tumour
MUTANT, MINOR, DISEASE, TUMOUR
We examined the relationship between ctDNA responses and radiographic responses for each patient during treatment. ctDNA was quantified using the allele frequencies of mutant tumour‐derived DNA. Of the 11 patients with detectable ctDNA at baseline, one did not have additional blood samples suitable for ctDNA analysis and one did not have measurable disease according to Percentage change in ctDNA level from baseline during the first months of treatment for each patient (In the responder group, two out of three patients had a rapid decline in ctDNA to <30% of baseline levels within 2 weeks. In both patients, the ctDNA continued to decrease until undetectable levels at the second blood draw 9 weeks after the start of treatment. The third radiographic responder (patient 09) had a slight increase in ctDNA during radiotherapy and did not experience a significant drop in ctDNA. Patients without a radiographic response showed a more variable ctDNA trend. Only one of these six patients had a drop in ctDNA level to < 30% of baseline at 2 weeks. Four patients in this group had minor changes in ctDNA levels at the first checkpoint (< 30% change from baseline). One patient did not have an additional plasma sample before week 9, when the ctDNA had increased dramatically.When following the sequential changes in ctDNA and radiographic tumour burden for each patient during treatment (Fig. Patient 09 was registered as a responder on CT scans after 11 months. This patient had two detectable cancer‐associated mutations in plasma at baseline, and while the level of the one with the highest AF (