Positron emission tomography costs less to patients than conventional screening for malignancy in dermatomyositis

Dermatomyositis (DM) is associated with malignancy and interstitial lung disease. Many malignancies associated with DM occur in organs not routinely screened by national guidelines; thus, best screening practices are still debated. Positron emission tomography (PET) has been suggested as a single study alternative to more complex screening panels and may also be valuable in detecting interstitial lung disease progression. Criticisms of PET screening exams have focused on cost and radiation exposure.

To compare the cost of PET and its variants to conventional malignancy screening panels, and to review concerns regarding radiation exposure in PET.

Four variants of PET and PET-CT were included in the study. The conventional screening panel was defined as CT of the abdomen and pelvis without contrast, CT of the thorax without contrast, CEA, CA 19.9, PSA (men), mammography (women), transvaginal ultrasound (women), cytopathology (women), and CA 125 (women). The MarketScan^® Commercial Claims and Encounters database, a collection of private insurance claims data from 53 million Americans, was queried for every instance of each test from 2005 to 2014 and the mean inflation-adjusted cost of each was recorded. The mean total cost to insurance companies and the mean out-of-pocket costs to patients for PET variants were compared to the costs for conventional panels. Additionally, the cost of pulmonary function tests (PFT) from the same period was evaluated.

From 2005-2014, the mean inflation-adjusted costs of PET have trended downward, but the mean cost of PET-CT have trended upward. The mean total cost to insurance companies for PET-CT whole body was $730.70 and $537.62 greater than the cost of conventional panels for men and women, respectively. The out-of-pocket patient costs for PET-CT whole body was $109.82 and $111.33 less than the cost of conventional panels for men and women, respectively. The mean total cost of PFT was $205.02.

The cost of PET-CT whole body was greater than conventional panels for insurance companies, but patient out-of-pocket costs were lower. PET-CT may also have added value in detecting and monitoring interstitial lung disease progression in DM patients. More data are needed on the efficacy of PET-CT in detecting malignancy in DM patients; however, the cost difference is less than expected, suggesting the single scan could be a reasonable alternative to the conventional screening panel in some patients.