Prostate Cancer

Prostate cancer is a disease in which the cells of the prostate become abnormal. They start to grow uncontrollably, forming tumors. A tumor is a mass or lump of tissue made of abnormal cells. Tumors may be malignant or benign. A malignant tumor can spread to other parts of the body. Malignant tumors are cancerous. Benign tumors cannot spread to other parts of the body. A tumor in the prostate interferes with proper control of the bladder and normal sexual functioning. Often the first symptom of prostate cancer is difficulty urinating. However, because a very common, non-cancerous condition of the prostate, benign prostatic hyperplasia (BPH), also causes the same problem, difficulty in urination is not necessarily due to cancer.

According to the American Cancer Society an estimated 186,320 new cases of prostate cancer will occur in the United States in 2008, with an estimated 28,660 deaths in 2007, prostate cancer is a leading cause of cancer death men. Although death rates have been declining among caucasian and African American men since the early 1990's, the rate in African American men remains more than twice as high as those in caucasian men.

Prostate Cancer Questions & Answers

  • What are some of the signs and symptoms of prostate cancer?

    Early prostate cancer usually has no symptoms. During the more advanced stages of prostate cancer individuals may experience the following:

    Weak or interrupted urine flow
    Inability to urinate or difficulty starting or stopping the urine flow
    The need to urinate frequently, especially at night
    Blood in the urine
    Pain or burning with urination
     

    Continual pain in the lower back, pelvis or upper thighs may be an indication of metastic disease. Many of these symptoms, however, are similar to those caused by benign conditions.

  • What causes prostate cancer?

    Little is known about the cause of prostate cancer compared to any other common cancer in the human body. There are no proven risk factors for the development of prostate cancer, but some risk factors have been proposed although the findings are often weak and controversial.

    Only two factors are proven to be essential for the development of prostate cancer: male hormones (testosterone, one type of androgen hormone) and age. The entire prostate requires hormones for growth and development and these are also essential for cancer maintenance and growth.

    Proposed risk factors for prostate cancer

    Family History and Genetics: Familial predisposition with early onset of prostate cancer probably accounts for about 9% of cases, with increasing risk as the number of affected relatives increases. A man's risk is two-fold higher if a first degree relative such as a father or brother has prostate cancer and the risk is 5-11 fold higher if two or three first degree relatives have cancer. Heredity appears to be one of the most consistent and strongest risk factors for the development of prostate cancer.

    Diet: Dietary fat may also cause prostate cancer, according to cross-cultural comparisons, but the relationship is complex and ill-defined perhaps due in part to the influence of diet on the production of sex hormones. Obesity and alcohol abuse may also be risk factors. One school of thought believes that high fat diet is a promoter of cancer after it has developed, accelerating its growth and aggressiveness so that it is more threatening.

    Smoking: Prostate cancer is one of the few cancers in the human body which has not been strongly linked to smoking.

    Viruses: Viral diseases such as herpesvirus type 2 and cytomegalovirus may be involved in prostate cancer, but the data are not conclusive. Human papillomavirus has been linked to a small number of cases of prostate cancer and this is an area of active investigation. It should be noted that HPV has been conclusively linked to cervical cancer, raising the possibility of a sexually transmitted virus associated with cancer.

    Venereal Diseases: Early studies which implicated venereal diseases such as gonorrhea have been refuted.

    Sexual Activity: Some investigators have suggested that sexual abstinence may contribute to prostate cancer risk, but there is no consistent evidence to support this contention despite multiple studies in the past 30 years. There is also no apparent increase in risk for men who have had multiple sexual partners.

    Occupation: Conflicting results have been obtained in the search for occupational exposure which increases the risk of prostate cancer. Farming has been named in many studies, perhaps due to contact with agricultural products or pesticides. Cadmium, rubber and zinc workers may be at increased risk, but this has been refuted. People exposed to radiation, including survivors the Hiroshima and Nagasaki atomic bomb blasts, have a significant increased risk of many cancers including leukemia, but apparently not for prostate cancer.

