There are significant geographic and ethnic differences in the incidence of prostate cancer. It is highest in Australia/New Zealand, the Caribbean and Scandinavia, and lower in Asian countries such as China, Japan and North Africa. The worldwide incidence of prostate cancer is the second highest among male malignancies and the first among American men. The incidence rate in China has been on the rise in recent years, with 3.4 per 100,000 population in 2002 and 11.8 per 100,000 population in Shanghai in 2007.
Prostate cancer patients are mainly older men, with a median age of 72 years for newly diagnosed patients and a peak age of 75 – 79 years. it is rare in men under 50 years of age, and the incidence and mortality rate increases in a straight line over 50 years of age. 60 – 79 years of age, the likelihood of developing prostate cancer is 13.7%.
The risk factors for prostate cancer are not fully defined, and some are well recognized. The incidence increases significantly with age. Genetics is one of the most important factors that determine the development of clinical prostate cancer. Studies have found that the risk of prostate cancer increases more than 1-fold in first-degree relatives and increases to 5 – 11-fold in 2 or more. The incidence is high in those with high animal fat, red meat, obesity, smoking, and low intake of vitamin E, lignans, and isoflavones; and low in those with soy and soy products, green tea, tomatoes, and sun exposure. Risk factors for the development of prostate cancer also include sexual activity and occupational social factors.
Early stage prostate cancer is usually asymptomatic. It is usually asymptomatic. It is often found incidentally during rectal examinations, ultrasound examinations, or prostate enlargement surgery specimens. However, if the tumor invades or obstructs the urethra or bladder neck, it may cause difficulty in urination, frequent and urgent urination, and even urinary retention, hematuria, and incontinence. When bone metastasis occurs, it can cause bone pain, pathological fracture, anemia, and neurological symptoms of spinal cord compression.
The diagnostic methods of prostate cancer include rectal examination, prostate specific antigen test, transrectal ultrasonography, prostate puncture biopsy, CT and MRI, whole body nuclear bone imaging, etc., which are explained below.
Rectal examination can help in the early diagnosis and staging of prostate cancer. Through rectal examination, nodules can be detected and the size, texture, pressure pain and mobility of nodules can be understood. However, rectal examination can affect the level of PSA value, so rectal examination should be performed after blood sampling for PSA.
Prostate-specific antigen is currently an important and reliable tumor marker for diagnosing prostate cancer, assessing the effect of various treatments and predicting prognosis; serum PSA value in healthy men is generally 0-4ng/mL; PSA level is in the gray zone, i.e. at 4-10ng/mL, free PSA is an effective method to improve the detection rate of prostate cancer; in addition, PSA density and PSA rate can also be used as In addition, PSA density and PSA rate can also be used as clinical reference indicators.
Transrectal ultrasound can clearly show the structure, migration zone and blood flow changes in the prostate, and accurately measure the volume of the prostate and intraprostatic masses; the typical sign of prostate cancer on ultrasound is a hypoechoic nodule in the periprostatic area, and transrectal ultrasound can guide systematic puncture biopsy of the prostate; as well as monitoring and evaluating the efficacy of various treatments.
CT is less sensitive than MRI in the diagnosis of early prostate cancer, and the purpose of CT examination is to assist clinicians in the clinical staging of the tumor. MRI can show whether the integrity of the prostate envelope invades the surrounding tissues and organs of the prostate, as well as lymph node invasion and bone metastases, which are more important for clinical staging.
Whole-body nuclide bone imaging is a non-invasive test that can detect bone metastases from prostate cancer 3-6 months earlier than conventional X-rays. It is more sensitive, but less specific.
Systematic puncture biopsy for prostate cancer diagnosis is the most reliable test to diagnose prostate cancer; prostate puncture bleeding affects imaging clinical staging, so MRI should be performed before puncture; study results show that the positive diagnostic rate of puncture with more than 10 stitches is significantly higher, but does not significantly increase complications; if repeated puncture interval is needed, the current interval is mostly 1-3 months.
Staging of prostate cancer can guide the selection of treatment and evaluate the prognosis. Staging can be clarified by rectal examination, CCT, MRI, bone scan and lymph node dissection, and PSA can assist in staging. Currently, the 2002 American Cancer Society TNM staging system is mostly used; T-stage indicates the local condition of the primary tumor, N-stage indicates the condition of lymph nodes, and M-stage mainly focuses on bone metastasis.
PSA less than 10 is low risk, 10 – 20 is intermediate risk, and 20 or more is high risk. gleason score, 7 is intermediate risk, less than 7 is low risk, and more than 7 is high risk. t2b is median. .
