Understanding your diagnosis

The three questions a diagnosis answers

When we look at your reports together, we are really trying to answer three questions:

1. What kind of cancer is it? — answered by the biopsy and the pathology report.
2. How far has it spread? — answered by staging investigations (CT, MRI, PET-CT, sometimes bone scan).
3. What makes this particular cancer tick? — answered by molecular and immunohistochemistry testing.

Together, these three answers tell us what treatment is likely to work, what the goal of treatment should be, and what to expect.

What a biopsy report actually tells us

A biopsy is a small sample of tissue taken from the area of concern. A pathologist looks at it under a microscope, applies stains, and writes a report. The report usually contains:

• The type of cell the cancer arose from. Carcinoma (from surface or glandular cells — the most common), sarcoma (from connective tissue), lymphoma (from lymph nodes), leukaemia (from blood-forming cells), and so on. Within carcinomas, "adenocarcinoma" means the cancer arose from a gland — common in breast, lung, colon, prostate, pancreas.
• The grade — how abnormal the cells look (more on this below).
• The architecture — whether the cells are still confined to their starting place ("in situ") or have invaded surrounding tissue ("invasive").
• The margins, if the biopsy was actually a surgical removal — whether the cancer was completely cut out with a clear edge of normal tissue around it.
• Special stains — known as immunohistochemistry (IHC) — which help confirm the diagnosis and identify treatment targets.

"The pathology report is the single most important document in your file. Everything else — the scans, the treatment plan, the prognosis — is built on top of what the pathologist sees down the microscope."

Grade vs stage — the difference

These two words are easy to confuse, but they mean different things.

A small (low stage) cancer can still be high grade, and a large (high stage) cancer can be low grade. Both pieces of information matter and they influence treatment in different ways.

The TNM staging system

Most solid cancers are staged using the TNM system. Each letter stands for a different piece of information:

• T (tumour) — how big the primary cancer is, and what nearby structures it has grown into. T1 is small; T4 is large or invading neighbouring organs. The exact size cut-offs depend on the cancer type.
• N (nodes) — whether nearby lymph nodes are involved, and how many. N0 means no involved nodes; N1, N2, N3 describe increasing involvement.
• M (metastasis) — whether the cancer has spread to distant organs (liver, lung, bone, brain, distant lymph nodes). M0 means no distant spread; M1 means distant spread is present.

The three letters are combined into an overall stage from I to IV. For example, T2 N1 M0 is a Stage II or III cancer (depending on the type) — moderate size, some local lymph node involvement, but no distant spread. T2 N1 M1 is Stage IV — same primary tumour and local nodes, but distant spread is present.

"In situ" vs "invasive"

You may see the words "carcinoma in situ" or "DCIS" (ductal carcinoma in situ) or "LCIS" on a biopsy report.

• In situ means the abnormal cells are confined to the layer they started in and have not crossed the basement membrane into surrounding tissue. In situ disease cannot spread to lymph nodes or distant organs while it remains in situ. It is sometimes called "Stage 0".
• Invasive means the cells have broken through into the surrounding tissue. Once invasive, a cancer has the ability — though not the certainty — to spread.

The distinction is important. In-situ disease is often curable with surgery alone or surgery plus radiation, and the prognosis is excellent. Invasive disease usually needs broader treatment.

What "metastatic" really means

"Metastatic" simply means the cancer has spread from where it started to another organ. It is also called Stage IV or "advanced". The word is frightening because, historically, metastatic cancer was uniformly fatal. That is no longer the case for many cancers — and even where cure is not yet possible, "metastatic" today often means years of life, much of it lived well.

It is important to understand that metastatic cancer is a spectrum, not a single thing:

The point is: the word "metastatic" on a report tells you the cancer has spread, but it does not, by itself, tell you the prognosis. The conversation that matters is the one about which kind of metastatic disease you have.

Why molecular testing matters in 2026

Twenty years ago, two patients with the same cancer type and same stage usually got the same treatment. Today, that is no longer good enough. The molecular profile of the tumour — its specific genetic alterations and protein expression patterns — often determines which treatment will work.

Examples of molecular tests that change treatment:

• HER2, ER, PR in breast cancer — determine whether hormone therapy or HER2-targeted treatment is appropriate.
• EGFR, ALK, ROS1, KRAS, BRAF, MET, RET in lung cancer — determine which targeted therapy may work, often with dramatic results.
• KRAS, NRAS, BRAF, MSI/MMR, HER2 in colon cancer — determine which biologic agents to use or avoid.
• BRCA1/2, HRD in ovarian, breast, prostate and pancreatic cancers — determine eligibility for PARP inhibitors.
• PD-L1, MSI-high, TMB across many cancers — predict response to immunotherapy.
• Comprehensive genomic profiling (NGS) — a single test that screens for dozens of relevant alterations, increasingly used in advanced cancers.

Molecular testing usually needs tissue from the original biopsy (which is why we ask you to bring the paraffin block). For some patients, a blood-based "liquid biopsy" can supplement the tissue test. Not every cancer needs every test — we'll discuss which tests are appropriate for your specific situation, and why.

Why you might need additional scans

Even if you arrive with a recent CT scan, we may recommend additional imaging. Common reasons:

• PET-CT — for more accurate staging in lymphoma, lung cancer, oesophageal cancer, head and neck cancers, and others. A PET-CT picks up small areas of active disease that a plain CT can miss.
• MRI — for soft-tissue detail, especially in brain, spine, pelvis (rectum, prostate, gynaecological), liver and breast.
• Bone scan — for assessing bone involvement in breast and prostate cancers.
• Echocardiogram — to check heart function before certain chemotherapy drugs (anthracyclines, trastuzumab).
• Brain MRI — for cancers with a tendency to spread to the brain (small-cell lung, some breast cancers, melanoma).

Putting it all together — the multidisciplinary view

For most cancers, the final plan is shaped by more than one specialist. A typical conversation involves the medical oncologist, the surgeon, the radiation oncologist, the pathologist and the radiologist. This is called a multidisciplinary team (MDT) discussion. You may not see it happen, but it informs the plan you receive. If your case has been discussed in an MDT, the recommendation comes with several pairs of expert eyes behind it.

Words you don't have to be afraid of

• "Aggressive" — in pathology, this is a description of how the cells look or behave, not a verdict on your fate. Many "aggressive" cancers respond very well to modern treatment.
• "Advanced" — usually means Stage III or IV. It does not mean untreatable.
• "Inoperable" — sometimes a cancer cannot be removed surgically but can still be cured with chemotherapy and radiation. Inoperable is not the same as incurable.
• "Poor prognosis" — a statistical statement about a group of patients. Statistics describe groups, not individuals. Many patients do far better than the average.

What we'll do together

You don't need to memorise any of this before your visit. We will go through your specific report with you, point by point, explain what each finding means for you, and write down the conclusions so you can take them home. Understanding your diagnosis is a process, not a single moment — and you are allowed to take your time.