Effect of Vascular Normalization by Antiangiogenic Therapy on Interstitial Hypertension, Peritumor Edema, and Lymphatic Metastasis: Insights from a Mathematical Model

TLDR

Preclinical and clinical evidence shows that anti‑angiogenic agents can reduce tumor vessel permeability and interstitial fluid pressure through vessel normalization, yet the effects on tumor IFP and interstitial fluid velocity remain unclear. The study uses a mathematical model to simulate IFP and IFV profiles in tumors, aiming to evaluate how anti‑angiogenic therapy influences these parameters. The model demonstrates that anti‑angiogenic therapy can lower IFP by decreasing tumor size, vascular hydraulic permeability, and/or vessel surface area per unit tissue volume. Within a specific window of anti‑angiogenic effects, interstitial convection rises dramatically inside the tumor while fluid convection out of the margin falls, improving drug delivery, limiting VEGF‑mediated peritumor hyperplasia and lymph node angiogenesis, reducing lymphatic metastasis risk, and decreasing peritumor edema and ascites. Cancer Res 2007;67(6):2729–35.

Abstract

Abstract Preclinical and clinical evidence shows that antiangiogenic agents can decrease tumor vessel permeability and interstitial fluid pressure (IFP) in a process of vessel “normalization.” The resulting normalized vasculature has more efficient perfusion, but little is known about how tumor IFP and interstitial fluid velocity (IFV) are affected by changes in transport properties of the vessels and interstitium that are associated with antiangiogenic therapy. By using a mathematical model to simulate IFP and IFV profiles in tumors, we show here that antiangiogenic therapy can decrease IFP by decreasing the tumor size, vascular hydraulic permeability, and/or the surface area per unit tissue volume of tumor vessels. Within a certain window of antiangiogenic effects, interstitial convection within the tumor can increase dramatically, whereas fluid convection out of the tumor margin decreases. This would result in increased drug convection within the tumor and decreased convection of drugs, growth factors, or metastatic cancer cells from the tumor margin into the peritumor fluid or tissue. Decreased convection of growth factors, such as vascular endothelial growth factor-C (VEGF-C), would limit peritumor hyperplasia, and decreased VEGF-A would limit angiogenesis in sentinel lymph nodes. Both of these effects would reduce the probability of lymphatic metastasis. Finally, decreased fluid convection into the peritumor tissue would decrease peritumor edema associated with brain tumors and ascites accumulation in the peritoneal or pleural cavity, a major complication with a number of malignancies. [Cancer Res 2007;67(6):2729–35]