TPE-IQ-2O PDT combined with surgery can reduce the tumor formation rate, size of orthotopically implanted esophageal carcinoma and primary tumor recurrence of subcutaneous tumors. (A) Schematic diagram of subcutaneous tumorigenesis, esophageal orthotopic tumor implantation and transesophageal PDT in nude mice. (B) Gross dissection specimens of the DEV group, EV/SV group, EV/SV surgery group, and EV/SV surgery combined with PDT group (the white circle indicates the recurrent focus at the incision, and the white arrow shows the esophageal tumor in situ). (C, D) Volumes of the subcutaneous tumor and implanted esophageal tumor in each group (volume = 1/2 long diameter×short diameter2; B, C and (D) show data for day 14 after tumor reduction with PDT administered every three days for 15 minutes each time, #P < 0.05 and ##P < 0.01 for pairwise comparison following Fishers exact Chi-square test, *P < 0.05 and ***P < 0.001 for pairwise comparison following Dunnett’s T3 post hoc test). (E) HE staining of implanted orthotopic esophageal tumors treated with or without TPE-IQ-2O PDT.