Evaluation of the VX2 rabbit auricle carcinoma as a model for head and neck cancer in humans

Introduction: This study investigates whether the VX2 carcinoma cell line, transplanted into the rabbit auricle, can be used as a head and neck cancer model. The biologic behaviour of this model is evaluated, comparing tumour transplantation with either tissue pieces or cell suspensions. Material: T hirty-six adult NZW rabbits received s.c. injections of VX2-suspensions (Gr oup S) and 11 rabbits received solid VX2-pieces (Group P) into both auricle s. Methods: In Group S, 16 rabbits mere sacrificed at various days before ( S1) and 15 after (S2) the 28th day following transplantation. In the other five rabbits transplantation failed. Animals from Group P were sacrificed e very 2 weeks after the 28th day. At autopsy the size of the primary tumours and of lymph node, lung and other metastases were assessed. If transplanta tion failed, the maximal tumour size and the time at which regression took place were recorded. Exponential trend lines mere used to create growth cur ves of metastases. Differences between groups were evaluated with the chi ( 2) test, correlations between parameters with Kendall's tau. Results: The t umour take-rate in Groups S and P was 78% and 59% respectively. The maximal size and time at which regression occurred was significantly different, am ounting to 83 +/- 7 mm(2) at 10.4 +/- 1.6 days (Group S) and 243 +/- 30 mm( 2) at 20.9 +/- 2.0 days (Group P), respectively. Development of lymph node metastases was not different. In Groups P and S2, over 90% of the necks con tained lymph node metastases. There was a higher incidence of lung metastas es in Group S2 when compared to Group P (47% vs. 14%) but it was not statis tically significant. A significant correlation (p < 0.05) between weight lo ss and the size of lung metastases was found. Conclusion: Transplantation o f the VX2-tumour with cell suspensions produces a useful head and neck canc er model for loco-regional disease in which anti-tumour regimens against bo th the primary and lymph node metastases can be tested. Transplantation wit h tumour pieces is not advised as the take-rate is low and spontaneous remi ssions occur at a late stage. (C) 2000 European Association for Cranio-Maxi llofacial Surgery.