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MINISTRY OF HEALTH OF UKRAINE
VINNITSA NATIONAL PIROGOV MEMORIAL MEDICAL UNIVERSITY
"CONFIRM"
at the methodical meeting
Department of Ray diagnostics,
Ray therapy and Oncology
Head of the department
As. of Prof., M.S.D. Kostyuk A.G.
________________________
"______" ________ 2013 year
METHODICAL GUIDELINES
For self-study for students in preparing for the practical (seminary) lessons
|Subject of Study | Oncology |
|Module No | 1 |
|Theme No | 18 |
|Topic of Lesson |Prostate cancer. |
| |Distribution Risk factors. |
| |Classification by TNM. Methods of diagnosis. |
| |Clinics. Treatment: surgery, |
| |radiotherapy, chemotherapy, combined. |
|Course | 5 |
|Faculty | General Medicine |
Topicality. Prostate cancer is a malignant (cancerous) tumor (growth) that consists of cells from the prostate gland. Generally, the tumor usually grows slowly and remains confined to the gland for many years. During this time, the tumor produces little or no symptoms or outward signs (abnormalities on physical examination). However, all prostate cancers do not behave similarly. Some aggressive types of prostate cancer grow and spread more rapidly than others and can cause a significant shortening of life expectancy in men affected by them. A measure of prostate cancer aggressiveness is the Gleason score (discussed in more detail later in this article), which is calculated by a trained pathologist observing prostate biopsy specimens under the microscope.
As the cancer advances, however, it can spread beyond the prostate into the surrounding tissues (local spread). Moreover, the cancer also can metastasize (spread even farther) throughout other areas of the body, such as the bones, lungs, and liver. Symptoms and signs, therefore, are more often associated with advanced prostate cancer.
Learning Objectives:
1 Incidence and epidemiology
2. Etiology and Risk factors.
3. Differential diagnosis between benign tumors and Prostate cancer.
4. The ways of spreading Prostate cancer.
5. Classification TNM. Stages of Prostate cancer.
6. Hystologic Classification Prostate tumors.
7. Main symptoms in dependent of localization.
8. Treatment tactics
9. Surgical treatment of Prostate cancer in dependent of localization
10. Choice the method of treatment (surgical, chemo- and radiotherapy).
11. Indications and contraindications for chemo- and radiotherapy.
12. Survival and prognosis.
13. Palliative care
Prostate cancer
What are prostate cancer causes?
The cause of prostate cancer is unknown, but the cancer is not thought to be related to benign prostatic hyperplasia (BPH). The risk (predisposing) factors for prostate cancer include advancing age, genetics (heredity), hormonal influences, and such environmental factors as toxins, chemicals, and industrial products. The chances of developing prostate cancer increase with age. Thus, prostate cancer under age 40 is extremely rare, while it is common in men older than 80 years of age. As a matter of fact, some studies have suggested that among men over 80 years of age, 50%-80% of them may have prostate cancer cells present in the prostate gland. More than 80% of prostate cancers are diagnosed in men older than 65 years of age.
There are differences in diagnosis and death rates among different racial groups. These differences in diagnosis and death rates are, however, more likely to reflect a difference in factors such as environmental exposure, diet, lifestyle, and health-seeking behavior rather than any racial susceptibility to prostate cancer. Recent studies indicate that this disparity is progressively decreasing with chances of complete cure in men undergoing treatment for organ-confined prostate cancer (cancer that is limited to within the prostate without spread outside the confines of the prostate gland), irrespective of race.
Genetics (heredity), as just mentioned, plays a role in the risk of developing a prostate cancer. Prostate cancer is more common among family members of individuals with prostate cancer.
Testosterone, the male hormone produced by the testicles, directly stimulates the growth of both normal prostate tissue and prostate cancer cells. Therefore, this hormone is thought to be involved in the development and growth of prostate cancer. The important implication of the role of this hormone is that decreasing the level of testosterone should be (and usually is) effective in inhibiting the growth of prostate cancer.
The roles of environment, nationality, diet, smoking, and obesity as risk factors for prostate cancer are being explored, but links have not been proven.
What are prostate cancer symptoms and signs?
