Personalised medicine, the next frontier in Lung Cancer

THE 65-year-old grandmother was diagnosed with Stage IV lung cancer. But she was not keen to undergo chemotherapy because she was worried about its side effects.

After examining the characteristics of her tumour, her medical oncologist, Dr Tan Yew Oo, recommended the use of an oral anti-cancer drug. Two months later, the woman was no longer coughing as much as she used to. Apart from acne rash on her face and diarrhoea at the start, she suffered minimal side effects.

Repeated chest X-Rays subsequently showed a dramatic improvement in her condition, with a reduction in size and number of cancer in both her lungs.

The woman joins a growing list of patients around the world who have benefited from a relatively new treatment strategy known as personalised medicine -- whereby a patient is given a specific drugs based, among other things, on the genetic and molecular characteristics of the tumour.

In an interview with My Alvernia, Dr Tan explains what personalised medicine is all about and how it can help advanced lung cancer patients.

How serious is lung cancer as a health problem?

Lung cancer is the most common cause of cancer deaths around the world. About 1,500 people in Singapore were diagnosed with lung cancer in 2008. In that same year, more than 160,000 people were estimated to have died from the disease in the United States alone.

How do you define “advanced lung cancer”?

Lung cancer can be divided into Small cell lung cancer (SCLC), which accounts for less than 15% of lung cancers, and Non-small cell lung cancer (NSCLC), which comprises more than 80% of lung cancers.

Patients who are diagnosed with advanced NSCLC have either Stage III or Stage 4 of the disease and their chances of survival are very poor. Only about 8.4% of patients of Stage III patients and less than 1.6% of patients in Stage IV are expected to survive for more than five years.

Those with advanced SCLC are divided into limited and extensive stages. Less than 1% of those in the latter stage are expected to live beyond five years.

What are the standard methods of treating advanced lung cancer?

Chemotherapy, combined with occasional radiation if the patient is physically fit, is the usual course of treatment for advanced lung cancer.

However, studies have shown that such standard anti-cancer drug treatment – or what we call cytotoxic chemotherapy -- while useful in some ways, is still insufficient in helping to boost a patient's chances of beating the odds. The five-year overall survival rate based on such a treatment remains dismal – hence the need for us to turn to new therapies that have proven to be more effective.

What does a personalised approach to cancer treatment mean?

This means tailoring a patient's treatment according to the biological make-up of the tumour as well as certain features of the patient.

As such, several factors -- his race, gender, smoking history, the type of lung cancer and whether there are mutations of the epidermal growth factor receptor (EGFR) gene in the cancer cells – will be taken into account before the oncologist decides what is the best course of treatment for the patient.

Studies have shown that personalised medicine have not only produced better results but also improved the patients' quality of life.

Can you share with us some examples of personalised medicine?

Some advanced lung cancer patients may respond better when anti-angiogenic drugs such as bevacizumab – which kills cancer cells by starving them of their blood supply – are added to the chemotherapy process.

Others, such as extensive stage SCLC patients, may be responsive to drugs such as cisplatin and etoposide, coupled with radiation therapy.

If there is EGFR gene mutation in the cancer cells, drugs such as gefitinib or erlotinib can be used to kill the cancer cells in the lungs.

Recently, it was found that Asian patients who were non-smokers or were light smokers could be treated with gefitinib without having to undergo chemotherapy.

In what ways is the personalised approach to medicine different from the standard anti-cancer treatment?

In the past, patients with advanced lung cancer were treated only with combination cytotoxic chemotherapy and they tended to have uniformly poor results and poor survival rates.

Nowadays, the oncologist will first seek detailed information about the patient as well as examine closely the nature of the tumour in order to prescribe a treatment that is tailor-made for his/her condition.

How long does this personalised approach to treating lung cancer last?

The standard practice is to treat patients with advanced NSCLC with four to six courses of chemotherapy. If bevacizumab is deemed beneficial for the patient, this drug is given with chemotherapy and continued until the patient shows signs of improvement.

However, if there is EGFR gene mutation in the tumour, molecular targeted drugs -- which target specific molecules involved in the tumour growth --- can be used instead of chemotherapy for as long as the patient is responding well to the drug. It can also be used as maintenance after the initial chemotherapy.

Radiation is recommended for some patients with Stage IIIA or Stage IV, where there is pain due to the cancer spread to the bones, or there's obstruction of major blood vessels. The procedure varies according to the patient's needs -- from 10 to 25 radiation treatments over two to five weeks.

Are there any side effects in using personalised medicine?

Personalised medicine has fewer side effects compared to past therapies. NSCLC patients who use the drug pemetrexed do not suffer from hair loss, extreme numbness or a significant drop in their white blood count -- which are normal occurrences during the standard chemotherapy treatment.

Drugs such as gefitinib or erlotinib can cause diarrhoea and acne rash but do not cause hair loss or a drop in blood count. Bevacizumab may cause high blood pressure or bleeding.

Does personalised therapy cost more than a standard cancer treatment?

Yes, although it also depends on how the drugs are used and how long the treatment lasts. On average, these drugs cost about 50% to 70% more than the standard cytotoxic chemotherapy. They may be used either on their own, or in combination with standard chemotherapy.

How long has personalised therapy been available in Singapore?

Personalised cancer therapy is an evolving trend in Oncology. Some of these drugs have been available in Singapore for about six years, but it is only recently that they have been better understood as to when they could be tailored for certain unique situations and clinical settings.

Many oncologists here, including my colleagues and I at the Singapore Oncology Consultants, are practising personalised therapies for cancer patients by using the latest evidence-based technology and drugs.

LUNG CANCER FACTS

- Tobacco smoking has been linked to lung cancer since way back in the 1950s, with nicotine acknowledged as the carcinogenic agent. Certain industrial chemicals, such as radon, vinyl chloride, nickel and chromium compounds and asbestos, may also have carcinogenic properties.

- In Singapore, men are more likely to get lung cancer than women since there are more male smokers.

- The most common reason for lung cancer causation is environmental factors. Hence, lung cancer will usually manifest in those who are in their 50s and 60s.

- Unlike cervical cancer or breast cancer, there is no good, cost-effective screening test for early detection of lung cancer. Quite often, when a patient shows symptoms of the disease, he already has locally advanced or even widespread lung cancer. More than 75% of lung cancers are detected when they are in Stage III or IV.

- The most common symptoms of lung cancer are cough, breathlessness, weight loss and chest pain. The less common ones include chest pain, blood in sputum, bone pain, fatigue, difficulty in swallowing, wheezing and noisy breathing.

- Eating more fresh vegetables and fruits may lower the risk of getting lung cancer. Certain foods containing provitamin A carotenoids, particularly ß-carotene, may also be useful in keeping the disease at bay.