Cancer/Carcinoma of Unknown Primary is when the doctors know you have cancer, but don’t know where it started.
My wife Karen was diagnosed with Cancer and the doctors ran a few inconclusive tests to try to determine where it started. After a biopsy didn’t indicate a conclusive source they advised that it didn’t really matter, because they were at least certain that it was gynecological in nature, and that all gynecological cancers prescribed the same initial treatment.
I was a bit concerned about that and asked the doc whether it would affect anything down the road, but he indicated that it wouldn’t. That wasn’t exactly true. After the first couple chemo meds failed to work we started to look for other options, including drug trials. Not knowing the primary source of the cancer was an automatic disqualification from many of the trials, and genetic testing to nail down the source of the cancer took a couple of months.
If possible, don’t stop asking for more tests until you know what the cancer is.