In the early stages, prostate cancer often causes no symptoms for many years. As a matter of fact, these cancers frequently are first detected by an abnormality on a blood test (the PSA, discussed below) or as a hard nodule (lump) in the prostate gland. Occasionally, the doctor may first feel a hard nodule during a routine digital (done with the finger) rectal examination. The prostate gland is located immediately in front of the rectum.
Rarely, in more advanced cases, the cancer may enlarge and press on the urethra. As a result, the flow of urine diminishes and urination becomes more difficult. Patients may also experience burning with urination or blood in the urine. As the tumor continues to grow, it can completely block the flow of urine, resulting in a painfully obstructed and enlarged urinary bladder. These symptoms by themselves, however, do not confirm the presence of prostate cancer. Most of these symptoms can occur in men with non-cancerous (benign) enlargement of the prostate (the most common form of prostate enlargement). However, the occurrence of these symptoms should prompt an evaluation by the doctor to rule out cancer and provide appropriate treatment.
Furthermore, in the later stages, prostate cancer can spread locally into the surrounding tissue or the nearby lymph nodes, called the pelvic nodes. The cancer then can spread even farther (metastasize) to other areas of the body. Symptoms of metastatic disease include fatigue, bone pain, malaise, and weight loss. The doctor during a rectal examination can sometimes detect local spread into the surrounding tissues. That is, the physician can feel a hard, fixed (not moveable) tumor extending from and beyond the gland. Prostate cancer usually metastasizes first to the lower spine or the pelvic bones (the bones connecting the lower spine to the hips), thereby causing back or pelvic pain. The cancer can then spread to the liver and lungs. Metastases (areas to which the cancer has spread) to the liver can cause pain in the abdomen and jaundice (yellow color of the skin) in rare instances. Metastases to the lungs can cause chest pain, shortness of breath and coughing.
What are the screening tests for prostate cancer?
Screening tests are those that are done at regular intervals to detect a disease such as prostate cancer at an early stage. If the result of a screening test is normal, the disease is presumed not to be present. If a screening test is abnormal, the disease is then suspected to be present, and further tests usually are needed to confirm the suspicion (that is, to make the diagnosis definitively). Prostate cancer usually is suspected initially because of an abnormality of one or both of the two screening tests that are used to detect prostate cancer. These screening tests are a digital rectal examination and a blood test called the prostate specific antigen (PSA).
In the digital rectal examination, the doctor feels (palpates) the prostate gland with his gloved index finger in the rectum to detect abnormalities of the gland. Thus, a lump, irregularity, or hardness felt on the surface of the gland is a finding that is suspicious for prostate cancer. Accordingly, doctors usually recommend doing a digital rectal examination in men age 40 and over.
The PSA test is a simple, reproducible, and relatively accurate blood test. It is used to detect a protein (the prostate specific antigen) that is released from the prostate gland into the blood. The PSA level is usually higher than 4ng/mL in people with prostate cancer than in people without the cancer. Situations of large prostate size, infection and inflammation are other reasons why the PSA may be elevated. The PSA, therefore, is valuable as a screening test for prostate cancer. Accordingly, doctors usually recommend doing a PSA in men age 40 and over. Subsequent screening is recommended based on individual preference and assessment of risk for developing prostate cancer. For example, patients with a high risk of developing prostate cancer due to a family history or a high initial PSA should have more frequent evaluation (usually annually).
Although, still considered controversial, most urologists recommend regular screening for prostate cancer in men who are likely to live for more than 10 years (for example, life expectancy >; 10 years). The American Urological Association (AUA) issued their latest guidelines for prostate cancer in 2011. According to these, men at the age of 40 should be offered a baseline PSA test and a prostate exam (digital rectal exam or DRE) to ascertain the risk of prostate cancer. Subsequent screening and tests may be performed according to the findings on this initial evaluation and an individual's risk of getting the disease on the basis of other factors such as race, ethnicity, and family history of prostate cancer. As mentioned, most urologists currently would advise some form of screening in men with a life expectancy greater than 10 years. Most frequently, it would be performed on an annual basis. Although, there is no definite cutoff age to stop prostate cancer screening, most physicians would rarely screen men more than 75 years of age for this disease.
