What is NOT considered definitive treatment for staging criteria?

The correct answer is that a core biopsy is not considered a definitive treatment for staging criteria. A core biopsy is a diagnostic procedure used to obtain tissue samples for analysis, which helps in determining the presence and type of cancer, as well as its characteristics. It provides critical information for staging but does not treat the cancer itself.

In contrast, other options such as partial cystectomy, excisional biopsy, and radical cystectomy are surgical procedures that involve the removal of tumor tissue. While partial cystectomy and radical cystectomy are definitive treatments for bladder cancer, excisional biopsy can also serve as both a method of obtaining diagnostic tissue and potentially removing cancerous tissue depending on the context. These procedures aim not only to assess the extent of the disease but also to remove cancerous tissue, contributing to the therapeutic management of the patient.

Thus, the distinction lies in the fact that core biopsy is primarily a diagnostic tool, making it the correct answer when identifying what is not classified as a definitive treatment according to staging criteria.