DANIEL CHAN ONE-ON-ONE
It may surprise many people to know that even in Singapore, where smoking restrictions are tighter than anywhere else in the world, lung cancer remains to be the second most common cause of cancer-related deaths among men and one of the top five among women. This is according to Singapore’s Cancer Registry 2015 Annual Registry Report.1
Dr. Daniel Chan, senior consultant medical oncologist at the Icon SOC Mount Elizabeth Medical Centre in Singapore, explained, “Singapore’s smoking prevalence fell dramatically from 20 per cent in 1984 to 13.3 per cent in 2013. However, the decline in the proportion of smokers had plateaued over the last 10 years, hovering around 23 to 24 per cent in males, and 3.5 to 4 per cent in females, and has not budged since. This means that the proportion of new smokers has gone up to equal or “replace” that of those who have died from or quit the habit, suggesting more aggressive efforts are needed to stop people from picking up smoking.”2
Dr. Chan was one of the doctors who spoke at a recently held cancer treatment symposium that focused on immunotherapy, as a new way of treatment that fights cancer by harnessing and augmenting the abilities of the body’s own immune system.
Dr. Chan has treated a number of Singapore and South-East Asian patients using immunotherapy, applied through an immune checkpoint blocker called pembrolizumab.
“In 2014, when pembrolizumab was first approved for use in the United States, there was a lot of skepticism in the medical community that something as gentle as immunotherapy could work for something as aggressive as cancer,” Dr. Chan said. “But from recent clinical trials we now know that it could be effective in the right circumstances.”
As a medical oncologist, Dr. Chan is especially concerned with cancer drug efficacy and safety, because lung cancer specifically is often diagnosed in its late stages and usually at a time when the patient is already in a frail state. This makes the cancer harder to control, not only because it has already spread to other parts of the body, but also because the sick patient is often already beset with other health conditions that make the body more vulnerable to the rigors of conventional treatments, as in the case with chemotherapy.
Unsurprisingly, in the past, a lung cancer diagnosis was considered by many to be a death sentence.
“Before immunotherapy came around, the median survival of stage 4 lung cancer patients was just a little over a year. And in that remaining time, the patients endured repeated chemotherapy, so their quality of life was very poor,” Dr. Chan said.
In contrast, studies on immunotherapy where pembrolizumab was used have shown median survival rates of 2.5 years and above. As the observation period for immunotherapy patients continues, researchers are finding that many patients are staying alive longer than they would have been expected to, had they undergone chemotherapy instead. Quality of life with the immunotherapy treatment is much better.
“The most common side effects I see with pembrolizumab are rash, fatigue, and thyroid gland dysfunction,” Dr. Chan said.
In lung cancer chemotherapy, patients normally experience nausea, vomiting, hair loss, low blood counts and a host of other adverse effects from their treatment.
“Pembrolizumab infusion is also fast. You get it once every 3 weeks and it takes half an hour, unlike chemotherapy for lung cancer, which includes hydration and antiemetics. This takes easily 3-4 hours,” Dr. Chan added.
Not all lung cancer patients are ideal for an immunotherapy treatment. Researchers have found that non-small cell lung cancer (NSCLC) patients who respond best to pembrolizumab are those whose cells show a high level of a protein biomarker on the cancer cell surface called PD-L1.
Therefore, PD-L1 testing proves to be an invaluable screening tool to determine the chances of treatment success with each individual NSCLC patient on pembrolizumab. It also improves the cost-effectiveness of the drug.
At present, immunotherapy treatment costs are not yet covered by PhilHealth, but are subsidized up to 55% by the Philippine Charity Sweepstakes Office (PCSO) upon confirmation that the patient is qualified for health care subsidy.
“I always muse that immunotherapy is really taking a leaf from traditional Chinese medicine, where they are always talking about keeping the immune system strong.
“Even in this day and age, people are still very resistant to chemotherapy because they hear it will weaken the immune system – and thus weaken the body. They think it is the chemotherapy – not the cancer – that will kill them. So when they get immunotherapy instead and see how it is more tolerable for the body, it is really a load off their minds,” Dr. Chan said.
In the Philippines, pembrolizumab is already approved for the treatment of non-small cell lung cancer, head and neck squamous cell carcinoma, melanoma, gastric cancer, urothelial cancer, and classic Hodgkin lymphoma. Potential patients may consult their medical oncologist to learn more about immunotherapy.
Dr. Daniel Chan, senior consultant medical oncologist at the Icon SOC Mount Elizabeth Medical Centre in Singapore stressed the efficacy and safety of immunotherapy in treating lung cancer