case_images: PMC9207502_01
case_images: (A) Timeline of the treatment: Every 3 weeks one cycle: Tislelizumab (200 mg, on day 1), gemcitabine (1,000 mg/m2, on days 1 and 8), and nab-paclitaxel (125 mg/m2, on days 1 and 8). (B) Radiotherapy: PTV: 3 Gy * 10f; PGTV: 5 Gy * 10f. CT scan, Computed Tomography scan; PTV, planning target volume; PGTV, planning gross tumor volume.
case_images: fonc-12-898119-g001.jpg
case_images: PMC9207502_01_fonc-12-898119-g001.jpg
case_images: f1
case_images: Timeline of events and the radiation target volume and precise radiotherapy planning are detailed in  Figure 1 .
case_images: Tumor responses after induction therapy. (A) PET-CT was performed before (size: 4.1 cm * 3.6 cm, SUV = 18.2) and after 4 cycles of the treatment (size: 2.3 cm * 1.5 cm, SUV = 4.8). (B) CA19-9 levels of this patient during the treatment.
case_images: fonc-12-898119-g002.jpg
case_images: PMC9207502_01_fonc-12-898119-g002.jpg
case_images: f2
case_images: A  ) . As shown in  Figure 2B , tumor marker CA19-9 decreased to 51.4 U/ml.
case_images: Postoperative pathology of the patient. No residual tumor cells, and the surgical margin was negative.
case_images: fonc-12-898119-g003.jpg
case_images: PMC9207502_01_fonc-12-898119-g003.jpg
case_images: f3
case_images: A  ) . As shown in  Figure 2B , tumor marker CA19-9 decreased to 51.4 U/ml. Surprisingly, not only did the patient receive pylorus-preserving pancreaticoduodenostomy (PPPD) successfully but also the postoperative pathology showed a pCR (  Figure 3  ).
case_images: The variation diagram of the maximum mutation abundance of ctDNA.
case_images: fonc-12-898119-g004.jpg
case_images: PMC9207502_01_fonc-12-898119-g004.jpg
case_images: f4
case_images: A  ) . As shown in  Figure 2B , tumor marker CA19-9 decreased to 51.4 U/ml. The variation diagram of the maximum mutation abundance of ctDNA dynamic changes in three defined time points was shown in  Figure 4 .