Convective transport of therapeutic agents in solid tumors can be improved
through intratumoral infusion. To optimize the convection, we investigated
the dependence of the hydraulic conductivity on tissue deformation induced
by interstitial fluid pressure gradient during the infusion. Two experiment
al systems were used in the investigation: 1) one-dimensional perfusion thr
ough tumor slices and 2) intratumoral infusion using a needle. With these s
ystems, we found that the apparent hydraulic conductivity (K-app) could be
altered by several orders of magnitude in fibrosarcomas through changes in
perfusion conditions. When the perfusion pressure was less than a threshold
level, fluid flow in tissues could not be detected. When the perfusion pre
ssure was increased above the threshold level, K-app depended on perfusion
system and pressure. The maximum variation in K-app in fibrosarcomas reache
d 80,260-fold in our experiments. The large variation in K-app could be exp
lained by perfusion pressure-induced tissue deformation. These experimental
data suggest that the hydraulic conductivity is very sensitive to tissue d
eformation and imply that it is possible to improve intratumoral infusion o
f therapeutic agents through optimization of infusion conditions.