Table 2.
High-risk retinoblastoma based on age at presentation: Tumour classification
| Feature | All ages (n = 616) | Age <1 year (n = 128) | Age 1–2 years (n = 149) | Age 2–3 years (n = 117) | Age 3–4 years (n = 104) | Age >4 years (n = 118) | p value |
|---|---|---|---|---|---|---|---|
| ICRB classification | |||||||
| Group A | 0 (0) | 0 (0) | 0 (0) | 0 (0) | 0 (0) | 0 (0) | N/A |
| Group B | 0 (0) | 0 (0) | 0 (0) | 0 (0) | 0 (0) | 0 (0) | N/A |
| Group C | 0 (0) | 0 (0) | 0 (0) | 0 (0) | 0 (0) | 0 (0) | N/A |
| Group D | 71 (12) | 14 (11) | 15 (10) | 13 (11) | 13 (13) | 16 (14) | 0.95 |
| Group E | 545 (88) | 114 (89) | 134 (90) | 104 (89) | 91 (88) | 102 (86) | 1.00 |
| Reese–Ellsworth classification | |||||||
| 1A | 0 (0) | 0 (0) | 0 (0) | 0 (0) | 0 (0) | 0 (0) | N/A |
| 1B | 0 (0) | 0 (0) | 0 (0) | 0 (0) | 0 (0) | 0 (0) | N/A |
| 2A | 0 (0) | 0 (0) | 0 (0) | 0 (0) | 0 (0) | 0 (0) | N/A |
| 2B | 0 (0) | 0 (0) | 0 (0) | 0 (0) | 0 (0) | 0 (0) | N/A |
| 3A | 0 (0) | 0 (0) | 0 (0) | 0 (0) | 0 (0) | 0 (0) | N/A |
| 3B | 0 (0) | 0 (0) | 0 (0) | 0 (0) | 0 (0) | 0 (0) | N/A |
| 4A | 2 (<1) | 1 (<1) | 1 (<1) | 0 (0) | 0 (0) | 0 (0) | 0.65 |
| 4B | 1 (<1) | 0 (0) | 0 (0) | 0 (0) | 0 (0) | 1 (1) | 0.38 |
| 5A | 272 (44) | 82 (64) | 66 (44) | 42 (36) | 49 (47) | 33 (28) | 0.007a |
| 5B | 341 (55) | 45 (35) | 82 (55) | 75 (64) | 55 (53) | 84 (71) | 0.03b |
| 8th edition cT AJCC classification | |||||||
| cT1 | 0 (0) | 0 (0) | 0 (0) | 0 (0) | 0 (0) | 0 (0) | N/A |
| cT2 | 30 (5) | 5 (4) | 7 (5) | 5 (4) | 7 (7) | 6 (5) | 0.91 |
| cT3 | 586 (95) | 123 (96) | 142 (95) | 112 (96) | 97 (93) | 112 (95) | 1.00 |
| cT4 | 0 (0) | 0 (0) | 0 (0) | 0 (0) | 0 (0) | 0 (0) | N/A |
| 8th edition pT AJCC classification | |||||||
| pT1 | 262 (43) | 64 (50) | 61 (41) | 53 (45) | 42 (40) | 42 (36) | 0.66 |
| pT2 | 167 (27) | 47 (37) | 31 (21) | 30 (26) | 21 (20) | 38 (32) | 0.11 |
| pT3 | 171 (28) | 16 (13) | 53 (36) | 29 (25) | 38 (37) | 35 (30) | <0.001c |
| pT4 | 16 (3) | 1 (<1) | 4 (3) | 5 (4) | 3 (3) | 3 (3) | 0.58 |
ICRB international classification of retinoblastoma, cT clinical tumour, pT pathological tumour, AJCC American Joint Committee Classification, N/A not applicable
aPost-hoc analysis (Chi-square test with Bonferroni correction) showed that only age ≤1 year was significantly different from ages 2–3 years (p = 0.011) and ages >4 years (p = 0.001)
bPost-hoc analysis (Chi-square test with Bonferroni correction) showed that only age ≤1 year was significantly different from ages 2–3 years (p = 0.008) and ages >4 years (p = 0.002)
cPost-hoc analysis (Chi-square test with Bonferroni correction) showed that only age ≤1 year was significantly different from 1–2 years (p = 0.001), 3–4 years (p = 0.001) and >4 years (p = 0.007)