Prostate Cancer: The Problem Of Diagnosis

The introduction into clinical practice of modern methods of diagnosis of prostate cancer increases the probability of detecting the disease early when it is still possible to use radical methods of treatment.
Diagnosis of the disease poses two major challenges: identifying the disease and determine the stage and extent of the process that is crucial for selecting treatment tactics.

Prostate cancer is detected in 4-7% of cases in men aged 50 years and older with no urological symptoms and diseases of the urogenital system in history. Moreover, prostate cancer 1-2-th stage, as a rule, clinically does not manifest itself, so the collection of history and the identification of symptoms are not clinically significant factors in the diagnosis of early stages. At later stages of the disease the patients complained of shortness of frequent urination "sluggish" jet, night thamuria. If such complaints required a more detailed examination to exclude prostate cancer zhelezy. Paltsevoe rectal examination is still the standard for screening diagnosis of primary tumors of prostate cancer, although this method is not sufficiently sensitive for the diagnosis of tumors, not beyond the prostate. Tumor size 1-1,2 cm, usually remains unnoticed. Nevertheless, digital rectal examination can be considered as a basic diagnostic method, mandatory in the primary inspection .

Digital rectal examination (PRI) to determine the approximate size of the prostate, its shape and texture. He also conducted to identify benign prostatic hyperplasia, tumors of the rectum, chronic prostatitis, as well as to assess the tone of the anal sphincter. The nature of tactile stimulation can affect the patient's different positions (on the side, Bozeman, etc.), as well as the degree of fullness of the bladder. The specificity of digital rectal examination for detecting prostate cancer is small: only in 26-34% of men with suspicious results found prostate cancer. Typically, a suspicion of prostate cancer in AT occurs only in the later stages of the process. Proportion of false-negative diagnoses in this study reaches 40-60%.

The diagnostic features of prostate cancer during the PRI is increased and the asymmetry of the prostate, the presence of solidification.

Transrectal ultrasound scan (TRUS) is the main method of instrumental studies of the prostate. The most informative for identifying the primary tumor results can be obtained in longitudinal transrectal scanning. The basic law is the reduction of echogenicity in the tumor sites, although pathognomonic ultrasound signs of adenocarcinoma, apparently, does not exist, and in 15-20% of patients whose clinical stage of prostate adenocarcinoma is installed by other methods, echographic changes are absent. Echographic signs of adenocarcinoma of the prostate are single, clearly defined foci of decreased echogenicity, multiple gipoehogennye areas with vague boundaries, iso-and hyperechogenic foci. Upon germination the tumor beyond the capsule of the prostate on the sonogram observed breakthrough capsules and hyperechogenic fat strips surrounding pancreas.

Less efficient scanning in the transverse plane, allowing only consider the symmetry of the prostate and seminal vesicles. Features transabdominal scanning is limited because of the low resolution, while defines the overall dimensions of the prostate, but to differentiate its internal structure can not.

In general, Predictability of a positive result when using only TRUS does not exceed 40-43%, so it is obligatory to mix it with other methods.

There TRUS with color Doppler mapping, which allows to study the vascular architecture of the prostate. In this case, the most informative is the longitudinal ultrasonic scanning, and to study the spectral characteristics of blood flow - a transverse scan. In parts of malignant lesions decrease resistance index by 12-15% compared to the blood flow unchanged prostate. For the diagnosis and differential diagnosis of color Doppler mapping has the support znachenie.Pochti all cancers originating in the prostate are adenocarcinomas. In many Western European countries and America with adenocarcinoma of the prostate - the most common internal cancers in men and in the U.S. in 1991 there were 122 thousand of cases, moreover, that lung cancer in the same year 101 thousand sick men. Annual mortality from adenocarcinoma of the prostate was in 1983 and 1984, 22.7 cases per 100 thousand populations, with incidence of 75.3 cases per 100 thousand populations. Morbidity and mortality from prostate cancer have a tendency to increase in all countries. From 1985 to 1995 the incidence of prostate cancer has increased from 6 to 12 cases per 100 thousand men
An important objective of cancer research for each body - to find serum markers that can determine the presence and degree of malignancy of the disease monitor its development in time and to confirm success or failure of treatment. In the presence of prostate cancer in the tumor cells not only increases production of PSA, but also significantly increases the synthesis antihimotripsina. As a result, an increasing number of related content and reduced free fraction of PSA with increasing total concentration of antigen.

