What is the significance of PSA being sensitive but not specific?

Prostate-Specific Antigen (PSA) is a protein produced by prostate cells, and while elevated levels can suggest the presence of prostate cancer, it is important to note that PSA is not specific to cancer alone. This means that elevated PSA levels can occur in benign conditions such as prostatitis and benign prostatic hyperplasia (BPH), as well as prostate cancer. Therefore, high sensitivity indicates that PSA testing is effective in identifying many cases of potential prostate issues, including cancer, but the lack of specificity means it cannot definitively confirm the presence of cancer.

The significance of PSA being sensitive but not specific lies primarily in its utility for monitoring known prostate cancer cases. After a diagnosis of prostate adenocarcinoma has been established, changes in PSA levels can help indicate tumor burden and treatment response. For example, if a patient undergoes treatment for prostate cancer and their PSA levels decrease, this is indicative of a favorable response to therapy and potentially a decrease in tumor burden. Conversely, rising PSA levels post-treatment could suggest recurrence or progression of the disease.

This characteristic is what makes option B the most accurate choice, as it highlights the role of PSA in assessing disease status rather than serving as a solitary diagnostic or screening tool.