There are a number of factors that can affect PSA levels, so PSA testing should be performed one week after prostate massage, 48 hours after rectal exam, cystoscopy, catheterization, 24 hours after ejaculation, one month after prostate puncture, and in the absence of acute urinary retention, prostatitis, or other conditions. Those with abnormal initial PSA test should be retested.
What should be done clinically for increased PSA? If <4ng/ml, abnormal rectal exam or imaging, puncture biopsy is recommended. when PSA is between 4 - 10ng/ml, but F/T>0.16, observation is recommended, FT<0.16< span="">, puncture biopsy is recommended. If >10ng/ml, direct puncture may be performed.
Prostate cancer is usually classified into four major types according to the mode of detection: latent cancer: primary cancer of the prostate is found only at autopsy. Incidental cancer: Prostate cancer is found accidentally by pathological examination of surgical tissue specimens after consultation for benign prostate disease. Occult cancer: No clinical manifestation of prostate disease, with lymph node metastasis or pathological fracture, confirmed as prostate cancer by pathology. Clinical cancer: clinically diagnosed as prostate cancer and confirmed by prostate puncture biopsy.
There are many treatment methods for prostate cancer, including active surveillance, surgical treatment, radiotherapy, endocrine therapy, cryotherapy, biological therapy, etc. The specific choice of single treatment or combined treatment must be individualized according to the different stages of prostate cancer development. At the same time, the patient’s age, general condition, economic condition and willingness to survive should be taken into account. The first four treatments are mainly described below.
Active surveillance, which refers to the active monitoring of the progression of prostate cancer. Treatment is given when tumor progression or clinical symptoms are apparent. The indications are low-risk prostate cancer patients with PSA at 4 – 10ng/ml, GS score ≤ 6, clinical stage ≤ T2a. 3 – 6 months later for follow-up, rectal examination, PSA examination, and imaging examination if there are abnormalities.
Radical prostate cancer surgery is one of the effective methods to cure limited prostate cancer. Indications for surgery take into account the risk factor class of the tumor, the patient’s life expectancy and general health status. This includes age life expectancy of 18 years or more, clinical stage T2 or less, PSA <20ng/ml, and GS score of 8 or less. If once diagnosed elective surgery is performed, but 6 - 8 weeks after prostate puncture, or 12 weeks after TUR-P is appropriate.
Currently, the main surgical procedures are: traditional open surgery, laparoscopic radical prostate cancer surgery, and in recent years, robotic radical prostate cancer surgery. The choice of specific surgical treatment plan depends on the patient’s condition and requirements, hospital conditions, physician’s technical level and experience and other comprehensive factors.
The main complications of surgery are: severe intraoperative bleeding, rectal injury, postoperative erectile dysfunction, urinary incontinence, anastomotic stenosis, deep vein thrombosis, etc. Laparoscopic surgery may also result in: incisional implantation metastasis, transit
Radiation therapy is also a treatment for prostate cancer, including external radiation therapy and brachytherapy. External radiation therapy is divided into: radical radiotherapy, adjuvant radiotherapy, and palliative radiotherapy. Brachytherapy is divided into two types: intracavitary radiation and intertissue radiation.
External radiation therapy has the advantages of good efficacy, wide indications and few complications. It is suitable for patients with all stages of prostate cancer. External radiation technology mainly includes conventional radiotherapy, 3D conformal radiotherapy and intensity modulated conformal radiotherapy.
The advantages of brachytherapy are: high local dose to the prostate and reduced radiation dose to the rectum and bladder. The indications need to meet the following 3 conditions at the same time: clinical stage of T1-T2a; GS score of 2-6; PSA <10ng/ml. Combined external radiation therapy and endocrine therapy can be considered depending on the patient's condition.
Possible complications of external radiation include the following: urinary system may develop urethral stricture, bladder fistula, hemorrhagic cystitis, hematuria, etc.; gastrointestinal tract may develop diarrhea, abdominal pain, rectal discomfort, rectal bleeding, etc.; skin may develop erythema, dry skin, flaking; other may lead to necrosis of pubic bone and soft tissue, scrotal or penile edema, etc.
Complications of brachytherapy include short-term complications and long-term complications. Short-term complications: urinary tract irritation such as urinary frequency, urinary urgency and pain, increased frequency of stool, and rectal irritation such as thick lining, mild blood in the stool and intestinal ulcers; long-term complications: chronic urinary retention, urethral stricture and urinary incontinence are common.
Endocrine therapy is one of the main treatments for prostate cancer. The aim is to simultaneously remove and block androgens of testicular and adrenal origin to inhibit or control the growth of prostate cancer cells. Strategies include surgical or pharmacologic debulking to inhibit testosterone production and block androgen binding to receptors. Methods include: denervation alone, maximal androgen blockade, intermittent endocrine therapy, neoadjuvant endocrine and adjuvant endocrine therapy.
