Prostate cancer: Advances in screening and treatment
September is National Prostate Cancer Awareness Month.
Prostate cancer is the most common nonskin type of cancer. Approximately one in seven men in the United States will be diagnosed with prostate cancer at some point in their lives.
Dr. Brian Helfand, a board-certified urologist and director of the Prostate Cancer Program at the John and Carol Walter Center for Urological Health at NorthShore University HealthSystem, answered questions about prostate cancer and the future of treatment for it.
Q. What is the prostate?
A. The prostate is a walnut-sized organ that is located just underneath the bladder. The urethra (or tube where a man urinates) runs through the center of the prostate.
The prostate's normal function is to secrete fluid that nourishes and protects sperm. During sexual intercourse, the prostate squeezes this fluid into the urethra and it is expelled as ejaculate fluid. Because of this function, I always tell patients that the prostate is necessary for normal sexual reproduction.
However, after reproductive years, the prostate can cause problems: 1) It can exhibit noncancerous growth called benign prostatic hyperplasia or 2) Develop cancer.
Q. What are symptoms and risk factors for prostate cancer?
A. Many men with prostate cancer have increased urinary symptoms such as a weakened or slow stream. In addition, men with metastatic prostate cancer often present with new bone or back pain and sometimes even with unexplained weight loss.
However, since the introduction of the serum blood test called prostate specific antigen (PSA), men are typically diagnosed when the cancer is still confined to the prostate. At this stage, the vast majority of men are without symptoms. This is the ideal time to diagnose and treat men.
African American men are considered to be at higher risk of prostate cancer and are recommended to have earlier prostate cancer screening.A family history of prostate cancer also increases the risk of being diagnosed. The American Urologic Association recommends earlier screening among men with a family history of the disease.
However, it is important to recognize that the vast majority of men do not report a family history of prostate cancer. As such, I believe that every healthy individual should have a discussion with his primary care physician or urologist about the risks and benefits of undergoing PSA testing.
The most common test that is used for prostate cancer screening is the PSA test. This is usually paired with a digital rectal examination.
Q. Besides the PSA testing, what other screenings are available?
A. Within the past several years there are newer blood tests that can estimate the risk of prostate cancer. One such test that will be available commercially is called the Genetic Risk Score. This blood test measures a number of different variations in a man's DNA that are associated with prostate cancer risk.
A man is born with a fixed number of these variations called single nucleotide polymorphisms and they do not change over a lifetime. The number of SNPS that an individual carries is associated with increased or decreased risk. Knowing this type of genetic information will help to stratify disease risk and also help guide the frequency and intensity of PSA testing.
Q. What are the guidelines for prostate cancer testing?
A. Unfortunately, different authoritative groups differ on guideline recommendations for prostate cancer screening. Some recommend a baseline PSA at age 45 and other groups recommend waiting until age 55.
However, I believe that a discussion about the risks of prostate cancer should be undertaken with every man at an early age. This informed discussion will act as a platform that can guide the timing and initiation of prostate cancer testing.
Q. How is the evaluation and treatment for prostate issues changing?
A. Historically, men with abnormal PSA values were evaluated further with prostate biopsies.
While this is a seemingly benign procedure that has overall very little risk, it is still invasive and can cause some minor amounts of pain for some men.
Within recent years, other commercially available tests have become available that can help guide the decision for prostate biopsy. These tests are blood tests and help to estimate the risk of finding cancer and even aggressive disease on a biopsy.
These tests, including prostate health index and the 4K Score, have been shown to improve the performance of a prostate biopsy and should be considered prior to getting a biopsy. In addition, many patients can also obtain an MRI of the prostate before considering a biopsy.
Q. If a biopsy shows prostate cancer, how does a doctor determine how quickly it will spread?
A. When a prostate biopsy is performed, the samples are evaluated under the microscope by a pathologist. The pathologist sends your physician a report that gives a diagnosis for each sample taken. Information in this report will be used to help manage care.
In most recent years, pathologists can grade prostate tumors according to how aggressive they appear in the microscope. The pathologists assigns numbers to the primary pattern and secondary patterns that they see within the tumor.
Ultimately, these numbers are added together to get a Gleason score. Higher Gleason scores are usually associated with increased chance of spreading beyond the prostate.
Q. What treatments are available for prostate cancer?
A. Not all prostate cancers require immediate treatment. Many men with low Gleason grade nonaggressive tumors can safely be monitored by active surveillance. Men with these indolent tumors have a less than 1 percent probability that they would die from these tumors. As such, many urologists now actively follow these patients with periodic prostate biopsies and regular PSA checks.
