05 MAY 2011

Radiation a double-edged sword

Written by: Dr Ang Peng Tiam

Last month, when our dinner conversation drifted to the nuclear catastrophe that hit Japan, a friend asked: ‘Can you get me some potassium iodide tablets?’ He was worried that the radiation from the damaged nuclear plant there would eventually contaminate the air, food and water in Singapore.

At that point in time, no one could be certain how badly the nuclear reactors were damaged and if a nuclear meltdown would occur. ‘Okay, I’ll text my pharmacist immediately and ask her to get some for you tomorrow,’ I replied while tapping out the message on my mobile phone.

Over the next few days, we scoured the island looking for these elusive pills. To my surprise, there were none to be had, at least none that I could get my hands on. What limited supply available had already been snapped up by other quick-thinking Singaporeans.

I checked with a senior endocrinologist and a nuclear medicine specialist on their views on this mad rush for potassium iodide. If the nuclear reactor were to suffer a meltdown, one of the many radioactive particles released would be radioactive iodine.

The thyroid gland, which is sited in front of our neck, has an affinity for iodine. The idea is that if we were to saturate the thyroid with iodine, then it would not absorb any radioactive iodine that might be present in the atmosphere.

Following the Chernobyl nuclear accident on April 26, 1986, there have been more than 2,000 reported cases of thyroid cancer and an increased incidence of other types of cancer linked to radiation exposure, including lung cancer, leukaemia and possibly breast cancer.

‘So, how?’ I asked my colleagues when I could not find any potassium iodide tablets. Suggestions like Lugol’s iodine (a solution of iodine and potassium iodide in water often used for disinfection) and intravenous contrast (iodine-based dye drunk to improve the visibility of internal organs in X-rays) were raised as possible alternatives to saturate the thyroid gland.

However, my colleagues told me that the risk of radiation-induced thyroid cancer was extremely small and loading up with iodine may not make any difference. If at all, children appeared to be at highest risk. I conveyed this to my friend and offered reassurance that his fears, although natural, were unfounded.

For oncologists, radiation, like fire, is a good servant but a bad master. Back in 1990, upon my return from a two-year fellowship in the United States, I received a call from one of my wife’s professors. His friend’s wife had been diagnosed with malignant lymphoma (cancer of the lymph nodes) and the main tumour was sited just behind the left knee. He wanted me to take special care of her. Amy was one of the most amazing patients I have ever looked after.

She carried herself in a dignified manner, gentle and kind to everyone she met – from the ward amah to the trainee nurse. We battled her lymphoma with a six-drug chemotherapy programme that was the vogue of the day.

Given weekly for 12 weeks, it ravaged the body and destroyed the cancer cells. Despite all the horrendous side effects, Amy tolerated the treatment with a smile on her face and a quiet faith that God would see her through the illness. In one of our quiet moments together, she told me that her prayer was simply to live long enough to see her children grow up and graduate from university.

The chemotherapy brought her into remission – there was no cancer detectable after the 12 weeks of treatment. Her problem was discussed at a tumour board – a meeting of cancer doctors from different specialities – and the recommendation was for a course of radiotherapy to be given to the knee, as added insurance. Life for Amy returned to normal after the treatment was over.

When I left for private practice in 1997, she continued her follow-up check-ups with me. Seven years after remission, she was, for all intents and purposes, cured of her lymphoma.

One day, she complained of pain when walking. To my horror, she had developed a radiation-induced cancer of the bone. Such types of cancer tend to be very aggressive and resistant to both chemotherapy and radiotherapy. Amy took it all in her stride.

She maintained her cheerful outlook and was grateful that God had answered her prayers – her son had already graduated from university. As the cancer was detected early, surgery was the treatment of choice. Despite surgery done at one of the top cancer centres in the United States, her cancer spread with a vengeance to the lungs and other parts of the body.

Within a year, Amy died. I was devastated not just because I had lost a friend and a patient, but also because I felt that I had been responsible. I kept questioning myself whether we made the right decision in offering her radiation back in 1990. In the end, I will never know. What I do know is that I continue to use radiation treatment every day. It is a tool that may again cut the doctor who wields it, but it also holds the power to heal many other patients.

This article first appeared in "Mind Your Body", a Straits Times Supplement.

POSTED IN Cancer Treatments, Up Close and Personal