How to diagnose prostate cancer?
The PSA test is not a reliable indicator of cancer and for these reasons its use in the diagnosis of prostate cancer is controversial.
It appears instead of fundamental importance to control over time the evolution of the disease. The PSA (Prostate Specific Antigen) is a protein that is produced by the prostate gland and is present in seminal fluid and, under physiological conditions, is found in small quantities in the blood. To perform this test, a simple blood test is performed that will be analyzed in order to measure the concentration of PSA in the blood. The values of total PSA generally considered the norm is 4 ng/ml (nanograms per milliliter); however, since the values of PSA can increase with age or in the presence of other conditions, not necessarily associated with the presence of cancer, the results of this test should not be interpreted in an absolute manner.
In general it is a good practice for the doctor to read and interpret test results: in this way data can be evaluated, by relating the patient's age and other conditions not related to a disease state. However, in general, a patient presenting PSA values between 2 and 4 ng/ml has a low probability of having a tumor.
WHAT ARE THE FACTORS THAT CAN AFFECT THE TEST RESULTS?
- recent ejaculation
- digital rectal examination
- transrectal ultrasound
- diagnostic procedures (e.g. cystoscopy)
Trauma due to cycling or driving a motorbike
IS THIS BECAUSE THE PSA IS NOT A MARKER FOR THE PRESENCE OR ABSENCE OF MALIGNANCY?
- About 20% of prostate cancers diagnosed by biopsy were detected in patients with "normal" PSA values;
- The values of PSA can be elevated even in the presence of prostatitis or benign prostatic hypertrophy;
- There may be small changes in PSA for reasons that are unclear but, definitely, not pathological.
In contrast, in men who have already been treated for prostate cancer, a PSA test performed to monitor the evolution of the disease it is very useful tool to evaluate the effectiveness of therapy; in fact after the treatment the PSA level returns to within the normal range in a time that varies according to the treatment received.
The severity of the tumor is defined by two parameters, the grading and the stage of disease.
The pathologist who receives the tissue taken by biopsy and which is analyzing under the microscope, can not only determine whether cancer cells are present, but can also define the grading. The grading, the degree of differentiation of tumor cells, is related to aggressiveness of the tumor, and indicates the speed with which the mass tends to grow and spread to other organs.
- A score of 2 to 4 indicates a well-differentiated tumor growth and with little tendency to spread to other organs;
- A score of 5 to 6 indicates a moderately differentiated tumor with an intermediate degree of aggressiveness;
- A score of 7 to 10 indicates an aggressive cancer poorly differentiated and more likely to spread to other organs.
The other factor used for the evaluation of prostate cancer is the stage of disease. The staging is used to define the location and size of the tumor: it also indicates whether the disease has spread to other organs. The method employed to describe the stage of the tumor disease, for all tumor types, is the so-called TNM system, where the letter T indicates the extent of the primary tumor, the letter N identifies the involvement of the lymph nodes, while the letter M records the presence of distant metastases.The TNM letters are complemented by a number. The T1 and T2 tumors are called 'localized', while the T3 are 'locally advanced'. When a cancer has reached the lymph nodes or other organs is called 'advanced' or 'metastatic'.
|T- Primary Tumor|
|TX||Primary tumor cannot be assessed|
|T0||No evidence of primary tumor|
|T1||Clinically unapparent tumor is not palpable
T1a Tumor incidental histological finding in 5% or less of tissue resected
T1b Tumor incidental histological finding in more than 5% of tissue resected
T1c Tumor identified by needle biopsy (e.g. because of elevated prostate-specific antigen (PSA) level)
|T2||Tumor that is palpable and confined within the prostate
T2a Tumor involves one half of one lobe or less
T2b Tumor involves more than half of one lobe, but not both lobes
T2c Tumor involves both lobes
|T3||Tumor extends through the prostatic capsule
T3a Extracapsular extension (unilateral or bilateral) including microscopic bladder neck involvement
T3b Tumor involves seminal vesicle(s)
|T4||Tumor is fixed or invades adjacent structures other than seminal vesicles: external sphincter, rectum, levator muscles, and/or pelvic wall|
|N - Regional Lymph Nodes|
|NX||Regional lymph nodes cannot be assessed|
|N0||No regional lymph node metastasis|
|N1||Regional lymph node metastasis|
|M - Distant Metastasis|
|M0||No distant metastasis|
|M1a Non-regional lymph node(s)|
|M1c Other site(s)|
In relation to the histological features of the tumor and the values of PSA, the risk classes are defined to guide the therapeutic choice. Beside the definition of grading, indicating the degree of differentiation of cancer cells, and the stage of the disease, which defines the extent of the tumor, over the years it has become increasingly important to pay attention to the concept of risk of disease progression. The definition of the class of risk makes it possible to relate the 'extent of the tumor', based on the staging of the disease, with the values of PSA and Gleason grading. This definition will guide the oncologist in selecting the most appropriate therapy.
various classes of risk have been identified:
- low risk
- intermediate risk
- high risk
The definition of risk classes is based on the Staging (defined using the TNM system), the grading (defined by Gleason score) and levels of PSA.
|Definition||PSA < 10 ng/mL
and GS < 7
|PSA 10-20 ng/mL
or GS 7
|PSA > 20 ng/mL
or GS > 7
any GS cT3-4 or cN+
Localized disease means that the tumor is limited to the prostate.
Locally advanced means that the tumor has spread outside of the prostate.