Considered normal content of total PSA less than 4 ng / l, increasing PSA levels over 10 ng / l is already an indication for a detailed examination to exclude prostate cancer even when normal data PRI. At higher mean total PSA prostate biopsy is mandatory. With a view to a more accurate interpretation of elevated values of total PSA is necessary to study the concentration of free PSA and the calculation of the ratio of free and total PSA. With the value of this index below 15% requires a biopsy of the prostate. With a value of more than 15% needed supervision and the patient retested after six months. The 15% is the boundary for the differential diagnosis of prostate cancer and benign prostatic hyperplasia.
In certain cases, an isolated indicator of the total PSA may correspond to different tumor size. Its significance is lost in the presence of poorly differentiated prostate cancer.

The level of PSA is the most accurate marker for screening diagnosis of prostate cancer, but its capabilities are limited in determining the stage of the process, as the PSA level does not depend on the volume of the tumor.
One of the most reliable ways to diagnose prostate cancer is multifocal needle biopsy, performed either under ultrasound guidance, or under finger control. In recent years, to obtain material from the prostate biopsy gun is used. It is recommended to select six cylindrical samples 15 mm long, situated evenly - three in each lobe srednesagittalnoy plane at an equal distance from each other. The depth of selection and orientation of the individual samples are selected so as to completely cross the peripheral zone of prostate with a thickness of srednesagittalnoy plane seldom exceeds 10 mm, and enter the central zone of prostate. The lower end of the extracted tissue mark the column before placing it in formalin, which allows further identification of tumor originating in the central zone. Multifocal biopsy provides an estimate of tumor volume, determine the stage of its development by Gleeson, and localize its position that it is important to develop proper tactics surgical treatment. The resulting volumetric information also distinguishes the way the fence tissue biopsy in the form of solid bars from the method of aspiration.

If you find pictures of biopsy for prostate cancer need to determine the degree of tumor differentiation, which largely depends on its biological behavior and, consequently, further treatment tactics. Commonly at the present time "WHO Histological Classification of Tumors of the prostate" (1980, N 22) focuses on formal and histological type of tumor that is not a determinant in establishing its biological behavior and to choose the most effective treatments. In this regard, more productive system of degrees of histological differentiation of prostate cancer by Glisson (1977), used in the U.S. national program to combat cancer.

The process of dedifferentiation is defined as the loss of the ability of newly formed tumor cells to form glands.
Under this system distinguishes five degrees of tumor differentiation. In the study of drugs with the presence of prostate cancer pathologist must distinguish between two major paintings: "primary" or dominant, occupying the largest area of the sample, and "secondary,” ie, the second largest, and then determine the degree of differentiation of Glisson each. Additional areas of the structure of smaller areas and areas that occupy less than 5% of the total area of cancer, are ignored. Amount of degrees and defines the index In the case of almost complete homogeneity of the structure for the index determined by the degree of Glisson doubles. The lower the index Glisson, the more effective treatment, and better prognosis for the patient.

The first three degrees (1, 2, 3), assessed as the most well-differentiated, similar in structure to the normal prostate gland. Epithelial tissues are well separated from the surrounding stroma, glands are formed by a single layer of epithelial cells surrounding the glandular lumen. Nevertheless revealed less orderly branching glands compared with benign prostatic ducts and acne. Malignant glandular structures tend to a variety of size and shape of glands, the value of clearances.
Differences of the first three degrees are insignificant. If the glands are homogeneous, and no signs of invasion or weakly expressed, the tumor could be attributed to the 1 st or 2 nd degree of differentiation. These degrees can also be installed, if the cells have a light cytoplasm, which is more than the dark, increasing the resemblance to normal tissue. In very small samples, unlike the normal tissue should be based not only on the architectonics, it must also be confirmed by cytological criteria, such as very large nucleoli.

