Radiographic response criteria for adults with LCH
| Response category* . | Radiographic response criteria (FDG PET) . | Radiographic response criteria (CT or MRI) . |
|---|---|---|
| Complete response | Normalization of lesions with FDG uptake equal to surrounding background tissue | Complete anatomic resolution of lesions or resolution of abnormal imaging features (enhancement, diffusion restriction, etc)† |
| Partial response | Reduction from baseline SUV of lesions, but persistent uptake greater than surrounding background tissue | Reduction, but not complete resolution of lesions/abnormal imaging features |
| Progressive disease | Increased SUV value of lesions as compared with before or appearance of new FDG avid lesions | Worsening of abnormal imaging features or growth of existing lesions or appearance of new lesions |
| Stable disease | Does not meet other criteria | Does not meet other criteria |
| Response category* . | Radiographic response criteria (FDG PET) . | Radiographic response criteria (CT or MRI) . |
|---|---|---|
| Complete response | Normalization of lesions with FDG uptake equal to surrounding background tissue | Complete anatomic resolution of lesions or resolution of abnormal imaging features (enhancement, diffusion restriction, etc)† |
| Partial response | Reduction from baseline SUV of lesions, but persistent uptake greater than surrounding background tissue | Reduction, but not complete resolution of lesions/abnormal imaging features |
| Progressive disease | Increased SUV value of lesions as compared with before or appearance of new FDG avid lesions | Worsening of abnormal imaging features or growth of existing lesions or appearance of new lesions |
| Stable disease | Does not meet other criteria | Does not meet other criteria |
SUV, standardized uptake value.
For LCH without radiographic abnormalities (e.g., skin, gastrointestinal tract), clinical criteria (physical exam, endoscopy) should be used to assess response.
Patients with endocrinopathies from pituitary involvement may require ongoing hormone replacement despite attaining a radiographic complete response. Patients with single- system pulmonary LCH and abnormal PFTs at baseline should undergo follow-up testing to assess response.