Figure 1. Plot of the normalized nutrient consumption rate (μm³) vs. tumour volume V (μm³), as given by Eq. (4) (solid line).

Here we assume a spherical shape and λ = 100 μm, which is close to the values found in experimental tumour spheroids¹. The dotted line is the normalized rate from Eq. (5), while the dashed line is from Eq. (6). The volume range corresponds to a minimum radius of 5 μm (i.e., approximately a single cell), up to a maximum of 2000 μm. The arrow marks the volume corresponding to a nearly spherical avascular tumour with a diameter of 1 mm.