Treatment outcomes in VS post-SRS
| Entity | Criteria | Reported Incidence | New Clinical Symptoms | Approximate Timeline |
|---|---|---|---|---|
| Tumor control | Lesion regression or stability | >90% | No | NA |
| Pseudoprogression | Transient increase in tumor volume over baseline | 5%–74% | No | 5–18 mo |
| Delayed pseudoprogression | Transient increase in tumor volume over baseline | 6%–17% | No | 36–48 mo |
| Tumor growth | Progressive increase in tumor size/volume for 3 consecutive scans, or 40% over baseline by some authors | <10% | Yes | Generally, not considered until 3 years post-SRS unless new symptoms |
Note:—NA indicates not applicable.