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Tumor Volume

Tumor Volume, notated \(V_{disease}\) in most Assess models, is the volume within the tumor that can be occupied by the drug. For cell impermeable drugs, tumor volume is set to represent the tumor interstitial space. This value is based on tumor size in liters (L) and the void proportion of tumors.

The typical value for void proportion for an IgG in a tumor is 0.2 but can be influenced by several factors including drug size (Thurber et al. 2012; Thurber et al. 2008; Krol et al. 1999). For drugs that permeate cells, tumor volume is set to the full volume of the tumor.

Example: A cell-impermeable drug

Assuming a nominal tumor size of \(10 cm^3\),

\[ V_{disease} = (Tumor Volume) * (Void Proportion) = 0.2 * 0.01 L = 2*10^{-3} L \]

For mouse tumor models, typical tumor volumes range from \(100 mm^3\) - \(500 mm^3\) when drug is administered

\[ V_{disease} = 0.2 * 125 mm^3 = 2.5*10^{-5} L \]


  1. Krol, A., J. Maresca, M. W. Dewhirst, and F. Yuan. 1999. "Available Volume Fraction of Macromolecules in the Extravascular Space of a Fibrosarcoma: Implications for Drug Delivery." Methods in Molecular Biology (Clifton, N.J.) Cancer Research 59 (16): 4136–41.
  2. Thurber, Greg M., and K. Dane Wittrup. 2012. "A Mechanistic Compartmental Model for Total Antibody Uptake in Tumors." Journal of Theoretical Biology 314 (December): 57–68.
  3. Thurber, Greg M., Michael M. Schmidt, and K. Dane Wittrup. 2008. "Factors Determining Antibody Distribution in Tumors." Trends in Pharmacological Sciences 29 (2): 57–61.