Prostate Cancer Q&A
Prostate cancer is very common. Every man has between a one in six to one in nine chance of developing prostate cancer in his lifetime. If screening is done it is usually recommended to start about age 50. If a man is African-American or has a first-degree relative (father or brother) who has had prostate cancer, he should talk with his doctor at age 40 or 45 about those risks and how to proceed.
Scientists have identified locations in the human genome that are associated with a mildly increased risk for developing prostate cancer—usually about 10-20%. Genetic testing, however, is not yet recommended for prostate cancer screening because doctors can do as good or better job at assessing risk simply by asking about a family history of prostate cancer.
Having other types of cancer does not appear to increase the risk for prostate cancer.
Other men, with average risk, should seriously consider a PSA screening that can act as a baseline for later screenings. The risk of prostate cancer does increase with age, but most prostate cancer is slow growing and can take from 10 to 20 years to become life threatening.
The PSA (prostate specific antigen) test measures the amount of a certain protein in the blood that is present only in the prostate. Prostate cancer is found in 20% to 30% of men with an elevated PSA test.
However, several things can cause an elevated PSA count:
- Enlargement of the prostate (which happens with age)
- Other changes that have nothing to do with prostate cancer
Sometimes, no cause can be found for an elevated PSA.
About 15% of prostate cancers will be present without a rise in PSA. Fortunately, most of those cancers are less aggressive.
Until 25 years ago, when the PSA test became widely available, a physical exam and symptoms were the only indicators of prostate cancer. Prostate cancer found with this method tends to be more advanced—already spread elsewhere in the body. Before PSA testing, one in five men who were found with prostate cancer had an advanced stage of the disease. With PSA testing prostate cancers can be diagnosed as much as 10 years earlier than with the previous methods. Now, with widespread screening, only one in 25 men is diagnosed at that late stage. Deaths from prostate cancer are now 40% lower than in 1994, when the highest number of deaths occurred.
With PSA testing, tumors may be discovered when they are as small as a millimeter. Doctors now believe that many tumors that size, which are most often low-grade, low-risk tumors, may not require treatment. That treatment, such as radiation or surgery, can cause side effects that could have been avoided with a more conservative, active surveillance, approach.
Research into the genetics of prostate cancers is helping doctors recognize which tumors are aggressive and which are so slow growing that they don't need to be treated.
Some are already available. The PCA3 test analyses a urine sample to see if PCA-3, a gene associated with the presence of prostate cancer, is present. Another test, looking for another gene present in prostate cancer, is already in late-stage clinical trials. Both tests have an advantage over the PSA because they are measuring biomarkers produced only by prostate cancer and not influenced by other medical conditions.
Researchers are also working to test changes in DNA that can be tracked. At Stanford, new technology has enabled the extraction of prostate cancer cells that circulate in the bloodstream in men with advanced prostate cancer, another valuable and minimally invasive method to track cancer activity.
To conduct the traditional biopsy, one or two samples are taken, with visibility provided by an ultrasound, from each of six zones in the prostate known to be the most likely spots for cancer. On average, a biopsy takes 12 separate samples from the prostate.
However, while ultrasound is very good at seeing large tumors, it doesn't always pick up on small cancers peppered throughout the prostate. Nor will an MRI alone give a complete read of prostate cancer. Taking tissue samples is the only way to confirm and grade prostate tumors.
A new form of combination biopsy, available at Stanford and a few other medical centers, takes its samples that are very precisely targeted with information gathered from an MRI. Called targeted prostate biopsy, this method uses the difference between normal tissue and cancerous tissue to identify cancer.
This method is also more likely to find more aggressive cancers. Targeted prostate biopsy also reduces the need to repeat biopsies because cancer was missed in a non-targeted prostate biopsy.
The difference between the two methods is most dramatic in men who, following standard biopsy that showed only low risk prostate cancers, then have a targeted prostate biopsy that finds very aggressive cancers.
