The exact cause of prostate cancer is not clear, which may be related to genetic changes. For example, changes in androgen receptor-related genes increase the risk of prostate cancer; Men with BRCA 1 gene have three times the risk of prostate cancer as men without BRCA 1 gene. Abnormal P53 gene is closely related to high-grade and high-invasive prostate cancer. Genetic changes may also be related to environmental factors such as diet. The more genetic changes, the greater the risk of prostate cancer. In a few cases, prostate cancer may be hereditary.
At present, the risk factors related to prostate cancer are summarized as follows:
Absolute risk factors:
Age: Age is the main risk factor for prostate cancer. Prostate cancer is very rare in men under 45, but with the increase of age, the incidence of prostate cancer rises sharply, and most patients with prostate cancer are over 65 years old. After the age of 40, the incidence of prostate cancer almost doubles every 10 year. The risk of prostate cancer in men aged 50-59 is 10%, while the risk of prostate cancer in men aged 80-89 rises sharply to 70%.
Family history: When a male relative in the family suffers from prostate cancer, the incidence of male in the family increases obviously. Male lineal relatives generally refer to father and brother. If one of the immediate family members has prostate cancer, the probability of prostate cancer will be twice as high as that of the general population. If there are two, it will be three times higher. This shows that the occurrence of prostate cancer may be related to one or a group of genes in the body, but these genes have not been fully understood by scientists so far.
Race: African Americans have the highest incidence of prostate cancer, followed by Hispanics and whites, while African Americans have the lowest incidence of prostate cancer in the world. The incidence of prostate cancer in Asian men living in the United States is lower than that in whites, but significantly higher than that in Asian men. Although the incidence of yellow race prostate cancer has not reached the level of European and American countries, it is increasing year by year in Chinese mainland, Taiwan Province, Hong Kong, Japan, South Korea and Singapore.
Pathological changes of abnormal cells in prostate: The incidence of prostate cancer is obviously increased in men with high prostate intraepithelial neoplasia. High-grade intraepithelial neoplasia (HIN) is a precancerous lesion, which shows abnormal cell growth morphology under microscope. Although it is not cancer, it often indicates the existence of prostate cancer, but it has not been detected yet.
Relative risk factors:
Diet: Some studies show that men who regularly eat foods high in animal fat are also prone to prostate cancer because these foods contain more saturated fatty acids. From the research results of 32 countries, it is found that the mortality of prostate cancer is related to total fat intake. However, people whose diets are rich in vegetables and fruits are less likely to get sick.
Androgen level: high androgen level in the body is also one of the possible causes of prostate cancer. Androgen can promote the growth of prostate cancer.
The rising prevalence of prostate cancer in China is related to the aging population, the improvement of living standards, the change of diet structure and environmental pollution. The results show that smoking, drinking alcohol, drinking milk frequently, eating more eggs and pork are the main risk factors of prostate cancer in China. Eating green vegetables, fruits and beans is an important protective factor.
Can benign prostatic hyperplasia become prostate cancer?
Prostate hyperplasia and prostate cancer are two different diseases. Although both occur in the prostate, in general, prostatic hyperplasia itself will not turn into prostate cancer. If the prostate is compared to an egg, then the envelope of the prostate is the eggshell, the peripheral area of the prostate is the protein, and the transitional area of the prostate is the yolk in the center. Prostatic hyperplasia mainly occurs in the transitional zone of the central area of prostate, while prostate cancer mainly occurs in the peripheral area of prostate. The anatomical position of the two is very different. In addition, prostatic hyperplasia and prostate cancer are two completely different pathological processes.
So far, only androgen can promote the transformation from pathological prostate cancer to clinical prostate cancer, but there is no evidence that it can promote the transformation from benign prostatic hyperplasia to prostate cancer. However, benign prostatic hyperplasia and prostate cancer can coexist. Don't think that benign prostatic hyperplasia will not cause cancer, and a small amount of prostate cancer will occur in the transitional zone of prostate (about 10%), so prostate cancer can sometimes be found in specimens after prostatectomy. Therefore, if the elderly urinate abnormally, it must not be taken for granted that it must be prostatic hyperplasia. Remember to go to the urology department of a regular hospital to rule out prostate cancer.
What are the signs and symptoms of prostate cancer?
