Not Enough Tissue for Mutation Testing: — What Happens Next

It depends on where the tumour is and how quickly the procedure can be booked. For an accessible site, a core needle biopsy under ultrasound or CT guidance can often be arranged within days, and laboratory processing follows after that. A more complex site — spine, liver, or a lesion near a major vessel — takes longer to arrange safely. Ask your oncologist to give you the expected booking time for your specific site, so you have a real timeline rather than an open-ended wait. That number also helps you decide whether liquid biopsy or retesting the block is faster in your case.

For the mutations it detects, the result is clinically reliable. The limitation is not accuracy but sensitivity: if the tumour is not shedding much DNA into the blood, the test may return negative even when the mutation is present in the tumour. This is why a positive liquid biopsy result is generally acted on, but a negative result does not always rule out the mutation. For some cancer types and some mutations, the sensitivity of liquid biopsy is high enough that ESMO and NCCN treat it as equivalent to tissue testing. For others, tissue remains the more reliable route when it is available.

Yes. If the stored tissue has been exhausted, a repeat biopsy of the tumour or a metastasis is the standard next step, provided there is a safe access route. A site that was previously biopsied can sometimes be sampled again. In other cases, a metastasis — for example in a lymph node or a liver lesion — may be easier to reach than the original tumour and can provide a fresh sample that is equally informative. Bring this question to your oncologist explicitly; do not assume that an exhausted block means testing is over. Liquid biopsy is also still on the table regardless of block status.

This is uncommon but not impossible, particularly with very early-stage disease or tumours that shed little DNA. When both routes have been exhausted or are not feasible, your multidisciplinary team may discuss two options: starting treatment based on the cancer type and clinical picture rather than full molecular data, or — if treatment urgency allows — waiting for a point when a sample becomes more obtainable. Neither is ideal, but they are recognised clinical situations with structured approaches. The important thing is that this conversation happens within your team, not as a private assumption that nothing more can be done.

Liquid biopsy testing is coordinated through CION's partner laboratory network. Your oncologist will advise whether it is appropriate for your cancer type, and the blood draw can be arranged at your treating centre. Results are returned through the same pathway as tissue testing. If you have been told a liquid biopsy might be an option and have not yet heard the specifics — including the expected turnaround — ask your care coordinator at the next contact rather than waiting for the information to come to you.

In some situations, yes. If the cancer type has a standard first-line treatment that does not depend on the mutation result — or if there is enough clinical urgency that waiting carries its own risk — your oncologist may recommend starting treatment in parallel with further testing. In other situations, the mutation result is what determines which treatment is correct, and starting before knowing could mean the wrong drug. This is a conversation worth having explicitly at your next appointment: ask whether waiting for the result or starting now is the safer path for your specific disease.