Results of the PSA test under 4 nanograms per milliliter of blood are generally considered normal. (See the next two sections on false-positive elevations of the PSA and on refinements in the PSA test.) There is a recent trend, however, to perform prostate biopsy in all patients with a PSA more than 2.5 ng/ml in order to detect prostate cancer at an earlier (and hopefully, completely curable) stage. The American Urological Association guidelines (2009) do not define a definite cutoff point but advise that all the other risk factors for prostate cancer should be taken into account while making a decision on whether to proceed for a biopsy. One of the important factors that need to be considered is the rate at which the PSA value has increased over time on repeated measurements (PSA velocity). PSA levels between 4 and 10 are considered borderline. These borderline values are interpreted in the context of the patient's age, symptoms, signs, family history, and changes in the PSA levels over time. Results higher than 10 are considered abnormal, suggesting the possibility of prostate cancer. It has been shown that the higher the PSA value, the more likely the diagnosis of prostate cancer. Moreover, the level of PSA tends to increase when the cancer has progressed from organ-confined prostate cancer to local spread to distant (metastatic) spread. Very high values, such as 30 or 40 and over, are usually caused by prostate cancer which is no longer confined to the prostate gland.
How is prostate cancer diagnosed and graded?
Prostate cancer is diagnosed from the results of a biopsy of the prostate gland. If the digital rectal exam of the prostate or the PSA blood test is abnormal, a prostate cancer is suspected. A biopsy of the prostate is usually then recommended. The biopsy is done from the rectum (trans-rectally) and is guided by ultrasound images of the area. A small piece of prostate tissue is withdrawn through a cutting needle. The TRUS (transrectal ultrasound)-guided Tru-Cut biopsy is currently the standard method to diagnose prostate cancer. Although initially a 6-core set was the standard, currently most experts advocate sampling a minimum of 10-12 pieces of the prostate to improve the chances of detection of the cancer and also to provide a better idea regarding the extent and areas of involvement within the prostate. Multiple pieces are taken by sampling the base, apex, and mid gland on each side of the gland. More cores may be sampled to increase the yield, especially in larger glands.
A pathologist, a specialist physician who analyzes tissue samples under a microscope, then examines the pieces under the microscope to assess the type of cancer present in the prostate and the extent of involvement of the prostate with the tumor. One also can get an idea about the areas of the prostate that are involved by the tumor by assessing which of the pieces contain the cancer and which of them do not. Another very important assessment that the pathologist makes form the specimen is the grade (Gleason's score) of the tumor. This indicates how different the cancer cells are from normal prostate tissue. Grade gives an indication of how fast a cancer is likely to grow and has very important implications on the treatment plan and the chances of cure after treatment. A Gleason score of 6 is supposed to indicate low-grade (less aggressive) disease while that of 8-10 demonstrates high grade (more aggressive) cancer; 7 is regarded as somewhere in between these two.
How is the staging of prostate cancer done?
The staging of a cancer refers to determining the extent of the disease (where in the body have the prostate cancer cells spread). Once a prostate cancer is diagnosed on a biopsy, additional tests are done to assess whether the cancer has spread beyond the gland.
Radionuclide bone scans can determine if there is a spread of the tumor to the bones. The radioactive substance highlights areas where the cancer has affected the bones. This test is usually reserved for men with prostate cancer who have deep bone pain or a fracture or who have biopsy findings and high PSA values (>;10-20 ng/ml) suggestive of advanced or aggressive disease.
Chest X-ray can be used to detect whether or not cancer has spread to the lungs. Ultrasound tests can be used to look for the effects of a urinary blockage on the kidneys. This study can also be used to assess the bladder for any sign of urinary obstruction due to prostate enlargement by looking at the thickness of the bladder wall as well as the amount of urine remaining within the bladder after an attempt at passing urine.
Additionally, CT scans (coaxial tomography) and MRIs (magnetic resonance imaging) can determine if the cancer has spread to adjacent tissues or organs such as the bladder or rectum or to other parts of the body such as the liver or lungs. Newer scanning using a method called PET scan can sometimes help to detect hidden locations of cancer that has spread to various areas of the body.
Cystoscopy is usually performed in selected situations. A thin, flexible, lighted tube with a tiny camera on the end is inserted through the urethra to the bladder. The camera transmits images to a video monitor. This may show whether the cancer has spread to the urethra or bladder and may be utilized to take a biopsy from these organs.
