It started with an ulcer on the left side of his tongue in April last year. The ulcer refused to go away even after a month.
Then, a lump appeared near the ulcer, but Mr Chang York Boon (above) was still not particularly concerned.
'I had a habit of grinding my teeth at night and hurting that part of my tongue was normal. Ulcers would come and go,' said the 40-year-old bachelor.
However, when the lump grew progressively, he began to worry and saw his family doctor who referred him to the ear, nose and throat department at Tan Tock Seng Hospital (TTSH).
'By then, it had measured 20mm by 17mm. It looked like a chestnut,' said Mr Chang, who is the deputy director of the office of estates at Republic Polytechnic.
At TTSH, he was put under observation for a month, during which he had weekly follow-ups. He was also given antibiotics, mouth rinses and ointments.
However, the lump remained.
A biopsy was done and it showed that he had stage 1 tongue cancer, an early form of the disease which is usually treated by surgery.
He was immediately sent to the radiology department to undergo magnetic resonance imaging (MRI) and computer tomography (CT) scans.
'I was quite dazed when the news broke. I stood outside the radiology department staring at its sign for 10 minutes; I don't remember what went through my mind,' he said.
It was only when a TTSH customer service officer approached him that he snapped out of his stupor.
He found it hard to accept the result. 'I didn't smoke or drink. I ate healthily and exercised regularly,' he said, adding that he used to jog around his housing estate once a week.
'I was fighting fit. Getting a gold for my IPPT (individual physical proficiency test) during national service and after was easy,' he said.
Refusing to accept the diagnosis, he consulted seven other oncologists, all of whom confirmed that he had tongue cancer.
He then returned to TTSH for treatment in July last year. There, he had his tumour - along with a 1cm margin of the surrounding tongue area - removed.
During the surgery, some of his lymph nodes were also removed for testing via a neck dissection.
A neck dissection involves the removal of the lymph nodes in the neck and tissues surrounding the lymph nodes. It is usually done as part of surgical treatment for tongue and other head and neck cancers.
'Thirty per cent of my tongue was removed,' he said.
As the surgery was successfully completed with most of his tongue intact, his speech and swallowing functions were not vastly affected.
He also did not require chemotherapy and radiotherapy as the cancer had not spread to his lymph nodes. Still, post-surgery recovery was not easy.
He said: 'After the operation, I struggled to speak. I had to communicate with the nurses by writing.
'I also had to be tube-fed through my nose, which made me nauseous.'
The neck dissection also affected the nerves in his left shoulder, making movement difficult.
Luckily, he recovered well.
After four days of tube-feeding, he was able to go on a a liquid diet.
After three weeks, he could start talking again.
'However, I was speaking with a German accent for a while,' he joked, explaining that his speech became slightly slurred.
Although the cancer is now in remission, he still needs to return to the hospital for monthly checkups.
Despite this dark and unexpected turn, he found strength in his journey from his religion, family, friends and colleagues.
'God showed me that He was on top of things - and that helped me a lot in my recovery' said Mr Chang who is a Christian. 'My family, friends and colleagues rallied around me and stronger bonds were forged.
'For a person battling cancer, such support matters a lot.'
This article was first published in Mind Your Body, The Straits Times.