"I couldn't believe it," Kessel said before Boston's game against Florida on Saturday night. "It was tough. I had a hard time with it."
Kessel, 19-year-old former University of Minnesota player drafted in the first round this year, is expected to rest for two weeks before getting back on the ice. Dr. David Judge, a team internist, termed the prognosis "excellent."
On Saturday, Kessel and the Bruins confirmed that the centre had surgery Monday for testicular cancer. Follow-up tests showed the cancer had not spread.
"We had some additional evaluations, some scans and some blood work, and all of that was very reassuring," Judge said. "It had not spread anywhere. It was very localized to the testicle. The outcome of all this is excellent and a very low likelihood of any recurrence."
A little more than a week ago, Kessel wasn't feeling great and went to visit Judge.
"One of the things we talked about was a lump he felt on one of his testicles," Judge said. "I had an exam with him that day and an ultrasound that confirmed there was a lump - a very small lump."
Kessel knew he had cancer last Saturday night, when he played in a 5-1 home loss against New Jersey. Three days later, he underwent the operation to remove his right testicle, which confirmed he had embryonal testicular cancer.
And he wasn't relaxed until tests were completed Friday, confirming the cancer was confined to his testicle.
"I was relieved (Friday)," Kessel said. "I was a little nervous the last week or so."
Kessel is the second Boston athlete this year to be diagnosed with cancer. Red Sox left-hander Jon Lester was diagnosed with lymphoma in August, but doctors labelled him cancer-free earlier this month after he underwent chemotherapy treatments.
The discovery of cancer and surgery has helped Kessel put hockey in perspective.
"You become more a spokesperson with stuff like this. I had to deal with stuff that a lot of people had to deal with," Kessel said. "If you're not feeling well go get checked out and make sure you're all right."
Kessel has five goals and four assists in 27 games this season.