Scanning electron micrograph of prostate cancer cells. Image courtesy of Anne Weston, Wellcome Images.
It’s Prostate Cancer Awareness Month: A Q&A with Drs. Kane and Parsons
After skin cancer, prostate cancer is the second most common cancer among males. More than 217,000 new cases are diagnosed annually. One in six American men will be told they have the disease at some point in their lives.
Yet prostate cancer remains an especially confounding disease. It grows so slowly that symptoms may not appear until late in life, if ever. Yet it’s also indisputably deadly. At least 32,000 American men die from it each year.
We asked two leading physician-scientists to talk about the study and treatment of prostate cancer: Christopher Kane, MD, chair of the Department of Urology and professor of surgery at the UC San Diego School of Medicine and J. Kellogg Parsons, MD, MHS, associate professor of surgery at UC San Diego Moores Cancer Center and vice chair of the National Comprehensive Cancer Network Expert Panel on Clinical Guidelines for the Early Detection of Prostate Cancer.
Question: The risk of prostate cancer increases with age. The US Preventive medicine task force now recommends against screening but the American Urologic Association states that screening at age 55 is associated with a reduction in prostate cancer death. How do we reconcile the differing recommendations?
Kane: The best argument in favor of screening is that more than 30,000 men die from prostate cancer each year in the United States. If you get screened, you can get treatment, if needed. Screening is gaining information about whether or not a person has prostate cancer and, if they do, the stage, grade and severity of the disease. Fortunately, most men who are diagnosed young are diagnosed at a stage where they can be cured, experience fewer side effects from treatment, and are more likely to benefit from treatment.
Parsons: Most urologists agree that beginning at age 45 to 55 years, men should get a PSA blood test and prostate exam every 1 to 2 years. Regular screening is particularly important for men who either have a family history of prostate cancer (even just one first-degree relative) or men who come from an African-American family. In African-American men, prostate cancer tends to be more aggressive at a younger age.
Q: What is the PSA test?
Kane: PSA stands for prostate specific antigen — a fluid which is normally present in semen. Elevated levels of PSA in blood serum are associated with benign prostatic hyperplasia (prostate enlargement) and prostate cancer. A test for PSA may be used to screen for prostate cancer and to monitor treatment of the disease.
Q: Last year, the United States Preventive Services Task Force said healthy men should no longer receive the PSA blood test for prostate cancer because the screening does not save lives overall and often leads to unnecessary, debilitating tests and treatments. What’s your opinion of the panel’s reasoning and decision?
Kane: I disagree with the task force’s conclusion, as do major health organizations. It’s true that PSA is an imperfect test. Although it is sensitive, meaning that most men with prostate cancer do have an elevated PSA, it is not specific for prostate cancer, meaning many men with an elevated PSA don’t have cancer. So the concern of the task force is that men with elevated PSAs go through additional diagnostic tests that can be uncomfortable and often don’t show cancer.
The other concern is that many men with slow-growing prostate cancer don’t necessarily need to be treated and “overtreatment” can lead to adverse sexual and urinary side effects. What the task force seems to minimize is that prostate cancer is the second leading cause of death in American men and many men with prostate cancer detected by PSA do have life threatening cancers and can be cured with current treatments. In fact, the best study examining the risks and benefits of screening did show a reduction in prostate death among men who got screened and treated.
Q: The lower the PSA test score, the better. What is a worrisome PSA number?
Kane: One of the popular misconceptions is that a normal PSA is anything under four. This is not true for everyone. PSA must be used in the context of age and ethnicity. An average PSA for a man in his 40s is about 0.8 nanograms per milliliter. An average PSA for a man in his 50s is about 0.9-1.0 ng/ml and really should be under 2.5. PSA velocity – the rate of change of PSA – is a very strong predictor of prostate cancer. PSA velocity is also correlated with grade and severity of cancer, particularly for younger men.
Q: For healthy men over age 50, is there a viable alternative to a PSA screening?
Kane: No, for prostate cancer screening, both a PSA and a digital rectal examination are the best tests for men to catch prostate cancer in its most treatable stage. I continue to recommend screening and risk stratification of whether a man has aggressive or more slow-growing prostate cancer. We should then institute safe, effective, curative therapy, usually with surgery or radiation therapy for men with aggressive prostate cancers, and carefully follow, without treatment, men with more indolent, non-aggressive cancers.
