Are two cancer treatments all he needs?

My husband was diagnosed on 1-1-09 with testicular cancer. He has a very large cancerous tumor in his lower pelvis and some in his lymphnodes on the left side. Since his last treatment and P.E.T. scan he only had one treatment. That was two months ago. My question is if the scan still showed cancer after cancer treatments two months ago, and he has not had any since, can the cancer die with no treatments?