To summarize, doctors do the staging of prostate cancer based primarily on the results of the prostate biopsy, possibly other biopsies, and imaging tests. In staging a cancer, doctors assign various letters and numbers to the cancer, depending on which of the classifications for staging they use. The numbers and letters in the different classifications define the volume or amount of the tumor and the spread of the cancer. The stage of the prostate cancer, therefore, helps to predict the expected course of the disease and determine the choice of treatment.
The stages of prostate cancer are categorized as follows:
• Stage I (or A): The cancer cannot be felt on a digital rectal exam, and there is no evidence that it has spread outside the prostate. These are often found incidentally after surgery for an enlarged prostate.
• Stage II (or B): The tumor is larger than a stage I and can be felt on a digital rectal exam. There is no evidence that the cancer has spread outside the prostate. These are usually found on a biopsy when a man has an elevated PSA level.
• Stage III (or C): The cancer has invaded other tissues neighboring the prostate, like the seminal vesicles.
• Stage IV (or D): The cancer has spread to lymph nodes or to other organs.
Most doctors currently use the 2002 TNM (Tumor, Node, Metastases) staging system for prostate cancer. This is based on a combination of three criteria: extent of the primary tumor (T stage), involvement of lymph nodes by the cancer (N stage), and the presence or absence of spread to distant areas of the body in the form of metastasis (M stage). The TNM 2002 staging system is as follows:
Evaluation of the (primary) tumor ("T")
• TX: The primary tumor cannot be evaluated.
• T0: There is no evidence of tumor.
• T1: Tumor is present but not detectable clinically or with imaging.
o T1a: Tumor was incidentally found in less than 5% of prostate tissue resected (for other reasons).
o T1b: Tumor was incidentally found in greater than 5% of prostate tissue resected.
o T1c: Tumor was found in a needle biopsy performed due to an elevated serum PSA.
• T2: The tumor can be felt (palpated) on examination but has not spread outside the prostate.
o T2a: The tumor is in half or less than half of one of the prostate gland's two lobes.
o T2b: The tumor is in more than half of one lobe, but not both.
o T2c: The tumor is in both lobes.
• T3: The tumor has spread through the prostatic capsule (if it is only partway through, it is still T2).
o T3a: The tumor has spread through the capsule on one or both sides.
o T3b: The tumor has invaded one or both seminal vesicles.
• T4: The tumor has invaded other nearby structures.
It should be stressed that the designation "T2c" implies a tumor which is palpable in both lobes of the prostate. Tumors which are found to be bilateral on biopsy only but which are not palpable bilaterally should not be staged as T2c.
Evaluation of the regional lymph nodes ("N")
• NX: The regional lymph nodes cannot be evaluated.
• N0: There has been no spread to the regional lymph nodes.
• N1: There has been spread to the regional lymph nodes.
Evaluation of distant metastasis ("M")
• MX: Distant metastasis cannot be evaluated.
• M0: There is no distant metastasis.
• M1: There is distant metastasis.
o M1a: The cancer has spread to lymph nodes beyond the regional ones.
o M1b: The cancer has spread to bone.
o M1c: The cancer has spread to other sites (regardless of bone involvement).
What are the treatment options for prostate cancer?
Deciding on treatment can be difficult, partly because the options for treatment today are far better than they were 10 years ago but also because not enough reliable data are available on which to base the decisions. Accordingly, scientifically controlled, long-term studies are still needed to compare the benefits and risks of the various treatments.
To decide on treatment for an individual patient, doctors categorize prostate cancers as organ-confined (localized to the gland), locally advanced (a large prostate tumor or one that has spread only locally), or metastatic (spread distantly or widely). The treatment options for organ-confined prostate cancer or locally advanced prostate cancer usually include surgery, radiation therapy, hormonal therapy, cryotherapy, combinations of some of these treatments, and watchful waiting. A cure for metastatic prostate cancer is, unfortunately, unattainable at the present time. The treatments for metastatic prostate cancer, which include hormonal therapy and chemotherapy, therefore, are considered palliative. By definition, the aims of palliative treatments are, at best, to slow the growth of the tumor and relieve the symptoms of the patient. Palliative treatments can prolong life in some and relieve symptoms in many such patients, though these treatments come at the expense of side effects.
What about prostate cancer surgery?
