FIG. 9.

Constructing a closed loop trajectory using C = 0 and C = 0.6, with C_avg = 0.375. (a) By using segments of a trajectory for C = 0 and C = 0.6, switching values at points A and B, we construct a closed periodic orbit. (b) Using the same total dose, we show the MTD and LDM trajectories starting from point A. The MTD trajectory eventually moves to the S corner, while the LDM trajectory moves to the R corner. Both trajectories initially move toward the H corner (tumor regression) before recurrence. (c) The MTD, LDM, and adaptive schedules are depicted. (d) We plot the average fitness $\langle f\rangle$ for the three different chemo-schedules. The adaptive schedule is able to maintain a higher average fitness throughout, although LDM initially achieves higher average fitness before declining.