Cancer is one of the most prevalent and feared types of diseases, this can be explained by demographic changes and the mortality of this group of diseases. Currently, in most industrialized nations and some developing nations life expectancy has incremented tremendously in the last century. As a result of this and other factors, the type of disease affecting populations has changed as well. One of these diseases is cancer, which should never be considered as a single type of disease rather a category with a great variety of diseases. Even though not all cancer has a high level of mortality, fear in patients remains because of the uncertainty of death.
One of the types of cancers in which this can be observed in prostate cancer. Prostate cancer is a malignant disease derived from the glandular epithelial cells in the prostate gland. In male patients, it is both the second most common type of cancer and the cause of mortality from cancer. Nevertheless, the 5-year survival rate for all cases of prostate cancer is 90%. However, if one considers only advanced stages of prostate cancer, the 5-year survival rate lowers to about 28%. Because of the differences in mortality between different stages, it is essential to diagnose prostate cancer at the earliest stage possible.
Prostate Cancer Diagnosis and Tests
The diagnosis of prostate cancer is a task, which requires lots of knowledge, experience, and preparation because this is a type of cancer that progresses for a long period of time asymptomatically. Therefore, the physician should identify any signs and symptoms of prostate cancer in order to perform an earlier diagnosis. In addition, screening could provide an early diagnosis of the disease but its effectivity has been limited, therefore the physician should evaluate the patient’s risk before performing evaluations and test for prostate cancer.
A prostate cancer diagnosis will begin by an initial evaluation of risk factors and the identification of signs and symptoms of prostate cancer. If the initial evaluation yields a high risk in patients or the patient ask for a screening test for prostate cancer, the physician should provide them. Later, the physician might solicit another test for prostate cancer to confirm the diagnosis of prostate cancer and determine the stage of cancer.
One of the first steps in the diagnosis of prostate cancer is the evaluation of risk factors in patients. Risk factors allow a physician to determine the probability a patient will have the disease and depending on this probability perform further evaluation and test on the patient. For prostate cancer, the main risk factors include age, race/ethnicity, geographical locations, family history, and genetic alterations. Other risk factors whose effect on the risk of prostate cancer has not been clearly defined include diet, obesity, smoking, chemical exposures, inflammation of the prostate, vasectomy, and sexually transmitted infections.
Age is the most significant and useful risk factor in the evaluation of patients. Prostate cancer is a disease associated with elderly patients as a result of numerous exposures to carcinogens and accumulation lesions and mutations in the genetic material of somatic cells. Most patients diagnosed with prostate cancer are older than 60 years old (6 out of 10 cases of prostate cancer are diagnosed after this age). Prostate cancer is rarely diagnosed in younger patients, and these patients often carry a genetic predisposition to develop prostate cancer. In these cases, prostate cancer tends to be aggressive and have a rapid development.
Studies have demonstrated that risk factors associated with environmental conditions have a greater influence on the risk of patients. Even though higher rates of prostate cancer are seen in African Americans, patients living in Africa have a lower risk of this type of cancer. Similarly, studies have shown Asian American patients have a lower risk than white patients have but have a higher risk than patients living in Asia. Therefore, living in certain countries (western countries) raises the risk of suffering from prostate cancer. It is believed the increases in risk in patients in these countries is the result of risks such as diet, obesity and chemical exposures. Nevertheless, as previously mentioned the role of these risk factors have not been precisely defined.
The other initial step in the diagnosis of prostate cancer is the identification of the sign and symptoms of prostate cancer. The clinical manifestations can be classified as local or metastatic. The first will result in the growth of the tumor and the pressure it causes in nearby structures. Therefore, significant tumor growth is required to cause symptoms in patients. Typical local symptoms include changes in urinary habits, hematuria, sexual dysfunction, pain, and neurological dysfunctions. Urinary changes in urinary habits are typical of disease associated with prostate enlargement. Three of these clinical manifestations, poor stream, urgency, and frequency, are grouped into a clinical description, prostatism. Other changes in urinary habits include hesitancy and dribbling.
If the prostate cancer grows enough and metastasize, signs and symptoms might appear in distal tissues and organs. Among these clinical manifestations are pain, weakness, fatigue and weight loss. The pain will typically manifest in pelvic bones and the lumbar spines but it can spread to, essential, any part of the body. If an elderly patient presents with pelvic and lumbar bone pain, the physician should always suspect the possibility of a malignant invasion of prostate cancer metastatic cells. The other symptoms, weakness, fatigue, and weight loss are the result of the wasteful metabolic process in the tumor cells.
If either the identification of risk factors or clinical manifestations suggest prostate cancer, two screening tests for prostate cancer may be performed. Currently, two screening tests are performed, the digital rectal exam and the prostate-specific antigen blood test. This test may even find evidence of prostate cancer even before the first signs and symptoms appear.
The digital rectal exam is a way to screen the prostate gland for cancer. This examination consists of the examination of the prostate gland by introducing a finger through the rectum and palpating the gland. It is an evaluation that must be done carefully in order to prevent injuries in the patient and maintain a good physician-patient relationship. Pathological signs found in a digital rectal exam include excessive protrusion, an asymmetry between lobes, hard and heterogeneous prostate gland. In terms of sensibility, it is not the best test but helps the physician identify some cases of prostate cancer. Additionally, if other masses nearby are palpated perhaps, the metastatic process has begun already. In order to improve results from this screening test, it is usually performed along with the prostate-specific antigen blood test.
