Prostate cancer

Introduction to prostate cancer Prostate cancer is one of the leading causes of male cancer death in Europe and the United States. The incidence rate increases with age. Half of the prostates over the age of 80 have cancer lesions, but the actual clinical incidence is far below this number. The prostate cancer has obvious regional and ethnic origin. According to statistics, the Chinese are the lowest, the Europeans are the highest, and Africa and Israel are in the middle. China and Japan are the low-incidence areas of prostate cancer, but there is no choice of men over 50 years old. The number of metastatic cancer lesions is similar to that of Europe and America. Therefore, some people think that the growth of oriental cancer is slower than that of Westerners, and there are fewer clinical cases. In addition, prostate cancer is also related to the environment. basic knowledge The proportion of sickness: 0.005--0.006% Susceptible people: male Mode of infection: non-infectious Complications: hematuria, urinary incontinence

Causes of prostate cancer

Causes:

The cause has not yet been fully identified and may be related to race, genetics, sex hormones, food, and the environment. According to research from countries such as Northern Europe, Sweden, and Finland, a large extent (40%) is due to genetic variation, recent molecular biology. The study also revealed a variety of chromosomal aberrations, and the complex and interdependent relationship between these factors and environmental carcinogens (60%) is not well understood.

Pathogenesis:

Several important steps in the cancer-causing mechanism of prostate cancer are now known. About 9% of prostate cancers and 45% of prostate cancers under 55 years of age are due to a hereditary oncogene, and it is clear that these genes are undoubtedly for prostate cancer. The understanding of the principle of cancer is extremely useful. Recently, Ohio reported that they found that the allelic imbalance in the 23.2 segment of the long arm of chromosome 16 may be a tumor suppressor gene of familial hereditary prostate cancer (Paris et al., 2000). One idea is that the intensity of the androgen receptor response to androgen in the epithelial cells is inversely proportional to the length of the CAG microsatellite in the 5promotor promoter region of the receptor gene. The shorter the length, the response of the cells to androgens The stronger the cells, the faster the cells grow. The length of CAG is shorter in blacks and cancerous whites than in the control group. Obviously, the length of the androgen receptor CAG microrepetition region is potentially related to the development of prostate cancer.

DNA methylation changes in the early stages of solid tumor growth, and prostate cancer is no exception. High methylation of DNA can lead to the inactivation of many tumor suppressor genes, such as hypermethylation of the short arm of chromosome 17. Inactivation, tumor suppressor genes in this area may lead to prostate cancer, the growth of prostate cancer depends on the balance between cell proliferation rate and mortality, normal prostate epithelial proliferation rate and mortality are very low, and It is balanced and has no net growth, but when epithelial cells are converted to high grade prostatic intraepithelial neoplasia (HGPIN), cell proliferation has exceeded cell death, and early cell proliferation in prostate cancer is due to apoptosis ( Apoptosis, rather than increased cell division, further leads to an increased risk of genetic dissimilation, precancerous lesions of the prostate and increased expression of cdc 37 in cancer cells, which may be an important step in the initiation of canceration.

Prostate cancer prevention

Prostate cancer mainly has the following preventive measures:

Census

An effective method currently accepted is the use of digital rectal examination plus serum PSA concentration determination.

Use male serum CSA levels to detect male citizens aged 40 to 45 years old, and follow up and measure once a year. This census method is cost-effective. For example, PSA exceeds 4.0 ng/ml and then undergoes digital rectal examination or ultrasonography. If positive or suspicious, do acupuncture again. Biopsy, this method is very effective in detecting early-stage localized prostate cancer. A population-based survey in Sweden found that the time span from the serum PSA concentration increased from 3 ng/ml to the clinical diagnosis of prostate cancer was 7 years. PSA screening for the population can be used for early diagnosis of prostate cancer and early treatment, because PSA blood concentration increases with age, the study of the Gunma University School of Medicine in Japan found that 60 to 64 years old, 65 to 69 years old, 70 to 74 years old, 75 ~ The normal upper limit of blood PSA age correction for men aged 79 years and older should be 3.0, 3.5, 4.0 and 7.0 ng/ml, respectively. The sensitivity, specificity and efficiency of these normal range are 92.4%, 91.2 respectively. % and 84.3%, the normal upper limit of serum PSA concentration in men aged 45-49 years and 50-59 years in Austria is 2.5 ng/ml and 3.5 ng/ml, respectively. Many studies can be used for serum PSA 4.0-10 ng/ml. Free PSA percentage To increase the sensitivity of PSA assays, generally the increase in free PSA is seen in benign prostatic hyperplasia, and free PSA is reduced in prostate cancer patients, so if free PSA > 25% of patients are likely (less than 10% probability) without prostate cancer If <10%, the patient is very likely (60% to 80% probability) to have prostate cancer. It is meaningful to do a prostate biopsy at this time.

