Final answer:
To determine if a tumor has responded to therapy, medical professionals rely on imaging studies and biopsies. While behavioral changes in subjects might suggest efficacy, only direct measurement of tumor size can confirm it. Recent treatments focus on targeted therapy and immunotherapy for precision and reduced collateral damage to healthy tissue.
Step-by-step explanation:
Determining Tumor Response to Cancer Therapy
In evaluating the response of a tumor to cancer therapy, medical professionals use a range of techniques and criteria. Primarily, they consider imaging studies, such as MRI or CT scans, to measure changes in the size of the tumor. Additionally, biopsies and microscopic examination of the tumor can provide information on the cellular level, assessing the presence of cancer cells after treatment.
When conducting a study to test the effectiveness of a new anti-cancer drug, scientists will measure the tumor sizes before and after treatment, often comparing a drug-treated group with an untreated control group. However, changes in physical appearance or behavior of test subjects (like mice appearing more energetic) are not reliable indicators of the drug's efficacy on the tumor itself. Therefore, surgical examination or further imaging is required to assess the actual change in tumor size.
Modern cancer treatments, in an attempt to minimize damage to healthy tissue, are focused on targeted therapy and immunotherapy, which aim for precision in targeting cancerous cells or enhancing the body's own immune system to fight off the cancer, thus hoping to improve the therapeutic ratio.