Because most prostate cancer originates from the peripheral zone of prostate, the incidence is hidden and the growth is slow, so early prostate cancer can have no early warning symptoms, only when the serum PSA value increases during screening and/or the rectal digital examination finds abnormal changes in prostate. Once symptoms appear, they often belong to the advanced stage of prostate cancer.
If the prostate tumor grows locally and compresses the prostate urethra, dysuria may occur, which is manifested as progressive dysuria (thin urine flow, biased urine flow, bifurcated urine flow or prolonged urine course), frequent urination, urgency, dysuria and dysuria. In severe cases, there will be urine drops and urinary retention. These symptoms are similar to benign prostatic hyperplasia (BPH), and are easy to be misdiagnosed and missed, thus delaying the early diagnosis and treatment of the disease.
For advanced prostate cancer, symptoms such as fatigue, weight loss and general pain may occur. Because pain seriously affects diet, sleep and spirit, after long-term torture, the whole body becomes weaker and weaker, emaciation and fatigue, progressive anemia, and finally cachexia appears in general failure.
When prostate cancer metastasizes to bone, it will cause bone pain at the metastatic site. Common bone metastasis sites include spine, hip, ribs and scapula. About 60% patients will have bone pain in the late stage, which is common in the waist, sacrum, buttocks and buttocks and pelvis. Bone pain has different manifestations. Some patients can show persistent pain, while others show intermittent pain. Bone pain can be confined to specific parts of the body, or it can be manifested as wandering pain in different parts of the body; Bone pain may change at different times of the day and react differently to rest and activities. If the bones are obviously brittle due to tumor invasion, pathological fractures are likely to occur. Some parts are common parts of arthritis, such as knee joint and shoulder joint. The pain in these parts is not necessarily caused by prostate cancer metastasis, and further examination is needed to determine whether there is prostate cancer metastasis.
1/2~2/3 patients had lymph node metastasis at the first diagnosis, mostly in the internal and external iliac region, retroperitoneum, groin, mediastinum and clavicle. If prostate cancer metastasizes to lymph nodes in adjacent areas, it is usually asymptomatic. In a few cases, when lymph nodes are widely transferred, lymph nodes are obviously enlarged, blood vessels are compressed, and lymphatic reflux of lower limbs is blocked, symptoms of swelling of lower limbs and scrotum will appear.
Advanced prostate cancer with spinal metastasis, if the spinal fracture or tumor invades the spinal cord, it can lead to nerve compression paralysis, and you need to go to the hospital for emergency treatment immediately.
If prostate cancer invades the bottom of the bladder or pelvic lymph nodes and spreads widely, unilateral or bilateral ureteral obstruction (the passage that drains urine from the kidney to the bladder) will occur. Symptoms and signs of ureteral obstruction include oliguria (anuria in bilateral ureteral obstruction), low back pain, nausea, vomiting and fever when complicated with infection.
Prostate cancer is usually not accompanied by hematuria and hemospermia; However, once hematuria and hemospermia appear, you should go to the urology clinic for relevant examination to rule out the possibility of prostate or seminal vesicle tumor.
Patients with extensive prostate cancer may suffer from tumor rupture and bleeding. In addition, patients with prostate cancer may be anaemic. The cause of anemia may be related to tumor bone metastasis, endocrine therapy or onset time. Generally speaking, the number of blood cells decreases slowly, so patients may not have any anemia symptoms. Some patients with severe anemia will have symptoms such as fatigue, postural hypotension, dizziness, shortness of breath and fatigue.
How can we find prostate cancer early?
Patients with early prostate cancer receive radical treatment in time, and the annual survival rate of 10 can reach over 95%. However, because the incidence of prostate cancer is relatively hidden, when obvious symptoms (hematuria, oppression, etc.) appear. ) appear. ) appears in the body, and the condition is often out of control. In China, more than 70% of patients are in advanced stage when they are first diagnosed.
Prostate cancer screening is the only effective method for early detection of prostate cancer. As early as 10 years ago, the United States began a general survey of prostate cancer. Early detection, early diagnosis and early treatment are the keys to tumor treatment. The earlier it is discovered, the better the treatment effect, and the greater the possibility of cure. At present, nearly 90% of prostate cancer patients in the United States belong to early prostate cancer, and the 5-year survival rate is over 90%. This is due to prostate cancer screening, which enables most patients to find and treat prostate cancer early. It is believed that with the continuous development and progress of China's economy and culture and the deepening of people's health awareness, prostate cancer screening will soon be carried out nationwide. Screening items mainly include: digital rectal examination and serum PSA (prostate specific antigen) examination, and further transrectal ultrasound examination of prostate when necessary. If any abnormality is found, a prostate biopsy is needed to make a definite pathological diagnosis.
