Prostate cancer is the presence of cancer cells in the prostate gland. Most often, this disease develops slowly and remains localized to the prostate. But, in some cases, it can progress to neighboring organs and lead to the formation of metastases, especially in the bladder, rectum or bones.
The prostate is a gland in the male reproductive system. It is located just below the bladder and, like a ring, it surrounds the urethra, the channel through which urine and semen exit the body. The role of the prostate is to produce prostatic fluid, one of the components of semen along with seminal fluid and sperm, to temporarily store semen before ejaculation, and then to contract during ejaculation, thus participating in the process of ejaculation/expulsion of semen.
Prostate cancer is the most common type of cancer in men: an estimated 1 in 9 men will be diagnosed with it, most often in their 60s. Although no specific cause has been discovered, there is a genetic predisposition.
Most prostate cancers grow very slowly. In fact, the vast majority of men who are found to have this cancer will die of some other cause. Often the tumor remains localized in the prostate and has limited health effects, sometimes causing urinary or erectile dysfunction. However, some cancers can grow and spread more quickly.
In the United States, prostate cancer is the most frequent male cancer (about 174,650 new cases in 2019). Prostate cancer is the second leading cause of male cancer death in North America, after lung cancer. The median age of diagnosis is 66, and 60% of prostate cancers are diagnosed after the age of 65, according to the American Cancer Society. About 1 in 41 prostate cancer cases result in the death of the patient. Most people do not die of the disease: the 5-year relative survival has improved dramatically, from 70% for cases diagnosed in 1990 to 90% in 2020.
Types of prostate cancer
According to the World Health Organization (WHO) classification, benign tumors and cancer precursors are to be distinguished from the malignant tumors of the prostate. The first two groups include:
- AAH (atypical adenomatous hyperplasia): Suspicious tissue
- ASAP (atypical small acinar proliferation): cancerous tissue
- LG-PIN (low grade PIN = low grade prostatic intraepithelial neoplasia): Harmless change
- HG-PIN (high grade PIN = high-grade prostatic intraepithelial neoplasia): Possible cancer precursor
The malignant tumors are further classified according to their origin in:
- Epithelial tumors (most common): They start from epithelial cells (surface cells, including glandular cells) and are therefore referred to as prostate cancer
- Sarcomas (very rare): they arise from cells of the intermediate tissue of the prostate (e.g. muscle cells, connective tissue).
- Secondary tumors (very rare): They grow from the neighborhood into the prostate or are metastases (daughter tumors) of malignant tumors elsewhere in the body.
95% of all prostate cancers are mainly caused by glandular cells and are therefore called adenocarcinomas. The rare remaining prostate cancers can also be derived from other epithelial cells.
Diagnosis and screening
Measurement of the prostate antigen level
Prostate cancer can be detected by seeing an increase in a protein in the blood: prostate specific antigen or PSA. PSA is a substance produced by the prostate. However, a high result on this test does not necessarily mean that there is cancer. Indeed, an amount of more than 4 nanograms/ml of this protein in the blood is associated with prostate cancer in about 25% of cases, and with another prostate disorder in 75% of cases. In the event that it is not cancer, an elevated PSA may correspond to benign prostatic hypertrophy, inflammation or infection of the prostate.
On the other hand, the PSA test does not detect all cases of cancer. In a study evaluating the effectiveness of the PSA test, 15% of men who tested negative (from a cohort of 2,950 men aged 62 to 91) had prostate cancer. The PSA test is also used to monitor the progress of prostate cancer.
The biopsy is not without side effects. The most common are blood in the urine, stool or semen for a very short time. Fever, and infection of the prostate can also occur.
If the prostate is abnormal on digital rectal examination and its palpation suggests cancer, the biopsy is performed, even if the PSA are normal.
If the prostate is normal on palpation and the PSA is greater than 4 ng/ml, the biopsy will be performed if the PSA increases over time.
The purpose of a rectal touch is the palpation of the prostate gland. To do this, the doctor inserts a finger (gloved) into the rectum of the patient and can thus estimate the size and consistency of the prostate. This gesture allows only a partial appreciation. But it can sometimes detect cancers in people who have a normal level of prostate specific antigen.
For this examination, an ultrasound probe is inserted into the rectum. It provides images of the prostate and its surroundings. It is painless and is used to diagnose prostate disease in tandem with prostate biopsy.
Biopsy during transrectal ultrasound
During an ultrasound, the doctor may guide a needle to take prostate biopsies, that is, to remove some prostate tissue for examination under a microscope. This allows the Gleason score to be calculated. Only a biopsy can diagnose prostate cancer with certainty. The biopsy is usually done using a needle inserted into the prostate. 10 to 12 tissue samples are taken in the same session, in different areas of the prostate
This technique is used for diagnostic purposes, not screening. This means that it is performed when a man has high PSA or when a digital rectal examination finds an abnormal prostate.
Symptoms of prostate cancer
At first, prostate cancer does not cause any symptoms. Furthermore, the symptoms mentioned below may be related to another prostate disease, such as benign prostatic hypertrophy.
- Difficulty urinating: difficulty starting to urinate or holding urine, inability to urinate, need to urinate frequently (especially at night), poor urine output, a burning sensation or pain when passing urine.
- Blood in urine or semen.
- Frequent pain or stiffness in the lower back, hips or upper thighs.
- Changes in urinary function: frequent urge, urge to urinate, urge to push, urine retention, burning while urinating.
- Genital changes: painful ejaculations, or difficulty getting an erection.
Note that some “at risk” men will never get prostate cancer. Several risk factors are being investigated.
- Age. In North America, prostate cancer mainly affects men over the age of 60. The average age at diagnosis is 65 years, and 80 years at the time of death. Only 0.5% of prostate cancers appear before age 50, and 22% between 55 and 64.
