Karl Stefanovic's ex-wife Cassandra Thorburn shares how mild pain she blamed on workouts was the ONLY symptom of her rare breast cancer: 'There was no lump'

Cassandra Thorburn has shared how a minor armpit pain she put down to her strenuous workouts was the only symptom of her breast cancer. 

The ex-wife of Karl Stefanovic says she never had any sort of lump, and none was found during a routine mammogram in February. 

However, the scan showed a 'grey area' near her underarm, which she soon learned was a rare form of the disease called occult breast cancer. 

Occult breast occurs refers to when cancer spreads to surrounding tissue, but the main tumour inside the breast cannot be located. It accounts for only around one per cent of cases.

'That doesn't make any sense. How can you be told you've got breast cancer without a lump?' she told nine.com.au of her initial thoughts after she was diagnosed. 

'They couldn't explain it. There was no lump I could have found on my own.'

Cassandra says that initially, she thought she was in the clear because, 'the mammogram didn’t show anything in my breast'.

The 55-year-old, who has stage three occult breast cancer, says looking back, she experienced some pain in her armpit area before the diagnosis. 

However, she was doing Muay Thai martial arts classes and blamed her exercise routine for the discomfort.  

'I was doing Muay Thai at the time, I was quite fit, and sometimes I thought, "Do I have a sore underarm?"' she said. 

The journalist is thankful for the routine screening, which she underwent after receiving a reminder letter. 

Had she not had the scan, she would not have caught the cancer until it was too late. 

Cassandra underwent chemotherapy, surgeries, and radiation. She still has rounds of radiation left, but is now cancer-free.  

The former Dancing With The Stars contestant shared her devastating health news in a video posted on Instagram in February.

Cassandra began the clip by referring to a post she had uploaded a day prior, in which she showed her recently shaved head. 

'I'm going to have to read this because on my walk this morning, I thought about all the reasons why I made that post yesterday,' Cassandra said. 

'Most of it is controlling the only part of my treatment and diagnosis that I can. That's the part about when the hair comes off and when you tell people. For my adult children and for myself, I'm not interested in hiding, and that's because I'm not alone.

'I'm not walking a path that is not well travelled by many women before me and I will not be the last.'

She ended her video with optimism, saying: 'It may have flipped my world in days, but there's no "why me?" There's no "poor me" here. Just a desire to stop this in its tracks.'

Cassandra was married to Today host Karl Stefanovic for 21 years before their acrimonious split in 2016. 

They share three children: Jackson, 25, Ava, 19, and River, 18.

Karl has since remarried, tying the knot with former model Jasmine Yarbrough in 2018. The couple share a daughter, Harper, five. 

Cassandra began her career as a media personality and television journalist, before putting her professional aspirations on hold to raise her three children.