Like other cancers, pathological biopsy is the gold standard for the diagnosis of prostate cancer. When prostate cancer is suspected, we can get the tissue by ultrasound-guided hollow needle puncture for pathological examination. Under the orientation of B-ultrasound, the fine needle is inserted into the prostate and the tissue is taken out, usually 12~ 16 tissue. Taking more materials can significantly improve the positive detection rate of prostate cancer. In Yongzhou Apollo Men's Hospital, experts from the multidisciplinary diagnosis and treatment team of genitourinary tumors will determine the types of tumors according to the samples obtained, stage them, and then formulate standardized treatment plans suitable for individual patients.
Who is more susceptible to prostate cancer and is the key target of screening?
At present, guidelines at home and abroad recommend early screening of high-risk men with serum prostate specific antigen (PSA) combined with digital rectal examination, and histopathological diagnosis and staging judgment of positive patients with clinical history. Because most patients with prostate cancer have elevated PSA levels before clinical symptoms appear.
Generally speaking, middle-aged and elderly men over 50 years old have a high incidence of prostate cancer, and with the increase of age, the incidence of prostate cancer gradually increases. Therefore, it is very meaningful to screen this group of people for prostate cancer. Men with a family history of prostate cancer should have regular physical examination and follow-up from the age of 40.
From 2065438 to May 2004, the Expert Knowledge of Basic Health Examination Project issued by Health Management Branch of Chinese Medical Association considered that the high-risk group of prostate cancer was men over 45 years old, with family history of prostate cancer, chronic inflammation, repeated urgency and hematuria. Their examination contents should include prostate tumor marker PSA/fPSA, prostate palpation, prostate ultrasound and family history of prostate cancer and chronic inflammation. Rational use of serum markers PSA and fPSA to screen prostate cancer is helpful for early detection, early diagnosis and early treatment of prostate cancer, thus significantly reducing the mortality rate of patients, prolonging their lives and improving their quality of life.
It is suggested that PSA and fPSA should be added to the routine blood examination of high-risk population over 45 years old, so as to realize early intervention and early diagnosis and treatment through screening.
Teach you to read PSA-related indicators on the laboratory sheet.
After getting the test sheet, most people often only care about the total PSA value, but there are some PSA-related indicators besides the total PSA value on the test sheet. Do you know what they mean?
The determination of serum total PSA is the most classic and basic PSA detection. However, with the extensive development of PSA testing, people gradually found that there are still some false positives and false negatives in screening patients with prostate cancer only by serum total PSA. In order to improve the accuracy of PSA detection, many concepts of PSA-related indicators have been put forward, including:
Free PSA: The total serum PSA consists of several subtypes of PSA, and there are mainly two subtypes: free PSA and bound PSA. Free PSA refers to PSA in blood that does not bind to plasma protein. Prostate cancer is negatively correlated with free PSA and positively correlated with bound PSA. Benign prostatic hyperplasia is positively correlated with free PSA. When the total serum PSA is between 4 ng/ml- 10 ng/ml, if the ratio of free PSA to total serum PSA is greater than 0.25, the possibility of prostate cancer is small, while if the ratio is less than 0. 15, prostate cancer should be suspected and further examination is needed.
PSA density: PSA density refers to the ratio of serum PSA value to prostate volume, which is calculated by formula after measuring the length, width and height of prostate by rectal ultrasound. PSA density is helpful to distinguish benign prostatic hyperplasia from prostate cancer. When the total serum PSA is between 4 ng/ml- 10 ng/ml, if the PSA density is less than 0. 15, the possibility of prostate cancer is small. However, if the PSA density is greater than 0.25, we should be alert to the possibility of prostate cancer and do further prostate biopsy.
PSA rate: PSA rate refers to the annual increase of serum PSA, mainly for patients with low serum PSA value (less than 4ng/ml). If the rising rate of PSA exceeds 0.75ng/ml per year, the possibility of prostate cancer will be suspected and further prostate biopsy is needed.