Простата қатерін анықтау: пайдасы мен зияны

Prostate cancer screening is the screening process used to detect undiagnosed prostate cancer in men without signs or symptoms. When abnormal prostate tissue or cancer is found early, it may be easier to treat and cure, but it is unclear if early detection reduces mortality rates. A 2013 Cochrane review concluded PSA screening results in "no statistically significant difference in prostate cancer specific mortality ". so that men are informed of the risks and benefits of screening. In 2012, the American Society of Clinical Oncology recommends screening be discouraged for those who are expected to live less than ten years, while for those with a longer life expectancy a decision should be made by the person in question. In general, they conclude that based on recent research, "it is uncertain whether the benefits associated with PSA testing for prostate cancer screening are worth the harms associated with screening and subsequent unnecessary treatment." Prostate biopsies are used to diagnose prostate cancer but are not done on asymptomatic men and therefore are not used for screening. Infection after prostate biopsy occurs in about 1%, while death occurs as a result of biopsy in 0.2%.

Prostate specific antigen (PSA) is secreted by the epithelial cells of the prostate gland and can be detected in a sample of blood. PSA is present in small quantities in the serum of men with healthy prostates, but is often elevated in the presence of prostate cancer or other prostate disorders. PSA is not a unique indicator of prostate cancer, but may also detect prostatitis or benign prostatic hyperplasia. A 2018 United States Preventive Services Task Force (USPSTF) draft adjusted the prior opposition to PSA screening. The final recommendation for that age group states screening should only be done in those who wish it. In those 70 and over, screening remains not recommended. The evidence surrounding prostate cancer screening indicates that it may cause little to no difference in mortality. Conversely, some argue against PSA testing for men who are too young, because too many men would have to be screened to find one cancer, and too many men would have treatment for cancer that would not progress. Low risk prostate cancer does not always require immediate treatment, but may be amenable to active surveillance. A PSA test cannot 'prove' the existence of prostate cancer by itself; varying levels of the antigen can be due to other causes. The USPSTF recommends against digital rectal examination as a screening tool due to lack of evidence of benefits. Although DRE has long been used to diagnose prostate cancer, no controlled studies have shown a reduction in the morbidity or mortality of prostate cancer when detected by DRE at any age. The American Urological Association in 2018 stated that for men aged 55 to 69, they could find no evidence to support the continued use of DRE as a first line screening test; however, in men referred for an elevated PSA, DRE may be a useful secondary test. A study by Krilaviciute et al. (2023) examined the effectiveness of the DRE as a standalone screening test for prostate cancer in >46,000 young men in Germany (age 45). It was found that DRE has a much lower detection rate for prostate cancer compared to PSA screening. Therefore, the authors recommend not to use DRE as a screening test for prostate cancer in young men, as it does not provide an improvement in detection compared to PSA screening.

Prostate biopsies are considered the gold standard in detecting prostate cancer. The biopsy technique includes factors such as needle angle and prostate mapping method. Patients with localized cancer and perineural invasion may benefit more from immediate treatment rather than adopting a watchful waiting approach.

MRI is used when screening suggests a malignancy. This model potentially minimizes unnecessary prostate biopsies while maximizing biopsy yield. Despite concerns about the cost of MRI scans, compared to the long term cost burden of the PSA/TRUS biopsy based standard of care, the imaging model has been found to be cost effective. MRI imaging can be used for patients who have had a previous negative biopsy but their PSA continues to increase. Consensus has not been determined as to which of the MRI targeted biopsy techniques is more useful. In a study involving 400 men aged 50 – 69, MRI screening identified more men with prostate cancer than PSA tests or ultrasound and did not increase the number of men who needed a biopsy. A large scale trial of MRI screening, TRANSFORM, began in the UK in spring 2024.

68Ga PSMA PET/CT imaging has become, in a relatively short period of time, the gold standard for restaging recurrent prostate cancer in clinical centers in which this imaging modality is available. For local recurrence, 68Ga PSMA PET/MR or PET/CT in combination with mpMR is most appropriate. PSMA PET/CT may be potentially helpful for locating the cancer when combined with multiparametric MRI (mpMRI) for primary prostate care. Prostate multiparametric MR imaging (mpMRI) is helpful in evaluating recurrence of primary prostate cancer following treatment.