An important exception to these rules determines well-differentiated tumor is cribrozny option, which also applies to the 3rd degree of differentiation by Gleeson. Difference kribroznogo option from cancer 4-th degree of differentiation - the small size of tumor systems, comparable to the size of large ducts, round shape, clear boundaries, well-defined stromal components.
Tumors of the 4-th degree of differentiation of Glisson a great variety of histological manifestations and the lack of formed glands, characteristic of the first three degrees.

Tumors of the 5-th degree of differentiation are the most poorly differentiated, with subtle or virtually absent glandular structures, with large fields of tumor cells almost without any clearances. Tumor cells typically have scant cytoplasm.
Under this option, described intraductalny cancer with the presence of small sites on the periphery and with total necrosis of tumor cells in the center of complexes. This is the only option for prostate cancer, which indicates necrosis of tumor cells. Statistically proven that the presence of such non-invasive plots associated with extremely poor prognosis, comparable with the prognosis in invasive cancer of the 5-th degree of differentiation.

Determination index Glisson in detecting cancer in prostate biopsy is absolutely necessary. However, Glisson, and the system is not without drawbacks First, the biopsy is not always possible to determine the biological behavior of tumor for an individual patient: prostate cancer is characterized by a large variety of histological structures even within the same tumor, and biopsy sample is very small. Secondly, the biological behavior of tumors may be due to loss of differentiation in small areas and is not associated with the dominant structures.

A more accurate prediction of the behavior of the tumor can be made on the basis of its volume, defined with radical prostatectomy. The volume of tumor usually correlated with the degree of differentiation, and equally with the presence of metastases in lymph nodes and distant metastases. Therefore, it is an important factor in determining the clinical stage of disease and in combination with the degree of differentiation most accurately reflects the biological behavior of tumors.
Computed tomography is not an effective method, it is not suitable for the differentiation of prostate cancer and benign prostatic hyperplasia. The main objective of CT is to evaluate the status of the pelvic and abdominal lymph nodes. In the diagnosis of lymph nodes is crucial change in their shape and increase in size by more than 1-1,5 cm
Magnetic resonance imaging (MRI) to evaluate the involvement in the process of the urethra, the various divisions of the prostate, bladder, fat, muscle, elevating the external sphincter, rectum, seminal vessels, and lymph nodes. The advantage of MRI compared with CT is the ability to select projections: axial, sagittal and coronal. Possible to obtain the three-dimensional image created by combining the coronary and sagittal projections. MRI better reflected vnutriprostatichescie changes than CT. Nevertheless, recognition of tissue that is affected by benign or malignant tumor is not sufficiently reliable.

Screening for prostate cancer should be carried out from out-patient clinic. All men over 50 regardless of the presence of complaints once a year is necessary that the digital rectal examination and determination of PSA levels. With an increase in PSA above 4 ng / ml shows a balance between free and total PSA and transrectal ultrasound performance.

Further examination of patients is preferable to carry out in specialized clinics - a urologic oncology. Implementation of transrectal prostate biopsy showed multifocal with an increase in PSA above 10 ng / ml, when the ratio of free and total PSA greater than 15% in identifying areas on transrectal gipoehogennyh scan and the presence of palpable solid education in the prostate.

All patients with a verified diagnosis must be met osteostsintigrafii to detect bone metastases. Application of computer, or magnetic resonance imaging showed ill, for which planned radical surgery or radiation treatment to ascertain the condition of pelvic lymph nodes.

In the diagnosis of prostate cancer is only one method - a biopsy - an invasive.

When performing transrectal biopsy are several possible complications: infection of the prostate with the subsequent development of acute prostatitis and urethrorrhagia. All patients who had undergone prostate biopsy, should be the appointment of oral antibiotics, preferably of cephalosporins, for the prevention of inflammatory complications. Urethrorrhagia is not abundant and in most cases, self-terminated within the first days after the biopsy. Absolute contraindications for the diagnostic search for prostate cancer does not exist, an obstacle may be used only in very severe condition of the patient.