In addition, there are other commercially available tests that can be used to help predict a man's risk of success on an active surveillance protocol. These tests such as Oncotype Dx (Genomic Health), Prolaris (Myriad) and Decipher (Genome Dx) can measure molecules within a biopsy sample to help predict the chances of a patient not developing more aggressive disease or experiencing metastasis while on active surveillance.
Men who are found to have intermediate or aggressive prostate cancer that is confined to the prostate should be counseled on the possibility of definitive treatment depending on their overall health and other medical problems.
Definitive treatment for prostate cancer is generally divided into two major types of treatments including surgery or radiation. Overall, both types of treatment have similar cancer control.
Historically surgery was performed by making an incision and removing the entire prostate (called a radical prostatectomy). However, this surgery is now most often performed using minimally invasive techniques including robotic-assisted surgery.
Most studies support that surgeon experience is the most critical for successful outcomes. As such, patients should inquire about surgeon experience and their overall surgical volume with the procedure.
There are many forms of radiation therapy that can be used to treat prostate cancer. The most common forms of radiation include implantation of radioactive seeds within the prostate (called brachytherapy), external beam radiation (generally referred to as intensity modulated radiation therapy) and proton therapy.
There are differences between each radiation technique. Discussion with a urologist and specialist in radiation (called radiation oncologist) should be obtained to evaluate whether radiation and what type of radiation is an appropriate decision for an individual patient.
Within the past several years newer therapies have been offered for the treatment of prostate cancer. These therapies have included techniques to freeze tumors (called cryotherapy) and focal ablation techniques with laser therapies. However, caution should be raised about these treatments as many are still considered experimental.
Finally, men who are diagnosed with prostate cancer that has spread beyond the prostate are often treated with medications to control their tumor. These medications are usually prescribed by a medical oncologist and are usually referred to as hormone therapies, also called androgen deprivation therapy.
The goal of these therapies is to deplete levels of male hormones such as testosterone. Since prostate cancer cells are stimulated by testosterone, depletion can help destroy tumor cells that have spread beyond the prostate.
Within the past several years many newer androgen deprivation therapies have come to the marketplace. All of these therapies have been associated with improved and prolonged survival for men with advanced prostate cancer.
Q. How successful are prostate cancer treatments?
A. Definitive prostate cancer treatments for prostate tumors that are localized to the prostate are very successful. Surgery or radiation will cure the disease for the vast majority of patients (over 85 percent) with prostate cancer that is confined to the prostate.
However, over a 20-year period about 15 percent of men will experience a recurrence of their prostate cancer. This is usually detected by the PSA blood test after therapy. If the prostate tumor recurs, then additional therapies including radiation and androgen deprivation therapies can be used to treat the tumor recurrence.
Q. What are the latest research developments concerning prostate cancer?
A. Advances in prostate cancer research have seemingly exploded over the past decade. I believe that this is largely related to the fact that we are now able to perform genetic testing.
Genetic testing allows physicians to personalize screening and treatments. In other words, it allows us to provide a specific therapeutic approach for a patient that is right for the patient based upon their own DNA.
For example, prostate cancer is the most heritable of all cancers. Data currently support that there are three components that are essential to estimating a man's risk of prostate cancer including 1) family history of disease 2) specific mutations within genes (including the breast cancer genes, BRCA1/2) and 3) Genetic Risk Score (a genetic test that can estimate disease risk based upon genetic variations called single nucleotide polymorphisms).
I believe that knowing this information can help guide the timing and initiation of prostate cancer screening.
If a patient has an elevated inherited risk such as a positive family history or high genetic risk score, then this patient would likely benefit from earlier screening. These tests have the ability to identify men who are most at risk of aggressive disease and screen them early so that we can find their tumors before they become aggressive.
In addition, genetic testing on prostate tumors has also been performed.
Interestingly, it has been shown that certain DNA mutations within tumors are more sensitive to specific androgen deprivation therapies or chemotherapies. Other DNA mutations appear to infer decreased sensitivity to radiation therapy.
Determining the type of mutation that is present in a biopsy specimen or surgical specimen may ultimately be used to dictate the type of therapy that a patient receives. This information will help provide the perfect treatment for a patient and should improve the overall response rate of tumors.
• Dr. Brian Helfand is director of the Urologic Division in the Personalized Program for Cancer Care at NorthShore, and participates in many research projects including clinical trials assessing the genetic basis for prostate cancer and aggressive forms of the disease. Helfand is also a clinical associate professor with the University of Chicago Pritzker School of Medicine.