    Vasectomy: Surgical sterilization with segmental removal of the vas deferens (vasectomy) has been proposed as a risk factor for prostate cancer but reports to date have been affected by patient selection bias. Further studies are needed to determine the validity of these findings; the level of risk, if confirmed, appears to be low. An expert panel convened by the National Institutes of Health in 1993 concluded that the possible increased risk of prostate cancer due to vasectomy was low or nonexistent and there was no need to discontinue vasectomy or reverse the procedure in men as a preventive measure.

    Benign Prostatic Hyperplasia (BPH): BPH is frequently seen in association with prostate cancer and there are a number of compelling similarities, including increasing incidence and prevalence with age, concordant natural history and hormonal requirements for growth and development. However, no causal relationship has been established.

    Prostatic Intraepithelial Neoplasia (PIN): Patients with high-grade PIN are at increased risk for prostate cancer and many are found to have cancer on repeat biopsy. PIN can only be identified through needle biopsy. It is uncertain whether the linkage of PIN and cancer represents an etiologic link or association.

    Old Age: Is prostate cancer an inevitable consequence of old age? If so, what are the changes that occur with aging which account for malignant change? Perhaps there is a breakdown of the immune system, the surveillance system of the body which discards tens of thousands of damaged or mutated cells daily. It is also possible that the immune system is overwhelmed by an increased number of genetically altered cells in the body which occurs naturally with age. The number of altered or damaged cells may increase because of progressive failure of the superoxide dismutase and other enzymes which act on a cell-by-cell basis to deal with environmental damage such as carcinogens, high fat diet, and other factors. The cumulative exposure to mutagens and carcinogens could influence all of these factors, thereby leading to cancer.

  • What are my treatment options for prostate cancer?

    Surgical removal of the prostate, referred to as radical prostatectomy, is a popular form of treatment for American men and is especially valuable for young men with organ-confined cancer.

    There are three open prostate cancer surgery principals to radical prostatectomy:

    Retropubic prostatectomy: Removal of the prostate through an incision in the lower abdomen.

    Advantages Disadvantages
    Best for large cancer Major surgery
    Most definitive treatment available Difficult for men with other health problems
    Optimal surgical margins Risk of blood loss and transfusion
    Pelvic lymph node dissection allows accurate staging Impotence rate high
      Risk of incontinence
      Doesn’t treat cancer if already metastasized

    Nerve-sparing prostatectomy: A variation on retropubic prostatectomy in which the surgeon preserves the nerves and blood vessels at the edge of the prostate, thereby preserving potency in many men.

    Advantages Disadvantages
    Most definitive treatment available Major surgery
    Greatest probability of retaining potency after radical prostatectomy Not possible with large cancer
    Optimal surgical margins Riskier than other methods when cancer is bilateral
    Pelvic lymph node dissection allows accurate staging No guarantee that potency will be retained
      Risk of blood loss and transfusion
      Risk of incontinence
      Doesn’t treat cancer if already metastasized

    Perineal prostatectomy: Removal of the prostate through an incision in the skin between the scrotum and anus.

  • What are the alternative treatment options for prostate cancer?

    There are a vast assortment of unproven proposed treatments for prostate cancer, none of which have been shown conclusively to be of great value in the treatment of prostate cancer. This does not mean that these treatments are useless, but they have not been tested by formal methods in medicine. Some of these approaches have been evaluated for safety and this section is meant to provide all of the possible options.

    Support for these alternative treatments is tempered by the understanding that simply having options available does not mean that those options are good; strong personal testimonials are not a proper substitute for careful and balanced investigation, and enthusiasm and faith may not be justification for alternative treatment when dealing with a serious illness such as prostate cancer.

    Current Therapies

    Chemotherapy: This may be of value for men with advanced high stage prostate cancer who have failed hormone therapy. However, chemotherapy cannot cure cancer and is considered palliative only. This form of therapy is of great value for rapidly growing cancers but it has little utility other than experimental treatment for palliation of prostate cancer.

