Beating the odds against skin cancer

Beach goers at Sentosa's Siloso beach.
Beach goers at Sentosa's Siloso beach. PHOTO: ST FILE

Some years ago, one of the moles on my right leg started itching.

I scratched it vigorously and a bit of it peeled off. The surrounding area became reddish and small bumps appeared around the main pigmented spot.

The thought that this could be a malignant melanoma crossed my mind. This is an occupational hazard.

Melanoma is a type of cancer that arises from the melanocyte (cells in the skin responsible for producing the pigment melanin, which makes our skin dark). It is the most lethal type of skin cancer.

I went to see a plastic surgeon.

“Nose job? Double eye-lids?” he asked as I sat down at the opposite end of the consultation table. 

I walked out with the smallest of wounds on my right leg and a sample of the mole in a bottle, 30 minutes later. Two days later, I received a call from the pathologist who reassured me that it was a benign tumour.

Many patients are often not so fortunate. Mr Lin, a Taiwan national working in Malaysia, started having difficulty in swallowing around February this year. “After a meal, I would often feel something stuck in my chest,” he said.

A month later, he decided to go back to Taiwan for a medical check-up. Gastroscopy – an examination of the oesophagus (gullet) and stomach using a flexible tube with a camera mounted on the end – was carried out on him. Melanoma was seen to be partially obstructing the lower oesophagus.

Melanoma is most commonly seen in the skin, and is by far more common among the Caucasians. Excessive exposure to the sun predisposes them to this disease.

However, it can arise in other parts of the body, for example, in the gastrointestinal tract or the eye.

When diagnosed early, the treatment of choice is removal by surgery along with a fairly wide margin of clearance.

The removal of the regional lymph nodes is often necessary if the cancer is advanced. 

The initial plan for Mr Lin was to carry out a major operation to remove a part of the oesophagus together with the part where the offending culprit was located.

In anticipation that he would not be able to eat as the tumour grew, the doctors carried out an operation to put a feeding tube through his abdominal wall directly into the stomach. When that time came, food could then be fed through the tube to ensure that he had adequate nutrition.

However, when the positron emission tomography (PET) scan was done, there was evidence that the cancer had spread to the lymph nodes in the chest, as well as to various parts of his abdomen.

Mr Lin said: “I was told that this cancer is rare and very difficult to treat. They said that chemotherapy does not work for this type of cancer.”

Melanoma is assessed based on how deeply it has invaded the layers of the skin. The deeper the cancer has penetrated, the higher the risk of it recurring at the same site and spreading.

Chemotherapy is often said to have a modest effect on melanoma.

In a recent study, only 5.5 per cent of patients treated with what is called the standard treatment – chemotherapy using a single drug – had a response to it.

My experience is that no fewer than 40 per cent of my patients with melanoma respond favourably to chemotherapy, using a cocktail of several chemotherapy agents that is often prescribed by many experienced oncologists.

The good news is that there are now two new targeted drugs, ipilimumab and vemurafenib, that have demonstrated definite effectiveness against melanoma. In the study above, 48 per cent of patients responded to one of them.

The bad news: Despite this, the overall survival rate of patients with metastatic melanoma remains dismal, with a three-year survival rate of only 21 per cent. 

Mr Lin was given a cocktail of chemotherapy drugs.

After six weeks of treatment, he underwent a repeat PET scan. To our delight, all the tumours had responded marvellously.

Happy but still doubtful, Mr Lin flew back to Taiwan to consult his doctors back home.

When he came back, he smiled as he entered my consultation room.

“They said it is a miracle. They were so amazed with the results that they decided to remove my feeding tube,” he said, as he lifted up his shirt to show me the closed abdominal wound.

I am not so sure I would call it a miracle but it is certainly a great result given the odds.

But there is a reality check: The present treatment will lose its effectiveness at some point.

When that happens, these newly discovered targeted drugs can be brought to the fore.

Dr Ang Peng Tiam is the medical director of Parkway Cancer Centre. He has been in practice for 29 years. In 1996, he was awarded Singapore’s National Science Award for outstanding contributions to medical research.