Technical factors affecting the reproducibility of intravesical mouse bladder tumor implantation during therapy with Bacillus Calmette-Guérin.

Four methods of intravesical implantation of the transplantable mouse bladder tumor, MBT-2, and their effects on intravesical therapy with Bacillus Calmette-Guérin (BCG) were compared, and modifications which improved implantation are described. Pretreatment of the bladder with N-methyl-N-nitrosourea (MNU) resulted in tumor implantation in approximately two-thirds of the animals; however, all tumors penetrated the bladder wall. Using the MNU implantation procedure, intravesical BCG therapy was shown to reduce MBT-2 outgrowth by 77%. Tumor cell instillation after electrocautery produced an incidence of tumor implantation similar to that of the MNU procedure. The efficacy of BCG for the electrocautery implantation procedure also was similar to the MNU method. With the electrocautery procedure, the electrode and tumor cells were introduced into the bladder via a catheter prepared from PE 10 polyethylene tubing. The procedure required two catheterizations and produced a 24% incidence of extravesical tumors. Use of a Teflon catheter and a single catheterization for tumor cell instillation resulted in a reproducible method for implanting MBT-2 tumors which were all confined within the bladder. The efficacy of BCG therapy was unchanged from that described for the other implantation techniques.