Physician dispensing: an old idea is new again.

Faced with declining reimbursement for infusional therapies, an oncology practice turned to physician dispensing to offset the loss. Its leaders quickly discovered that the dispensing-vendor landscape was limited, and few guidelines existed for product line development. Yet the approach offers a competitive response to the changing health care landscape. With physician-dispensing prescription costs 50 percent below the national average and generic substitution 50 percent higher than the national average, the potential cost savings for payers and consumers is staggering.

Potential clinical utility of gene-expression profiling in identifying tumors of uncertain origin.

AIM: To evaluate the potential impact of a gene-expression-based test on the diagnosis of primary tumors in difficult-to-diagnose cases. MATERIALS & METHODS: The Tissue of Origin Test uses 2000 gene measurements to classify the most likely primary tumor. We categorized 284 consecutive samples by pretest diagnosis, then recategorized the samples using test results to identify cases with changes in diagnosis. RESULTS: A total of 64% of incoming diagnoses were nonspecific. A leading diagnosis for the primary site was provided for remaining cases, indicating an unresolved differential. Overall, the test predicted a change in the most likely primary site, either a change from nonspecific to specific site or a change from one specific primary site to another in 81% of the cases and confirmed the suspected primary site for 15% of cases. CONCLUSION: A new molecular diagnostic has the potential to change both primary site identification and therapy selection for the majority of patients tested.

Validation and reproducibility of a microarray-based gene expression test for tumor identification in formalin-fixed, paraffin-embedded specimens.

Tumors whose primary site is challenging to diagnose represent a considerable proportion of new cancer cases. We present validation study results for a gene expression-based diagnostic test (the Pathwork Tissue of Origin Test) that aids in determining the tissue of origin using formalin-fixed, paraffin-embedded (FFPE) specimens. Microarray data files were generated for 462 metastatic, poorly differentiated, or undifferentiated FFPE tumor specimens, all of which had a reference diagnosis. The reference diagnoses were masked, and the microarray data files were analyzed using a 2000-gene classification model. The algorithm quantifies the similarity between RNA expression patterns of the study specimens and the 15 tissues on the test panel. Among the 462 specimens, overall agreement with the reference diagnosis was 89% (95% CI, 85% to 91%). In addition to the positive test results (ie, rule-ins), an average of 12 tissues for each specimen could be ruled out with >99% probability. The large size of this study increases confidence in the test results. A multisite reproducibility study showed 89.3% concordance between laboratories. The Tissue of Origin Test makes the benefits of microarray-based gene expression tests for tumor diagnosis available for use with the most common type of histology specimen (ie, FFPE).