Table 2.
Characteristics of the study population
| Characteristic | Cases* N=60 |
References† N=295 |
| Sex, n (%) | ||
| Male | 38 (63.3) | 190 (64.4) |
| Female | 22 (36.7) | 105 (35.6) |
| Median age at index date‡ (IQI) | 11.3 (8.4–16.1) | 11.1 (7.7–15.7) |
| Age group at index date, n (%) | ||
| Age <10 years | 21 (35.0) | 130 (44.1) |
| Age ≥10 years | 39 (65.0) | 165 (55.9) |
| Treatment protocol, n (%) | ||
| NOPHO ALL1992 | 24 (40.0) | 120 (40.7) |
| NOPHO ALL2000 | 22 (36.7) | 105 (35.6) |
| NOPHO ALL2008 | 14 (23.3) | 70 (23.7) |
| Cell line, n (%) | ||
| B-precursor ALL | 55 (91.7) | 253 (85.8) |
| T-ALL | 5 (8.3) | 42 (14.2) |
| Risk group, n (%) | ||
| Non-high-risk | 46 (76.7) | 230 (78.0) |
| High-risk | 14 (23.3) | 65 (22.0) |
| Median time from diagnosis to index date (years, IQI) | 3.8 (3.2–5.1) | 3.8 (3.2–5.1) |
| Type of event, n (%) | ||
| Relapse | 49 (81.7) | – |
| SMN | 11 (18.3) | – |
*Cases, survivors of childhood ALL developing a relapse or an SMN as the first event.
†References, survivors of childhood ALL still in first remission matched on age, sex, treatment protocol and risk group.
‡Index date, the date of event for cases and the corresponding date for references.
ALL, acute lymphoblastic leukaemia; IQI, interquartile interval; NOPHO, Nordic Society of Paediatric Haematology and Oncology; SMN, second malignant neoplasm.