Prostate cancer is a common malignant tumor in men. 679,000 new cases were reported worldwide in 2002, accounting for 11.7% of all new malignant tumors, ranking 5th among common malignant tumors and 2nd among malignant tumors in adult men. In the United States, the incidence of prostate cancer has surpassed that of lung cancer, becoming the first tumor that endangers men’s health. Although the incidence rate of prostate cancer in China is lower than that of European and American countries, the incidence rate has been gradually increasing in recent years with the change in lifestyle, living environment and longer life expectancy. In Shanghai, the incidence of prostate cancer in 2007 has jumped from the 3rd place to the first place among malignant tumors of the genitourinary system, and has rapidly risen from the 9th place to the 5th place among the top 10 male tumors. It is predicted that in 10 years, the incidence of prostate cancer in Shanghai will rise to the top three among malignant tumors in men.
Early prostate cancer is usually asymptomatic and difficult to diagnose. Rectal finger examination, serum prostate-specific antigen (PSA) test, prostate magnetic resonance imaging (MRI) and transrectal prostate puncture biopsy pathology are the basic methods to diagnose prostate cancer, the first two are common means of prostate cancer screening, especially the clinical application of serum PSA test provides great help for early diagnosis of prostate cancer. The vast majority of prostate cancers are detected by PSA abnormalities, accounting for 80%, while only 20% are found to have nodal abnormalities on rectal finger examination. The frequency of prostate cancer screening should ideally be once a year. If progressive elevation of PSA level and/or abnormal rectal examination is found during annual screening, further examination is needed. With prostate cancer screening, the incidence of prostate cancer-related complications and prostate cancer-related mortality can be reduced, which can effectively improve survival rates. Usually men should start prostate cancer screening at age 50; or at age 40 if there is a family history of prostate cancer.
Causes
The exact cause of prostate cancer is still unknown and may be related to genetic alterations. The risk factors associated with the occurrence of prostate cancer have been summarized as follows
1. Absolute risk factors.
(1) Age: Patients with prostate cancer are mainly older men, with a median age of 72 years for newly diagnosed patients and a peak age of 75-79 years. In the United States, greater than 70% of prostate cancer patients are over 65 years of age.
(2) Family history: If an immediate family member (brother or father) has prostate cancer, his or her risk of developing prostate cancer increases by a factor of 1. The relative risk increases by a factor of 5 to 11 when two or more immediate family members have prostate cancer. Epidemiological studies have found that patients with a positive family history of prostate cancer are diagnosed approximately 6 to 7 years earlier than those without a family history.
(3) Ethnicity: Although the incidence of prostate cancer among the yellow race has not yet reached the level of European and American countries, the incidence of prostate cancer are showing a trend of increasing year by year.
(2) Relative risk factors: The identification of these factors is still under discussion, but a diet high in animal fat is an important risk factor. Other risk factors include low intake of vitamin E, selenium, lignans, and isoflavones. Sunlight exposure is negatively associated with prostate cancer incidence, and sunlight increases vitamin D levels, which may be a protective factor for prostate cancer. Green tea consumption is relatively high in Asian regions with low incidence of prostate cancer, and green tea may be a protective factor for prostate cancer.
Clinical manifestations
Early prostate cancer is usually asymptomatic, but when the tumor invades or obstructs the urethra or bladder neck, symptoms similar to lower urinary tract obstruction or irritation may occur, and in severe cases, acute urinary retention, hematuria, and urinary incontinence may occur. Bone metastasis can cause bone pain, pathological fracture, anemia, spinal cord compression leading to lower limb paralysis, etc.
Ancillary tests
Rectal examination Most prostate cancers originate from the peripheral zone of the prostate, so rectal examination is of great value for early diagnosis and staging of prostate cancer.
2.Prostate specific antigen (PSA) test PSA, as a single test, has a higher prediction rate of positive prostate cancer diagnosis compared with rectal examination, and can also improve the diagnosis rate of limited prostate cancer and increase the chance of radical prostate cancer treatment.
3.Transrectal ultrasonography Under the guidance of transrectal ultrasonography, suspicious lesions can be found in the prostate and surrounding tissues, and the volume and size of the tumor can be initially determined.
4.Prostate puncture biopsy Systematic puncture biopsy of the prostate is the most reliable test to diagnose prostate cancer.
Pathological examination of prostate puncture biopsy tissue is the gold standard for prostate cancer diagnosis. Other tests are: ECT bone scan, chest X-ray, abdominal ultrasound, pelvic MRI, etc. The purpose of these examinations is to make a comprehensive assessment of the disease and determine whether the disease is early or advanced, and whether the tumor is confined to the prostate or has metastasized to distant organs or lymph nodes. For example, chest X-ray can observe whether there are lung metastases; abdominal ultrasound can observe whether there are metastases in the liver, spleen, kidneys and other important organs; ECT bone scan is more important to identify whether there are bone metastases; pelvic MRI can determine whether there are enlarged pelvic lymph nodes; and MRI can further observe whether there is local outward invasion of the prostate to the seminal vesicle gland, rectum and bladder neck. The results of these tests can play a decisive role in the choice of treatment plan for the patient.
Differential diagnosis
1. Prostatic hyperplasia: Prostate cancer should be differentiated from prostate hyperplasia. Prostatic hyperplasia occurs mainly in the migratory zone in the central region of the prostate, whereas prostate cancer occurs mainly in the peripheral zone of the prostate, and there is a great difference between the two in terms of anatomical location. However, prostate enlargement and prostate cancer can co-exist, so don’t think that if you have benign prostate enlargement, you won’t get cancer, there is a small percentage of prostate cancer (about 10%) that occurs in the migratory zone of the prostate, so sometimes prostate cancer can be found in specimens after prostate enlargement surgery. The actual fact is that you can find a lot of people who are not able to get a good deal on this kind of things.
