Prostate cancer is one of the most common forms of cancer among American men. With slightly over 161,000 new cases each year, it accounts for nearly 20% of all new cancer developed by men. The disease mainly effects older men, and develops in the prostate gland which produces seminal fluid. Prostate cancer is a slow-developing disease, and is usually not life-threatening. Prostate cancer can cause difficulty in urination and sexual function.
Prostate Cancer Risk Factors
The risk of getting prostate cancer gets higher as men age.
- Under age 49 = 1 in 354 risk of prostate cancer
- Age 50 to age 59 = 1 in 52 risk of prostate cancer
- Age 60 to age 69 = 1 in 19 risk of prostate cancer
African American men are 97% more likely to get prostate cancer than Caucasians. Oriental men are less likely to get prostate cancer than Caucasians, but this difference is reduced among groups that adopt an “American” diet high in red meat and fat.
Men with a father, brother or son who got prostate cancer are twice as likely to get the disease as men with no first-degree relative who has or had the disease.
Diet and Lifestyle
- Obesity is thought – but not conclusively proven – to increase the risk of prostate cancer.
- Increasing age
Some foods and vitamin supplements are thought – but not conclusively proven – to increase the risk of prostate cancer. They include:
- Red meat and high fat are thought to double the risk of prostate cancer.
- High doses of calcium -2000 mg per day or more – are thought to increase prostate cancer risks by 5 times.
- High levels of zinc – 80 mg per day or more – are thought to double prostate cancer risk.
Dietary Risk Reduction
Some foods and vitamin supplements are thought – but not conclusively proven – to reduce the risk of prostate cancer. They include:
- Three weekly servings of fish high in Omega 3 fatty acid (such as salmon) are thought to lower prostate cancer risk by about a quarter.
- Two or more servings a week of tomato sauce or other cooked tomato products are thought to lower prostate cancer risk by about a third.
- Five or more servings a week of cruciferous vegetables such as broccoli, cauliflower, cabbage, Brussels sprouts and bok choy are thought to lower the future risk of prostate cancer by 20%.
- The benefit has been observed eight years after starting to eat five weekly portions of these vegetables.
- The 1, 25 (OH)2 D3 form or vitamin D is thought to reduce prostate cancer risk by almost half.
Prostate Cancer Warning Signs
Although there are warning signs for prostate cancer, they are not usually present during when the disease first develops. Because of this, it is critically important for men at risk because of age, family history or lifestyle factors such as diet or obesity to be tested regularly. Warning signs include:
- Need to urinate frequently, especially at night
- Difficult to start urinating
- Weak or interrupted urine flow
- Pain or burning when urinating
- Difficulty having an erection
- Painful ejaculation
- Blood in urine or semen
- Pain or stiffness in lower back, hips or upper thighs
Prostate Cancer Detection, Diagnosis and Staging
Men should have annual prostate screenings when they turn 50. Men at higher risk, including African Americans, men with a family history of the disease and obese men, should start being screened when they’re 45. Screening can detect prostate cancer early, before symptoms develop. Prostate cancer caught then can almost always be treated effectively. To learn more about prostate cancer screening, watch this video.
Prostate-Specific Antigen Test
Prostate-specific antigen, or PSA, is a substance produced in the prostate and found in the blood. PSA is tested by drawing a sample of blood. Levels under 4 nanograms per milliliter are normal, 4 to 10 nanograms per milliliter are intermediate and more than 10 nanograms per milliliter high. Elevated PSA levels can indicate prostate inflammation, infection and benign prostatic hyperplasia in addition to prostate cancer. The test simply indicates a problem that should be examined more closely.
Digital Rectal Examination
In a digital rectal exam the physician inserts a gloved finger in the rectum and feels the prostate to detect lumps or abnormal areas indicating possible prostate cancer.
Transrectal ultrasound bounces sound waves off the prostate and measures the echoes to produce a sonogram image of the prostate. The procedure is usually performed in conjunction with a biopsy.
Biopsy is the removal of some of the suspected mass for examination by a pathologist who checks for cancer cells and, if they are found, determines how aggressively the cancer is growing.
Transrectal Biopsy – In a transrectal biopsy a needle guided by an ultrasound image is inserted through the rectum into the prostate to remove a small sample of suspected tissue.
Transperineal Biopsy – In a transperineal biopsy a needle is inserted in the skin between the scrotum and rectum and into the prostate to retrieve a sample of suspected tissue.
Tissue removed through transrectal or transperineal biopsies is microscopically examined by a pathologist. Because healthy prostate cells all have the same shape and appearance, the pathologist can determine how far the disease has progressed by how much the cancer cells’ appearance differs from the appearance healthy cells. The Gleason grading system assigns levels of one through five to the degree of difference. Cancer most like healthy cells is ranked one and the most changed cancer cells are ranked five. The pathologist assigns Gleason grades the most common pattern of cancer cells and the next most common. The two grades are added together to get the Gleason score. Generally, the higher the number of the Gleason score, the more aggressive the cancer.
After prostate cancer is confirmed, tests and scans are often used to determine if, and how far, the cancer has spread to other parts of the body. This determines the stage of the cancer, and is used to help doctors decide on the appropriate treatment.
Radionuclide Bone Scan
Radionuclide bone scans are used to find out if there are rapidly-dividing cells (such as cancer cells) in the bones. A small amount of radioactive material is injected intravenously and concentrates in the bones where it is detected by a scanner.
