Pathwork Diagnostics

Initial presentation:
A 56 year old woman presents with metastatic cancer to the liver and porta hepatis, 18 years after stage I colon cancer and 2 years after stage II ER positive/HER2 negative poorly differentiated ductal carcinoma of the left breast. She has been monitored by colonoscopy every 5 years since her diagnosis of colon cancer.

Workup:

Initial treatment and patient progress:

• Patient initially treated with capecitabine, oxaplatin, bevacizumab and had stable disease;
• discontinued due to anaphylactic reaction to oxaplatin.
• Patient was stable for 18 months at which time a CT of the chest, abdomen, and pelvis
• showed progression in 3 pulmonary nodules and possibly the liver.
• Patient then started on single-agent irinotecan and adjuvant exemestane for breast
• cancer. CT showed improvement in the liver and porta hepatis lymph nodes but probable
• progression in the pulmonary nodules.

Clinical Question:
Is this metastatic colon cancer, or metastatic breast cancer, or is it a new malignancy?

Pathwork® Tissue of Origin Test ordered.

Results - Tissue of Origin Test:
Interpretation from Pathwork Diagnostics’ pathologist: “The Tissue of Origin test indicates a
COLORECTAL ORIGIN in this case with VERY HIGH CONFIDENCE, based on a Similarity Score of 88.9.
The Tissue of Origin Test has effectively ruled out a derivation from the 14 other tissue types with scores
ranging from 3.3 to 0.1. Similarity Scores below 5 indicate a greater than 99% probability of that tissue type not
being the correct tissue of origin.

Post Tissue of Origin Test:

• The Tissue of Origin results confirmed the recurrence of colon cancer, 18 years after the initial diagnosis, and ruled out breast or another primary.
• Continue with irinotecan for 2-3 more months and follow up with CT scan of chest, abdomen, and pelvis.

“As a result of the Tissue of Origin assay, I feel more confident choosing the appropriate treatment for this patient.”
-- Dr.S.S., Sacramento, CA