Prostate cancer is the first tumor that endangers men’s health in western countries. With the aging of our society, increasing life expectancy per capita and changing lifestyle, the incidence and mortality rate of prostate cancer has been steadily increasing year by year; in Shanghai, for example, the incidence rate of prostate cancer has increased from 1.9/100,000 men 20 years ago to 25.87/100,000 men, jumping to the first place of male genitourinary tumors, which sounds an alarm for men’s health. The “alarm bell” is sounding for men’s health.
Due to the overall lack of attention to early diagnosis of prostate cancer in China and the lack of systematic and effective screening mechanism, so that most patients are already in the middle and late stages when they are diagnosed, losing the indication for radical surgery and can only receive endocrine therapy and radiotherapy, with poor prognosis.
The age of prostate cancer
Prostate cancer mainly occurs in older men, with a peak age of 75-79 years. 70% of prostate cancer patients are over 65 years old, and it is rare to see them under 50 years old. The likelihood of prostate cancer in individuals younger than 39 years of age is 0.005 percent, increasing to 2.2 percent in the 40-59 age group and 13.7 percent in the 60-79 age group.
Factors influencing the development of prostate cancer
One of the most important risk factors for prostate cancer is heredity. If one immediate family member has prostate cancer, his or her risk of developing prostate cancer increases by a factor of one, while the relative risk increases by a factor of five to eleven if two or more immediate family members have prostate cancer.
A diet high in animal fat is an important exogenous risk factor. With the improvement of living standards, the consumption of animal fats and meat among the main food sources of urban residents has increased significantly, while the consumption of grains and vegetables has continued to decrease, with the proportion of soy products, which have a protective effect, decreasing significantly in the food. Thus, the westernization of lifestyles has led to an imbalance of risk and protective factors for prostate cancer.
Other risk factors include decreased intake of vitamin E, selenium, lignans, isoflavones, and decreased sunlight exposure. Green tea consumption is relatively high in Asia, where the incidence of prostate cancer is low, and green tea may be a preventive factor for prostate cancer.
What are the symptoms of prostate cancer?
Early prostate cancer is usually asymptomatic, but when the tumor invades or obstructs the urethra or bladder neck, symptoms of lower urinary tract obstruction such as straining to urinate, thinning of the urinary line, dribbling of urine, or symptoms of lower urinary tract irritation such as frequent urination, urgent urination, and increased nocturia may occur, similar to BPH. Some patients present with symptoms of bone metastasis at the first diagnosis, such as bone pain, pathological fracture, anemia, spinal cord compression leading to lower limb paralysis, etc.
How to achieve early screening of prostate cancer
PSA is by far the most specific marker of prostate cancer. Under normal conditions, the contents of the PSA-rich prostate alveoli are separated from the lymphatic system by a barrier consisting of the endothelial layer, basal cell layer and basement membrane. When a tumor or other lesion disrupts this barrier, the glandular contents can leak into the lymphatic system and subsequently enter the bloodstream, leading to an increase in peripheral blood PSA levels. The current consensus at home and abroad is that a total serum PSA >4.0ng/ml is abnormal.
In the United States, Europe and other western countries, with the promotion of serum PSA screening combined with rectal screening, the early diagnosis rate of prostate cancer has been increasing, and the survival rate and quality of life of patients have been greatly improved. In China, experts from the Chinese Medical Association Urology (CUA) have reached a consensus that “routine PSA and rectal screening should be performed for men over 50 years of age with lower urinary tract symptoms, and for men with a family history of prostate cancer, regular screening and follow-up should begin at age 45.
PSA should be performed in men with abnormal rectal examinations, clinical signs (such as bone pain, fractures, etc.) or imaging abnormalities”. Therefore, rectal examination combined with PSA examination is currently recognized as the best primary screening method for early detection of prostate cancer.
