How many main stage groups are in the Summary Staging 2018 classification system?

The Summary Staging 2018 classification system consists of six main stage groups. This system is designed to categorize the extent of cancer spread at diagnosis into easily understandable categories, which can enhance communication among healthcare providers and support data collection for cancer registries. The six main stage groups are categorized as follows:

1. In situ (localized)

2. Localized (confined to the organ of origin)

3. Regional (spread to nearby structures or lymph nodes)

4. Distant (metastatic disease)

5. Unknown (insufficient information to determine the stage)

6. Regional by extension or metastasis

These categories help in standardizing cancer staging, thus providing a comprehensive way to assess and compare outcomes across various cancer populations. The structure of these main stage groups allows for a clear understanding of the disease’s progression, which is crucial for treatment planning and prognosis.