Collingwood legend Anthony Rocca has revealed his unexpected diagnosis of Non-Hodgkin's lymphoma.

At 46, Rocca, a beloved figure in AFL history, had been experiencing sharp, stabbing back pain at night for several weeks. Trusting his intuition, the former Magpie forward and current coach of the Northern Knights in the Coates Talent League consulted Collingwood's doctor, Dr. Ruben Branson. A series of tests led to the shocking diagnosis of Non-Hodgkin's lymphoma, a type of cancer that begins in the lymphatic system.

"I'll beat this," Rocca told the Sunday Herald Sun.

"No one likes the dreaded โ€˜c' word, it is even hard for me to say it now. No one likes to be told you have got that sort of illness. But I am the sort of person who deals with what is front of me. When I found out, I was like, โ€˜How do we treat it? How do we deal with it? When can we get started on treatment? And what's the plan?'"

Rocca will be stepping down from his Northern Knights coaching role for the rest of the season to focus on his treatment, which will involve six months of chemotherapy.

Despite the diagnosis, he remains optimistic, buoyed by medical advice that his condition is "very treatable" and the unwavering support of his family and friends, including his wife Enza, and children, Mia, 18, and Max, 14.

"I've been told it is quite a common lymphoma, it is Non-Hodgkin's lymphomaโ€ฆ it is very treatable," Rocca said.

"I will hopefully get into chemo in the coming weeks, which will be a six-month situation. The statistics tell us that it is very treatable. I'm feeling OK at the moment. A lot of people tell me if you are going to be anywhere in the world with a type of cancer, Melbourne is the best place to be (for treatment)."

Rocca, who played 242 AFL games and kicked 415 goals with Collingwood and Sydney over a 15-season career, shared his story publicly to encourage others to seek medical advice if they experience unusual symptoms.

"There are probably plenty of tradies out there, or workers (in any industry), both men and women who are experiencing pain," he said.

"I would just say to them โ€˜if you are not feeling right, go and get checked and get on top of things early'."

Rocca recalled the pain that led to his diagnosis: "Something in the back of my mind was telling me it was quite different to what I had experienced in the past. I had this back pain, but I was still training and going to the gym and doing boxing sessions. It wasn't affecting me during the day. But I would wake up in the middle of the night, and it was like a strange, stabbing pain, almost like a thoracic soreness, but I knew it wasn't that because I've had thoracic soreness before."

A series of ultrasounds, CT scans, and PET scans revealed swollen lymph nodes, leading to the final diagnosis of Non-Hodgkin's lymphoma.

ADELAIDE, AUSTRALIA - AUGUST 13: (L-R) Magpies head coach Nathan Buckley and Anthony Rocca fowards development coach look on during the round 21 AFL match between Port Adelaide Power and the Collingwood Magpies at Adelaide Oval on August 13, 2017 in Adelaide, Australia. (Photo by Daniel Kalisz/Getty Images)

Rocca expressed deep gratitude for the support from his family, particularly his wife Enza.

"They've been awesome," he said.

"(Enza) has been so strong and supportive. She's been the rock of the family. It's very important for me to stay positive for her and the kids."

As Rocca steps away from his coaching duties, the Northern Knights will be led by fill-in coach Monty Stuart, alongside assistant coaches Ben Shelton, Matt Waters, and Ricky Nolan.

Rocca expressed his appreciation for the support from the AFL and is eager to return to his coaching role once he regains full fitness.

"I've loved the enjoyment of seeing the boys develop, it's pure footy," he said.

"I can set up the program however I want it to be, and a game style how I want it to be. They (the players) really tip in and it is so rewarding."