The surgical treatment for prostate cancer is commonly referred to as a radical prostatectomy, which is the removal of the entire prostate gland. The entire prostate, seminal vesicles, and ampulla of the vas deferens are removed, and the bladder is connected to the membranous urethra to allow free urination.
The radical prostatectomy is the most common treatment for organ confined or localized prostate cancer in the United States. The potential complications of a radical prostatectomy include the risks of anesthesia, local bleeding, impotence (loss of sexual function) of patients, and incontinence (loss of control of urination).
Great strides have been made in lowering the frequency of the complications of radical prostatectomy. These advances have been accomplished largely through improved anesthesia and surgical techniques. The improved surgical techniques, in turn, stem from a better understanding of the key anatomy and physiology of sexual potency and urinary continence. Specifically, the recent introduction of nerve-sparing techniques for the prostatectomy has helped to reduce the frequency of impotence and incontinence.
Radical prostatectomy can be performed by open surgery, laparoscopic surgery, or by robotic surgery (robotic assisted radical prostatectomy). Currently, many radical prostatectomy surgeries in the U.S. are performed using the of the Da Vinci robotic system. For robot-assisted surgery, five small incisions are made in the abdomen through which the surgeon inserts tube-like instruments, including a small camera. This creates a magnified three-dimensional view of the surgical area. The instruments are attached to a mechanical device, and the surgeon sits at a console and guides the instruments through a viewing device to perform the surgery. The instrument tips can be moved in a variety of ways under the control of the surgeon to achieve greater precision in surgery. So far, studies show that traditional open prostatectomy and robotic prostatectomy have had similar outcomes related to cancer-free survival rates, urinary continence, and sexual function. However, in terms of blood loss during surgery and pain and recovery after the procedure, robotic surgery has been shown to have a significant advantage.
If post-treatment impotence does occur, it can be treated by sildenafil (Viagra) tablets, injections of such medications as alprostadil (Caverject) into the penis, various devices to pump up or stiffen the penis, or a penile prosthesis (an artificial penis). Incontinence after treatment often improves with time, special exercises, and medications to improve the control of urination. Occasionally, however, incontinence requires implanting an artificial sphincter around the urethra. The artificial sphincter is made up of muscle or other material and is designed to control the flow of urine through the urethra.
Transurethral resection of the prostate (TURP) involves the removal of a part of the prostate by an instrument inserted through the urethra. It is used as an alternative to prostatectomy in patients with extensive disease or those who are not fit enough to undergo radical prostatectomy to remove tissue that is blocking urine flow. This is often referred to as a channel TURP.
What about radiation therapy for prostate cancer?
The goal of radiotherapy is to damage the cancer cells and stop their growth or kill them. This works because the rapidly dividing (reproducing) cancer cells are more vulnerable to destruction by the radiation than are the neighboring normal cells. Clinical trials have been conducted using radiation therapy for patients with organ-confined (localized) prostate cancer. These trials have shown that radiation therapy resulted in a rate of survival (being alive) at 10 years after treatment that is comparable to that for radical prostatectomy. Incontinence and impotence can occur as complications of radiation therapy, as with surgery, although perhaps less often than with surgery. More data are needed, however, on the risks and benefits of radiation therapy beyond 10 years, especially because late recurrences (reappearances) of the cancer can sometimes occur after radiation.
Choosing between radiation and surgery to treat organ-confined prostate cancer involves considerations of the patient's preference, age, and coexisting medical conditions (fitness for surgery), as well as of the extent of the cancer. Some patients with organ-confined prostate cancer are treated with radiation. Sometimes, oncologists combine radiation therapy with surgery or hormonal therapy in an effort to improve the long-term results of treatment in the early or later stages of prostate cancer.
Radiation therapy can be given either as external beam radiation over perhaps six or seven weeks or as an implant of radioactive seeds (brachytherapy) directly into the prostate. In external beam radiation, high energy X-rays are aimed at the tumor and the area immediately surrounding it. In brachytherapy, radioactive seeds are inserted through needles into the prostate gland under the guidance of transrectally taken ultrasound pictures. Brachy, from the Greek language, means short. The term brachytherapy thus refers to placing the treatment (radiation therapy) directly into or a short distance away from the cancerous target tissue. The theoretical advantage of brachytherapy over external beam radiation is that delivering the radiation energy directly into the prostate tissue should minimize damage to the surrounding tissues and organs.