A computerized tomography (or CT or Cat) scan can provide a more-detailed image of prostate. CT scans are a series of X-rays combined by a computer in a cross-section view. They can be performed with injected contrast material to highlight suspicious masses. Since the basic imaging mechanism of a CT scan is X-rays, patients receive a low dose of radiation during the procedure. The radiation dosage is significantly lower with low-dose helical CT scans, but masses detected with this technology must be reexamined.
Magnetic resonance imaging (or MRI) uses magnetism, radio waves and computer image manipulation to produce an extremely detailed image without radiation. Because of the extremely powerful magnetism of MRI scanners they cannot be used on patients with any metal implants or pacemakers.
Positron-emission tomography (or PET) scans are three-dimensional images of the metabolic functioning of body tissues. PET scans can be used to determine the type of cells in a mass and to detect whether or not a tumor is growing. Patients receiving PET scans are injected with a radioactive drug with about as much radiation as two chest X-rays.
Seminal Vesicle Biopsy
In seminal vesicle biopsy a needle is inserted into the glands that produce semen to extract liquid which is examined for the presence of cancer cells.
Cancer is in the prostate only, and too small to be felt in a digital rectal examination. Stage I prostate cancer is most often discovered during surgery for some other condition, such as benign prostatic hyperplasia. The Gleason grading system score of stage I prostate cancer is usually low.
Cancer is in the prostate only, but larger than stage I.
Cancer has spread beyond the prostate to nearby tissue such as the seminal vesicles.
Cancer has spread to other parts of the body. Metastatic prostate cancer often invades the bones, bladder, rectum, liver or lungs.
Prostate Cancer Treatment
Because prostate cancer is often slow-growing, watchful waiting is a possible choice for men with Stage I or Stage II cancer with low or intermediate Gleason grades. This is a less-frequently-chosen response for Stage III and IV patients, but even they are sometimes appropriate candidates for watchful waiting. Digital rectal examinations and prostate-specific antigen tests are done every six months and a prostate biopsy is performed yearly to detect growth or changes in the cancer.
Radical prostatectomy is the removal of the entire prostate gland and some surrounding tissue. Radical prostatectomy is most frequently performed with an incision in the lower abdomen, but at times the incision is in the area between the scrotum and rectum. Radical prostatectomy is often associated with impotence and incontinence.
If cancer has not grown to or beyond the edge of the prostate gland, a nerve-sparing prostatectomy is possible. In this procedure the surgeon removes tissue near , but not all the way too, the edge of the prostate. The erectile nerves alongside the prostate are spared, and normal sexual function is often retained.
Transurethral resection removes some, but not all prostate tissue using a resectoscope (a fiber-optic tube with a viewing lens, light and cutting instrument at the end).
New laparoscopic surgical techniques, including robotically-assisted surgery, use a smaller incision – and frequently have fewer side effects – than conventional surgery.
Pelvic lymphadenectomy is the surgical removal of the lymph nodes in the pelvis. It is usually performed at the same time as a radical prostatectomy.
Orchiectomy, the removal of one or both testicles, is usually done along with a radical prostatectomy for more advanced (usually stage IV) prostate cancer.
External-Beam Radiation Therapy
External-beam radiation therapy is used in both curative and palliative treatment. A map of the tumor’s location is created with a CT scan, and the tumor is radiated from different angles to maximize the dose delivered to the tumor with minimum impact on surrounding healthy tissue.
Thompson Cancer Survival Center was one of the first facilities in the world to treat patients with intensity modulated radiation therapy. Since 1998 more than 1,000 patients have received IMRT treatment at Thompson. Now both Thompson Downtown and Thompson at Methodist offer this treatment. In IMRT the multileaf collimator reshapes the treatment field between individual doses of radiation, so the beam is matched to the shape of the tumor from all angles.
Prostate dose escalation
The higher radiation dosage of prostate dose escalation has increased patients’ disease-free survival rates from 15% to 85% in a Fox Chase Cancer Center study. The improvement was so dramatic that Thompson adopted the technique as soon as the study was published in 1996. Prostate dose escalation relies upon 3-D treatment planning, a technique pioneered at Thompson.
Prostate Seed Implants
Thompson at Methodist and Thompson Downtown both perform prostate seed implants. Radioactive pellets are implanted directly into the tumor.
Thompson Downtown has developed real-time technology in which the tumor is mapped with an ultrasound probe and seed placement planned in the operating room immediately before the implant procedure.
This assures that seeds are planted based on the size, shape and location of the tumor at the time of the procedure. Seeds are tracked so the radiation dose is evaluated during the procedure and adjustments can be made immediately.
Chemotherapy is not widely used to treat prostate cancer. It is most often used for advanced metastatic disease or when hormone therapy was no longer effective. Recent advances are expanding chemotherapy’s role in prostate cancer care, and clinical trials of several new applications are now under way.
Testosterone is the main ingredient in cancer cell growth, so hormone therapy stops or reduces the release of testosterone. The majority of prostate cancer cells are stopped by hormone therapy, but some are unaffected. The cancer cells not effected by hormone therapy continue to grow and eventually take over the tumor. When this happens hormone therapy is no longer effective.
In cryotherapy a probe is inserted into the prostate and argon gas or liquid nitrogen is pumped in to freeze the prostate cells. Although advances have been made in cryotherapy, it still has a relatively high incidence of impotence and incontinence side effects.
High-Intensity Focused Ultrasound
High intensity focused ultrasound is an experimental technique which kills prostate cells with high heat generated by sound waves.