Pros and cons of prostate screening
One of them was made in the United States, the second in Europe. Reports on the results obtained on March 18 were posted on the website of the extremely authoritative medical weekly New England Journal of Medicine.
The pros and cons of such monitoring have been discussed for a long time. Prostate cancer is a very insidious disease. It does not give certain symptoms for a long time, which, moreover, even after the manifestation, are easily confused with the consequences of the usual age-related enlargement of the prostate. Prostate tumors in most cases grow very slowly and do not go beyond this organ. However, they are also capable of spreading metastases throughout the body, most often in the kidneys, pelvic bones, ribs and vertebrae. In this case, the disease, as a rule, quickly leads to death.
Prostate cancer is also extremely common. When microscopically examining the tissue of this gland, tumor cells are found in half of men who have reached the age of 50, and in almost all men over 90 years old. According to medical statistics, it is the second most common cause of death from malignant tumors among men in many developed countries. In the United States, approximately 27 thousand people die from this disease every year.
In principle, the diagnosis of prostate cancer does not pose any particular problems. The doctor may suspect the occurrence of a tumor based on measuring the concentration of one of the plasma proteins, prostate-specific antigen. The production of this enzyme, which is secreted by prostate epithelial cells, increases with the increase in the size of the gland. Such an increase is often quite benign, but it can also be explained by the appearance of a cancerous tumor. After receiving an alarm signal from the laboratory, the doctor can probe the prostate through the rectum, look at it through a fiber-optic probe that is inserted into the bladder, or send the patient for an ultrasound examination. These methods together make it possible to reliably detect prostate tissue seals, which may turn out to be cancerous foci. For the final detection of the tumor and to determine the degree of its aggressiveness, it is necessary to take tissue samples from several areas of the gland and send them for histological analysis. Only in this way can a doctor make a correct diagnosis of the disease.
That's where the dog is buried, as they say. In the United States, doctors prescribe prostate-specific antigen measurements to approximately 25 million middle-aged men every year. If its concentration turns out to be low, patients are calmed down and released in peace. However, an increase in the level of prostate-specific antigen does not necessarily indicate the presence of cancer. Additional examinations cost quite a decent amount and also do not give unambiguous results until a biopsy is performed. For the patient, this procedure is unpleasant and not always safe.
But it's not just the difficulties of diagnosis. It is not so easy for doctors to decide what to advise an elderly man who has prostate cancer detected with absolute reliability. Oncologists do not yet know how to distinguish "calm" malignant neoplasms of the prostate gland from aggressive ones. There are many chances that the detected tumor will not particularly bother the patient, even if he lives to the Methuselah years. Therefore, many urologists in such cases prefer to simply observe patients and for the time being not to take decisive action. However, often such patients are offered to take courses of hormonal and radiation therapy or just immediately operate on the prostate. Such procedures are fraught with a considerable risk of serious complications, including urinary incontinence and impotence. The degree of this risk is far from small – from 30% to 50%.
What happens? Mass primary examinations for prostate cancer are expensive for healthcare and push doctors to prescribe a rather dangerous and, most importantly, often unnecessary treatment. All this could be ignored if it could be proved that these examinations seriously reduce mortality from prostate cancer. However, medicine has not yet had such evidence.
The surveys reported by the New England Journal of Medicine were conducted just to clarify this key problem. In general, they were conducted approximately the same way, the differences were only in details. American doctors for seven years observed about 77 thousand men aged 55 to 74 years. Half of the patients were tested annually for prostate-specific antigen or had a rectal examination of the prostate. The rest of the prostate condition was checked irregularly or not checked at all. Although a total of 17% more cases of prostate cancer were detected in the first group, the mortality rate from this disease was approximately the same – 50 people in the first group and 44 in the second. Moreover, in the first group during the observation, a total of 312 people died for various reasons, and the second only 225. The authors of the report do not exclude that some of them were shortened by too radical treatment of prostate cancer.
The second examination gave slightly different results. It covered 162 thousand elderly residents of seven European countries, who were also divided into two groups. Some participants had their prostate antigen levels checked every four years, while others were not given such tests at all. In the first group, the death rate from prostate cancer was 20% lower than in the second. However, such a difference does not indicate a high efficiency of prostate-specific antigen monitoring. Analysis of the collected data shows that in order to prevent one death, it is necessary to check on average over 1400 men, of which 48 people should, without any benefit, but with a high risk, go under the surgeon's knife or undergo radiation or hormone therapy.
In general, we have to admit that the results of American and European doctors have not been able to unequivocally answer the question whether or not elderly men should regularly check the level of prostate-specific antigen. Probably, these disputes will continue until more reliable methods of mass detection of prostate tumors and prediction of their aggressiveness appear. Hopefully, this will not happen in the very distant future.
Portal "Eternal youth" www.vechnayamolodost.ru
24.03.2009