Endocrine therapy is indicated for: metastatic prostate cancer; limited early stage or local progression; inability to operate or radiotherapy; neoadjuvant endocrine therapy before radical treatment; adjuvant therapy with radiotherapy; local recurrence with curative treatment and inability to treat locally; distant metastasis with curative treatment and patients with persistent androgen suppression in the androgen non-dependent phase.
Denervation therapy includes surgical denervation and pharmacological denervation. Surgical debulking refers to the removal of the testicles, which is a simple, fast-acting and inexpensive procedure. Pharmacological denervation refers to the use of luteinizing hormone-releasing hormone analogs such as goserelin and treprostin, which are used for 3 – 4 weeks to achieve the post-surgical denervation level of androgens.
The aim of maximal androgen blockade is to remove or block both testicular and adrenal sources of androgens. A common approach is denervation + anti-androgen drugs such as goserelin or treprostinil + drugs such as bicalutamide or flutamide.
Intermittent endocrine therapy means that patients with prostate cancer receive endocrine therapy, which is stopped when PSA drops to normal or minimal levels, and continued if there is an exacerbation of symptoms, or if PSA rises significantly to a certain level.
The objectives are to delay progression to an androgen non-dependent state; prolong tumor-free progression and overall survival in some patients; reduce adverse effects; improve quality of life; and greatly reduce the cost of treatment.
Intermittent endocrine therapy is indicated for all patients on endocrine therapy with the best limitations. The criteria for stopping treatment are: PSA≤0.2ng/ml and maintained for 3-6 months. The current domestic recommendation is to restart treatment when PSA >4ng/ml. The method mostly uses maximal androgen blockade therapy, but also drug depot.
Neoadjuvant endocrine therapy is a period of endocrine therapy before radical prostatectomy. The aim is to reduce the tumor volume, reduce the clinical stage, reduce the positive prostate margin rate, and thus improve the survival rate with reliable method efficacy. The duration of treatment is 3-9 months.
After radical surgery or radiotherapy, the treatment is supplemented by endocrine therapy, called adjuvant endocrine therapy. The aim is to treat residual lesions at the cut edge, treat residual positive lymph nodes, treat micro-metastases, and improve long-term survival. The timing of treatment is started immediately after surgery or radiation therapy.
Side effects of endocrine therapy, including: gastrointestinal and hepatic toxic reactions; hot flashes and sweating; gynecomastia feminization; anemia; osteoporosis; and sexual dysfunction.
Biochemical recurrence after radical surgery is defined as clinical recurrence of patients when PSA levels are ≥0.2 ng/ml for 2 consecutive times, while local recurrence, regional lymph node metastasis or distant metastasis are present. Active surveillance is available for low-risk patients, and salvage radiotherapy is used for patients with life expectancy >10 years and biochemical or clinical local recurrence. Patients with biochemical recurrence and very high clinical extensive metastasis are treated with endocrine therapy as early as possible.
Recurrence of prostate cancer after radiotherapy, including biochemical recurrence, clinical local recurrence, and distant metastasis. Three consecutive elevations of PSA after radiotherapy to the nadir are defined as biochemical recurrence. Clinical recurrence includes local recurrence of prostate cancer, and distant metastasis. In case of low-risk patients, active surveillance or salvage therapy such as radical prostate cancer surgery, brachytherapy, cryotherapy, etc. Distant metastasis after radiotherapy or patients with clinical local recurrence but unwilling to salvage treatment can be treated with endocrine therapy.
Hormone non-dependent prostate cancer refers to prostate cancer that recurs and progresses after continuous endocrine therapy. These include: androgen-independent prostate cancer and hormone-refractory prostate cancer.
The treatment of hormone-non-dependent prostate cancer is firstly to maintain the testosterone depot level, and secondly second-line endocrine therapy, such as adding anti-androgen drugs, stopping anti-androgen drugs, interchanging anti-androgen drugs, or using adrenal androgen inhibitors. Third, chemotherapy may be used. Such as paclitaxel, mitoxantrone or estradiol nitrogen mustard + VP16.
For patients with radical prostate cancer, clinical manifestations, serum PSA test and rectal examination are the routine follow-up methods. 2 years or less, follow-up every 3 months; 2 – 5 years, follow-up every 6 months; more than 5 years should be followed up annually. Patients undergoing endocrine therapy should be followed up every 3 months. Patients without distant metastases may be followed up once every 6 months, and those with distant metastases may be followed up once every 3 – 6 months. The follow-up interval should be shortened if there is disease progression.