Osteosarcoma - possible recurrence?

Scuba

My close friend's son had osteosarcoma, localized, knee replacement, 12 months out Went to the doc the other day and during an x-ray saw "spot' on his spine. From what I've read, most recurrences are in the lungs, he was Stage 1, no lymph nodes, no mets. Has anyone gone thru this? Would like to hear ur thoughts and stories. Thanks.