Figure 15. Role of the tumor cell microenvironment in efficacy of the treatment.

(Top; A-D) Profiles of cancer cells at day 10 in response to injected chemoattractants on the periphery of the resection site in different tissue environment. (Bottom; A-D) Profiles of chemoattractants that correspond to each case in top panels. Diffusion coefficients of all variables were reduced on the left half side of the domain (Ω_L = [0, 0.5] × [0, 1]) while they were fixed on the right half domain (Ω_L = [0.5, 1] × [0, 1]) relative to control (D) in whole domain (in (D); Ω = [0, 1]²): D _L = 0.025D in (A), D _L = 0.075D in (B), D _L = 0.1D in (C), D _L = D in (D). As the diffusion coefficient D _L on the left half plane is decreased (from (D) to (A)), i.e., brain tissue is getting tougher, the efficacy of bringing those invasive cancerous cells back to the resection site is decreased. (E) Population of localized invasive cells within a narrow strip (Ω_p) on the periphery of the resected area (Ω_s) from the first surgery in the whole domain (Ω) at day 10. Ω_p = {P = (x, y) : dist(P, Ω_s) < w ^th} where w ^th = 0.2, 0.7, 1.2 mm. (F) Population of localized invasive cells within Ω_p in the left (Ω_L) and right (Ω_R) half domain at day 10. Parameters: ψ ₁ = 0.2, ψ ₂ = 0.0, ψ ₃ = 1.0. Efficacy of localization strategies depends on microenvironmental factors such as stiffness of tissue and brain tissue composition/geometry even with chemo-drugs since effective transport of key molecules (chemoattractants and chemo-drugs) by the diffusion process depends on these active microenvironmental players, requiring a careful priori assessment of patient-specific data.