Miroshnichenko's belief that he'd beat cancer and play hockey again drove him throughout his battle. The native of Ussuriysk, Russia, was playing for Omsk Krylia in Russia's second division before he received his diagnosis on Feb. 4, 2022, which was also his 18th birthday.
"It was just a shock for everyone, for me, for my family, for my friends," Miroshnichenko said. "In my family, it never happened. None of my relatives had ever been diagnosed with any kind of cancer."
Hodgkin's lymphoma is a cancer that begins in the lymphocytes, white blood cells that help fight infections and other diseases. According to the American Cancer Society's website, it is most common in early adulthood, and again after age 55.
Miroshnichenko's symptoms began with what he thought was normal cough.
"I was coughing on and off for about three months," Miroshnichenko said. "Then, I started experiencing some itchy skin, which was kind of weird, and then I started sweating quite a bit. A couple months later, when the team was doing the usual checkup on all the players, the blood results came back not bad, but there were some flags. And they ran the tests again and when they came back, it didn't look the way they wanted them to look.
"Afterwards, they sent me to Germany (for further testing) and that's when the whole picture came into view."
Miroshnichenko remained in Germany after receiving his diagnosis and immediately began the first of four cycles of chemotherapy. The second round was the hardest.
He spent three days in the hospital afterward, lost all his hair and more than 30 pounds, which he later regained; he's listed now at 6-foot-1, 185 pounds.
The good news was tests taken after the second cycle showed he was cancer-free.
"As soon I found out, it was real excitement and relief," Miroshnichenko said. "The doctors were shocked because it only took two full treatments, and everything was gone."
Miroshnichenko had to remain in Germany until he completed all four cycles of chemotherapy, though. With recovery time required between each cycle, Miroshnichenko was separated from his family and friends in Russia for more than four months.
"It was insanely hard because you're just talking through the phone," he said. "Obviously, family, everybody is worried: my mom, my sister, my grandparents, my friends, and everyone. Even though I knew I was getting better, on the other side of the phone you can't see much, and you don't know what they're talking about."
About a month into his treatments, Miroshnichenko received a call from Hockey Hall of Famer Mario Lemieux, who was diagnosed with Hodgkin's lymphoma while playing for the Pittsburgh Penguins during the 1992-93 season. Lemieux returned later that season to win the Art Ross Trophy as the NHL's leading scorer with 160 points (69 goals, 91 assists) in 60 games.
Miroshnichenko said Lemieux's message was, "Life doesn't end. You're going to recover. Don't worry about it. Get it out of your head and go through recovery."
Not thinking about cancer was impossible at that point, though. Not thinking about hockey wasn't easy either.
"I couldn't take it out of my mind," Miroshnichenko said. "Everyone was calling me, everyone was supporting me, so there was no way. Plus, I knew the draft was coming up."
Miroshnichenko completed his treatments and returned to Russia only a few weeks before heading to Montreal for the NHL draft and being selected by Washington on July 7, 2022. By then, he'd been cleared to resume training. Before long, he was asking doctors when he could play.
"Hockey was always a part of my life," he said. "I just couldn't wait to come back to what I love to do, and I was just excited to get back to the game and just enjoy my life again."