PET Scanning: Worth the Cost in Cancer? Not Only Worth the Cost, but Sometimes a Cost-Cutter!

Over the last 2 decades, positron emission tomography (PET) scanning has evolved from a specialized imaging modality available at only a few select academic institutions into a widely available technology central to the evaluation and management of patients with known or suspected malignancy. This promulgation of PET imaging has not come in an explosive and uncontrolled fashion. Quite the contrary: each step forward in the acceptance of PET, and-equally importantly-the coverage of PET by the Centers for Medicare and Medicaid Services (CMS), has come to be through the collection and presentation of evidence in support of PET’s role in oncology. In its most recent decision memo, CMS approved the use of PET for initial evaluation and subsequent evaluation of nearly all solid tumors, based on evidence provided by the National Oncologic PET Registry and others.[1]

One of the common misperceptions about PET is that it is costly. PET is generally considered an “expensive” imaging test, yet when compared with the summed charges of contrast-enhanced CT studies of the neck, chest, abdomen, and pelvis, the cost of PET imaging may be quite comparable. Similarly, at many facilities the charges for MRI and PET are similar. As the cost of the scanners has declined, and the radiopharmaceuticals for PET (primarily fluorodeoxyglucose [FDG]) have become widely available, the overall charges associated with PET imaging have come into line with those of other advanced imaging techniques.

Although limited in number, there are peer-reviewed publications that examine the cost-effectiveness of PET in various clinical scenarios. Perhaps the most well-known of these is the PLUS trial,[2] in which researchers in the Netherlands examined the use of FDG-PET added to a conventional workup vs a conventional workup alone in the presurgical evaluation of patients with early-stage lung cancer. In this trial, “conventional workup” was defined as the imaging obtained per standard clinical practice using available guidelines. The authors found that in those patients who underwent presurgical evaluation with conventional workup alone, 41% of thoracotomies were futile. In contrast, the patients evaluated with FDG-PET in addition to a conventional workup had a futile thoracotomy rate of only 21%. The authors concluded that the added cost of PET imaging was offset by the savings achieved through the avoidance of unnecessary surgery, with a savings of approximately €1,289 per patient.

A more recent study in patients with advanced gastric cancer came to similar conclusions.[3] Patients with locally advanced gastric cancer were evaluated with FDG-PET/CT in addition to a standard workup with diagnostic CT, endoscopic ultrasound, and laparoscopy. PET/CT detected unsuspected metastatic disease in 10% of patients, including bone, liver, and nodal sites. Through the avoidance of the costs and morbidity of unnecessary surgery, the estimated cost savings per patient was approximately $13,000. Although additional studies exist in the literature, more data are clearly needed to demonstrate the value of PET in a variety of malignancies and clinical scenarios.

In the meantime, decisions continue to be made regarding the utility of PET for the management of patients with cancer. Although practice algorithms and policy decisions tend to be binary (covered vs noncovered, recommend vs avoid), the truth is that the usefulness of PET in particular clinical scenarios is always a matter of probability. Certain situations, such as clinically early-stage breast carcinoma in the absence of signs or symptoms of distant spread, are associated with a low likelihood that PET would show unsuspected or management-altering disease. However, that likelihood is not zero, since a small percentage of such patients will be found to have an unsuspected site of metastatic disease that results in a substantial change in management. In other situations, such as inflammatory breast carcinoma with palpable axillary adenopathy, the statistical likelihood of additional distant disease is higher. But as high as that likelihood might be, the value of PET will never reach 100%. Coverage decisions and algorithms are based on these likelihoods, but by their nature they may limit the autonomy of the oncologist to make patient-specific decisions regarding PET utilization based on all the available evidence.

In summary, PET has proven to be an invaluable tool in the diagnosis, staging, and management of the oncologic patient. The expansion of PET indications has come with demonstration of value through the peer-reviewed literature. Although gaps in knowledge still exist, particularly in regard to evolving targeted therapies and rare tumors, PET has clearly shown its value, and in certain situations can actually lessen the overall cost of care through the avoidance of unnecessary or futile interventions.

Financial Disclosure:The author has no significant financial interest in or other relationship with the manufacturer of any product or provider of any service mentioned in this article.

References:

1. Hillner BE, Siegel BA, Liu D, et al. Relationship between cancer type and impact of PET and PET/CT on intended management: findings of the National Oncologic PET Registry. J Nucl Med. 2008;49:1928-35.

2. Verboom P, van Tinteren H, Hoekstra OS, et al. Cost-effectiveness of FDG-PET in staging non-small cell lung cancer: the PLUS study. Eur J Nucl Med Mol Imaging. 2003;30:1444-9.

3. Smyth E, Schöder H, Strong VE, et al. A prospective evaluation of the utility of 2-deoxy-2-[18F]fluoro-D-glucose positron emission tomography and computed tomography in staging locally advanced gastric cancer. Cancer. 2012;118:5481-8. PET Registry. J Nucl Med. 2008;49:1928-35..