Chemotherapy Biotherapy Certification ONS Practice Testq

Which tumors usually show a lower response rate to chemotherapy?

1. Larger tumors

2. Smaller tumors

3. Localized tumors

4. Metastatic tumors

The correct answer is: Larger tumors

Larger tumors typically show a lower response rate to chemotherapy due to several factors. One primary reason is the presence of a higher number of cancer cells in larger tumors, which can lead to a greater extent of tumor heterogeneity. This heterogeneity can result in varying sensitivities to chemotherapy agents among different cells within the same tumor, making it more challenging to achieve an effective response. Additionally, larger tumors may have developed mechanisms of drug resistance over time, such as reduced drug uptake or enhanced efflux, which means that the chemotherapy drugs have a harder time reaching the inner cells of the tumor. The larger size also often correlates with a more advanced stage of cancer, where the biological behavior of the tumor may be more aggressive and less responsive to standard treatments. In contrast, smaller or localized tumors tend to have a higher response rate because they often have fewer cancer cells and are less advanced, allowing for more effective targeting by chemotherapy. Metastatic tumors, while they can be challenging to treat due to their widespread nature, sometimes respond well to specific systemic therapies designed for those situations. Thus, larger tumors are more likely to exhibit lower response rates to chemotherapy compared to their smaller or localized counterparts.