Appeal type: Medical Necessity
Decision: Overturned

Summary Reviewer 

The patient is a 60-year-old male who underwent a prostate biopsy in January 2019 and was diagnosed with prostate cancer. The patient has requested coverage for PET imaging CT attenuation skull base to mid-thigh. The Health Insurer has denied this request and reported that the requested services are not medically necessary for the evaluation of this patient. The physician reviewer found that a diagnosis of prostate cancer commonly presents patients with decisions that have no clear-cut answers. The patient is faced with a decision concerning the best therapeutic approach. Choices include: a radical prostatectomy, either with robotic assistance or via an open approach; external beam radiation; brachytherapy; and chemical or surgical castration. Some patients will even opt for no treatment. Further complicating the decision are the possible complications of therapy, including impotence, incontinence, infection, and bleeding. The prognosis also varies directly with Gleason scores. This particular patient has a relatively low-grade prostatic malignancy, based on his Gleason score. The next issue is how to monitor these patients. The National Comprehensive Cancer Network (NCCN) recommends following PSA levels, and when PSA levels increase on two successive assays, considering imaging such as chest x-rays, bone scans, CT, MRI, and PET scans.  Prostate bed biopsy is also a consideration. It is expected that, following complete resection of the malignancy, the PSA will drop to 0. Progressive increases in PSA indicate that there is residual or recurrent tumor. One problem is the lack of accuracy of the various imaging modalities when the post-radical prostatectomy PSA levels are low, but rising. These patients generally will have a recurrence, but it will often be undetectable with conventional imaging modalities. Bone scans will be rarely positive in patients with PSA levels less than 10. Plain x-rays will generally not detect a lesion until 50% of the bone mineralization is lost or gained (sclerotic metastases). CT scans and MRI are dependent on the site scanned, and will only pick up gross anatomic distortions or disease.  Microscopic or small lesions will be very difficult to detect. In order to effectively cover the areas detectable by PET scanning, one would have to perform CT or MRI scans of the head, neck, chest, abdomen, and pelvis. The value of PET scanning, especially when combined with CT scans is that they depend on metabolic changes to detect abnormalities. The U.S. Food and Drug Administration has approved a new radiopharmaceutical used for PET scanning of the prostate. This agent, fluciclovine (marketed as Axumin) offers two distinct advantages. Axumin can detect recurrent disease at PSA levels far less than can be detected by more conventional imaging techniques. Additionally, since Axumin accumulates in non-bony metastases as well as in bone, it offers the advantage of potentially localizing tumor in the prostate bed or in lymph nodes that might not be noted on cross-sectional studies. At this time, Axumin is only approved for cases that are post therapy, and is not approved as an initial screening or staging device. Once recurrence is identified and localized, targeted therapy such as radiation can be utilized.  The use of Axumin PET/CT scan has also been supported by the National Comprehensive Cancer Network (NCCN) guidelines. The recommended Axumin PET/CT scan may assist in detecting metastases not appreciable by other modalities. Therefore, the requested PET imaging CT attenuation skull base to mid-thigh is medically necessary for the evaluation of this patient.