- Family history. The risks are higher when the father or a brother has already suffered from this disease, which suggests a genetic predisposition. This hypothesis is reinforced by the discovery that carriers of the BRCA1 and BRCA2 genes have an increased risk of prostate cancer.
- Ethnicity. Men of African descent are more at risk than Caucasians, who are more at risk than Asians. It is estimated that Indians and Chinese are approximately 50 times less affected by prostate cancer than Westerners. However, when they migrate to countries where the disease is more common, their risk also increases. This suggests that factors not only related to genes but also to diet are having an influence.
- Obesity: A seriously overweight man has a higher risk of getting advanced prostate cancer.
- Inflammation or infection of the prostate increases the risk of prostate cancer when it lasts for a long time.
- Tall men have a higher risk of prostate cancer.
- Men who have been exposed to pesticides have a slightly higher risk of prostate cancer, especially if they have a history of prostate cancer in their family.
- Men who have been exposed to cadmium or rubber derivatives in the workplace
Food rich in fat (processed meats and red meats)
It has been known for several years that a diet containing a large amount of foods high in fat (lipids) is associated with an increased risk of prostate cancer. However, the type of fat that we should monitor for is less clear.
The animal fats contained in red meat were first pointed out in epidemiological studies. However, the most recent study (2009) found that heavy eaters of processed meats (cold meats, bacon, sausages) are at the highest risk for prostate cancer. Large consumers of red meats would also be, but to a lesser extent. More studies are underway.
There is no certainty about the influence of smoking on the incidence of prostate cancer. However, a recent study shows that smokers with prostate cancer have a higher death rate.
Prevention of prostate cancer
Reduce your fat intake
Eating too much of foods high in fat, such as meats or dairy products, has been shown to increase the risk of prostate cancer. Cold (bacon, ham, sausages) and red meats are particularly pointed out. Limit your intake of such foods or opt for those that are reduced in fat.
Eat a lot fruits and vegetables
Eating lots of fruits, vegetables, legumes, nuts, foods high in whole grains, and fish can be beneficial strategies for preventing many diseases. In addition, a healthy and balanced diet will allow you to maintain a healthy weight. Overweight and obesity are also believed to be risk factors for prostate cancer.
Eat more tomatoes
Some scientific studies suggest that increased consumption of foods rich in “lycopene”, an antioxidant nutrient, may help prevent the development of prostate cancer. Tomatoes are an example of a food that contains them in abundance.
As you probably know, smoking increases the risk of developing several types of cancer, including prostate cancer. In addition to reducing your risk at this particular cancer, quitting smoking permanently can have many other benefits for your health, well-being, and quality of life.
Visit your doctor regularly
The best way to limit the impact that prostate cancer could have on your life is to find it early. Visit your doctor and discuss your prostate cancer risk and screening measures. Screening for prostate cancer can be done with two additional tests. First, the doctor can do a digital rectal exam. On the other hand, a blood test can detect an elevation of PSAs, that is to say the prostate specific antigen. These two tests are not performed in all men, but are recommended in some, namely men aged 50 or older who have a life expectancy of at least 10 years.
Take vitamin D supplements
Based on the results of various studies, various health agencies are recommending men at risk to take a vitamin D supplement of 25 µg (1000 IU) per day in the fall and winter. Such vitamin D intake would reduce the risk of prostate cancer and other cancers. These studies suggest that people at higher risk of vitamin D deficiency — this includes the elderly, people with dark skin pigmentation and people who rarely get in the sun — to do the same during the whole year.
Treatment of prostate cancer
Several treatment options are available, depending on the stage and how quickly the prostate cancer is progressing. They should be discussed with your doctor who will inform the patient of the risks and benefits inherent in each treatment.
Watchful waiting (more or less active, depending on the case) may be chosen as a treatment option when the tumor is well circumscribed (cancer cells are confined to the prostate). Medication is not given and surgery is not performed, but the tumor is closely monitored.
In fact, if the tumor grows very slowly, and the affected person is old, the tumor will not have time to grow before other health problems arise. Indeed, as more invasive treatments often cause complications (pain, inability to have an erection, urinary incontinence, infection), it is sometimes preferable to observe without intervening.
This involves removing all the cancer cells by operating on the prostate (total prostatectomy or radical prostatectomy) and certain adjacent tissues (seminal vesicles). This surgery causes fewer and fewer problems, such as urinary incontinence and erectile dysfunction, as surgical techniques have advanced. Erectile dysfunction occurs in about 1 in 5 men in their 50s who have a prostatectomy. Erectile and urinary functions usually return to normal within 2 to 3 years after the operation.
Radiotherapy consists of destroying cancer cells using external electromagnetic radiation (emitted by a radiotherapy machine), trying to spare peripheral healthy tissue. Radiotherapy is an alternative to surgery.
Brachytherapy using rays emitted by radioactive seeds inserted and left in the prostate allows the rays to have a very localized and targeted area of action.
This long-term approach aims to deliver drugs that will work to deprive cancer cells of the male hormones they need to grow. It makes it possible to reduce the size of the tumor and to consider radiotherapy treatment. It is also indicated to slow the progression of prostate cancer.
Chemotherapy is reserved for cancers that no longer respond to hormone therapy. It consists of administering, by injection or in the form of tablets, toxic chemical agents to kill the cancer cells. There are several types of chemotherapy, which have different mechanisms of action and different side effects.
The prostate is a gland the size of a walnut. It is located under the bladder and surrounds the urinary canal; it is essential in humans for the production of sperm, and therefore for reproduction. Prostate cancer is the most common type of cancer in men in the United States.
However, in general, it progresses slowly and can often be cured or treated successfully. The sooner this type of cancer is detected, the better the response to treatment and the better the chances of recovery.