Incomplete cryo- of radiofrequente ablatie van een niertumor stimuleert de groei van achterblijvende tumorcellen: Studie in een muismodel

Incomplete thermal ablation stimulates proliferation of residual renal carcinoma cells in a translational murine model Aim:: Aim of the study was to compare the effect of incomplete thermal ablation versus partial nephrectomy (PN) on growth stimulation and cellular survival in renal tumours. Methods:: Renca tumours were transplanted under the renal capsule in Balb/C mice (4-6 mice/group) and not (control), or incompletely treated with radiofrequency ablation (RFA), cryoablation (CA) or partial nephrectomy (PN). After 2 hours and 1, 3, 7, 14 days, the presence of proliferation (Ki67), apoptosis (Casp3), hypoxia, inflammation (CD45, F4/80) and heat shock proteins (HSP70 en HSP90) was evaluated using immunohistochemistry. Results:: There was an increased proliferation and decreased apoptosis of residual tumor cells after RFA and CA. Proliferation rate was higher (p < 0.05) and apoptosis lower (p < 0.05) following RFA compared to CA. Hypoxia and HSPs were increasingly present from 2 hours up to 7 days following ablation (p < 0.0001). Inflammatory cells were present at later timepoints (peak at 1 week). These factors were not or minimally present following PN. Conclusion:: There is an increased proliferation and decreased apoptosis of residual cells after incomplete RFA and CA. This effect is stronger following RFA compared to CA, and not present following PN. Growth stimulatory factors, such as hypoxia and HPSs could play an important role in this phenomenon. This study underlines the importance of achieving complete tumour destruction.