The other screening test, the prostate-specific antigen blood test, has revolutionized the diagnosis of prostate cancer. It the most clinically relevant biological marker of this disease. Numerous studies have shown a decrease in mortality as a result of early detection of the disease. Nevertheless, as a random screening test, the research remains inconclusive. This test has low sensitivity, as shown by studies in which about 70 to 80% of patients with positive prostate antigen blood test will have a negative biopsy result. However, it still remains a useful test for prostate cancer, to determine which patients have prostate biopsy tests.
Currently, the cutoff level of prostate-specific antigen blood levels is 4 nanograms per milliliter of blood. The cutoff level was chosen because most male patients will have results for this test lower than this value. If a male patient has a higher value than 4 nanograms per milliliter and less than 10 nanograms per milliliter, he will have a 25% probability of having prostate cancer. If the value is higher than 10 nanograms per milliliter, the probability rises to over 50%. However, currently, the cutoff level for performing a biopsy varies according to the physician’s criteria. Also, beyond screening and determining the need for further testing, this test for prostate cancer has other utilities. Among these are the staging process of the disease and the follow-up of prostate cancer treatment.
After either or both screening tests are performed, if these suggest the presence of prostate cancer in the patient, another test must be solicited. This additional test will confirm the diagnosis and provide information to determine the stage of cancer. Among these tests are imaging studies and biopsies. There is a great diversity of imaging tests for prostate cancer, such as transrectal ultrasound, magnetic resonance imaging, and bone scans. Even though computed tomography scans can be useful to determine the metastasis of prostate cancer to nearby areas, it is not as useful as magnetic resonance imaging.
Initial imaging studies include the transrectal ultrasound test. During this test, a small lubricated probe is inserted into the rectum and through usual ultrasound imaging. This study is usually performed after high prostate-specific antigen levels in the blood or abnormal digital rectal exam results. It is usually used to study the prostate or to guide needles to extract samples for prostate biopsies.
The other imaging studies are typically used to determine the spread of prostate cancer into other tissues. One of the first tissue prostate cancers metastasizes to bare bones, especially pelvic bones and lumbar spine. In this test for prostate cancer, a low-level radioactive material is injected into the bloodstream. Later, as a result of the hypermetabolic state of malignant cells, the radioactive material will move into the areas of metastasis in the bone. Later, these areas are detected and reported for further studies. Among the studies performed after a bone scan are a bone biopsy and magnetic resonance imaging test. A magnetic resonance imaging test is one of the most useful imaging tests for prostate cancer. It allows a detailed evaluation of the prostate, seminal vesicles, and other nearby structures. Therefore, it will be particularly useful for staging prostate cancer in patients. Sometimes contrast material (gadolinium) or a probe (endorectal coil) are used to provide more detail in this imaging study.
A physician might perform the initial evaluation, screening test, and an imaging test but the definite diagnosis of prostate cancer can only be done through a biopsy. Biopsies will allow the physician to determine the prescience of malignant cells in the prostate gland, bone tissues, and lymph nodes. Additionally, biopsies determine the grade according to the Gleason score and help determine the stage according to the TNM staging. Samples for prostate cancer biopsy are usually removed by a core needle biopsy. Through guidance by the transrectal ultrasound, the needle is guided into the prostate gland and a small cylinder of the gland is extracted. Multiple samples are extracted, in most cases, up to 12 samples are extracted.
Samples are studied in through microscopes in a laboratory to determine the grade of the tumor. The grade of the tumor is determined according to the observed characteristics and the Gleason score, which evaluates how different is cancer from regular prostate tissues. Depending on the similarity to normal prostate tissues, values of 1 to 5 are assigned, (1 meaning tissue with a normal appearance and 5 meaning extremely abnormal appearance). Depending on the area of each of the 12 samples, the number of samples and the appearance of a score from 2 to 10 is calculated.
Other findings in biopsies include the presence of the results in which there are neither cancer nor normal cells. Biopsies with these results are reported as suspicious and include prostatic intraepithelial neoplasia. These changes are often classified into two groups according to the grade, lowgrade and high-grade prostatic intraepithelial neoplasia. Additionally, lymph node biopsies will determine the presence of cancer cells in the lymph nodes.
Finally, after the evaluation of the patient through all the steps previously mentioned, the physician integrates the findings into the TNM staging system. There are 5 essential aspects to consider in the staging, the extent of the primary tumor (T), the spread to nearby lymph nodes (N), the metastasis to other parts of the body (M), the level of PSA at the time of diagnosis, and the Gleason score. As a result of the integration of the 5 aspects, the stage is determined as 1 (the least advanced) to 4 (the most advanced).
Staging is an essential step in the diagnosis of prostate cancer. It allows the physician to determine prognosis, a treatment plant, and other recommended management. Because of this, it is essential that all physicians manage the essential aspects of the diagnosis and test of prostate cancer. This is what will allow the early diagnosis, which yearly saves hundreds of lives and improves the quality of life of many.