A number of biomarkers for prostate cancer exist. These include the following blood, urine and tissue based tests:
EpiSwitch® PSE is a blood test used for screening and diagnosing prostate cancer utilizing epigenetic markers to identify specific changes in regulatory looping structures (chromosome conformation signatures) associated with prostate cancer. Used in conjunction with a PSA test, the PSE test boosts accuracy from 55% to 94% offering a more effective and precise method for detecting and diagnosing prostate cancer. The 4Kscore combines total, free and intact PSA together with human kallikrein 2. Researchers at the Korea Institute of Science and Technology (KIST) developed a urinary multi marker sensor with the ability to measure trace amounts of biomarkers from naturally voided urine. The correlation of clinical state with the sensing signals form urinary multi markers was analyzed by two machine learning algorithms, random forest and neural network. Both algorithms provided a monotonic increase in screening performance as the number of biomarkers was increased. With the best combination of biomarkers, the algorithms were able to screen prostate cancer patients with more than 99% accuracy. As of 2018 a draft for new recommendations suggests that screening be individualized for those between the ages of 55 to 69. It notes a small potential decrease in the risk of dying from prostate cancer, but harm from overtreatment. The American Cancer Society "recommends that asymptomatic men who have at least a 10 year life expectancy have an opportunity to make an informed decision with their health care provider about screening for prostate cancer after they receive information about the uncertainties, risks, and potential benefits associated with prostate cancer screening. Prostate cancer screening should not occur without an informed decision making process. Men at average risk should receive this information beginning at age 50 years. Men in higher risk groups should receive this information before age 50 years. Men should either receive this information directly from their health care providers or be referred to reliable and culturally appropriate sources." Other guidelines and centers specializing in treating prostate cancer recommend obtaining a PSA in all men at age 45. The American Urological Association in 2018 states that men under the age of 55 and over the age of 69 should not be routinely screened. The greatest benefit of screening appears to be in men ages 55 to 69 years. To reduce the harms of screening, a routine screening interval of two years or more may be preferred over annual screening in those men who have participated in shared decision making and decided on screening. Screening is done by PSA (blood test). The Canadian Urological Association in 2017 suggested screening be offered as a possibility to those who are expected to live more than 10 years, with the final decision based on shared decision making. Some men have germ line mutations associated with prostate cancer development (e. g., BRCA1, BRCA2, HOXB13). Screening and its frequency is established after consulting with a geneticist. Publications authored by governmental, non governmental and medical organizations continue the debate and publish recommendations for screening. One in six men will be diagnosed with prostate cancer during their lifetime but screening may result in the overdiagnosis and overtreatment of prostate cancer. Though the death rates from prostate cancer continue to decline, 238,590 men were diagnosed with prostate cancer in the United States in 2013 while 29,720 died as a result. Death rates from prostate cancer have declined at a steady rate since 1992. Cancers of the prostate, lung and bronchus, and colorectum accounted for about 50% of all newly diagnosed cancers in American men in 2013, with prostate cancer constituting 28% of cases. Screening for prostate cancer varies by state and indicates differences in the use of screening for prostate cancer as well as variations between locales. Out of all cases of prostate cancer, African American men have an incidence of 62%. African American men are less likely to receive standard therapy for prostate cancer. This discrepancy may indicate that if they were to receive higher quality cancer treatment their survival rates would be similar to whites. Prostate cancer is also extremely heterogeneous: most prostate cancers are indolent and would never progress to a clinically meaningful stage if left undiagnosed and untreated during a man's lifetime. On the other hand, a subset are potentially lethal, and screening can identify some of these within a window of opportunity for cure. Thus, PSA screening is advocated by some as a means of detecting high risk, potentially lethal prostate cancer, with the understanding that lower risk disease, if discovered, often does not need treatment and may be amenable to active surveillance. Screening for prostate cancer is controversial because of cost and uncertain long term benefits to patients. Horan echos that sentiment in his book. Private medical institutes, such as the Mayo Clinic, likewise acknowledge that "organizations vary in their recommendations about who should – and who shouldn't – get a PSA screening test. They conclude: "Ultimately, whether you should have a PSA test is something you'll have to decide after discussing it with your doctor, considering your risk factors and weighing your personal preferences." A 2009 study in Europe resulted in only a small decline in death rates and concluded that 48 men would need to be treated to save one life. But of the 47 men who were treated, most would be unable to ever again function sexually and would require more frequent trips to the bathroom. Men report low levels of distress surrounding PSA screening. Men who present for PSA or have PSA levels at baseline scored low on cancer distress on numerous scales. A study published in the European Journal of Cancer (October 2009) documented that prostate cancer screening reduced prostate cancer mortality by 37 percent. By utilizing a control group of men from Northern Ireland, where PSA screening is infrequent, the research showed this substantial reduction in prostate cancer deaths when compared to men who were PSA tested as part of the ERSPC study. A study published in the New England Journal of Medicine in 2009 found that over a 7 to 10 year period, "screening did not reduce the death rate in men 55 and over." The "Comparison Arm" has yet to report as of early 2018.