I have smelt fear often enough in patients. The adults try and hide it, but Carlsen Shiedinata is still a boy. At 13, the Indonesian teenager is old enough to know he mustn't cry but he was pale and trembling the first time he came into my consulting room.

He was afraid he was going blind, and dying from a mysterious illness that took 7kg off his 46kg frame.

It started with pain in his left cheek. The Indonesian family were concerned enough to come here for an ENT (ear, nose and throat) check up. 'Only sinusitis,' they were told.

Relieved, the family went back home. However, in spite of antibiotics, the pain persisted and his right cheek began to swell.

Carlsen then went to China with his father and grandfather to visit his ancestors' tombs.

His mother told me: 'When he came back, I immediately knew something was wrong. He had lost so much weight."

His right eyelid had flopped and he couldn't open that eye. And when the eyelid was lifted, the eyeball could not move.

They rushed him back to Singapore. Scanning confirmed their worst fears. A biopsy was carried out and even before the results were ready, they took him to see me.

The results were out the next day. There was good news and bad. The good news was that it was indeed a lymphoma, as I suspected - so we knew what we were dealing with. The bad news was that it was a Burkitt's lymphoma - the most aggressive form of lymphoma. This cancer has the ability to double its size every five days.

It was no wonder that the poor boy lost the function of his right eye in just two weeks.

There are many types of lymphoma - the slow-growing kinds, which we call low-grade lymphomas, and the fast-growing ones called high-grade lymphomas. Among the high-grade ones, some are more aggressive than others.

Most people assume that it is better to have low-grade lymphoma because it sounds less frightening.

But actually, young patients with high-grade lymphoma have a better chance. It requires urgent treatment and the treatment is tough - there is hair loss and risk of severe infection. But once the treatment is over, there's a reasonable chance (between 60 and 90 per cent) of a complete cure.

On the other hand, for older patients, say 60 years old and above, low-grade lymphoma doesn't seem to be as threatening. Low-grade lymphoma tends to be slow growing. Even without treatment, it may have a natural history beyond 10 years

However, unlike aggressive lymphoma, it cannot be cured unless it is diagnosed very early. As this type of lymphoma tends to grow without symptoms, 85 per cent of patients are diagnosed late, often when the bone marrow is already affected.

There is a middle-aged woman whom I have been seeing for the last 14 years. Her 'cancerous" lymph nodes have fluctuated in size - sometimes they grow bigger and at other times, they subside a little.

However, I have had no reason to treat her disease throughout this period, as they have not caused her any problems.

About a quarter of low-grade lymphomas undergo spontaneous remission. For no known reason, the cancer cells commit 'hara kiri' and all evidence of the lymphoma disappears.

One of the major advances in the treatment of lymphoma is the discovery of an antibody against the lymphoma cell. This antibody, called Rituximab, has the ability to block the CD20 antigen, which is found in many patients with lymphomas.

This is a form of targeted cancer therapy where the drug homes in on the lymphoma cells and kills them. Patients treated with this antibody significantly improve their chances of a cure.

This was my weapon of choice for Carlsen. He was treated with a combination of chemotherapy together with this antibody. Within three weeks, he could open his eyes, and by the end of the second cycle, he regained his sight with near full movement of his eyes.

When he saw me last week, he was back to his old weight and his eyes gleamed. He told me that the turning point in the fight was when I showed him on my computer, how other patients had regained the functions of their eyes after treatment. That gave him 'semangat" (courage), he told me.

'Now I can play Warcraft, soon I can go to school. I am not afraid anymore," he said.

Dr Ang Peng Tiam
angpt@parkwaycancercentre.com

Dr Ang, the medical director of Parkway Cancer Centre, has been treating cancer patients for nearly 20 years. In 1996, he was awarded Singapore's National Science Award for his outstanding contributions to medical research.

This story was first published in Mind Your Body, The Straits Times, on July 2, 2008.