The 57-year-old frontman has revealed that he has recently found out he has the disease and he is currently undergoing treatment, which doctors have told him has a ''90 per cent success rate''.
Announcing the news on Instagram on Monday (17.06.19), Mustaine wrote: ''I've been diagnosed with throat cancer. It's clearly something to be respected and faced head on - but I've faced obstacles before. I'm working closely with my doctors, and we've mapped out a treatment plan which they feel has a 90% success rate. Treatment has already begun.''
The 'Sweating Bullets' rockers have postponed all of their 2019 dates as a result, but they have vowed that their Megacruise, which takes place between October 13 and October 18, which sees them headline with acts including Anthrax, Testament and Suicidal Tendencies also due to perform, will still go ahead and they will be there in ''some form''.
Mustaine - who is joined by David Ellefson, Kiko Loureiro and Dirk Verbeuren in the Grammy-winning thrash metal group - continued: ''Unfortunately, this requires that we cancel most shows this year. The 2019 Megacruise will happen, and the band will be a part of it in some form. All up to date information will be at megadeth.com as we get it. Megadeth will be back on the road ASAP.''
The Rock and Roll Hall of Famers are also still ploughing ahead with work on their first new record since 2016's 'Dystopia', whilst Mustaine says he is ''thankful'' to his fellow bandmates, team and his doctors for their support at this difficult time.
The 'Symphony of Destruction' singer concluded: ''Meanwhile, Kiko, David, Dirk and I are in the studio, working on the follow up to Dystopia - which I can't wait for everyone to hear.
''I'm so thankful for my whole team - family, doctors, band members, trainers, and more.
''I'll keep everyone posted.⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀
''See you soon
''Dave Mustaine (sic)''
A number of Mustaine's peers have sent their well wishes to him on social media.
Hatebreed frontman Jamey Jasta, 41, tweeted: ''Sending love brotha. (sic)''
Thrash metallers Overkill wrote: ''Sending positive vibes to @DaveMustaine who has just been diagnosed with throat cancer. Stay strong brother!''
Mustaine - who has Electra, 21, with wife Pamela Anne Casselberry and Justis, 27, from a previous relationship - was a member of rival band Metallica before he was let go in 1983 because of his battle with alcoholism and drugs.
He was replaced by current lead guitarist Kirk Hammett and went on to form Megadeth that same year.
Prior to joining the 'Nothing Else Matters' group, Mustaine was in the band Panic.
Laura Marling's latest album 'Song For Our Daughter' was due for release later this year, until Marling announced that she had decided to bring the...
Artists are coming up with different ways to entertain and help out this year.
It's been five years since Purity Ring released Another Eternity, but little has changed in their overall sound and macabre lyrical themes now that...
We need music now more than ever.
Mystery Jets, Purity Ring and more coming soon...
Just over two years since the release of her vibrant debut album, Anna Burch is back with her second full-length album: 'If You're Dreaming'.
What have we been listening to on repeat?
The Chats' debut album High Risk Behaviour is the most punk thing we've heard in years.