B.C. Premier John Horgan says he has been diagnosed with cancer after a biopsy of a growth on his throat late last week.

In a statement Thursday, he said pathology reports following his surgery confirmed the mass was cancerous.

"My prognosis is good and I expect to make a full recovery," wrote Horgan, 62.

"The surgery and biopsy that were done last week were successful and I am grateful to the amazing health-care team for all the support I've received."

The premier said he will begin radiation treatment in the next several weeks until it finishes toward the end of December.

Horgan said he still plans to participate in cabinet meetings and fulfil his other duties virtually over the course of his treatment. Solicitor General Mike Farnworth, whom Horgan appointed deputy premier last week after announcing the surgery, will attend in-person events in his place.

"I would, again, like to thank everyone who sent their well wishes. Your support gives me strength and humbles me. I look forward to being back in the legislature and travelling in the new year," Horgan said in his statement.

The premier spoke on Oct. 28 about having noticed the lump on his throat several months earlier. He said he'd been in and out of hospital for testing, which confirmed the need for the biopsy last Friday.

Horgan was previously diagnosed with bladder cancer in 2008, when he was in his 40s. He was declared cancer free after surgery and treatment.

"It's important, I think, for people to understand that this isn't the first time I've experienced a health issue like this, and it's the extraordinary efforts of our public health-care system that gives me complete confidence that all will be well for me," he said during last week's news conference.

Farnworth has said he expected to attend briefings and meetings on the premier's behalf, and will assist in whatever way is required. Farnworth, the NDP's house leader, was first elected to the legislature more than 30 years ago.

Last month, Horgan's caucus marked one year since winning a majority government in the provincial election. Horgan first became premier in June 2017, after forming a minority government.

On Thursday, Health Minister Adrian Dix said he'd spoken with Horgan about his personal health and said support crosses party lines.

"He is, of course, determined and positive and thoughtful and, as someone who has dealt with cancer and survived before, he understands both the challenges but he's engaging with real optimism," Dix said, speaking just before beginning a COVID-19 briefing.

"I think the qualities that make him a great premier but also a great friend and a really great human being are going to help him in this, are the supportive people across the political spectrum and the people of B.C."

The B.C. Liberals, who are in Opposition, said the premier has the support of its members.

"Our thoughts are with John Horgan and his family today. We wish him the best and hope for a speedy and full recovery," a statement read.