Cardiologist and health advocate Willie Ong revealed that he is currently battling cancer.

On the Facebook page of the doctor, it has been revealed that he has been diagnosed with a 16x13x12 centimeter sarcoma in the abdomen. 

"The tumor was hidden behind the heart and in front of the T10 Spine. The mass partially/completely blocked Doc Willie's esophagus, Inferior vena cava, and right atrium," the Facebook post read.  

As per mayoclinic.org, sarcoma is "the general term for a broad group of cancers that begin in the bones and in the soft (also called connective) tissues (soft tissue sarcoma). Soft tissue sarcoma forms in the tissues that connect, support and surround other body structures."

In a recorded video, Doc Willie shared that it was during his birthday last year when he felt pain in an area of his back that affected his sleep.

"Noong birthday ko around 8 months ago doon na ako nakaramdam ng back pain. Matagal na akong may back pain, matagal na akong may sakit ng likod but this time, biglang may masakit banda sa taas... Hindi ako  makahiga sa gabi. Kapag hihiga ako sa gabi, sasakit ang parteng' yun," he relayed.

It was around August 18 or 19 this year before he got admitted to the hospital when he experienced severe back pain that he described as the worst pain he experienced.

"Sobrang sumakit siya bigla. Sobrang sakit. Worst pain of my life. 10 out of 10. Iiyak ka. Buong gabi walang tulog," he said.

Willie revealed that his sarcoma is very rare and aggressive.

"Nalungkot ako? Nung una. Pero hindi eh, masaya na ako na basta may purpose pa ang Diyos," he said.

Willie is now undergoing chemotherapy.

"Pray na gagaling pero sabi ng doktor ko itong sarcoma ay mahirap na kalaban. Isa sa pinakamahirap na cancer na kulang ang research, kulang ang bagong gamot, medyo miracle dapat," he revealed.