The problem
When someone is diagnosed, they are given radiation or chemotherapy that was designed to work. But every tumour is different, and there is no way to know in advance whether the drug will work on this patient's cancer. So it is given by protocol and hope. When it fails, months are lost, and the options only get fewer.
Why current approaches fail
Treatment is chosen up front, then nobody checks whether it is actually reaching the tumour. By the time a scan gives the answer, months have passed and options are gone.
The drug is picked from the cancer type and protocol, not from whether it works on this particular tumour.
Existing tests look at gene activity or imaging. None show whether the drug is acting on the tumour's DNA.
Response is judged by a scan months later. If it failed, the time and the option are already lost.