Prostate Cancer Screening & Diagnostic Methods
- The number of prostate cancer cases has risen by 3% per year from 2014 through 2019, according to an American Cancer Society study. Improved testing methods and more men screening for prostate cancer have contributed to the growth.
- Research published in The New England Journal of Medicine suggests another possible reason for increased prostate cancer diagnoses and possible overdiagnosis. “Population-based prostate cancer screening has historically relied on PSA levels, which has led to the diagnosis of many prostate cancers that are not a threat to the patient’s life,” the study said.
- The protein-specific antigen (PSA) test screens for prostate cancer by looking for larger amounts of protein-specific antigen in the blood.
- Imaging tests are sometimes used to diagnose prostate cancer as well, with the two most common being MRI and PSMA PET-CT scans.
- Prostate-specific membrane antigen (PSMA) positron emission tomography-computed tomography (PET-CT) allows physicians to visualize prostate cancer cell clusters anywhere in the body and is notably helpful for people with prostate cancer at high risk of spreading or those who have recurrent cancers.
- Magnetic resonance imaging (MRI) uses a magnetic field, radiofrequency pulses, and computer technology to generate highly accurate body images. They help look at the prostate and inside the prostate for any potential tumors.
- Both tests help doctors accurately assess the extent of prostate cancer and plan the appropriate treatment strategies.
But as medical advancements detect more cases, experts are asking a critical question: Are men being overdiagnosed, and could screening protocols be refined to better balance early detection with unnecessary treatment risks?
Read MoreWATCH: The PSA blood test and a rectal exam are vital for prostate cancer screening.
In recent years, other test methods, including prostate-specific membrane antigen (PSMA) positron emission tomography-computed tomography (PET-CT) scans and MRI imaging, have gained increasing support from cancer experts. PSMA PET-CT scans are a relatively new imaging technique that allows physicians to visualize prostate cancer cell clusters anywhere within the body. PSMA PET-CT is helpful for people with prostate cancer where there’s a high risk of the disease spreading outside the prostate gland or those who have recurrent cancers.
Magnetic resonance imaging (MRI) uses a magnetic field, radiofrequency pulses, and computer technology to generate highly accurate body images.
Expert Resources on Prostate Cancer Treatment
Imaging Tests Used to Diagnose Prostate Cancer
The prostate-specific membrane antigen (PSMA) positron emission tomography-computed tomography (PET-CT) scan works by locating a radiotracer drug given to a patient. According to the National Institute of Biomedical Imaging and Bioengineering, “Radioactive tracers are made up of carrier molecules bonded tightly to a radioactive atom…Some tracers employ molecules that interact with a specific protein or sugar in the body and can even employ the patient’s cells.”
The drug seeks out PSMA (the protein highly present in high amounts on prostate cancer cells). Once the drug has bound to PSMA, it emits signals that identify the body’s PSMA-rich regions. A PSMA PET-CT scan can pick up this information to precisely highlight prostate cancer cells and their exact location within the body.
PSMA PET-CT can also help cancer doctors in treatment decisions when PSA is detectable but still too low to be detected by conventional scans.
Dr. Asit Paul, a hematologist-oncologist at the Massey Cancer Center, explains the regular PET-CT scan as follows: “PET-CT is a hybrid imaging system that combines two different modalities to image cancers. In a PET scan, radioactive material is injected into the body, which travels through the bloodstream and preferentially accumulates in the cancer cells more than normal cells.”
There is one downside to the PSMA PET-CT scan in prostate cancer patients, which is that not all prostate cancer patients express PSMA, meaning the PSMA-PET CT scan will not detect cancer in these patients.
When reading PSMA PET-CT scan results, the images from a PSMA PET-CT scan look like regular CT scan images on which areas with cancer are brightly highlighted in yellow.
However, normal tissues that are not cancerous but express PSMA appear bright on these images. Distinguishing cancer from normal tissues, therefore, requires specialized training.
The out-of-pocket cost of a PSMA PET-CT scan can vary widely, from just over $1,000 to almost $10,000.
WATCH: Biopsy can put your mind at ease.
MRI Imaging Tests Look Inside the Prostate
Getting a prostate MRI is a critical part of the diagnostic process.
“[MRIs are] particularly useful for looking at the prostate and inside the prostate for any potential tumors,” radiation oncologist Dr. Nicholas Nickols tells SurvivorNet.
WATCH: Getting a quality prostate MRI is critical for the diagnostic process.
“You give yourself the best chance of getting good information by going to a center that performs a lot of these and ideally is involved in cutting-edge research about improving imaging and interpretation of the scan,” urologist Dr. Geoffrey Sonn explained.
How Low-Risk Prostate Cancer Is Treated
Active monitoring is the best choice for patients who are diagnosed with low-risk, localized prostate cancer.
Dr. James Wysock, a urologist specializing in urological cancers at the Perlmutter Cancer Center, NYU Langone Health, explained to SurvivorNet that if prostate cancer is detected at a “very early stage and a low volume, we have many different options for managing it and higher expectations of that prostate cancer will be completely controlled. And so as we continue improving our diagnostic tests and paradigms, that’s the ultimate goal.”
WATCH: What are my treatment options for low-risk prostate cancer?
“Watch and Wait” is particularly recommended for patients whose cancer is:
- Small
- Expected to grow very slowly
- Confined to one area of the prostate
- Not causing any signs or symptoms.
- Gleason score of 6
The Gleason Score uses tissue from a biopsy; this test grades cancer from 6 (less aggressive) to 10 (most aggressive) and a measurement of PSA levels to gauge the cancer’s likelihood of progression.
Doctors sometimes recommend that patients with a Gleason score of 7 consider this approach. However, due to the slightly higher risk, doctors will usually recommend closer and more frequent monitoring.
Related: When Active Surveillance Isn’t Enough
About 50% of men who opt for active surveillance will have changes within five years that require active treatment.
Doctors may recommend switching to treatment based on specific criteria:
- PSA levels: A rapid increase or a level consistently higher than the typical range for age may signal the need for intervention.
- Digital rectal exam findings: Detection of new or enlarging nodules could indicate cancer growth.
- Gleason Score: An increase in Gleason score, particularly to 7 or above, from repeat biopsies suggests more aggressive cancer.
Questions To Ask Your Doctor
- Will my insurance cover the costs of imaging tests?
- Should I get an MRI of my prostate?
- Should I get a PSMA PET-CT scan?
- What did the tests show, and what does it mean for treatment?
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