    Advantages Disadvantages
    Does not require surgery Serious side effects, some of which may be irreversible (side effects are dependent on the drug used)
    Does not require external beam radiation therapy Not curative
    May provide symptomatic relief of bone pain Still experimental and of little or no proven value for survival
    May improve survival  

    Considerable effort is being expended to change this situation, but the situation at present is not favorable. Some of the drugs and their actions are noted below:

    Suramin: This drug was originally developed to treat parasitic infections but has been shown to block growth factors that stimulate cancer cell growth in test tubes and animal models. Up to 30% of men taking Suramin have a favorable response to their bone pain and the response can last up to three months. Side effects are serious, including kidney and nerve damage. The drug is administered as a shot or intravenous infusion.

    Finasteride (ProscarR): This drug inhibits five alpha-reductase, the enzyme that converts testosterone to its more active form, dihydrotestosterone. This may be of value in preventing prostate cancer but there are no data to support this contention at present. Justification for its use in prostate cancer is based largely on its ability to depress serum PSA and its lack of significant side effects. A large national chemoprevention trial has been ongoing for a number of years, randomizing 18,000 American men between the ages of 55 and 70 into those receiving this drug and an equal group receiving placebo. The results of this trial should be available after the turn of the century.

    Octreotide acetate (Sandostatin): This drug inhibits growth hormone and may block growth factors that stimulate prostate cancer cell growth.

    Linomide: This experimental drugs exerts its effect by blocking new blood vessel formation, thereby starving cancer of its nutrients. This is an interesting hypothesis that remains untested in humans.

    Lovastatin: This drug is used for treatment of high serum cholesterol and the question has been raised whether this may have an effect on hormonal activity and prostate cancer.

    Estramustine (emcyt): This toxic drug combines the cell killing effect of estradiol and nitrogen mustard. It is the only drug approved for palliation of progressive or metastatic prostate cancer. Side effects include breast enlargement and tenderness which were both observed in more than 60% of men.

    Other Chemotherapeutic Drugs: Drugs commonly used for other forms of cancer may show a small effect for prostate cancer. These drugs include methotrexate, cyclophosphamide, methylglioxal and adriamycin.

    Low Dose Radiation: Certain radioactive drugs, referred to as radioisotopes, have shown encouraging results in the treatment of bone pain from metastatic prostate cancer. Examples include Strontium-89 (metastron), Rhenium-186 and Samarium-153. Combinations of radioisotopes and other chemotherapeutic agents may provide greater benefit.

    Steroids: The bone pain from prostate cancer is also treated with corticosteroids, non-sex hormones produced by the adrenal glands. Side effects include blood pressure abnormalities, diabetes, ulcers and tissue swelling.

    Biophosphinates: These drugs prevent bone destruction by metastatic prostate cancer. Examples include Clodronate, Etidronate, and Pamidronate.

    New Therapies

    Gene Vaccine: The use of dendritic cell infusions may stimulate the body's immune defenses to attack cancer cells directly or expose them to attack by other immune cells. Preliminary results are encouraging, but this remains experimental.

    Thermal Therapy: Direct application of very high temperatures will destroy cancer cells, and this method has been exploited with laser therapy, microwave hyperthermia and electrocautery and electrovaparization. These techniques are of proven value for treatment of benign prostatic enlargement but none has been shown to be of value in prostate cancer.

    Gene Therapy: This is an unproven therapy for prostate cancer and is still being investigated in laboratory animals and cell cultures.

    Dietary Therapy: Diet may be of great value in preventing prostate cancer, but it is of no proven value in modifying progression of symptoms or metastases once the cancer is established. Despite the lack of evidence, such approaches are very popular but it must be remembered that the advantages or disadvantages have not, to date, been measured. Accordingly, such approaches may be useful adjuncts to conventional therapy. These are described under the section on Cancer Prevention.

