A new method for establishing an intrapulmonary tumor in the rabbit

Local treatments against malignant intrapulmonary tumors, such as radiotherapy, photodynamic therapy, and laser ablation therapy, are sometimes used in preference to surgery or chemotherapy. The efficacy of such treatments is dependent not only on the pathological type of the primary tumor, but also on loco-regional settings such as location of the lesion and relationship between the tumor and surrounding organs as well as tissues. Therefore, in order to evaluate the efficacy of a newly developed local treatment, it is essential to have a model in which a tumor can be established at an intended location. In this study, we developed a model for the establishment of an intrapulmonary tumor, using the rabbit. After induction of general anaesthesia, a catheter was inserted via the airway into the lung of a Japanese white rabbit, under X-ray guidance. The lung was then inoculated with a collagen gel matrix containing a suspension of VX2 cells derived from rabbit skin squamous cell carcinoma. Subsequent tumor growth was evaluated with X-ray imaging and pathological examination. Growth of a solitary tumor at the target site was pathologically confirmed in 9 of 12 rabbits that were inoculated with 1 x 10(8) cells. In addition, tumor growth could be followed in 8 of 9 rabbits by chest X-ray examination. That is, a solitary intrapulmonary tumor could be established in 8 of 12 animals (67%). The rabbit model reported here enables establishment of a solitary intrapulmonary tumor and thus can provide a suitable experimental setting for evaluation of local treatments of intrapulmonary tumors.