Tumour-Agnostic Treatment — when the biomarker matters more than the cancer

Tumour-agnostic (also called "histology-independent" or "site-agnostic") treatment is approved based on a specific molecular marker found in a tumour — not on which organ the cancer originated in. If your biopsy or blood test shows a qualifying marker, the same treatment may be considered whether your cancer started in the colon, the stomach, the endometrium, or almost anywhere else in the body.

This is a genuinely different approval logic from how most cancer drugs reach patients. A traditional approval is organ-specific — a drug is studied in one cancer type and then labelled "for" that cancer. Tumour-agnostic approval, first used in 2017 for pembrolizumab in MSI-High and dMMR solid tumours, instead studies patients across many different cancer types who all share one biomarker, then approves the drug against that marker directly. Per NCCN and ASCO patient-education material, MSI-High and dMMR occur in only a minority of solid tumours overall, though they are more common in specific cancers such as endometrial and colorectal cancer — this pathway applies to a subset of patients tested, not to everyone.

Biomarker testing itself — MSI, dMMR, TMB and related panels — is coordinated through CION's accredited partner pathology and genomic-testing laboratories, not performed in-house at a consultation.

Marker names and thresholds shown are commonly cited in NCCN/ASCO patient-education material, indicative as of August 2026 — regulatory approval and availability for a specific drug against a specific marker can differ by country and is confirmed case by case. NTRK fusion is included because it is also evaluated tumour-agnostically, but it opens up a targeted therapy, not immunotherapy — a distinction worth knowing since the two are often confused. This table explains terminology only; it is not an assessment of your own report.

• Not a guarantee of response — a qualifying biomarker raises the chance immunotherapy may help, in a proportion of patients; it does not promise it will work for you.
• Not the majority — most solid tumours are microsatellite-stable and TMB-low; a tumour-agnostic pathway applies to a subset of patients tested, not to everyone.
• Not a replacement for standard workup — staging, organ function and prior treatment history still shape the final treatment plan.
• Not a same-day answer — NGS-based TMB testing and some MSI/dMMR methods can take one to three weeks to return from an accredited lab.
• Not interpreted here — this page explains what these terms mean in general; only your oncology team can tell you what your own report means.

For cancers rare enough that no clinical trial ever tested a drug specifically against them — certain sarcomas, cancers of unknown primary, or uncommon salivary gland or biliary tract cancers — a site-specific approval simply does not exist to reach for. Tumour-agnostic pathways created, for the first time, a route to a proven treatment class when the cancer type itself is too uncommon to have its own dedicated approval.

This is a genuinely new concept for most patients, and for a rare-cancer diagnosis specifically, it can be the difference between "there is no approved option for your cancer type" and "there is an approved option for your biomarker." It does not change how rare the underlying cancer is, or guarantee a response — it simply opens a door that traditional, organ-by-organ drug approval could not.

• What Is PD-L1 Testing and Why Does It Decide Your Treatment? — PD-L1, unlike the tumour-agnostic markers above, is scored differently for almost every cancer type; see how that testing actually works.
• Understanding Your PD-L1 Score: TPS, CPS and What the Numbers Mean — if your report already shows a PD-L1 TPS or CPS number, this page decodes what it means.
• What Is EBV, HPV or Hepatitis Status Got to Do With Immunotherapy? — another example of a marker that matters for specific cancers only, unlike the tumour-agnostic markers on this page.
• Immunotherapy at CION Cancer Clinics — the full picture of how CION supports patients through the immunotherapy decision and journey.

This page explains general tumour-agnostic biomarker terminology for education only and does not interpret any individual patient's report. Biomarker testing (MSI, dMMR, TMB) is coordinated at accredited partner laboratories. Bring your report to a consultation for a doctor's assessment of what it means for you.

Thousands of families have decoded their reports with us

A biomarker report can feel like it holds your whole future in a few unfamiliar terms. Our oncologists take the time to explain what yours actually means, in plain language.