Clinical Utility and Cost-effectiveness of the Pathwork Tissue of Origin Test in Cancer Diagnosis

Clinical Utility and Cost-effectiveness of the Pathwork Tissue of Origin Test in Cancer Diagnosis

Pathwork Diagnostics

Results of a study conducted at Virginia Commonwealth University of the Pathwork Diagnostics’ Pathwork tissue of origin test have been published online in the American Journal of Clinical Pathology, in a paper entitled “Clinical verification of the performance of the Pathwork tissue of origin test: utility and limitations”. The Pathwork tissue of origin test is an FDA-cleared, Medicare-covered molecular diagnostic for identifying tissue of origin.

It utilises a tumour’s own genomic information to assist pathologists and oncologists in diagnosing challenging cancer cases, such as those that are metastatic or have a complex clinical history. In the study, the analytic and clinical performance of the tissue of origin test was examined in 43 poorly differentiated and undifferentiated tumour samples. Results showed 97% (95% confidence interval, 80.4 to 99.8%) agreement between the tissue of origin test result and the reference diagnosis, which was determined based on clinical correlations and immunohistochemical findings, and was among the 15 tumour tissue types covered by the tissue of origin test.

Pathwork tissue

The Pathwork tissue of origin test measures gene expression levels of 2,000 genes. It uses algorithms to compare the tumour’s gene expression pattern with that of 15 tumour types, representing 58 morphologies and 90 per cent of all solid tumours. The test provides objective genomic information to help the physician diagnose what type of cancer the patient has. An accurate diagnosis allows oncologists to match therapy to the cancer.In a related development, results from a study involving the Pathwork tissue of origin test have been presented at the American Association for Cancer Research – International Association for the Study of Lung Cancer joint conference on The Molecular Origins of Lung Cancer: Biology, Therapy and Personalised Medicine in San Diego, CA. The study, “Cost-effectiveness of gene-expression profiling for tumour-site origin”, was authored by John Hornberger, Irina Degtiar, Hialy Gutierrez, Ashwini Shewade, W David Henner, Shawn Becker and Stephen Raab.

Retrospective

The retrospective, observational study examined treatment changes made in patients by physicians who received tissue of origin test results. Changes in planned chemotherapy, surgery, radiation therapy, blood tests, imaging and referral to hospice care before and after test results were recorded. Estimates of the effect of changes in chemotherapy on survival were based on National Comprehensive Cancer Network (NCCN) and other treatment guidelines. Costs were estimated based on data from NCCN and Centres for Medicare and Medicaid Services fee schedules.

Changes in overall survival, costs and cost per quality-adjusted life year (QALY) gained were estimated. In the study, use of chemotherapy regimens consistent with guidelines for the final tumour-site diagnosis increased from 42 per cent to 65 per cent. Overall survival was projected to increase from 15.9 months to 19.5 months, a mean gain of 3.6 months. The average increase in survival adjusted for quality of life was 2.7 months, and the average cost per QALY gained was US$46,858.