radiotherapist [9].
The different treatments for prostate cancer are:
- Initial active surveillance
Active surveillance is proposed in cases where the patient’s cancer is localized and has a low risk of progression. In this case, the patient is not given immediate treatment but is actively monitored for cancer progression through various tests performed on a regular basis.
When the doctors see that the cancer is progressing, treatment is quickly started [9].
- Surgical treatment
Surgical treatment involves a total or radical prostatectomy to remove the prostate and seminal vesicles [9]. In some cases, the surgeon may perform a lymph node dissection to remove nearby lymph nodes [9].
Complications from this procedure are rare. However, prostatectomy does have frequent and prolonged side effects such as urinary and sexual problems [9].
- External radiation therapy
External beam radiation therapy is often used to destroy cancer cells using X-rays [9]. Radiation therapy should be performed on a regular schedule, on average one session per day, four to five days per week, for six to eight weeks [10]. There are some side effects, such as urinary, sexual and digestive problems [9].
- Brachytherapy
Brachytherapy is a form of radiation therapy that involves placing radioactive implants in the patient’s prostate near the tumor [9]. These implants destroy the cancer cells by emitting radiation. Brachytherapy is performed under local anesthesia and is recommended for the treatment of localized cancers with a low risk of progression. The radioactivity remains contained within the prostate and does not spread to the rest of the body. [10].
- Drug treatment
There are two types of drug treatment for prostate cancer:
- Hormone therapy: this treatment blocks male hormones, particularly testosterone, which promotes the development of cancer cells [9].
- Chemotherapy: This is usually given through intravenous infusions and involves the destruction of cancer cells through the administration of chemicals [9]. Chemotherapy is recommended when the cancer has progressed to a more advanced stage and has metastasized [9]. It may be combined with hormone therapy in some cases.