What Are the Causes of Prostate Cancer?

Prostate cancer is an epithelial malignancy that occurs in the prostate. In 2004, "Pathology and Genetics of Tumors of the Urinary System and Male Reproductive Organs" included pathological types of prostate cancer including adenocarcinoma (acinous adenoma), ductal adenocarcinoma, urothelial carcinoma, squamous cell carcinoma, and adenosquamous carcinoma. . Among them, prostate adenocarcinoma accounts for more than 95%. Therefore, we usually refer to prostate adenocarcinoma as prostate adenocarcinoma. In 2012, the incidence of prostate cancer in China's tumor registration areas was 9.92 per 100,000, ranking sixth in the incidence of male malignant tumors. The age of onset was low before the age of 55, and gradually increased after the age of 55. The incidence increased with age, and the peak age was 70 to 80 years. Patients with familial hereditary prostate cancer have an earlier age of onset, with 43% of patients 55 years of age.

Basic Information

English name

prostate cancer

Visiting department

Urology

Multiple groups

Middle-aged and elderly men with family history

Common causes

May be related to genetic factors, sexual activity, eating habits

Common symptoms

Hematuria, frequent urination

Causes of prostate cancer

The occurrence of prostate cancer is related to genetic factors. If the relative risk of a person without prostate cancer in the family is 1, the absolute risk is 8; then the relative risk of prostate cancer family members with prostate cancer is 5, the absolute risk It is 35 to 45. In addition, the incidence of prostate cancer is related to sexual activity and eating habits. People with more sexual activity have an increased risk of prostate cancer. High-fat diet is also related to the onset. In addition, the incidence of prostate cancer may be related to race, region, and religion.

Clinical manifestations of prostate cancer

Prostate cancer is often asymptomatic in the early stages. With the development of tumors, the symptoms caused by prostate cancer can be summarized into two categories:

Compression symptoms

Compressing the urethra with increasing prostate glands can cause progressive dysuria, manifested by thin urinary lines, short range, slow urinary flow, interrupted urinary flow, dripping after urination, endless urination, and laborious urination. Urgency, nocturia, and even incontinence. Tumors compressing the rectum can cause difficulty in stool or intestinal obstruction. They can also compress the vas deferens and cause a lack of ejaculation. Compression of the nerves causes perineal pain and can radiate to the sciatic nerve.

2. Metastatic symptoms

Prostate cancer can invade the bladder, seminal vesicles, and vascular nerve bundles, causing hematuria, blood sperm, and impotence. Pelvic lymph node metastasis can cause edema in both lower limbs. Prostate cancer is often prone to bone metastases, causing bone pain or pathological fractures and paraplegia. Prostate cancer can also invade the bone marrow and cause anemia or reduced whole blood.

Prostate cancer diagnosis

Clinical diagnosis of prostate cancer mainly depends on digital rectal examination, serum PSA, transrectal prostate ultrasound, and pelvic MRI. CT is less sensitive than MRI in the diagnosis of early prostate cancer. Due to the high bone metastasis rate of prostate cancer, a radionuclide bone scan is usually performed before deciding on a treatment plan. Definitive diagnosis of prostate cancer requires a prostate biopsy for pathological examination.

The malignant degree of prostate cancer can be evaluated by histological classification. The most commonly used is the Gleason scoring system. The malignant degree of prostate cancer is divided into 2-10 points based on the sum of the scores of the major structural regions and the minor structural regions in the prostate cancer tissue. The best differentiation is 1 + 1 = 2 points, and the worst is 5 + 5 = 10 points.

Prostate cancer treatment

For patients with early prostate cancer, radical treatment can be adopted. Methods that can cure early prostate cancer include radioactive particle implantation, radical prostatectomy, and radical external radiation therapy.

The indications for implantation of radioactive particles should meet the following three conditions: PSA <10ng / ml; Gleason score is 2 to 6; clinical stage is T1 to T2a.

The indications for radical prostatectomy should meet the following 4 conditions: PSA <10 20ng / ml; Gleason score 7; clinical stage T1 T2c; patients with life expectancy 10 years.

Radical radiotherapy is suitable for patients with localized prostate cancer. Three-dimensional conformal radiotherapy and intensity-modulated conformal radiotherapy are mainly used. In addition, external radiation therapy can also be used as an adjuvant therapy for patients with pathological changes of pT3 ~ 4, seminal vesicle invasion, positive resection margin, or persistently elevated PSA after surgery. Palliative treatment.

For patients with intermediate stage prostate cancer, comprehensive treatment methods should be adopted, such as surgery + radiotherapy, endocrine therapy + radiotherapy, etc.

For patients with hormone-sensitive advanced prostate cancer, endocrine therapy is the main method. Endocrine therapy methods include castration (surgical castration or drug castration) and anti-androgen therapy (bicalutamide or flutamide) or castration + resistance. Androgen therapy. The effect of surgical castration or drug castration is basically the same. But almost all patients eventually develop hormone-independent prostate cancer or hormone-resistant prostate cancer. For castration-resistant prostate cancer patients, second-line endocrine therapy or new endocrine therapy drugs (abiraterone, enzalutamide, etc.) can be used. Patients with hormone-resistant prostate cancer should continue to be castrated, while using docetaxel and mitoxantrone-based chemotherapy. Patients with prostate cancer with bone metastases should be treated with bone protection agents (mainly bisphosphonates) to prevent and reduce bone-related events, relieve bone pain, improve quality of life, and improve survival. External radiotherapy or radionuclides can also improve local bone pain.

According to research in the United States, the use of PSA to screen prostate cancer has problems of overdiagnosis and overtreatment. In order to improve this situation, the "Prostate Cancer Clinical Practice Guidelines" developed by the National Comprehensive Cancer Network in 2010 will for the first time include close observation instead of "active treatment" as one of the options for patients diagnosed with prostate cancer by prostate biopsy. Ask the doctor to fully explain the dangers of close follow-up and the dangers of overtreatment to the patient, and the patient will make a decision. The basic conditions for patients who can be closely followed are: patients whose biopsy pathology shows low-risk prostate cancer (T1 to T2a tumors, Gleason score of 2 to 6 points, PSA <10ng / ml. And life expectancy is less than 10 years; Patients with extremely low-risk prostate cancer (T1a stage tumor, Gleason score 6 points, PSA <10 ng / ml, biopsy <3 needles, positive cut of each tumor tissue 50%, PSA density <0.15 ng / ml · g. Patients with a life expectancy of less than 20 years. The close observation plan is to check PSA every 6 months and digital rectal examination every 12 months. After the first prostate biopsy, especially for the first biopsy 10 Needle-positive patients should undergo another biopsy within 18 months. In addition, low-risk patients with a life expectancy greater than 10 years should undergo repeated biopsies at approximately every 12 months. If disease is found during close observation If there is a tendency to progress, corresponding treatment methods should be adopted.

Prostate cancer prevention

Studies have shown that tomatoes and other lycopene-containing foods may be effective in preventing prostate cancer. The results of two large-scale prostate cancer prevention trials show that the application of finasteride or dutasteride (a drug for the treatment of prostate hyperplasia) can reduce the prevalence of prostate cancer by 25%, but may increase the incidence of high-grade prostate cancer. risk.