With 1 in 9 men diagnosed with prostate cancer — the most common cancer for men — urologists are working to develop new treatments, from 3D Tesla MRIs to electrical currents that destroy tumors.
“There are a lot of new treatments available in the metastatic prostate cancer landscape, which is cancer that has spread beyond the prostate to the lymph glands, or to other organs or the bones,” said Dr. Dipen Parekh, chairman of urology at Sylvester Comprehensive Cancer Center.
Prostate cancer is the most common cancer diagnosis made in men with an estimated 248,530 new cases in the U.S. expected in 2021, according to the North American Association of Central Cancer Registries.
The majority of cases are in older men: In 2017, there were 37,763 prostate cancer cases in men ages 70–74, according to the Centers for Disease Control and Prevention, compared with only 546 cases in men ages 40–44.
“The prostate is like a doughnut with a big hole in the middle and the urethra runs right through the middle of it,” said Dr. Jonathan Silberstein, chief of urology at Memorial Healthcare System. “As men get older, the prostate continues to grow and it constricts the urethra resulting in slowing of the stream.”
When urine flow is restricted, men often visit a doctor with symptoms that include trouble getting started, waking up at night, incomplete emptying or a weak stream.
“The prostate may be enlarged with cancer or it may be enlarged without cancer, and either way that may be the first presenting sign,” Silberstein said.
An enlarged prostate does not mean one has prostate cancer. Prostate cancer has few, if any, symptoms, with many men presenting with an elevated prostate-specific antigen blood test, or PSA. This test measures the protein produced by normal, as well as malignant, cells of the prostate gland, and can help men understand their risk for prostate cancer.
Silberstein points outs that many men who have elevated PSA levels do not necessarily have prostate cancer, which makes the test controversial.
About 1.2 million men with elevated PSA levels each year go on to have biopsies, Silberstein said, but only a quarter of this group have prostate cancer. The biopsies, conducted with needles that obtain tissue samples of the prostate, risk infections, hospitalization, and often create a great deal of anxiety.
“Historically, if a man had an elevated PSA test, then a prostate biopsy was the next step,” Silberstein said. “An MRI of the prostate is done to obtain pictures, a little bit like a GPS of the prostate, as it can determine where in the prostate there is an abnormality.”
The diagnostic accuracy has increased, Silberstein said, and new MRI technology allows doctors to determine if the patient needs a prostate biopsy, and if he does, it offers a more accurate biopsy and subsequent treatment plan.
Those men determined to have lower-risk, localized prostate cancers, may undergo an “active surveillance” strategy, which includes frequent blood tests, MRIs, and biopsies, Silberstein said. This therapy obviates the need for surgery and radiation, which have side effects that include leakage of urine, requiring a catheter, and erectile dysfunction.
Haitians, Dominicans at higher risk
But certain groups are at higher risk for prostate cancer.
African American men experienced the highest rate of new prostate cancer, in 2017, with 163.8 cases per 100,000, the CDC said, compared to 96.7 cases per 100,000 for white males. Native Americans had the lowest rate, with 52 cases per 100,000.
In Miami, Haitians and Dominicans tend to have much more aggressive prostate cancer than their African American counterparts, said Dr. Murugesan Manoharan, chief of urologic oncology at Miami Cancer Institute at Baptist Health South Florida.
“They get the cancer very early, and very aggressive,” said Manoharan.
After a diagnosis comes a risk assessment, which determines whether the patient is facing a low- or high-risk prostate cancer. Genomic tests allow doctors to predict whether the prostate cancer may grow slow or quickly.
Manoharan uses a 3 Tesla MRI with computer-aided detection that allows a radiologist to identify prostate cancer lesions.
“Based on the MRI, rather than doing random biopsies, meaning putting needles blindly into the prostate, doing a targeted and focused MRI fusion biopsy gives you a better chance of accurately diagnosing it, and then deciding which way to go,” Manoharan said.
If the cancer requires surgery, a patient can expect to go home within 24 hours, Manoharan said, due to advances in robotics and surgical skills.
If radiation is required, proton therapy can deliver a high dose to a specific area with minimal impact on surrounding tissues.
“It’s called TrueBeam or pencil-beam technology, which offers a more precise radiation field, a good outcome and minimizes side effect,” Manoharan said.
Ablation technology is also used, in which energy from heat, cold, lasers or chemicals kills the cancerous cells. But the process also can kill surrounding tissue that is not cancerous.
“We can use heat, or we can use cool such as a cryo-therapy, both can be delivered into the prostate,” said Manoharan, noting the procedures often can be done in a few hours in a hospital. “Then they can go home and get on with it.”
NanoKnife technology, a minimally invasive probe that destroys tumors using electrical current, is also relatively new in prostate cancer treatments.
“There are only three centers across the county involved in current FDA trials, for NanoKnife technology, and Miami Cancer Institute is one of them,” Manoharan said. “It is a very minimally invasive procedure.”
Holes are made in the cell membrane, using non-thermal electrical energy that leads to fluid leaking out, and then cell death.
Targeted therapies for prostate cancer
If the disease has spread to the bones or elsewhere outside the prostate, targeted therapies such as hormonal treatment, chemotherapy, radiopharmaceuticals, immunotherapy and focused radiation can be employed.
Parekh and his Sylvester team use high-intensity focused ultra-sound, or HIFU, which fuses MRI and biopsy data with real-time ultrasound imaging that allows urologists to view detailed 3D images of the prostate.
The ultrasound waves are used to ablate, or burn off, the tissues in the targeted area, and present fewer side effects compared to total prostate removal, or radiation therapy.
“This really marks a paradigm shift in the way we treat prostate cancer,” Parekh said. “Just like in breast cancer, if you have a small lump in the breast, you don’t remove the entire breast anymore, you just remove the lump.”
Parekh said the same situation applies to the prostate, in selected patients, as the main area of cancer is treated, and then the gland is monitored accordingly.
“By doing that, we have the potential to cure the cancer, and yet spare the collateral damage of the more radical treatments like radiation and surgery,” said Parekh.
Prostate specialists are working to catch the cancer before it spreads, which impacts a patient’s survivorship rate.
The relative five- and 10-year survival rates for 99 percent of men with newly diagnosed, localized prostate cancer are close to 100 percent, Silberstein said, depending on the stage and grade.
“If the cancer has already left the prostate at the time of diagnosis, the five-year survival rate drops dramatically from about 100 percent down to about 25 percent,” said Silberstein.