Lymphoma is one of the most common cancers in dogs, and it usually shows up as a lump under the jaw that was not there last month. A blood test now turning up in general practice aims to find it earlier, sometimes in dogs that look completely healthy.
The test is IDEXX Cancer Dx, a liquid biopsy that searches a blood sample for markers of cancer elsewhere in the body. On dvm360’s new oncology podcast, IDEXX oncologist Pamela Jones walked through what a positive result means in a dog with no symptoms. In the first 3,000 dogs screened in a prospective wellness study, more than half of the ones flagged while apparently healthy turned out to have lymphoma once vets looked further, including early disease in lymph nodes that felt normal. Treatment has been moving too: a lymphoma drug can now be given at home.
The catch is who gets tested. Jones compared it to breast cancer screening in men: the disease occurs, but at low enough rates that screening everyone produces a pile of false positives, follow-up tests and overdiagnosis. She made the same point about testing every golden retriever at six months old.
What this means for your dog: this is a conversation for middle-aged and older dogs, or for breeds and families with a heavy cancer history. It is not a routine add-on for a puppy. If your dog screens positive and feels well, there are two fair paths. One is more testing, usually an aspirate of a lymph node. The other is a watch-and-wait plan with a clear list of what to watch for, including lethargy, lost appetite, behavior changes and any new swelling. Your vet should be willing to talk through both, and the dvm360 interview covers the reasoning in more depth.