Digital marketer Tony Leo, 38, used to be an active person who frequented the gym and played football regularly.

In 2007, after an exhausting climb up Mount Kinabalu in Malaysia that he had to abort halfway as he was having trouble scaling it, Mr Leo, who is Malaysian, decided to have a medical examination.

In the months preceding the climb, long-lasting headaches that would only disappear with sleep had not hinted at any major illness.

The examination, too, did not reveal anything of concern. But his examining physician at the Universiti Malaya Medical Centre in Kuala Lumpur tested his blood as a precautionary measure, only to detect abnormalities warranting a trip to the haematology ward for Mr Leo, who was diagnosed with chronic myeloid leukaemia (CML).

His mother, who was present, broke down in tears, but Mr Leo would not be cowed by his devastating diagnosis.

"I watched (the American sitcom) Seinfeld in the first hour I woke up and the last hour before I went to sleep," Mr Leo, who is single, recalled fondly.

As laughter could not be the only medicine, Mr Leo was prescribed 400mg of imatinib, a drug used to treat the cancer, which affects the blood and bone marrow.

The drug would control his disease so well that he did not have to drastically change his lifestyle. There were also no debilitating symptoms.

But the medicine came at great expense for Mr Leo, who worked as a singer-songwriter then and had neither a fixed income nor health insurance.

The drug costs RM32 (S$10) for 100mg, and Mr Leo needed 400mg a day. Fortunately, the Max Foundation, a cancer patient support group from the United States, intervened.

It introduced Mr Leo to the pharmaceutical firm, Novartis, which supplied the medicine for free in exchange for his medical records to aid research.

With his medication secured, Mr Leo could focus on recovery, a process he deemed a "second chance to see what was important".

Relatives he thought he had at most a cordial relationship with started to shower him with love and concern.

They included aunts who would regularly buy supplements for him and an uncle who burst into tears upon hearing of his diagnosis.

Mr Leo, who is now based in Singapore for work, also read everything he could about CML.

"It is important to know the illness in-and-out," he said.

He is keenly aware of the biological mechanisms behind CML and the side effects of his medication, which include high water retention, body cramps and skin de-pigmentation.

"I was like local coffee (before treatment), and then when I first took the medicine I became like flat white coffee and now I am like a nice latte," he said, joking.

However, Mr Leo conceded that not every CML patient is as lucky, with some becoming so weak they have to use wheelchairs.

"There are no words that can perfectly soothe the aching heart," he acknowledged.

But having lived the pain first-hand, he is resolved to attend as many Max Foundation events as possible - in Malaysia and Singapore - sharing his story and inspiring patients, caregivers and volunteers with his musical and theatrical performances.

"People really need to know that there is life after cancer," he said.

INFOGRAPHIC

Learn about common cancers in Singapore with this interactive 3D guide. http://str.sg/anatomycancer