    Meditation: The mind exerts considerable effects on the body and many of these effects cannot be measured. Meditation is one form of mind-body therapy in which an altered state of consciousness is reached by focused concentration, usually resulting in relaxation or heightened awareness. Other therapies that are related include biofeedback, in which electrical monitors provide the patient with control of the bodies automatic physical processes; isualization, in which physical responses are evoked by focusing on mental images; Chinese acupuncture with needles inserted into the skin to induce natural painkillers such as endorphins; and other forms of therapy.

  • What do I do when prostate cancer recurs?

    Any man with prostate cancer, regardless of stage or treatment, should include in his action plan a contingency plan for recurrence. The first step in this action plan is to be aware of how to detect a recurrence and how to deal with it.

    Your cancer may be recurring if:

    Your physician feels a lump on digital rectal examination after primary treatment
    Rising or persistently elevated PSA
    Repeat biopsy is positive
    Positive bone scan
    Positive ultrasound or MRI
    Positive prostatic acid phosphatase
    Bone pain
    Increasing fatigue, gradual weight loss and loss of appetite
    Increased severity of existing symptoms

    Persistently elevated or rising PSA is often the first evidence that cancer has not been fully eliminated or is recurring. It may precede any clinical symptoms by 18 months or more. The definition of abnormal PSA after treatment depends on the form of treatment and the nadir reached during treatment (nadir refers to the lowest level reached after treatment).

    A promising new imaging technique, Prostascint ™, may indicate the site of recurrence in a patient with persistently elevated or rising PSA with no other signs of recurrence. This test is based on immunoscintigraphy with antibodies directed against prostate specific membrane antigen. For more informationon Prostascint, visit www.cytogen.com

    Secondary Treatment of Cancer After Recurrence

    If the first-line therapy has failed, there are still many options and some men experience lengthy survival even in this situation. Many of the secondary therapies are suboptimal due to side effects, whereas others are useful for palliation but are not curative.

    Secondary Treatments:

    Hormone therapy
    Chemotherapy
    Salvage therapy
    Experimental therapy
    Expectant mangement

    Hormonal Therapy: The mechanism of action and benefit of hormonal therapy is similar whether it is used as a primary or secondary therapy. Of considerable debate is the timing of hormonal therapy. Some doctors prefer to institute hormonal therapy as soon as recurrence is identified and therapy is then continued indefinitely. Others wait until bone pain or other symptoms occur and provide therapy only until there is resolution of symptoms. Still others argue that if relapse occurs during use of hormonal therapy, the treatment should be stopped because the cancer cells are becoming unresponsive.

    Chemotherapy: These drugs may provide symptomatic relief, but are not curative. These are described in the section Alternate Therapies.

    Salvage Therapy: Salvage therapy refers to the use of first-line therapy after cancer recurs. For example, radical prostatectomy can be performed after failure of radiation therapy, but the patient should be in good health and motivated to receive this treatment. The side effects are considerably greater, probably due to the scarring effect on tissue from the radiation therapy, the increased possibility of higher stage cancer, and the increased difficulty of the procedure.

    Salvage Cryosurgery: After first-line radiation therapy can also be effective, but carries a heightened risk of incontinence and impotence then its use as a first-line treatment.

    Salvage Radiation: Radiation therapy is often employed patients with positive surgical margins or extraprostatic extension identified at radical prostatectomy. In such cases, the dose may be less than when it is used as a first-line therapy. Up to 45% of men treated with salvage radiation after prostatectomy were free of cancer at five years.

    Salvage Hormonal Therapy: The utility of androgen deprivation therapy at the time of radiation therapy is under active investigation.

    Experimental Treatments: These are dealt with in the section on Alternate Treatments.

    Expectant Management (Symptomatic Treatment): In men with recurrent or metastatic prostate cancer, cure is less likely and the focus of treatment is on avoiding unwelcome symptoms such as bone pain. In such cases, the focus is quality of life.