There is some discomfort in both methods. The goal is to find those prostate cancers that have the most chance of spreading to other parts of the body.
Many men will be found with small prostate tumors and are advised against treatment because the tumors are known to be slow-growing and low risk. Doctors prefer to keep a close eye on those tumors with active surveillance, sometimes called watchful waiting, with periodic biopsies and PSA testing.
The idea is to avoid treatment that's not needed. Prostate cancer is typically slow growing and can take from 10 to 30 years to become life threatening. The risk of prostate cancer grows with age; even men diagnosed at 70 or 80 will not live long enough for their cancer to cause problems.
To help reduce unnecessary treatment, new tests are being developed to better identify the genes involved in the most aggressive cancers.
All treatments for prostate cancer are associated with risks of significant side effects. However, for potentially aggressive cancers, treatment is advised. When treatment is carried out by an experienced doctor, the risks of side effects are minimized and most men report an excellent quality of life after treatment.
Many treatment options for localized prostate cancer are now available:
- Laparoscopic surgery or open surgery
- External radiation, brachytherapy
- Cryosurgery and other forms of non-surgical elimination of tumors
Radiation and surgery appear to have the same rate of effectiveness and side effects. Radiation should follow surgery, if that combination of therapy is chosen.
For advanced prostate cancer, chemotherapy may be the first treatment suggested.
Several factors need to be considered thoughtfully before choosing a specific therapy. Those factors may include:
- The aggressiveness and extent of the prostate cancer
- The patient's age, general health and symptoms
- What the patient wants
- The doctor's experience and expertise
Have a frank discussion with your doctor about expected cure rates and side effects. Do not hesitate to ask for a second opinion before making a final decision.
Prostate surgery has evolved from those pre-1980 days when such surgeries were seriously debilitating. Men often left those operation unable to control their urine and without sexual function. Then, doctors made some anatomical discoveries that pinpointed the location of the important nerve bundles. Those discoveries made it much easier now to preserve sexual function and avoid urinary incontinence.
Laparoscopic surgery is another new option. Its smaller incisions heal more quickly. In 2001, a robotic assistant was added to the operating room to help a surgeon be even more precise, reduce blood loss and quicken recovery.
The next step will be the introduction of a special microscope to visualize those important nerves and blood vessels individually and not just as a bundle for a higher degree of preservation during surgery.
Chemotherapy for prostate cancer that has spread beyond the prostate is also available in new options based on the newly discovered genetic knowledge about individual prostate tumors. Each prostate cancer has its own unique makeup, so no single chemotherapy will work for every prostate cancer. Some new therapies are focused on attacking prostate tumors through those unique tumor genes.
The timing of chemotherapy, biologic therapy, and hormone therapy is also becoming more nuanced and more effective. At Stanford, new clinical trials are available for men with prostate cancer that has resisted other treatments.
New forms of radiation can treat prostate cancer with more precision and in less time.
- Dietary studies have demonstrated a relationship between the risk of prostate cancer and eating red meat, especially processed meats and those cooked at high temperatures on a grill. To reduce that risk, eat red meat that is rare or cooked at lower temperatures or choose white meats, such as chicken or fish.
- Evidence suggests that a heart-healthy diet, which is high in vegetables, fruits and whole grains—and low in saturated fats and red meat—is also the best diet for prostate cancer prevention. Eating more vegetables is also recommended, especially cruciferous vegetables like broccoli, bok choy, cauliflower and Brussels sprouts.
- Some studies have suggested that high selenium intake might prevent prostate cancer, but later research on more than 30,000 men showed supplemental selenium did not reduce the rate of prostate cancer. Nor have soy protein and pomegranate juice been proven to be beneficial.
- Aspirin has been shown to have a risk reduction effect of 10-15% if taken daily for five years or more. The effect seemed to be greatest in reducing the most aggressive types of prostate cancer. However, starting aspirin after diagnosis did not seem to change the course of the disease.
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