[matthewrudy]

I'm surprised about this.

I get that there can be circulating cells, but the probability of them successfully metastasising in the early stages is very low.

Normally it's only later stage cancers that end up spreading.

I guess it's down to the immunosuppression making metastasis more viable.

[throwaway234287]

I'm not an expert, but my understanding is that the probability or rate (or expected time) of metastasizing varies a lot depending on the type of the tumor. (I looked into this a bit when I was diagnosed; it was more or less likely to metastasize within a somewhat short time, depending on the exact type of the tumor.)

I'm sure the immunosuppressants needed after a transplant would increase the risk in any case.

[btilly]

If it wasn't a surprising situation, it wouldn't have been in a medical journal.

However its possibility isn't crazy. Per https://www.ncbi.nlm.nih.gov/pmc/articles/PMC22534/ it seems that cancer cells can be detected in the blood before the cancer itself is detectable by traditional means. Therefore an undiscovered cancer could well have left circulating cells in multiple organs.