2. Prostatitis: Generally speaking, prostatitis belongs to the category of inflammation and is not directly related to prostate cancer. The most common cause of prostatitis is in young and middle-aged men, while prostate cancer is mostly seen in older men. Prostatitis can be accompanied by fever and painful burning urination during acute attacks, and can also cause a temporary increase in serum PSA, but these inflammatory symptoms usually subside quickly after anti-inflammatory treatment, and PSA can drop rapidly to normal levels within a short period of time. Many of the triggers that lead to prostatitis, such as alcohol consumption and a spicy diet, are not conducive to prostate cancer prevention, so abstaining from these bad habits and dietary habits is very beneficial to maintaining a healthy prostate.
Disease Treatment
1.Watch and wait treatment:Watch and wait treatment means actively monitoring the progress of prostate cancer and giving other treatments when the lesion progresses or clinical symptoms are obvious. Indications
①Patients with low-risk prostate cancer and short life expectancy
②Patients with advanced prostate cancer: limited to the requirement to avoid adverse effects accompanying from the treatment.
Radical prostatectomy is the most effective way to treat limited prostate cancer. At present, open radical surgery for retropubic prostate cancer and laparoscopic radical surgery for prostate cancer are mostly used in clinical practice. It is suitable for limited prostate cancer.
3.External radiation therapy for prostate cancer: The purpose of external radiation therapy is divided into three categories.
① Radical radiotherapy is one of the most important treatments for patients with limited prostate cancer;
Adjuvant external radiotherapy is mainly applied to patients with invasion of seminal vesicles after radical prostate cancer surgery, positive cut margins and persistently elevated PSA after surgery;
③ Palliative radiotherapy for advanced or metastatic prostate cancer.
External radiotherapy techniques include conventional radiotherapy, three-dimensional conformal radiotherapy (3D-CRT) and intensity-modulated conformal radiotherapy (IMRT). 3D-CRT and IMRT use spiral CT thin-section scanning to map the geometric model of the patient’s target area and normal tissues and create digital reconstructions to achieve a higher conformal dose of external irradiation and standard dose of irradiation at the edge of the target area. Compared with 3D-CRT, IMRT can increase the local irradiation dose and the total irradiation dose of the target area without increasing the acute and late side effects.
4.Prostate cancer brachytherapy: Brachytherapy includes intracavity irradiation, intertissue irradiation, etc. The radiation source is sealed and placed directly into the natural cavity of the human body or into the treated tissue for irradiation. Inter-tissue implantation treatment with permanent radioactive particles is more commonly used, which aims to increase the local dose to the prostate and decrease the radiation dose to the rectum and bladder by implanting radioactive particles into the prostate through accurate positioning of the three-dimensional treatment planning system.
5.Experimental local treatment of prostate cancer: Local treatment of prostate cancer, in addition to the established methods such as radical prostate cancer surgery, external radiation and brachytherapy, also includes experimental local treatment such as cryotherapy, high energy focused ultrasound and radiofrequency ablation of intra-tissue tumors for prostate cancer. Compared with radical prostate cancer surgery and radiotherapy, its therapeutic effect on clinically limited prostate cancer needs to be evaluated and improved by more long-term clinical studies.
Endocrine therapy for prostate cancer: The purpose of endocrine therapy is to reduce the concentration of androgens in the body, inhibit the synthesis of androgens of adrenal origin, inhibit the conversion of testosterone into dihydrotestosterone or block the binding of androgens to their receptors in order to inhibit or control the growth of prostate cancer cells.
The Department of Urology of Tianjin People’s Hospital is in the leading position in the diagnosis and treatment of prostate cancer in Tianjin, adopting radical surgery, intensity-modulated radiotherapy and endocrine therapy according to the different stages of prostate cancer, and achieving good treatment results. The study on the effect of neoadjuvant endocrine therapy on the efficacy of locally advanced prostate cancer (No. 09KZ59) was identified by experts and reached the leading level in China.
Disease Prevention
Many dietary factors can increase the risk of prostate cancer. Several studies have shown that a high-fat diet can stimulate prostate cancer growth; conversely, fruits and vegetables and a low-fat diet may help reduce the risk of prostate cancer. These healthy foods include soy (tofu and soy milk), tomatoes, pomegranates, green tea, red grapes, strawberries, blueberries, peas, watermelon, garlic, and citrus.
1, maintain a proper weight, keep the body mass index (BMI) less than 30, body mass index = weight (kg)/height 2 (m2).
2.Adhere to physical exercise, the amount of exercise should be appropriate.
3.Choose a plant-based diet.
4.Do not smoke and do not abuse alcohol.
5.Limit the intake of fat, fat intake should not exceed 20% of the total calorie intake.
6, do not eat junk food, try to avoid saturated fat in the diet.
7, eat more fish, because fish is rich in beneficial fatty acids.
8.Eating fruits and vegetables every day and limiting the intake of sugar and salt can both prevent cancer and keep the heart healthy.
9.Eat more fiber-rich foods, at least 30 grams per day.
10.Eat soy products 1 or 2 times a day, which can be low-fat soy milk, tofu, soy protein powder, etc.
11.Take sufficient doses of calcium and vitamin D to prevent osteoporosis.