PET-CT Scans Making Waves in Prostate Cancer Detection
American Cancer Society estimates in the United States alone there will be 299,010 new cases of prostate cancer. There will also be 35,250 deaths from prostate cancer. This makes prostate cancer the second most common cancer in American men. About 1 man in 8 will be diagnosed with prostate cancer during his lifetime and out of these 1 in 41 will die from it. Most of these cases are men 65 years or older.
In current practice, prostate screening can be done by doing a blood test examining prostate-specific antigen (PSA) levels in the blood. High levels in the blood would possibly indicate malignancy. Another test is doing a digital rectal exam (DRE). This involves a rectal examination palpating the prostate gland to see if the gland is enlarged. If these two examinations are abnormal a biopsy is usually done to determine if the prostate gland has cancerous cells.
There are a few limitations to these examinations described above. The PSA levels and DRE examination can’t confirm cancer. Normal conditions or lifestyles may rise your PSA levels naturally and are not abnormal even though the levels are high. Speaking with your provider and getting a full history will help ruling these out first. DRE examinations are less effective than PSA blood tests but sometimes can find cancers in men with normal PSA levels. Abnormal findings of these exams are based by each providers discretion and may vary. Biopsy’s are good in examining tissue in the prostate. Most often the doctor will do 12 core samples from different parts of the prostate. Local anesthetic is used to reduce discomfort during this procedure. To be effective 12 core samples are obtained to evaluate for abnormal tissue.
Recently new PETCT tracers such as 18F-DCFPyl (also known as piflufolastat F 18 or Pylarify) have been an excellent way to detect prostate cancer cells. The tracer 18F-DCFPyl in PETCT imaging attaches to prostate-specific membrane antigen (PSMA), a protein that is often found in large amounts on prostate cancer cells. The scan covers a large area from the top of the head to mid-thigh. Having such a large area to scan is beneficial because you can look for distant metastasis if any. The information from the scan can show if the patient has prostate cancer in the bones and soft tissue. This scan also has a higher sensitivity to detecting cancerous cells compared to CT, MRI and Bone scans. It is believed that this scan will the gold standard because of its ability to scan a large area, detect small lesions, evaluate patients with increased low PSA levels after treatment, ability to detect cancer in the bones and soft tissue. This is the information your provider and oncologist need to stage or restage your cancer. This helps your provider choose the most effective treatment for your specific condition. In some cases, this gives peace of mind to some of the patients when the scan shows no distant metastasis. If it does happen that there is distant metastasis it is also beneficial to have this scan because you can get treatment soon and effectively before the disease progresses onto other sites. This is disease is considered a salvageable disease when it is detected early on. That is why the PETCT PSMA scan is highly recommended.
What can you expect when setting up this scan? Your doctor will call our facility to set up your appointment. They will make sure your insurance gets authorization to approve the scan before you arrive. The day before the scan, one of our Nuclear Medicine Technologist (NMT) will call you to confirm your appointment and give you a few instructions. Part of these instructions are to hydrate the morning of the scan, fast for 4hrs, and wear comfortable clothing without metal material. The day of the scan you will come in to our facility. You will get registered and fill out a few forms. Next you will come into our nurse’s station to get an IV and start drinking oral contrast. Then you will be brought to our PETCT suite. Here the NMT will ask you several questions to get a good history. After this you will get injected with 18F-DCFPyl and wait an incubation period of 90 to 120 mins. During this time, you will keep hydrating with water and be encouraged to use the restroom frequently. Once the incubation time is completed you empty your bladder on last time and will get on our scanner. You will be imaged for about 30 mins. The scanner will do 2 different types of scans at the same time, a PET and CT (PETCT). The PET will show highlighted areas where the 18F-DCFPyl accumulates concerning for prostate cancer cells. The CT will tell you the specific location of where the 18F-DCFPyl is located. The fusion imaging is the best way to evaluate these scans. In total you are looking at being with us for 2.5 to 3 hrs. Since you received a pharmaceutical you will be asked to keep a 6 ft distance from children and pregnant women for the next 10hrs. After this period the pharmaceutical will completely out of your system. Hydration also helps this process work better. Within the next 2 business days your provider will get the results from the scan. After this your provider or oncologist will discuss your results and decide on a treatment plan.
PETCT PSMA imaging is one of best available scans for patients with prostate cancer. As it continues to show its ability to detect prostate cancer cells due to the higher sensitivity in PETCT imaging, this will be the best choice of scan for prostate cancer patients.
Written by Humberto Molina, CNMT, RT(R)(CT)
Nuclear Medicine Supervisor at Midland Health