2. Avoid risk factors

This is difficult to do because there are many clear risk factors, genetics, age, etc., but potential environmental risk factors such as high-fat diets, cadmium, herbicides, and other undetermined factors may be avoided. It is known that about 60% of the factors leading to prostate cancer come from the living environment. The Swedish study shows that occupational factors are related to prostate cancer. The statistically significant occupations are agriculture, related industrial soaps and perfumes and leather. Industry, so farmers, tanners and management staff in these industries have a significant increase in morbidity, and people exposed to chemicals, herbicides, and fertilizers have increased the risk of prostate cancer. According to New Zealand reports, food contains anti-drugs. Oxide fish oil can protect and reduce the risk of prostate cancer. Taiwan reports that magnesium in drinking water can prevent prostate cancer. In addition, it adheres to a low-fat diet, eats soy-like foods rich in vegetable protein, and consumes Chinese green tea for a long time. Measures such as the content of medium and trace element selenium and vitamin E can also prevent the occurrence of prostate cancer.

3. Chemical prevention

According to the intervention of drugs, chemoprevention can be divided into the following major categories, such as tumor suppressor, anti-tumor growth drugs and tumor progression inhibitors. Because of the occurrence of prostate cancer, development is a long-term process, so we can Chemoprevention or drug inhibition of the occurrence and development of prostate cancer, for example, finasteride can inhibit the conversion of testosterone into an active substance that acts on the prostate, dihydrotestosterone, so it may inhibit the testosterone on prostate cancer cells. Growth, the current role is still in clinical research observation, to be confirmed, other drugs such as retinal have the role of promoting cell differentiation, anti-tumor progression, is also in clinical research, may become a potential chemopreventive drug.

Prostate cancer complications Complications, hematuria, incontinence

1, lymphatic metastasis

The first lymph node invaded by prostate cancer is the obturator-sacral chain. In fact, the lymph nodes in the obturator are generally not invaded. Clinically, the intra-orbital lymph nodes are called closed-cell lymph nodes, which are located inside the external iliac vein and along the iliac crest. Vascular travel is the most important should clear lymph nodes.

The diagnosis of lymph node metastasis relies on CT and MR in recent years, but small lesions can not be found. Lymphatic angiography can detect 70% to 90% of metastases, but false negatives and false positives are higher. In recent years, less application, the most valuable diagnostic improvement. Lymph node dissection, which removes the lymph nodes between the internal and external iliac vessels and the obturator, as a more accurate staging, can avoid the previous removal of the iliac vessels, obturator, pelvic wall, anterior lymph nodes, lymphatic leakage, lymphadenopathy, lower extremity swelling and other complications Symptoms, because even extensive cleaning does not prevent existing spreads.

2, distant transfer

Intravenous urography revealed ureteral obstruction, indicating that the tumor has invaded the seminal vesicle, bladder neck and lymph nodes, and there is the possibility of distant metastasis.

3, bone transfer

Common, second only to lymph nodes, systemic isotope scan enhancement and plain film should be thought to be metastasis, lung x-ray can be found in lung metastasis, often lymphatic vessel spread, nodular.

Prostate cancer symptoms Common symptoms Urinary tract obstruction Urinary pain Urinary incontinence Urinary frequent radiation Testicular pain Painful hematuria Prostatic hyperplasia Loss of appetite

In the early stage of prostate cancer, most patients with prostate cancer have no obvious symptoms, which are often found by chance during physical examination, and can also be found in surgical specimens of benign prostatic hyperplasia.

As the tumor continues to develop, prostate cancer will have a variety of different symptoms, mainly in three aspects:

Blocking symptoms

There may be dysuria, urinary retention, pain, hematuria or urinary incontinence.

2. Local invasive symptoms

The rectal space of the bladder is often involved first. This gap includes the prostate, seminal vesicle, vas deferens, and the lower end of the ureter. Organs such as tumor invasion and compression of the vas deferens can cause low back pain and side testicular pain. Some patients also complain of ejaculation pain.

