The news comes just over a week after undergoing surgery to remove a tumour from the singer's stomach.
"Devin asked me to give you this update without him because, frankly, he's not feeling very well," Fischetti said. "But, he asked me to send you his love and gratitude for all the love and prayers you've sent his way."
"I wish we had better news to share," he continued. "It's devastating news but at the same time, there's nobody I know stronger than Devin Lima. No one has a stronger body, mind or soul. If anybody can defeat this, it's Devin. I know with your prayers and your thoughts and your positive energy coming down his way, there's no doubt that he will beat it."
Fischetti also expressed Devin's desire to get back to performing LFO's hit songs such as 'Summer Girl.'
"It's a motivating factor to be back on that stage again, singing again, recording new music. It's my hope and prayer that we have that opportunity again. Actually, I know that we'll have that opportunity again," he stated.
The pop band is best known for their 1999 hit 'Summer Girls' and recent single 'Perfect 10'.