Persisters

After surgery or curative treatment, everyone gets regular blood tests for leftover cancer DNA, and the pooled results power forecasts of who will relapse and trials of acting early.

If most tumours escape a drug by the same back-up route, blocking that route from the start may prevent resistance rather than chase it.

Most stage II patients never relapse, yet all are offered a year of immunotherapy. Use a blood test to treat only those with detectable residual disease.

If a blood test reliably shows whether cancer will come back after surgery, trials could use it instead of waiting years for relapse. Regulators have a process to bless such a test; oncology should use it.

Because cervical tumours carry viral DNA that normal cells do not, a blood test for HPV DNA is a near-perfect tumour marker for tracking response and relapse.

Instead of trying to kill every hidden cancer cell after surgery, keep them dormant for life with low-toxicity drugs, the way extended hormone therapy already does in breast cancer.

Individualised mRNA cancer vaccines take weeks to manufacture and work best against minimal residual disease. Making the vaccine at surgery and giving it only when a blood tumour DNA test turns positive matches both facts and concentrates the cost on the minority who will relapse.

Fluid taken from the lower back contains DNA from brain tumours. Testing it can diagnose, monitor and detect resistance without brain surgery.

Dormant cancer cells hide in bone marrow. A lab-built model of that hiding place would let us watch them sleep and wake, and test drugs on them.

Aggressive glioblastomas, sarcomas and gastric cancers keep amplified cancer genes such as EGFR, MYC, MDM2 and CDK4 on free-floating DNA circles (ecDNA) whose copy number rises and falls quickly, letting the tumour dial resistance up and down. Cells carrying ecDNA depend on CHK1, giving a first drug target.

Blood tests can now find leftover cancer months before scans, but most patients who test positive have nothing to enrol in. One standing trial per country would fix that.

Use a blood test after surgery to decide who gets chemotherapy: spare the negatives, and find something that actually works for the positives.

Pack-year rules miss people who get lung cancer without heavy smoking, including East Asian women who never smoked, as Taiwan's TALENT study showed. Eligibility by a validated risk model with a set threshold, plus a never-smoker arm where family history matters, would find more cancers per scan.

Trials often measure a stand-in for survival, such as time until the cancer grows on scans. An independent body would test, for each cancer and treatment type, whether the stand-in actually predicts survival, and publish the answer.

Sleeping cancer cells survive by recycling their own contents. An old malaria drug blocks that recycling and is being tested in people with no visible cancer but detectable residual cells.

Dozens of companies sell blood tests for tumour DNA and they report different results on the same sample. Government-issued reference samples with known amounts of tumour DNA would expose the differences.

Cancer cells travelling in the blood can be counted. If a drug clears them, that is an early sign it may stop spread, and it reads out in weeks rather than years.

Use an ultra-sensitive blood test after two cycles to decide who needs more than R-CHOP and who can stop early.

Instead of treating everyone after surgery, test blood every few months and treat only when tumour DNA reappears.

Rare cancers often share a broken cellular machine even when they arise in different organs. Grouping patients by that shared fault makes trials possible.