Potential disadvantages of radiation therapy include a transient swelling of the prostate that may cause obstruction to the flow of urine and increase symptoms that may already be present because of an enlarged prostate. Side effects of external beam radiation include skin burning (less frequent today than in the past with the use of more powerful modern radiation therapy machines which allow the radiation oncologist to be more precise about what tissues receive what percentage of the radiation beam's energy) and hair loss at the area where the radiation beam goes through the skin. Both can cause severe fatigue, diarrhea, and discomfort on urination. These effects are almost always temporary. However, there are concerns about the long-term effects of radiation, and although still not proven, some studies have reported a higher chance of developing bladder or rectal cancer many years after undergoing radiation for prostate cancer. Although surgery can be done in case radiation therapy fails to cure prostate cancer (salvage radical prostatectomy), it is fraught with greater surgical difficulty and involves a significantly higher chances of complications like impotence and urinary incontinence.
What about hormonal treatment for prostate cancer?
The primary male (androgenic) hormone is called testosterone. It stimulates the growth of cancerous prostatic cells and, therefore, is the primary fuel for the growth of prostate cancer. The idea of all of the hormonal treatments (medical and surgical), in short, is to decrease the stimulation by testosterone of the cancerous prostatic cells. Testosterone normally is produced by the testes in response to stimulation from a hormonal signal called LH-RH. The LH-RH stands for luteinizing hormone-releasing hormone and is also called gonadotropin-releasing hormone. This hormone comes from a control station in the brain and travels in the bloodstream to the testes. Once there, the LH-RH stimulates the testes to produce and release testosterone.
Hormonal treatment, also referred to as androgen deprivation (depriving the prostate of testosterone), can be accomplished surgically or medically. The surgical hormonal treatment is removal of the testes in an operation called an orchiectomy or a castration. This surgery thus removes the body's source of testosterone. The medical hormonal treatment involves taking one or two types of medication. One type is referred to as the LH-RH agonists. These drugs act like the leutinizing hormone-releasing hormone normally secreted by the hypothalamus in the brain, which in turn, stimulates the pituitary gland attached to the brain to release leutinizing hormone, which stimulates the testes to make testosterone. They work by competing with the body's own LH-RH. These drugs thereby inhibit (block) the release of LH-RH from the brain. The other type of drug is referred to as anti-androgenic, meaning that these drugs work against the male hormone. That is, they work by blocking the effect of testosterone and other male hormones made by the adrenal glands on the prostate cancer cells.
Today, most men electing hormonal treatment choose medication over surgery, probably because they view surgical castration as more devastating cosmetically or psychologically. Actually, however, the effectiveness and side effects of medical hormonal treatment as compared to surgical hormonal treatment are very much the same. Medication treatment is more expensive than is an orchiectomy. Both types of hormonal treatment usually effectively eliminate stimulation of the cancer cells by testosterone. Some tumors of the prostate, however, do not respond to this form of treatment. Some prostate cancers respond temporarily, but then progress in spite of the hormonal treatment being continued. They are referred to as androgen-independent prostate cancers. The principal side effects of all of these hormonal treatments (that is, the side effects of androgenic deprivation) are enlarged breasts (gynecomastia) that often are tender, flushing (like hot flashes), and impotence.
The LH-RH agonists, leuprolide (Lupron), goserelin (Zoladex), triptorelin (Trelstar), and histrelin (Vantas) are given as monthly injections in the doctor's office. Those offering Depot preparations may be given less often. The anti-androgenic drugs, flutamide (Eulexin), bicalutamide (Casodex) or nilutamide (Nilandron), are oral capsules that are used usually in combination with the LH-RH agonists. The LH-RH agonists are often effective alone. The anti-androgenic drugs are added, however, if the cancer progresses despite the use of the LH-RH agonists. The hormonal treatments may have value, as well, when combined with radiation therapy. Current evidence suggests that hormonal therapy enhances the therapeutic effect of radiation in cases of locally advanced prostate cancer. Today, newer treatments for prostate cancer which are hormonally based are emerging, including LH-RH antagonists (degarelix [Firmagon]), as well as another way to block androgen synthesis called abiraterone (Zytiga).
