Alteration in subclinical lesions of epidermal growth factor receptor-mutated non-small cell lung cancer transplanted tumors in nude mice suggest the delineation of clinical targets volume Changes of subclinical lesions after EGFR-TKI treatment

Abstract ObjectiveTo investigate the alteration of subclinical lesions of subcutaneous xenograft tumors in nude mice after EGFR-TKI treatment. MethodsHuman lung adenocarcinoma cell lines were subcutaneously transplanted on the right hind legs of the nude mice in control and treatment groups. Three-dimensional pathological section was taken to observe the subclinical lesion areas when the tumors’ long diameters in the control group grew to specified length. In the Gefitinib treatment group, the subclinical lesions were observed likewise after tumor shrinkage. The results were compared. ResultsThe long diameters of transplanted tumors in group C were 5, 10, 15, and 20mm, the smallest infiltration range of subclinical lesions was 0.23, 0.78, 1.24, and 2.98mm. The edge of transplanted tumor was extended 5.14mm, to include 95% of subclinical lesions. The long diameter of the transplanted tumor in the T group shrank to 15, 10, 5, and 0mm, the smallest infiltration range was 5.74, 2.13, 2.13, and 0.11mm, the edge of the transplanted tumor was extended 8.99mm to include 95% of subclinical lesions. The extended range in T group was significantly larger than group C (P=0.000). ConclusionThe subclinical lesion receded after gefitinib treatment, but was wider than that of tumor of subclinical lesion without treatment. Even if the complete imaging response was achieved, there were still small infiltrating lesions.