Jon,

Cancers, like leukemia, lymphoma can show low WBC, and lymphocytes, which are part of WBC, I believe, and many other conditions, diseases, cancer treatment. I would think cancer itself, not just metasteses, whould show abnormality in whatever test is used, and don't think they would differentiate between the two, except a biopsy, and you would have to have or had cancer for a metasteses, but I don't know much about this. I have a few herniated discs, and had then pressing on the nerves. A nerve test by a neurosurgeon can tell if there is nerve abnormality. One is called an EMG, electromylegram, which I had. Maybe go to a different ENT or do if you didn't.