Q: What about prevention? Does diet play a role?
Parsons: We have followed large groups of patients in epidemiological studies, and, over time, based on what they tell us they eat, we have been able to make conclusions about what would be some of the most advantageous dietary changes.
The over-arching message is that a heart-healthy diet, when applied to the prostate cancer patient, shows evidence of having the same great results. That diet is high in vegetables, low in fat, low in meat. Vegetables are particularly important. Some vegetables seem to have more bang for the buck than others, including tomatoes, carrots, and a group of vegetables called “crucifers.” Crucifers include broccoli, Brussels sprouts, turnips, cabbage, radishes – vegetables that tend to have a sharp taste. That tangy flavor, some scientists think, contains naturally occurring anti-cancer chemicals.
Kane: We think a low-fat, heart-healthy diet may help prevent prostate cancer. There is some new information that some medications – finasteride and dutasteride – may prevent prostate cancer, but there are side effects and costs, so a patient should discuss that very carefully with his doctor prior to taking medication for prevention.
Q: Are there particular foods to avoid?
Parsons: Red meat in general should be a rare guest at the anti-prostate cancer diet dinner table. But more importantly, any meat that is charred is ill-advised. The charring produces something called PhIP, a chemical that is linked to prostate cancer development and growth.
Q: How does exercise fit in?
Parsons: Studies show that even just 30 minutes of walking or moderate exercise a day can reduce the chances of prostate cancer developing or coming back after it has been treated. The reasons why are unclear, and are currently being studied. It might be through improvements in overall health.
Q: Is it true that you can have prostate cancer and not need treatment?
Kane: It’s true that there are some men with very low-risk, low-grade prostate cancer who may not need to be aggressively treated. That’s an important decision they need to make with their physician. However, that’s the minority: 15 to 20 percent of newly diagnosed men have that very low-grade, low-volume, low-PSA, slow-growing form of prostate cancer. There are also men who are older or who are in poor health where it is less important to diagnose what is often a relatively slow-growing cancer.
At UC San Diego Health System, we offer many men with low risk prostate cancer, active surveillance rather than aggressive treatment. However that decision is based on careful individualized assessment of risks and benefits. Many men with prostate cancer who were destined to have adverse outcomes from their cancer are cured with current treatments. Also current treatments are more refined and have fewer side effects than in prior eras.
Parsons: There has definitely been growing interest in an approach that’s been referred to in various contexts as “watchful waiting,” “active surveillance,” and “observation.” Excellent research has demonstrated that, in appropriate men with prostate cancer, this approach is safe and spares many of them the possible side effects of treatment. The regimen involves careful monitoring with PSA blood tests and, on occasion, repeat prostate biopsy. Newer research also suggests that prostate MRI may be helpful in some of these men for monitoring tumors.
Q: What new medical therapies are on the horizon?
Kane: There are a lot of exciting new treatments for men with prostate cancer. We are now preforming genetic tests of a man’s individual cancer. We are performing some of the most advanced prostate cancer imaging and offering MRI targeted prostate biopsies. We have a number of innovative clinical trials to improve outcomes in men undergoing both nerve sparing robotic prostatectomy as well as sophisticated radiation therapy. We have immune therapy called Provenge®, as well as new hormonal blocking agents (abiraterone and enzalutamide), all of which which has been in the news. Moores Cancer Center has a prostate cancer program rivaling the best in the country, but our hallmark is individualized and compassionate care.
Parsons: A number of effective new medications have been approved by the FDA in the last few years, including abiraterone (Zytiga®), enzalutamide (Xtandi®), sipuleucel-T (Provenge®), Radium-223 (Xofigo®), and denosumab (Xgeva®,Prolia®). These medications were originally tested in patients with very advanced cancers, but some also hold promise in treating patients with earlier stages of prostate cancer.
In addition, there are encouraging developments in the field of prostate cancer detection. At Moores, we offer the FDA-approved PCA-3 urine test in appropriate patients to help make decisions about prostate biopsy; we are also studying the use of advanced MRI technology to detect tumors.
If you are interested in participating in a prostate cancer clinical trial, click here for more information.