'Survivor' Season 33 Runner-Up Ken McNickle Reveals Cancer Diagnosis

Ken McNickle -- "Survivor" season 33 runner-up -- has cancer.

The reality star announced his diagnosis in a vulnerable Instagram post in which he wished he had taken care of himself "better and sooner." He added, "As I’ve said before, if you have a health concern, don’t sit on it. Get yourself checked. There’s no valid reason not to. Not one."

He did not reveal what type of cancer he has and didn't divulge his treatment plans.

His post included a series of photos of himself sitting at his doctor's office with some white patches on his chest. He added text over the photos that admits he sometimes feels like giving up, but then thinks about his family and regains the will to persevere.

He explains ... "Because there's always a choice. And I'm choosing optimism, health, happiness, and the knowing that the spirit has me. And most importantly, I'm choosing love."