Ask an Oncologist: Dr Donald Poon from Mount Elizabeth Novena Hospital Singapore

Ask a Doctor ForumCategory: OncologyAsk an Oncologist: Dr Donald Poon from Mount Elizabeth Novena Hospital Singapore
dr. Donald Poon asked 2 years ago
I am Dr Donald Poon, Medical Oncologist based in Mount Elizabeth Novena Hospital Singapore. I manage all tumour types, with a special interest in the following fields:
  • Geriatric Oncology (elderly with cancer)
  • Gastrointestinal/Hepatobiliary/Pancreatic Tumours
  • Neuroendocrine Tumours/Carcinoid
  • Sarcoma/Melanoma
I graduated from the National University of Singapore in 1996, and underwent advanced specialty training in medical oncology at National Cancer Centre, Singapore (NCCS), and subsequently practised as a consultant in NCCS before leaving NCCS to help build up a comprehensive oncology service in Raffles Cancer Centre in Raffles Hospital in 2010. I was Assistant Professor in Medicine at Duke-NUS Graduate Medical School 2008 – 2010. I was also Honorary Medical Director of Singapore Cancer Society from 2007 to 2009, and founding President of the Society of Geriatric Oncology in Singapore. In recognition of my efforts in patient care, I received the Humanity Healthcare Award in 2006 and STAR Excellent Service Award in 2009. In addition to general medical oncology, I have keen interest in sarcoma, melanoma, stomach cancer, colorectal cancer, liver cancer, pancreatic cancer, bile duct cancer, GIST, neuroendocrine tumours/carcinoid tumours and geriatric oncology. I developed a Geriatric Oncology programme that specialises in treating elderly patients with all varieties of cancer, and was given the SingHealth HMDP training award in Geriatric Oncology in Moffitt Cancer Centre, USA in 2006. I previously received a National Medical Research Council (NMRC) grant award of more than S$1 million in my research in liver cancer as a Co-Principal Investigator. My research in Geriatric Oncology was also selected for oral presentation at the prestigious 2008 American Society of Clinical Oncology Annual Meeting. I am also an active clinical investigator in multiple investigator-initiated and industry-sponsored clinical trials. Apart from being regularly invited to be a speaker as teaching faculty in various specialty forums in the region and internationally such as the European Society of Medical Oncology (ESMO) Neuroendocrine Tumour Preceptorship Programme, my often cited research work in oncology has been extensively published in more than 40 scientific papers in high impact factor international oncology journals such as Cancer, Journal of Clinical Oncology, and Lancet Oncology. Learn more about Mount Elizabeth Novena Hospital here: https://patients.smarterhealth.sg/hospital/mount-elizabeth-novena-hospital-singapore/ Learn more about me here: https://patients.smarterhealth.sg/specialist-doctor/donald-poon/ I am excited to be here to discuss Medical Oncology. Whether you've got questions about elderly cancer, gastro cancers, bone or skin cancer or neuroendocrine cancers, ask me anything! === Want to ask a question? Submit your question at the bottom of this page. Don’t forget to include your name and email address to get notified when the doctor answers your question.
144 Answers
Rina Apriana answered 2 years ago
Doctor, if I've already went for surgery and chemotherapy, can I still undergo immunotherapy?
dr. Donald Poon replied 2 years ago

It depends on what tumour it is that you underwent surgery for. Immunotherapy is indicated for stage 3 non-small cell lung cancer after the primary treatment. The lung tumour will need to be PD-L1 positive for immunotherapy to be effective in this context. PD-L1 is a protein on the cancer cell that the lab can test to see if the cells are susceptible to immunotherapy. If immunotherapy is given for lung cancer, it is for 1 year. The infusions are done once every 3 weeks, lasting half hour each. In some forms of breast cancer especially the triple negative type, immunotherapy is also indicated in the post-surgery setting. You will need to discuss this with your oncologist.

Laras Mawadah answered 2 years ago
Doctor, my father in law was diagnosed with lung cancer. He is 73 years old. He has undergone surgery and chemotherapy. With his old age, does he have hope to be totally cured? And is my husband at risk to inherit lung cancer too although he doesn’t smoke?
dr. Donald Poon replied 2 years ago

Yes total cure is always possible if surgery and adjuvant chemotherapy has been done. Smoking cessation is key to prevent new lung cancers from developing if your father-in-law is a smoker.

Lung cancer is not inheritable as a condition. Your husband’s chances of lung cancer compared to the average population is not increased if he does not smoke.

Rian answered 2 years ago
Doctor, my mother is 38 years old and was diagnosed with late-stage liver cancer. She never showed any symptoms though or complained. She also keeps a healthy lifestyle as far as I know. Is there any chance to be cured? What therapy will work best for her?
dr. Donald Poon replied 2 years ago

Liver cancer is usually due to an underlying chronic hepatitis B or C viral infection. She should be screened for it. The family should also be screened for carrier status by doing a blood test as these viruses are frequently transmitted from mother to child during childbirth with exposure to maternal blood. If positive, effective antiviral drug such as entecavir may be taken to treat it. A carrier of hepatitis B virus has about 200 times increased risk of liver cancer compared to the non-carrier.

Liver cancer can be cured by surgery. If surgery is not possible, liver transplant should be explored as she is young.

Other methods to treat if advanced include Y90 SIRT, radio-frequency ablation therapy, TACE, sorafenib, levantinib, regirafenib, immunotherapy atezolizumab and bevacizumab combination, pembrolizumab depending on the situation. Do discuss options with the oncologist.