Generally, hormonal treatment is reserved for individuals who have advanced prostate cancer with local spread or metastases. Occasionally, an individual with organ-confined (localized) prostate cancer will receive hormonal treatment because he has severe associated medical problems or simply because he refuses to undergo surgery or radiation. Hormonal treatment is used less frequently in men with organ-confined (localized) prostate cancer. Remember that the intent of hormonal therapy usually is palliative. This means that the goal is to control the cancer rather than cure it because a cure is not possible.
What is chemotherapy for prostate cancer?
Chemotherapeutic agents, or chemotherapy, are anticancer drugs. They are used (for hormone resistant prostate cancer) as a palliative treatment (palliation to relieve symptoms) in patients with advanced cancer for whom a cure is unattainable. Recall that the goal of palliation is simply to slow the tumor's growth and relieve the patient's symptoms. Chemotherapy is not ordinarily used for organ-confined or locally advanced prostate cancers because a cure in these cases is possible with other treatments. Currently, chemotherapy is used only for advanced metastatic prostate cancers that have failed to respond to other treatments.
Several chemotherapeutic agents have been used effectively to palliate metastatic prostate cancer. One such agent is estramustine (Emcyt). Another agent called mitoxantrone (Novantrone) has been shown to be effective in combination with prednisone for palliating androgen-independent prostate cancer. As mentioned previously, metastatic tumors that have not responded specifically to hormonal therapy are referred to as castrate-resistant prostate cancers. Newer chemotherapy medicines like docetaxel (Taxotere) and carbazitaxel (Jevtana) have shown some promise in prolonging the survival of some patients with extensive prostate cancer. Other chemotherapy drugs include etoposide (VP-16), vinblastine (Velban), vinorelbine (Navelbine), paclitaxel (Taxol), and carboplatin (Paraplatin). They may also decrease the pain related to widespread cancer. However, this comes at the cost of significant side effects that may impact quality of life.
The more common side effects of chemotherapy include weakness, nausea, hair loss, and suppression of the bone marrow. The suppression of marrow, in turn, can decrease the red blood cells (causing anemia), the white blood cells (leading to infections), and the platelets (resulting in bleeding).
Hormonal therapy is the mainstay of treatment for symptomatic, advanced-staged prostate cancer. A vast majority of prostate cancers, particularly initially, are dependent on testosterone (the male hormone produced by the testes) for their growth and spread. The objective of hormonal treatment is to withdraw this source of sustenance for prostate cancer cells in an attempt to slow down or control this disease. The following are treatments available for hormonal therapy:
Orchiectomy is the surgical removal of the testicles. Luteinizing hormone-releasing hormone (LHRH) agonists, such as leuprolide (Lupron, Viadur, Eligard), goserelin (Zoladex), or buserelin (Suprefact), stop the production of testosterone from the testes and induce a state of "medical castration" (castration without surgery). Many men prefer this over surgical castration.
Antiandrogens, such as flutamide (Eulexin) or bicalutamide (Casodex), block the action of testosterone on the prostate cancer cells and other parts of the body. Each of the above two classes of medicines produce symptomatic relief in about 80% of patients. Improvement is often dramatic.
Side effects of these medications vary. Orchiectomy and LHRH agonists may cause impotence, hot flashes, and loss of sexual desire. Antiandrogens may cause nausea, vomiting, diarrhea, and breast enlargement or tenderness. Any of these therapies can weaken bones and lead to osteoporosis and bone fracture.
Literature.
Basic.
1. Sorcin V, Popovich A, Dumanskiy Yu, et al. Clinical oncology. Simferopol, 2008; 192 p.
2. Schepotin IB, Evans SRT. Oncology. Kiev, 2008; 235 p.
Additional.
1. National Comprehensive Cancer Network. NCCN Practice Guidelines in Oncology: Cancer Screening. v. 2012.
2. Manual Of Clinical Oncology, - Dennis A. Casciato, Barry B. Lowitz, 2000
3. Oxford Handbook of Oncology, - Oxford University Press, 2002
4. Basics of Oncology, - Frederick O. Stephens · Karl R. Aigner, 2009
5. HARRISON’S Manual of Oncology, - Bruce A. Chabner, Thomas J. Lynch, Jr., Dan L. Longo, 2008
Methodical guidelines written
by Assistant oncology department Ph.D. Lysenko S.A.
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