Why you should rethink PET/CT imaging for prostate cancerPosted on: 06.28.18 by Digirad
The large majority of the nuclear imaging community would be quick to point out that PET/CT imaging with either 18Fluorodeoxyglucose (18FDG), or Sodium 18Fluoride (NaF18), is not effective in prostate cancer diagnosis. In fact, it’s not even approved for initial prostate treatment strategy.
With oncology imaging, most other cancers are green-lighted for both initial and subsequent treatment strategies. Prostate imaging, however, is only approved in the latter.
Radiopharmaceuticals and diagnosis
Because prostate cancer is a slow growing, less aggressive disease, the common sugar-based FDG is not an effective agent for diagnosis, but it can be used appropriately to identify metastasis in the body during subsequent treatment.
Sodium 18Fluoride (NaF18), has been used in bone imaging and was previously covered through the National Oncologic Pet Registry (NOPR). However, when the radiopharmaceutical reimbursement was discontinued in December 2017, it lost some of its popularity among physicians. Based on the NOPR study results, coverage is expected to be addressed in the future.
While prostate cancer is consistently one of the top three cancers in the nation, there are very few effective imaging solutions. Blood work, specifically through monitoring the prostate-specific antigen (PSA) level, delivers the majority of diagnoses. Any deviation from normal is an indicator, and may lead to surgery, cryotherapy, or radiation, as necessary.
One new radiopharmaceutical, two benefits
The relative newcomer to prostate cancer detection is Axumin (18F-Fluciclovine), which is indicated for PET imaging in men with suspected prostate cancer recurrence based on elevated PSA levels following prior treatment (chemical recurrence). By continuously monitoring PSA levels following treatment, Axumin can be used as soon as PSA levels begin trending upward leading to quicker detection.
Other imaging methods rely on physical changes in the body, whereas Axumin detects changes on the physiological level, which can develop weeks, even months earlier than physical changes. It ultimately presents a huge opportunity to fill the void in prostate imaging solutions.
An Axumin PET scan accurately identifies the cellular activity and location of a reoccurrence. While 18FDG is ideal for soft tissue, and NaF18 for bone imaging, Axumin offers the best of both worlds. Imaging studies show skeletal mass and metastasis throughout the body, including the prostate bed. When using Axumin, the imaging process begins right away and there is little to no bladder uptake visualized, whereas the traditional method of imaging with 18FDG typically has a great deal of bladder uptake. This bladder uptake, in some cases, obscures residual prostate cancer that may be in the prostate bed or regional lymph nodes.
The challenge with Axumin is its availability. It is currently available from only a handful of radiopharmacies throughout the U.S. and is only produced on certain days, with doses available during a short window of time. However, additional manufacturing sites are planned for 2018.