Ria dewi answered 2 years ago
Hello Doctor. My husband was 43 years old when he was diagnosed with bone cancer, and he passed away when he was 45. We have one son. Is there any chance our son will inherit the disease? What can I do to prevent it?
dr. Donald Poon replied 2 years ago

Bone cancer (osteosarcoma) is not associated with any mutated gene that can be inherited in the majority of cases. So do not worry unnecessarily.

If it is an inheritable form, there are mainly 2 types.

The first type is Li Fraumeni syndrome, a mutation in the p53 tumour suppressor gene in germline cells. There will be a strong family history of cancers not limited to bone cancers, may include breast cancer, soft tissue sarcoma and solid tumours of any type. The inheritance is autosomal dominant – one out of two chance of the affected?s children having this mutation. Is there a strong family history of cancers in your husband's family?

The second type is called retinoblastoma Rb1 gene mutation. Does your husband have a childhood eye problem causing blindness in one or both eyes? If so, he may harbour an Rb1 gene mutation with osteosarcoma developing in adulthood. The chance of your child inheriting the Rb1 gene mutation in this case will be also 1 in 2.

These gene mutations may be tested through a blood test but you must seek a genetic counsellor?s help before taking these genetic tests.

If your husband’s family history is devoid of high cancer incidence and he did not have eye problems leading to blindness when young, then you do not need to consider germline genetic testing for your child.

Darmin Ros answered 2 years ago
Doctor, I am 40 years old and have been smoking since I was a teenager. Currently I cough a lot and feel pain in my chest, and it even makes it hard for me to move around. I am worried about lung cancer. What are the symptoms actually, Doc? Is it too late for me to undergo an examination now?
dr. Donald Poon replied 2 years ago

This is most likely coughing due to the thickened dry mucosal lining of the throat and airways. Research has found that COVID-19 infections are more severe in smokers due to the damaged airway lining that makes infection by the virus easier and impaired lung function making infection more severe.

For lung cancer, you should do a baseline chest x-ray. A CT scan of the lungs will be needed depending on the chest x-ray findings to rule out lung cancer.

Do see a doctor.

Isnawati answered 2 years ago
Doctor, are there any side effects of hormonal therapy in cancer treatment? I am currently under treatment for early stage breast cancer.
dr. Donald Poon replied 2 years ago

For adjuvant breast cancer hormonal therapy, there are 2 main different types of hormonal therapy. Aromatase inhibitors such as letrozole, anastrozole, and exemestane are used for post-menopausal women. Selective estrogen receptor modulators like tamoxifen are used for pre-menopausal women. Some women are rendered menopausal by monthly to 3 monthly injections before use of aromatase inhibitors.

The common side effects of aromatase inhibitors include joint aches, bone loss giving rise to osteoporosis, fatigue, mild hair loss, and slightly higher risk of Long term heart problems.

The common side effects of tamoxifen include weight gain, disruption of menstrual cycle with womb lining thickening resulting in heavier bleeding, potential complications include deep vein thrombosis, early stage womb uterine cancer, liver adenoma and triglyceride elevation.

Do discuss with your oncologist on strategies to prevent these side effects and surveillance for the potential longer term complications.

Makmur answered 2 years ago
Is chemotherapy necessary for stage-1 breast cancer? My mother was diagnosed with breast cancer. We are worried about the side effects of chemotherapy. Are there any alternatives, Doc?
dr. Donald Poon replied 2 years ago

It depends on the size and profile of the tumour. If it is estrogen and progesterone receptor positive (ER/PR) and Her-2 negative breast cancer, you may ask your oncologist about Oncotype-DX or Mammaprint genetic profiling of the tumour, these are FDA approved tests that will depend if chemotherapy is useful in reducing risk of recurrence. If these tests show that chemotherapy is not beneficial, then hormonal therapy will do.

If it is Her-2 positive breast cancer, the answer is yes, combined antibody trastuzumab and pertuzumab therapy may be needed in addition to chemotherapy.

If it is triple negative breast cancer – ER/PR/Her-2 negative, adjuvant chemotherapy is usually advised as this is an aggressive breast cancer with high risk of systemic spread.

Sri Darmiati answered 2 years ago
Doctor, my daughter has had chemotherapy six times for cervical cancer. After therapy, the doctor said the result was not good and the cancer was malignant and now my daughter cannot defecate. How do we treat this? The doctor gave her oral medications and also medication that has to be inserted into her anus, but her stools are still as hard as pebbles. Please give us your advice, Doc. Thank you
dr. Donald Poon replied 2 years ago

Unfortunately the details given are not sufficient for me to reply satisfactorily. The questions to ask the oncologist include the following –
1) Stage of cancer
2) Has the cervical tumour invaded the rectum causing rectal obstruction?
3) Has a PET or CT scan been done?
4) Has radiotherapy been given to the cervix tumour before?
5) What are the names of the chemotherapy drugs given for 6 cycles?
6) Has tumour profiling been done for presence of driver mutations?

Thank you

Febina answered 2 years ago
Doctor, I am afraid. There is a lump on my right breast. It hurts when I have my period. I am worried if this may be cancer. Can it be cured by herbal medicines?
dr. Donald Poon replied 2 years ago

Please see a doctor for the breast lump. A mammogram / ultrasound examination will be in order. A biopsy may be needed to ascertain the nature of the lump. It may not be cancer but even if it is, early surgery and treatment usually results in a cure. Herbal medications will only delay proper treatment and lower chances of cure with the delay.

Prisilian Haniwati answered 2 years ago
Doctor, if a woman has breast cancer in her 30s, is there any chance to be cured without undergoing a mastectomy?
dr. Donald Poon replied 2 years ago

There may be more conservative surgery done called wide excision / lumpectomy without mastectomy. Even if a mastectomy needs to be done – there are other options of breast reconstruction post mastectomy. Surgery is still the mainstay for cure in breast cancer treatment.

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