Mustaine was diagnosed with throat cancer in June this year, announcing the news to fans via a post on his Facebook page.
Now, speaking to Rolling Stone, Mustaine has given an update about his diagnosis, treatment and what comes next.
"I’m on the other side of the majority of the treatment, and I feel really strong," Mustaine says. "After the radiation, the guy said all of my test results looked amazing."
"I figured, I’m not gonna let this beat me... I’m not gonna let this even scare me."
On receiving the diagnosis, Mustaine says his initial reaction was: "'Fuck.' And I thought, 'OK, Mustaine. You can do this.'"
"We commenced kicking this thing’s ass. I thought about every single trick that I had learned about healing my body and the things I’d learned from martial arts, and I did everything that the doctor said to a T, and hopefully this is the end of it and I never hear of it again. But I feel great.
"I’ve got people around the globe praying for me. I take good care of myself, and I don’t know how anybody can expect any other outcome than this, knowing me. I never settle for anything but complete success or, in this case, victory."
He also reflected on the support he got from the global metal community, saying: "A lot came from people that I knew but I didn’t know cared. Most notably, I got a text message back from my old brother, James Hetfield, and I was so, so happy to hear from him. Contrary to what anybody says and contrary to any of the act that we put on, I love James and I know that James loves me and cares about me.
"You can see that when the moment of truth is here and I’m telling the world that I’ve got a life-threatening disease. Who comes to stand next to me? James.
"And I got a text message from Ozzy, and one from Paul Stanley. It was great to get one from Ozzy; I didn’t expect it from Paul Stanley. That was super bitchin’ because in the beginning, when Kiss first came out, I was just a kid and I loved them.
"I’m really grateful for everybody. Even the people who have a hard time with my behavior and my big mouth, I’m just so grateful for them showing care for me. Like they say, at the end of the day, all we’ve got is each other here in this crazy metal community."
In August, it was revealed that Five Finger Death Punch (opens in new tab), Megadeth (opens in new tab) and Bad Wolves (opens in new tab) would head out on tour together across Europe in 2020. Speaking about the tour, Mustaine says: "I’m so excited, and I can’t wait to fire up my guitars."
Find full tour dates below.
Five Finger Death Punch, Megadeth & Bad Wolves 2020 tour
Jan 14: Kiev Palace Of Sports, Ukraine **
Jan 16: Moscow Adrenaline Stadium, Russia **
Jan 18: St. Petersburg A2, Russia **
Jan 20: Helsinki Hartwell Arena, Finland
Jan 22: Stockholm Hovet, Sweden
Jan 23: Oslo Spektrum, Norway
Jan 24: Copenhagen Royal Arena, Denmark
Jan 26: Amsterdam AFAS Live, Netherlands
Jan 28: Paris Zenith, France
Jan 30: Cardiff Arena, UK
Jan 31: London Wembley Arena, UK
Feb 03: Berlin Max-Schmeling Halle, Germany
Feb 04: Hamburg Sporthalle, Germany
Feb 06: Frankfurt Festhalle, Germany
Feb 08: Oberhausen Koenig-Pilsener Arena, Germany
Feb 09: Stuttgart Schleyerhalle, Germany
Feb 10: Munich Olympiahalle, Germany
Feb 12: Warsaw Torwar, Poland
Feb 14: Prague Tipsport Arena, Czech Republic
Feb 16: Milan Alcatrazz, Italy
Feb 17: Zurich Hallenstadion, Switzerland
Feb 19: Vienna Stadthalle, Austria
Feb 20: Budapest Sportarena, Hungary
** 5FDP headline show without Megadeth and Bad Wolves