3. Other metastatic symptoms

Prostate cancer is prone to bone metastasis. It can be disease-free at the beginning, and there are also cases of prostate cancer caused by nerve compression or pathological fracture caused by bone metastasis.

98% of prostate cancer is adenocarcinoma, 2% is squamous cell carcinoma, 75% originates from the peripheral zone, 20% originates from the transition zone, 5% originates from the central zone, and the prostate cancer staging is as follows:

T1: T1a is clinically negative, TUR specimen cancer accounts for less than 5% of total volume, T1b is clinically negative, TUR specimen cancer accounts for more than 5% of total volume, T1c is clinically negative, PSA>4g/L, and biopsy confirms cancer.

T2: T2a is limited to 2 leaves, and T2b is limited to 2 leaves.

T3: T3a penetrates the capsule and T3b invades the seminal vesicle.

T4: Violation of surrounding tissues.

N: N0 lymph nodes without metastasis, N1 basin lymph node metastasis; N2 distant lymph node metastasis.

M: M0 has no metastasis in the distance, and M1 distant organ metastasis.

According to glandular differentiation, pleomorphism, and nuclear abnormality classification, prostate cancer is divided into two major and minor grades, each of which is divided into primary and secondary grades. Each fraction is 1 to 5 points, and the scores of the two grades are added. The total score is 2 to 4 points, which is a well-differentiated cancer, 5 to 7 points are moderately differentiated cancer, and 8 to 10 are poorly differentiated cancer.

Prostate cancer is mostly androgen-dependent. Its occurrence and development are closely related to androgen. Non-hormone-dependent type is only a minority. Prostate cancer can be spread through local, lymph and blood. The blood is transferred to the spine and pelvis.

Prostate cancer screening

Laboratory inspection

1 serum prostate specific antigen (PSA) is elevated, but about 30% of patients may not increase PSA, but fluctuate within the normal range (normal range <4.0ng/ml) such as PSA measurement and digital rectal examination (DRE) The combination will significantly increase the detection rate.

2 elevated serum acid phosphatase is associated with prostate cancer metastasis, but lacks specificity. In recent years, radioimmunoassay can improve its specificity. Prostate acid phosphatase monoclonal antibody, prostate antigen determination needs to improve its specificity, C stage prostate cancer 20% to 70% have elevated acid phosphatase, and lymph node metastasis is also elevated. If it continues to increase, there must be bone metastasis. Serum acid phosphatase and prostatic acid phosphatase are elevated after surgery, which is a good prognosis. The symbol of prostate cancer acid phosphatase in the capsule is secreted by prostate cells, excreted by the prostate duct, prostate cancer, the acid phosphatase produced by cancer cells is not catheterized or the catheter is obstructed by cancerous lesions, the enzyme is absorbed into the blood circulation, and even Acid phosphatase is elevated.

Film degree exam

1. B-ultrasound examination of hypoechoic nodules in the prostate, but must be differentiated from inflammation or stones.

2. Radionuclide bone scans often show metastatic lesions earlier than X-ray films.

3. CT or MRI examination can show changes in prostate morphology, tumor and metastasis. The main CT manifestations of prostate cancer are low-density areas where the enhancement of the tumor is not enhanced when the scan is enhanced. The capsule is irregular, the fat around the gland disappears, and the seminal vesicle is affected. After the invasion, the state of the seminal vesicle can be blurred, the angle of the seminal vesicle disappears or the seminal vesicle increases. When the tumor invades the bladder or the surrounding organs of the prostate, the pelvic CT can change accordingly. When the pelvic lymph node has tumor metastasis, the CT can be based on the pelvic lymph node. Change the size of the group to determine whether there is a transfer.

MRI examination of prostate cancer mainly uses T2 weighted sequence. In the T2-weighted image, such as high signal, there is a low-signal defect area in the peripheral zone of the prostate. If the prostate band structure is destroyed, the prostate should be considered when the peripheral band and the central band disappear. cancer.

4. Prostate biopsy can be used as a method to diagnose prostate cancer. Failure to puncture and remove tumor tissue cannot be denied.

