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Fighting Oral Cancer with Drool

Principal Investigator, Dr Rahul Nagadia, Associate Consultant, National Dental Centre Singapore explains more about this deadly disease and how he hopes his research on saliva will save lives. 

How did you become interested in this field of research?
I originally trained as a dentist and specialised in Oral and Maxillofacial Surgery. My interest has always been in oral cancers. Because of this, I wanted to be able to provide care for cancer patients, so I also pursued a degree in Medicine. During my medical student days, I worked in the University’s research laboratory during term breaks and weekends. My supervisor was conducting research on various markers and proteins found in body fluids. This piqued my interest in investigating salivary markers for oral cancers. 

What is oral cancer and why are you interested in focusing on oral cancer detection in your research?
Oral cancer is also known as mouth cancer. It usually affects the lips, tongue, gums, cheek lining, back of the throat and roof of the mouth.  In Singapore and globally, only half of patients with oral cancer survive more than five years after diagnosis and treatment. That’s because they are diagnosed at the later stages of the disease when it is more difficult to treat.

Warning signs of pre-cancerous growths and early oral cancers include ulcers, sores and red or white patches in the mouth which do not heal.  But they are usually painless at this stage, so most people either ignore them or self-medicate using gels. Ideally, they should see a doctor if the ulcer or patch doesn’t clear up within two weeks, but many only seek help when they start feeling pain. Unfortunately, by then, the cancer has already advanced, often spreading to the jaw bone, neck and/ or other parts of the body.  

How can a saliva test help?
At present, the only way to know if an ulcer or patch in the mouth is at risk of becoming cancerous or is cancerous is to do a biopsy. This involves taking a small sample of the tissue and studying it under the microscope which requires the expertise of specialists. 

To enable early detection, we must enable family doctors (GPs) or dentists to be able to do a test easily and quickly. During routine check-ups when they notice an ulcer or a patch in the mouth or if the patient complains of pain, they can administer a saliva test. 

This way, we hope that we can detect and promptly treat more pre-cancerous or early-stage cancer tumours so that we help patients avoid extensive surgeries that may cause disfigurement and the need for chemo-radiotherapy when the cancer advances.  

In addition, we can potentially use saliva markers to gauge a patient’s response to treatment and to monitor for signs of cancer recurrence.

Why saliva?
Oral tumours and precancerous lesions or patches in the mouth shed cells and protein into saliva. Therefore, by testing saliva for the presence of abnormal genetic material or protein in these cells can signal that there are precancerous growths or tumours in the mouth. 

We are working with researchers at the National Cancer Centre Singapore to identify the indicators or biomarkers that will most accurately detect oral cancer and precancerous growths that have a high risk of developing into cancer. Once we have successfully identified these biomarkers, the next step is to develop tests for use in dental clinics, family clinics or even at home. 

Why is it urgent to focus on early detection of oral cancer?
From 2008 to 2012, about 500 people were diagnosed with oral cancer in Singapore, which is an average of more than 100 cases a year. The majority of patients were diagnosed with from tongue cancer. This is because, oral cancer mainly affected men aged over 60 years old who had risk factors like smoking, excessive alcohol consumption or betel nut/ tobacco chewing. 

Today, as a result of ongoing public health campaigns on the effects of smoking and alcohol consumption, the number of older men getting oral cancer has reduced. However, we are still seeing a steady trend in terms of the number of cases diagnosed. Studies show that the profile of oral cancer patients has changed – more younger patients aged 40s and 50s, especially women, are getting the disease. We do not know the exact reason but one hypothesis is the increase of Human Papilloma Virus (HPV) infection in younger patients due to lifestyle habits. 

We also hope to tap on the potential of saliva tests to identify the presence of these viruses or viral protein at an early stage so that we can intervene early.