What Is Precision Oncology, and How Does It Differ From Chemotherapy?

What is precision oncology?

If you or someone in your family has been given a cancer diagnosis and you are reading about precision oncology from another country, the first questions are usually the same. What is it, how is it different from the chemotherapy you already know about, and does it apply to your situation at all? This article was prepared by the YOUNIFY Clinic medical team in plain language, without promising more than the evidence supports. You can also read an overview of our precision oncology service.

This is educational information. It is not a diagnosis, not personal medical advice, and it is not intended to prompt anyone to change a treatment plan that is already underway.

Precision oncology is an approach that chooses treatment by looking at the molecular characteristics of one particular person's tumour, rather than at the organ of origin alone. Genomic alterations and biomarkers are identified in the tumour itself, and those findings are then weighed alongside all the other clinical information.

Put simply, the traditional question is where the cancer sits, and treatment follows from the organ. A precision approach adds a second question: what mechanism appears to be driving this particular tumour? Two people whose lung cancers look identical under the microscope may carry different gene alterations and may respond differently to the same drug class.

A handful of terms are worth knowing before you read a report or talk to your oncologist.

• Gene — the genetic instruction set that governs how a cell behaves.
• Mutation — a change in those instructions that makes a cell behave abnormally.
• Biomarker — a measurable biological indicator, taken from tumour tissue or from blood, that gives some indication of how a disease may respond to a class of treatment.
• Driver alteration — a genomic change believed to be driving tumour growth, as opposed to one that is simply present alongside it.
• Actionable alteration — a genomic change for which a drug directed at that target currently exists.

The biomarkers discussed most often in clinic include EGFR, ALK, ROS1, HER2, BRAF, KRAS, RET, NTRK and MET, along with immune-side indicators such as PD-L1, MSI and TMB. Each one carries a different meaning in a different context, and none of them is relevant to every cancer type.

How it differs from chemotherapy

The core difference is how the target is chosen. Chemotherapy acts broadly on rapidly dividing cells throughout the body, which is why healthy fast-dividing tissue is also affected. A precision approach uses a drug directed at a specific mechanism that has actually been detected in the tumour, so a biomarker result must come first.

A common misunderstanding is that precision approaches have replaced chemotherapy altogether. They have not. Chemotherapy remains a necessary and effective standard treatment in many diseases and many situations. Sometimes the two are combined, sometimes they are used in sequence, and for a patient with no matched target chemotherapy may still be the most appropriate option available. The choice is an individual clinical decision, not a general ranking of one modality over another.

The two are not opposites. They are separate tools within one care plan, and the decision about what to use, when, and in what order belongs with the oncologist already treating you. Please do not adjust or stop existing treatment on your own. If you want to understand how each drug class works, read how targeted therapy and immunotherapy work.

The four-step pathway

A precision pathway generally has four connected steps: imaging, genomic profiling of the tumour, a multidisciplinary meeting to interpret the report, and treatment planning based on what was found. Every step exists for the same reason, which is to make sure decisions rest on sufficient information rather than on assumption.

Step 1 — imaging (CT / MRI). Imaging describes the location, size, appearance and spread of disease, and is used to track change over time. It also gives the genomic report its context, because a gene result on its own cannot tell anyone which direction the disease is moving.

Step 2 — genomic profiling of the tumour. Two complementary routes exist. Tissue NGS reads the genetic sequence from a tumour tissue sample, and is described in detail in comprehensive genomic profiling. Blood-based testing reads ctDNA, the fragments of tumour DNA circulating in the bloodstream, and is covered in liquid biopsy and ctDNA. The medical team chooses between them based on the quantity and quality of available tissue, how urgent the clinical question is, and what is appropriate for that individual. For patients travelling from abroad, existing pathology blocks and reports from your home hospital can often be reviewed first, which sometimes avoids a repeat procedure entirely.

