Figure 6.

Here, we explore treatment outcomes when the second strike is applied at different time points. To easily compare between these outcomes, we display multiple overlapping simulations in the different subfigures. For each simulation, the second treatment was applied only once. Even though the second treatment reduced the tumor population by only 20%, it proved to be effective when applied in the appropriate timeframe (the times of treatment are marked as red/blue dots). A, The trajectory of relapse in the absence of a second strike. In B, we show 15 characteristic outcomes of what would happen if the first and second treatments were applied simultaneously. In 4 cases, relapse was earlier than it could have been in the absence of a second strike, in 9 cases, relapse was later than it would have been, and in 2 cases, the tumor was eliminated. As shown in C, applying treatment in the time window after the tumor starts to decline due to treatment, but before reaching the nadir, shows that all cases resulted in successful tumor elimination (blue dots indicate the time of application). D, Applying the second treatment in the time period where the tumor was near its nadir led to delayed relapses that could last several years. Despite the failure to eliminate the tumor in this window, there are opportunities to apply additional useful strikes (see Fig. 7). E, Demonstrates the ineffectiveness of a second treatment after the tumor is beyond its nadir and has begun growing again.