The 32-year-old said in October that he was under treatment after being diagnosed with a grade four glioblastoma tumor.
“Significant reduction. These are the words I received today and I can’t stop repeating them over and over, ”he wrote.
Parker went on to thank the UK National Health Service, which he called “wonderful”, his wife Kelsey Hardwick and their two children, as well as their fans.
“For everyone here – their love, light and positivity inspired me. Each message did not go unnoticed, they gave me a lot of strength,” wrote Parker. “This journey is a roller coaster for sure.”
In October, Parker told the British agency OK! Magazine that doctors described the tumor as “the worst case scenario” and informed the couple that it was terminal.
The singer said he went to the hospital after suffering two seizures over the summer. Parker said to OK !, “They pulled the curtain around my bed and said, ‘It’s a brain tumor.’ All I could think was, ‘Holy shit!’ I was in shock. It’s stage four glioblastoma and they said it’s terminal. It was a lot to deal with myself. I haven’t sued it yet. “
The median survival time for patients with grade four glioblastoma, one of the most serious types of tumors, is between one year and 18 months, according to the non-profit organization The Brain Tumor Charity.
Parker gained fame as part of The Wanted, a five-member boy band whose successes included “All Time Low” and “Heart Vacancy”.
The group had a series of five singles at the top of the UK, including the first two, while their 2011 track “Glad You Came” reached third place on the US Billboard charts. They split up in 2014 to pursue solo projects.
CNN’s Rob Picheta contributed to this report.