===== Graded Prognostic Assessment (GPA) =====

The **Graded Prognostic Assessment (GPA)** is a scoring system used to estimate **survival outcomes** in patients with **brain metastases**.

=== **GPA Scoring Criteria** ===

^ **Factor** ^ **Score 0** ^ **Score 0.5** ^ **Score 1.0** ^
| **Age** | ≥ 60 years | 50-59 years | < 50 years |
| **Karnofsky Performance Status (KPS)** | < 50 | 50-70 | 80-100 |
| **Number of Brain Metastases** | > 3 | 2-3 | 1 |
| **Extracranial Disease Status** | Present | - | Absent |

=== **Prognostic Groups** ===

^ **GPA Score** ^ **Median Survival** |
| **0.0 - 1.0** | ~3 months |
| **1.5 - 2.0** | ~6 months |
| **2.5 - 3.0** | ~12 months |
| **3.5 - 4.0** | ~24 months |

**Interpretation:**  
- The **higher the GPA score, the better the prognosis**.
- GPA is widely used to guide treatment decisions for **patients with brain metastases**.

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**Example Usage:**  
To calculate a patient’s GPA score, sum the individual factor scores.  
For instance, a **45-year-old patient (1.0), KPS 80 (1.0), 2 metastases (0.5), and no extracranial disease (1.0)** would have a **total GPA score of 3.5**, correlating with a **median survival of ~24 months**.

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**References:**  
- Sperduto et al., "Graded Prognostic Assessment: A Systematic Approach to Prognostication in Patients with Brain Metastases."