Former Wales captain Matthew Rees admits he experienced "dark days" during his successful battle with testicular cancer.
Rees was diagnosed with the illness last October, but having undergone treatment he made his return in Cardiff Blues' 28-23 RaboDirect PRO12 victory over Ulster on Saturday.
The 33-year-old British and Irish Lions hooker, who resumed full training in February, completed his playing comeback as a second-half replacement at the Arms Park.
"I think the most important thing in life is your health. If you haven't got your health, you haven't got anything," Rees said.
"Obviously there were some days where I thought I would never play the game again and some days where I thought I can get back on the field.
"It was just a case of being positive all the way and speaking to the nurses on a regular basis about the success rate, where I was going.
"I had some dark days, but it's a challenge and I have overcome that and obviously come out the other side and it's just good to be back involved in the rugby side of it.
"I'm glad to say I have come out the other side and am obviously back on the field. An experience like that in your life will change you."
Rees has revealed that he was able to resume conditioning work while undergoing treatment.
"It was unknown territory to know how I was going to react, but I was lucky enough to keep on ticking over through the five months which I was off and kept myself in pretty good shape," he told www.walesonline.co.uk.
"I had a six-week block which I targeted as a mini pre-season to get back in time for the tail end of the season and hopefully play the last couple of games."