Table A1.
Subgroup Analysis of Therapeutic Response and Outcome According to BRAF Status, First-Line Therapy, and RO Involvement
| Outcome | All Patients | VLB Steroid Regimen | No Systemic Chemotherapy | ||||||
|---|---|---|---|---|---|---|---|---|---|
| BRAF | WT | P | BRAF | WT | P | BRAF | WT | P | |
| SS, MS RO−, and Lung+ LCH at diagnosis | |||||||||
| Sample size, No. | 139 | 138 | 64 | 55 | 73 | 81 | |||
| Responders, No. (%) | — | — | — | 60 (93.7) | 54 (98.2) | .37 | — | — | — |
| Patients with second-line therapy, No. (%) | 11 (7.9) | 4 (2.9) | .11 | 8 (12.5) | 3 (5.5) | .22 | 3 (4.1) | 1 (1.2) | .35 |
| 5-year cumulative incidence of reactivations, % ± SE | 40.1 ± 4.7 | 27.6 ± 4.6 | .009 | 41.0 ± 6.7 | 37.6 ± 7.2 | .13 | 38.3 ± 6.7 | 17.5 ± 5.2 | .04 |
| Reactivation in ROs, No. (%) | 10 (7.2) | 1 (0.7) | .01 | 6 (9.4) | 0 (0) | .03 | 4 (5.5) | 1 (1.2) | .19 |
| Patients with PC, No. (%) | 33 (23.7) | 17 (12.3) | .02 | 24 (37.5) | 11 (20) | .04 | 8 (11) | 6 (7.4) | .58 |
| MS RO+ LCH at diagnosis | |||||||||
| Sample size, No. | 33 | 5 | 32 | 5 | 0 | 0 | |||
| Responders, No. (%) | — | — | — | 15 (46.8) | 4 (80) | .34 | — | — | — |
| Patients with second-line therapy, No. (%) | 21 (63.6) | 1 (20) | .14 | 21 (65.6) | 1 (20) | .14 | — | — | — |
| 5-year cumulative incidence of reactivations, % ± SE | 52.3 ± 10.6 | 40.0 ± 21.9 | .89 | 52.3 ± 10.6 | 40 ± 21.9 | .89 | — | — | — |
| Reactivation in ROs, No. (%) | 2 (6.1) | 0 (0) | 1 | 2 (6.2) | 0 (0) | 1 | — | — | — |
| Patients with PC, No. (%) | 15 (45.5) | 1 (20) | .37 | 14 (43.7) | 1 (20) | .63 | — | — | — |
NOTE. Dashes indicate not applicable.
Abbreviations: BRAF, BRAFV600E mutated LCH cases; LCH, Langerhans cell histiocytosis; Lung+, lung involvement; MS, multiple system; PC, permanent consequence; RO+, risk organ involvement; RO−, no risk organ involvement; SE, standard error; SS, single system; VLB, vinblastine; WT, wild type BRAF LCH cases.