Table 2.
Characteristics of first ROI identified as treatment effect
| Characteristics of first ROI | Total cohort | PP group | TN group | p value a |
|---|---|---|---|---|
| Spatiotemporal radiographic features | ||||
| Onset after RT completion, median (range), months | 6.5 (0–239) | 1.0 (0–4) | 11.0 (3–239) | <.00001 |
| Periventricular location, % | 48.4 | 33.3 | 59.5 | .09098 |
| Ring‐like enhancement around RC, % | 37.5 | 70.4 | 13.5 | .00009 |
| Functional imaging features, % (n) | ||||
| With functional imaging | 77.4 (48/62) | 92.0 (23/25) | 67.6 (25/37) | .07587 |
| Elevated rCBV in MRP | 75.0 (30/40) | 88.8 (16/18) | 63.6 (14/22) | .19976 |
| Restricted diffusion in DWI | 54.1 (20/37) | 57.7 (8/14) | 52.2 (12/23) | .75603 |
| Clinical features | ||||
| Onset during active treatment, % | 54.7 | 85.2 | 32.4 | .00044 |
| Amount of Ctx received prior to onset, median (IQR), months | 3.0 (1–9) | 1.0 (1–3) | 7.5 (2–12) | .00574 |
| With concurrent new symptoms, % (n) | 65.6 (40/61) | 69.2 (18/26) | 62.9 (22/35) | .82835 |
| Symptoms related to ROI, % (n) | 60.0 (24/40) | 59.1 (13/22) | 61.1 (11/18) | .61115 |
| Receiving any treatment for ROI, % | 78.1 | 88.9 | 70.2 | .20967 |
| Receiving steroids, % | 54.7 | 74.1 | 40.5 | .03592 |
| Receiving bevacizumab, % | 18.8 | 11.1 | 24.3 | .29698 |
| Receiving surgical debulking, % | 35.9 | 51.9 | 24.3 | .07991 |
| Histopathological features, % (n) | .03592 | |||
| Treatment effect only | 16.0 (8/50) | 0.0 (0/24) | 30.8 (8/26) | |
| Treatment effect with rare atypical cells | 62.0 (31/50) | 70.8 (17/24) | 53.8 (14/26) | |
| Treatment effect with foci of solid tumor | 22.0 (11/50) | 29.2 (7/24) | 15.4 (4/26) |
a
For difference between groups; false discovery rate–adjusted for multiple hypothesis testing.
Abbreviations: Ctx, chemotherapy; DWI, diffusion weighted imaging; IQR, interquartile range; MRP, magnetic resonance perfusion; PP, pseudoprogression; RC, resection cavity; rCBV, relative cerebral blood volume; ROI, region of interest; RT, radiotherapy; TN, treatment‐induced brain tissue necrosis.