Kathy, I was using androgel for three years before I was diagnosed with PCa. It brought my T level up from <100 to around 300 and seemed to give me more energy. But I discontinued using it as soon as I was diagnosed.
After radical prostatectomy my oncologist advised me not to use androgel just in case some of my cancer cells had escaped. He told me testosterone causes PCa to spread and not enough studies are available to indicate the use of testosterone replacement is advisable even after radical prostatectomy.
However, my first blood work done three months after surgery showed my T level had spiked up to 600 without using any hormone replacement. My PSA is undetectable so far and my T level is a bit above average. My oncologist is still wondering about the increased T level after surgery. He doesn't understand the correlation but my T level is 6x what it was before I started using the androgel 3 years ago. My next blood test is in June and we're anxious to see if there's any change.
Right now (with my increased T level) I have more sex drive than I've had in years...... and trimix is a real blessing at this moment in time...... As I continue to heal I'm hoping I will get to a point that I no longer need trimix pills or pump. But I'll do whatever it takes. 
best regards, hj