My cancer progressed on treatment. What should happen next?
Progression is the point to re-check the biology, not just switch drugs. Ask whether the tumor should be re-tested (a new biopsy or a blood-based ctDNA test), whether resistance mutations could explain the change, and whether a documented clinical trial search has been done before the next line begins, because some trials exclude patients after certain prior therapies.
Why progression changes the questions
Tumors change under treatment pressure. The mutations found at diagnosis may no longer describe the cancer that is growing now. A result that was negative two years ago may not be negative today.
That is why many guidelines support repeat molecular testing at progression for cancers such as lung, breast, and colorectal cancer, where resistance mechanisms can point to specific next options.
- Has the tumor been re-tested since it progressed, by tissue or blood?
- Could a resistance mutation explain what happened?
- Are there trials I should consider before the next line, rather than after it?
- What would make one next option better than another for me specifically?
How a molecular review helps before the next visit
A review reads every report you have side by side: original pathology, earlier genomic panels, recent ctDNA, and treatment history. You leave with a short written summary, the testing gaps, and a prioritized list of questions your oncologist can act on. It supports their decision; it does not replace it.
Related questions
Is a blood test enough to re-test after progression?
Sometimes. Liquid biopsy can detect many resistance mutations, but a negative result does not always rule them out, and tissue may still be needed. Your oncologist can weigh which fits your situation.
How quickly should this be done?
Ideally before the next treatment starts, since some trial eligibility depends on prior therapies.
Reviewed 2026-10-11 by Kim Lockheimer, PhD, DFM.