Prof Iain Tan is a senior consultant in the Division of Medical Oncology at the National Cancer Centre Singapore, where he is deputy chairman and leads the colorectal cancer service within the gastrointestinal oncology team.
His listed clinical interests are colorectal, hepato-pancreato-biliary, peritoneal-based and upper gastrointestinal cancers. He is also a senior clinician scientist and an associate professor at Duke-NUS Medical School, with research in gastrointestinal cancers, drug resistance and non-invasive diagnostics.
Clinical focus
Medical oncology — GI/colorectal.
Qualifications (as publicly listed)
MBBS (NUS), MRCP (UK), FAMS (Medical Oncology), PhD.
Where they practise
- Clinic / practice: National Cancer Centre Singapore — Division of Medical Oncology (see our clinic listing) — 30 Hospital Boulevard
- Hospital / training affiliation(s): National Cancer Centre Singapore; Duke-NUS Medical School
Getting to the clinic
Prof Iain Tan practises in the Division of Medical Oncology at the National Cancer Centre Singapore, at 30 Hospital Boulevard within the Outram health campus. The nearest train station is Outram Park MRT, an interchange on the East-West Line (EW16), North-East Line (NE3) and Thomson-East Coast Line (TE17), making it accessible from many parts of Singapore with few changes. From the station, follow signs through the campus toward the cancer centre along largely sheltered routes.
The Outram campus is served by several bus routes, and taxis or ride-hailing services can set you down at the building’s drop-off point, helpful for patients who are unwell or fatigued. As part of a public hospital campus, there are visitor carparks on site for those who drive, with charges applying. Allow extra time on a first visit to register, locate the correct clinic and complete any pre-consultation checks.
What GI and colorectal medical oncology covers
Gastrointestinal oncology deals with cancers of the digestive tract and related organs. Prof Tan leads the colorectal cancer service within the gastrointestinal oncology team, and his listed interests are colorectal, hepato-pancreato-biliary, peritoneal-based and upper gastrointestinal cancers. As a medical oncologist, his role centres on systemic treatment — chemotherapy, targeted therapy and immunotherapy — coordinated with surgeons and radiation oncologists as part of a multidisciplinary plan.
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Colorectal cancer, in particular, is treated according to its stage and molecular features, with treatment sometimes given before or after surgery. His research interests include drug resistance and non-invasive diagnostics, reflecting how tumour profiling increasingly helps tailor treatment to the individual cancer.
What to expect at a consultation
A first consultation usually involves a careful review of your diagnosis, scans, colonoscopy or endoscopy findings, biopsy and pathology results, and any treatment so far, along with a history of your symptoms, other conditions and medicines. The doctor will examine you and explain the type and stage of the cancer. Further tests, such as additional imaging, blood tests including relevant tumour markers, or molecular profiling, may be recommended.
The oncologist will then discuss the aims and options for treatment, including likely benefits, side effects and schedule, and how systemic treatment fits with any planned surgery or radiotherapy. There is usually time for questions and to involve family in the discussion before decisions are made.
Preparing for your appointment
It helps to bring:
- Photo identification and any GP, polyclinic or specialist referral letter.
- Relevant scans, endoscopy, biopsy and pathology reports, and previous treatment summaries.
- A full list of current medicines and supplements with doses.
- A written timeline of your symptoms and any bowel changes.
- Details of your family history of bowel or related cancers.
- A list of questions, and ideally someone to accompany you.
After your consultation and follow-up
After the consultation you will usually receive a treatment plan or a list of tests to complete first. Treatment is monitored at follow-up with examinations, blood tests including tumour markers, and scans to check response and manage side effects. Gastrointestinal cancer care is multidisciplinary, so referrals to colorectal or other surgeons, radiation oncologists or supportive services may be arranged. Continuity of care matters, and a second opinion is reasonable. Seek urgent help for fever during treatment, heavy bowel bleeding, severe abdominal pain or any red-flag symptom your team has described.
Booking, referrals and fees
As Prof Tan practises within a public cancer centre, a GP or polyclinic referral is commonly used and can support subsidy eligibility for those who qualify. For eligible treatments and procedures, MediSave, MediShield Life and Integrated Shield Plans may apply within set limits, while outpatient consultations are usually out of pocket. Confirm current fees, subsidy status and appointment details directly with the centre before attending.
Common questions
Which cancers fall under GI oncology?
These include colorectal cancer, liver, pancreas and bile-duct cancers, stomach and oesophageal cancers, and peritoneal-based cancers. Treatment depends on the specific type and stage.
Will I need chemotherapy before or after surgery?
It depends on the cancer and stage. Systemic treatment is sometimes given before surgery to shrink a tumour, sometimes after to reduce recurrence risk, and sometimes as the main treatment.
What is tumour profiling?
Tumour profiling examines the molecular features of a cancer, which can help match treatment to the specific tumour and predict how it may respond.
How are treatment decisions made for bowel cancer?
Decisions are based on the cancer’s stage and molecular features, your overall health and wishes, and discussion within a multidisciplinary team including surgeons and radiation oncologists.
How molecular profiling shapes bowel cancer treatment
Colorectal and other gastrointestinal cancers are no longer treated as a single disease. Beyond the stage of a cancer, which describes how far it has spread, the molecular features of the tumour increasingly guide which treatments are likely to work. Testing the tumour for specific genetic changes can help predict whether certain targeted therapies or immunotherapies are suitable, and can sometimes spare patients treatments that are unlikely to help them. This reflects Prof Tan’s research interest in tumour profiling and non-invasive diagnostics, and in practice it means that a sample of your cancer may be analysed in detail before a treatment plan is finalised. The results help match the medicine to the individual cancer rather than applying a one-size-fits-all approach.
How systemic treatment fits with surgery
For gastrointestinal cancers, the timing of medicines relative to surgery is an important part of the plan. Systemic treatment is sometimes given before an operation to shrink a tumour and make surgery more effective, sometimes afterwards to reduce the chance of the cancer returning, and sometimes as the main treatment when surgery is not the right option. Which sequence suits you depends on the type and stage of cancer and is decided together with surgeons and, where relevant, radiation oncologists. Understanding where each step sits in the overall plan can make a complex course of treatment easier to follow.
Related guides
Sources & verification
See also: our editorial directory of cancer specialists (oncologists & haematologists) in Singapore and our shortlist of oncology clinics.
This is an independent, factual profile compiled from the public sources listed above — not a paid listing, advertisement or endorsement. Details can change; always verify a doctor’s current registration on the Singapore Medical Council public register and confirm specifics directly with the clinic. This page is general information, not medical advice or a recommendation of any individual practitioner. See our editorial policy.
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