Imaging tests for early diagnosis of prostate cancer
Magnetic resonance imaging (MRI) has strong advantages in the diagnosis of prostate cancer. It can show the prostate cancer lesions, the integrity of the prostate envelope, and whether the surrounding tissues and organs are invaded by different signal values. Magnetic resonance spectroscopy (MRS) can show different spectral lines according to the metabolism of citrate, choline and creatinine in prostate cancer tissues as compared to those in prostate hyperplasia and normal tissues, which is valuable in the diagnosis of prostate cancer.
The most common site of distant metastases from prostate cancer is the bone. Nuclear bone scan (ECT) can detect bone metastases 3 to 6 months earlier than conventional X-ray.
Although MRI, ECT and other imaging tests can greatly improve the initial qualitative diagnosis of prostate cancer, the final definitive diagnosis still requires ultrasound-guided prostate puncture biopsy.
When is a prostate puncture biopsy needed?
Prostate puncture biopsy is the most effective way to diagnose prostate cancer. As an invasive diagnostic method, its indications include: nodules found by rectal examination; hypoechoic prostate nodules found by ultrasound or suspicious signals found by MRI; tPSA >10ng/ml; tPSA 4-10ng/ml, serum free PSA (fPSA) measured, if f/tPSA is less than 0.15, prostate puncture biopsy is also required. Commonly used methods include transrectal and perineal prostate puncture. Currently, ultrasound-guided transrectal prostate puncture biopsy is more commonly used and has a high accuracy rate.
How to treat prostate cancer
Treatment should be individualized according to the patient’s condition, life expectancy, prostate cancer classification and stage, hospital equipment and technical conditions.
For patients with low-risk prostate cancer and short life expectancy, watchful waiting treatment can be adopted, but the progress of prostate cancer should be actively monitored during treatment, and conversion to other treatments can be considered when there is lesion progression or significant clinical symptoms.
The most effective treatment for patients with limited prostate cancer in good health, without severe cardiopulmonary disease, and with a life expectancy of ≥10 years is radical prostatectomy, with three main procedures, namely the traditional trans-perineal, retropubic and, in recent years, the development of laparoscopic radical prostatectomy.
Radiation therapy for prostate cancer has the advantages of good efficacy, wide indications and few complications, which can significantly reduce the volume of prostate and improve the symptoms of urinary obstruction. It is suitable for patients with all stages of prostate cancer.
In response to the apoptosis of prostate cells without androgen stimulation, endocrine therapy can be used to control the growth of prostate cancer cells by reducing the concentration of androgens in the body or blocking the binding of androgens to their receptors. Commonly used methods include.
① Surgical or pharmacological debulking;
②Maximum androgen blockade;
③Intermittent endocrine therapy;
④ Neoadjuvant endocrine therapy before radical treatment;
⑤ Adjuvant endocrine therapy.
Localized treatments such as cryotherapy, high-energy focused ultrasound and radiofrequency ablation of tumors are less invasive, but their efficacy and safety need to be evaluated and improved by longer-term clinical studies.
Prevention of prostate cancer
The development of prostate cancer is the result of the interaction of genetic factors and environmental exposures. Because the disease progresses slowly, the stimulation of causative factors often manifests itself as an increased incidence decades later, therefore, the current trend of prostate cancer incidence in China must be given sufficient attention.
The traditional Chinese diet has less fat and meat and more soy products, which contain a lot of phytoestrogens that can inhibit the growth of prostate cancer cells; in addition, Chinese people have the habit of drinking tea (especially green tea), and some studies have shown that green tea can reduce the risk of prostate cancer development. Therefore, reducing the intake of animal fat and increasing the intake of vegetables, soy products, green tea and red wine may reduce the risk of prostate cancer.
Prospects for early diagnosis of prostate cancer
The incidence of prostate cancer in China is increasing year by year, but the case composition is predominantly advanced. A comparative study of the survival rates of limited prostate cancer and metastatic prostate cancer showed that early detection of prostate cancer and radical treatment is the best way to improve the prognosis, and it is more effective to reduce the proportion of patients with advanced stages than to optimize the treatment of patients with advanced stages. Therefore, a well-established mechanism of PSA screening and ultrasound-guided prostate puncture biopsy will contribute to the early diagnosis and timely treatment of prostate cancer.