Chemotherapy Biotherapy Certification ONS Practice Testq

When is chemotherapy generally most effective?

1. During the terminal phase

2. In the presence of low growth fractions

3. In high growth fractions and with a short cell cycle time

4. After surgical removal of cancer

The correct answer is: In high growth fractions and with a short cell cycle time

Chemotherapy is generally most effective during periods of high growth fractions and when the cancer cells have a short cell cycle time. High growth fractions indicate that a large number of cancer cells are actively dividing, which is crucial because chemotherapy targets rapidly dividing cells. The effectiveness of chemotherapy relies on its ability to interfere with the cell cycle; the faster the cells divide, the more susceptible they are to the cytotoxic effects of the drugs. In addition, a short cell cycle time means that cancer cells progress quickly through the phases of growth and division, making them more vulnerable to chemotherapy. Since these drugs are designed to disrupt the processes involved in cell division, targeting cells that are proliferating rapidly maximizes the potential for successful treatment outcomes. In contrast, during the terminal phase of cancer, the disease may have progressed to a point where chemotherapy could have diminished effectiveness, as the cancer might no longer respond to treatment. Low growth fractions signify that fewer cancer cells are dividing, which reduces the impact of chemotherapy because fewer cells are in the target phase during treatment. Lastly, while chemotherapy may be administered after surgical removal of cancer to eliminate residual disease, it is the timing of treatment in relation to the cancer’s growth characteristics that primarily determines effectiveness.