Elevated serum acid phosphatase is associated with prostate cancer metastasis, but lacks specificity. In recent years, radioimmunoassay can improve its specificity. Prostate acid phosphatase monoclonal antibody, prostate antigen determination needs to improve its specificity, C stage prostate cancer 20 %70% of acid phosphatase is elevated, and lymph node metastasis is also elevated. If it continues to increase, there must be bone metastasis. Serum acid phosphatase and prostatic acid phosphatase are decreased after surgery, which is a good prognosis. It is a symbol that the prostate cancer acid phosphatase secreted by the prostate cells in the capsule is excreted by the prostate duct. When prostate cancer is passed, the acid phosphatase produced by the cancer cells is not discharged from the catheter or the catheter is obstructed by the cancer lesion, and the enzyme is absorbed into the blood circulation and even acidic. The phosphatase is elevated.

Diagnosis and diagnosis of prostate cancer

diagnosis

1. Early asymptomatic, can be found in the physical examination of the prostate induration, hard as a stone, the surface is not flat.

2. Late symptoms of prostatic hypertrophy, such as frequent urination, dysuria, fine urine flow, difficulty urinating, etc., may be associated with prostatic hypertrophy at the same time, but at this time, rectal examination can be found to be hard and with surrounding tissues. Fixed, poor activity, very important for clinical diagnosis, there may also be metastatic symptoms such as low back pain, hematuria, with weight loss, fatigue, loss of appetite and so on.

3. The serum PSA level of patients with prostate specific antigen (PSA) serum can be increased, the ratio of free PSA to total PSA is decreased; serum acid phosphatase may be increased when there is metastasis, and the coincidence rate of the two combined examinations is higher.

4. B-ultrasound examination of hypoechoic nodules in the prostate, but must be differentiated from inflammation or stones.

5. Radionuclide bone scans often show metastatic lesions earlier than X-ray films.

6. CT or MRI examination can show changes in prostate morphology, tumors and metastasis.

7. Prostate biopsy can be used as a method to diagnose prostate cancer. Failure to puncture and remove tumor tissue cannot be denied.

Differential diagnosis

Prostate cancer is a malignant disease that should be detected early and treated early, so it must be differentiated from some diseases to confirm the diagnosis.

(1) should be differentiated from benign prostatic hyperplasia

The two are generally easy to identify, but in the prostatic gland of the prostate, some areas of the epithelial cells are atypical and can be mistaken for cancer. The difference is that the acinar is larger in the proliferating gland and the surrounding collagen fiber layer is intact. The epithelium is double-layered and high-column. The nucleus is smaller than that of prostate cancer patients, and it is located at the base of the cell. The glands are arranged regularly to form obvious nodules.

(2) Identification with prostate atrophy

Prostate cancer often begins in the atrophy of the gland. It should be noted that the atrophic acinar sometimes gathers tightly, the atrophy becomes smaller, the epithelial cells are cuboid, the nucleus is large, and it is like cancer, but this type of atrophy changes mostly affects the whole lobules. The collagen connective tissue layer is still intact, the matrix is not invaded, and it itself is sclerotic atrophy.

(3) Identification with prostate squamous epithelium or transitional metaplasia

Often occurs in the healing part of the infarcted area of the gland, the squamous epithelium or transitional epithelium differentiates well, without degenerative or dividing phase, the most prominent feature of metaplasia is ischemic necrosis or fibrous connective tissue matrix lacking smooth muscle.

(4) granulomatous prostatitis

The cells are large and can be aggregated into flakes. They have transparent or reddish stained cytoplasm, small vesicular nuclei, much like prostate cancer, but they are macrophages, and the other cells are pleomorphic and nucleus pyknosis. It is vacuolized, small in size, arranged in rows or clusters, sometimes visible in some acinar. When identifying, attention should be paid to the formation of granuloma prostatitis. The relationship between lesions and normal glandular ducts is unchanged. Sexually altered amyloid and multinucleated giant cells, while prostate cancer cells are low-column or cuboid, with clear cell walls, dense eosinophilic cytoplasm, larger nuclei, staining and morphology, and inactive division The acinus is small, lacking a curved tube, the normal arrangement is completely lost, irregularly infiltrating into the matrix, the collagen connective tissue layer is no longer present, the acinus contains a small amount of secretion, but few amyloid, prostate cancer If there is a significant degenerative change, the tissue structure disappears completely and there is no tendency for acinar formation.

(5) In addition, prostate cancer should be differentiated from prostate tuberculosis and prostatic stones.

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