Step 3 — the molecular tumour board. This is a multidisciplinary meeting that interprets the genomic report together with the full clinical picture. It matters, because a single report often lists many alterations and not every line has treatment meaning. Reading it as a team reduces both over-interpretation and the risk of overlooking something useful.

Step 4 — treatment planning. After that review, the plan may involve an oral TKI (an oral tyrosine kinase inhibitor), consideration of immunotherapy, continuing the existing standard treatment, or referral for care the clinic does not provide itself. Treatments given intravenously, including immunotherapy, as well as chemotherapy, radiotherapy and cancer surgery, are arranged through coordinated referral to a partner facility.

Who this approach may suit

In general this approach is considered for people who already have a cancer diagnosis, particularly in tumour types where biomarkers clearly matter. It is not a test for someone without a diagnosis, and it is not a cancer screening tool for the general population.

The situations most often considered include:

• A diagnosis of advanced or metastatic cancer, with the next line of treatment being planned
• Disease progressing on current treatment, where you want to know whether the tumour's genomic profile suggests other options
• Cancer types where biomarkers commonly guide planning, such as lung cancer, gastrointestinal cancers (stomach, oesophagus, pancreas, liver and biliary tract), colorectal cancer, breast cancer and prostate cancer
• Rare cancers, or cancer of unknown primary origin
• Wanting additional molecular information to bring back to your treating oncologist as part of a second opinion

Whether it is appropriate has to be judged individually: tumour type and stage, treatment already received, general fitness, other medical conditions, and what the patient and family actually want from the next phase of care.

Limitations you should know

These limits are worth understanding before anything is arranged, so that expectations match reality. They do not mean the testing is pointless. They mean the result is one input into a decision, not a finished answer.

• Not every tumour carries a genomic alteration for which a targeted drug exists. A proportion of people test and find no target that can be used to select a drug, and that is an ordinary result.
• Reports frequently include variants of uncertain significance, which should not be used on their own to choose treatment.
• Testing depends on tissue or blood of adequate quality; some people need a fresh sample.
• Even when a matched target is found, no one can predict in advance whether an individual will respond. Outcomes vary from person to person.
• Resistance can develop after a period of treatment, so follow-up and repeat assessment are part of the plan.
• Turnaround time depends on the type of test and the laboratory. The medical team will tell you the expected time frame before anything is sent.
• This approach does not replace standard treatment, and it is not a reason to stop or delay treatment you are currently receiving.

Costs depend on which tests are used and on the treatment plan. The medical team will assess and explain all costs in full before anything begins.

What to expect at YOUNIFY

At YOUNIFY Clinic a precision oncology pathway starts with a conversation and a review of the records you already have, not with ordering tests. A test without a clinical question behind it rarely changes a decision. For international patients, English-speaking coordination is arranged in advance so that records can be reviewed before you travel.

• 1. Consultation and record review — the medical team goes through pathology, imaging and treatment history, and listens to what the patient and family are hoping to understand.
• 2. Imaging where needed (CT / MRI) — to establish the current status of the disease.
• 3. Deciding on genomic testing — tissue, blood, or both, with a clear explanation of what each result can and cannot answer.
• 4. Molecular tumour board review — the report is interpreted alongside the full clinical picture.
• 5. Summarising the plan with you — the available options, the trade-offs of each, and what remains unknown. The final plan is a shared decision between patient, family and the medical team.
• 6. Follow-up and reassessment — symptoms, side effects and imaging reviewed at appropriate intervals.

If the plan calls for chemotherapy, radiotherapy, cancer surgery or any intravenous treatment, the medical team arranges a coordinated referral to a partner facility and helps keep records moving between institutions so nothing is repeated unnecessarily.

If you would like more information to bring back to the oncologist who is treating you, you can read about our precision oncology service or contact the medical team on WhatsApp at +66 81 556 9696. The team is glad to explain what each test can and cannot answer before you decide anything. Whatever you decide, please discuss it with your treating physician first and continue your current treatment unless they advise otherwise.