Prostate, an accessory gland of the male reproductive system
The prostate is a small, chestnut-sized gland localized in the pelvis of men: in front of the rectum, and underneath the bladder. The urethra goes from the bladder through the prostate, and on the way, two ejaculatory ducts open into it. During ejaculation, sperm goes through these ducts into the urethra, and the prostate adds its product, the prostatic fluid to it, to create semen. This fluid makes around a third of ejaculate volume, and its purpose is to nourish and provide a longer lifetime for spermatozoa. The prostate has another role too: its muscle fibers help control the flow of urine and semen.
A common malignancy of men
Prostate cancer is the most commonly diagnosed malignant disease and one of the leading causes of death in men worldwide. It is notably more common in developed countries, where up to 1 in 6 men will be diagnosed with prostate cancer during their lifetime. Though only approximately 1 in 41 men diagnosed with prostate cancer die from it, it is estimated that in 2022 this disease will take around 34.500 lives in the US only. The number of new cases worldwide exceeds 1,4 million each year, about 250.000 of which are in the United States.
Prostate cancer and age
Age is strongly associated with a high risk of prostate cancer. The incidence rate of the disease increases sharply between the ages of 50 and 90 when it is the most prevalent. The autopsy studies of prostate carcinoma incidence note that microscopic prostate cancer can be found in around 60% of men in their 60s, and 80% of men in their 80s, while it is only fatal for around 3,8% of them, which justifies the saying that “more people die with prostate cancer than from it”.
The mean age at which the diagnosis is made is 67 years. Most of the men are diagnosed with prostate cancer between the ages of 65 and 75 (35%), around 31% are diagnosed between the ages of 55 and 65 and around 25% after the age of 75. While around 10% of diagnoses are made in men aged 45-55, prostate cancer is exceptionally rare in men younger than 45.
Since systematic screening for prostate cancer in individuals at risk became available around 30 years ago, prostate cancer is more often discovered at an early stage and in asymptomatic men. This, along with the typically indolent and slowly-progressive nature of the disease, accounts for a rather good prognosis, with 5-year survival rates near 100%, and 10-year survival rates around 98-99%.
Some other risk factors for prostate cancer
- Family history of prostate cancer
Around 20% of those diagnosed with prostate cancer have a family history of the disease. Genes are probably not the only culprit for this relation, but also a shared lifestyle.
- African-American ethnicity
African-Americans have a higher incidence of prostate cancer than other racial groups in the USA, which is attributed to socioeconomic and biological factors. African-Americans are also more prone to having an aggressive form of the disease.
The role of diet in the development of prostate cancer is shown in the studies of migrants that move from less developed to highly developed countries and change their diet to a typical western one. High calorie intake and excessive consumption of red meat, dairy products, and highly processed food full of saturated fats, are proven to be significant risk factors for the development of prostate cancer. Lack of certain vitamins, such as vitamins D and E, is considered a risk factor too. On the contrary, viands such as soy and green tea are associated with a decreased risk of prostate cancer.
Heavy alcohol consumption, smoking, obesity, and physical inactivity have all been connected to a higher risk of prostate cancer. Coffee consumption, on the other hand, seems to be a protective factor.
- Infections and inflammation of the prostate
Symptoms of prostate carcinoma
The screening for prostate carcinoma is very simple and widely available: it involves determining the levels of a marker called PSA (Prostate Specific Antigen) in blood. The cutoff values of PSA vary with age; high levels indicate a possible prostate neoplasm and require further investigation. With the help of screening, prostate cancer can sometimes be discovered before it gives any symptoms.
Early symptoms of prostate cancer are lower urinary tract symptoms, which are generally common in older men, often due to a harmless condition called benign prostatic hyperplasia (BPH). These symptoms include:
- Urination difficulties: straining to urinate, poor and/or intermittent stream, dripping at the end of urination
- Frequent urination and urination during the night, often accompanied by an urgent need to urinate and/or incontinence
- Feeling of incomplete emptying after urination.
Early prostate cancer may also be presented with:
- Blood in urine
- Erectile dysfunction.
Symptoms of advanced disease are symptoms of the disease spreading to other tissues and organs:
- Tingling, leg weakness or paralysis, pain, urinary or fecal incontinence, due to a compression of the spinal cord
- Severe bone pain, due to metastases, particularly common in the vertebrae, hips, pelvis, and ribs
- Leg swelling, due to cancer spreading to pelvic lymph nodes
- Fatigue and/or loss of weight.
Apart from determining blood levels of PSA, to diagnose a patient with prostate carcinoma, a doctor will perform a digital rectal examination of the prostate and/or trans-rectal ultrasound and take a small tissue sample (biopsy) for pathohistological confirmation. Additional diagnostic modalities including MRI, CT or PET scan, chest X-ray, or abdominal ultrasound will be performed to determine the spread of the disease and the clinical stage.
Stage, treatment, and prognosis
The treatment strategy depends mainly on the clinical stage of the disease, along with factors such as the age and general state of the patient, the aggressiveness of the disease, and the pathologic grade of carcinoma. Roughly speaking, early prostate carcinomas are the ones still limited to the prostate, while the advanced disease is characterized by the involvement of surrounding or distant organs and tissues.
High-risk early prostate carcinomas are treated surgically, by removing the entire prostate and surrounding lymph nodes (a procedure called a radical prostatectomy). Intermediate-risk early carcinomas are treated with radiotherapy, while low- and very low-risk prostate carcinomas are followed up and only treated if they start to progress. The goal of early-carcinoma treatment is to cure, and the prognoses are, as mentioned, very good, with a happy ending in 99-100% of the cases.
Advanced prostate cancer is, unfortunately, considered incurable. The goal of the treatment in patients with metastases and/or locally aggressive carcinoma is to keep the disease under control. The surgical treatment, in this case, is rarely an option, and the treatment consists of a combination of chemotherapy, radiotherapy, and/or immunotherapy, as well as lowering levels of testosterone by orchiectomy (castration) or the use of specific pharmaceutics. The prognosis is poor: according to the American Cancer Society, the 5-year survival rates for distant-stage prostate cancer drop to only around 30%.
A good reason to check your PSA today, isn’t it?
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