Associate Professor Dr Tan Hiang Khoon is an esteemed head and neck surgeon, specialising in resection of complex head and neck malignancies, and is one of the pioneers in the development of endoscopic and robotic head and neck and thyroid surgery in Singapore. He is a strong proponent of multi-disciplinary and inter-professional collaboration to advance patient-centric care.
Dr Tan Hiang Khoon is the Academic Chair of Surgery, Academic Clinical Program, and Chairman Division of Surgery & Surgical Oncology, at Singapore General Hospital & National Cancer Centre, Singapore.
He recently visited Dhaka to attend the 15th International Surgical Congress & SAARC Surgical Care Society Meeting 2019, and was generous enough to provide some much-needed insights on head and neck cancer. The following are some excerpts of the meeting.
What are the types of head and neck cancers?
The cancers are largely divided into 4 main groups: salivary gland cancer, thyroid gland cancer, squamous cell carcinoma, and nasopharyngeal carcinoma.
Other than these, cancers can also be detected in the head and neck areas, such as skin cancer and sarcomas, for which, treatment may be applied.
What are the symptoms?
Squamous cell carcinoma, also known as SCC, leads to ulcer or a mass in the mouth, tongue or throat. It can also present as a lump in the neck when the cancer spread to the lymph nodes in the neck.
When SCC affects the vocal cord, the symptoms are often more conspicuous by the coarseness of the voice.
Nasopharyngeal carcinoma, mainly genetic, is prevalent amongst those of Southern Chinese descent, and occurs at the back of the nose. The symptoms here are nose bleeding, tinnitus (ring in the ear) blocked ear and blocked nose.
Tumours of the salivary gland and thyroid gland often presents lumps in these areas. A lump with no pain should not be ignored, as it may be more dangerous than a painful lump.
What is the most prevalent cancer and the risk factors associated with it?
Squamous cell carcinoma is caused by the following risk factors: betel nut chewing, smoking, high intake of alcohol, and Human Papillovirus. South Asia has a high prevalence of this sort of cancer in the head and neck region.
Thyroid gland cancer can occur due to exposure to radiation. Salivary gland cancer can arise from certain benign tumours but more commonly, both of these cancers happen spontaneously without known risk factors.
What are the lifestyle and health choices that should be followed to avoid these problems in the first place?
Smoking should be stopped. Consumption of alcohol should be moderate. Chewing betel nut should be avoided entirely. To get rid of HPV virus (Human papillomavirus), one must be faithful to one partner and not have multiple sexual partners. Five percent of thyroid gland cancer is related to hereditary causes, and more research is being conducted on it.
What are the kind of treatments available?
For squamous cell carcinoma, two main treatment modalities are available — surgery and radiotherapy. In some patients where the tumour presented at a late stage, chemotherapy is administered in conjunction with radiotherapy. In addition, better understanding of tumour biology has led to new class of drugs that can target specific cancer cells. There are also new drugs that can work with the body immune system to eradicate cancer cells.
For thyroid gland cancer, surgery is the first line of treatment. For patient with high risk of recurrence, radioactive iodine is given, in addition to surgery, to kill remnant cancer cells that may be present in the body. Very rarely, radiotherapy may be used. This is often in cases where the tumour cannot be completely removed by surgery.
Surgery is also the treatment of choice for salivary gland cancers. In more aggressive cancers, radiotherapy is also given after surgery.
What are the major breakthroughs in the field?
There are improvements in three major areas. One is in the improvement of surgical techniques, which allows the replacement of tissue by allowing the development of microvascular reconstruction. The tissue (muscle, skin, or bone) and blood vessels are taken from the wrist or the leg to reconstruct or replace tissue that are removed during the resection of the tumour. The use of Robotic surgery also enable surgery to be performed in hard to reach areas, such as the back of the mouth or deep in the throat.
Advances in radiotherapy technique and methods such as IMRT (Intensity Modulated Radiotherapy) and Proton Beam Therapy, help to reduce collateral damage to surrounding normal tissue, which in turn, reduce the side effects of radiotherapy.
In addition, more and more molecular therapeutic drugs and immunotherapeutic drugs are being created to improve the targeting of cancer cells and the efficiency of the treatment with reduction of side effects.
Last but not least, it is very important that clinicians recognise the importance of Quality of Life of Head and Neck Cancer patients. The treatment of these cancers can have devastating effect on function and appearance of the patients. The Head and Neck specialists, including surgeons, medical oncologists, radiation oncologists must always be mindful of the consequences of treatment, and every effort must be made to elevate the undesirable effect of treatment.