Table 3.
High-risk retinoblastoma based on age at presentation: histopathology features
| 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 |
|---|---|---|---|---|---|---|---|
| Growth pattern (n = 610) | |||||||
| Endophytic | 287 (47) | 57 (46) | 64 (43) | 59 (50) | 54 (52) | 53 (45) | 0.90 |
| Exophytic | 241 (40) | 59 (47) | 68 (46) | 42 (36) | 33 (32) | 39 (33) | 0.36 |
| Mixed | 63 (10) | 7 (6) | 13 (9) | 14 (12) | 11 (11) | 18 (15) | 0.21 |
| Diffuse infiltrating | 18 (3) | 2 (2) | 3 (2) | 2 (2) | 6 (6) | 5 (4) | 0.27 |
| Tumour differentiation (n = 615) | |||||||
| Well-differentiated | 134 (22) | 71 (56) | 31 (21) | 11 (9) | 8 (8) | 13 (11) | <0.001a |
| Moderate differentiation | 150 (24) | 35 (28) | 35 (24) | 34 (29) | 21 (20) | 25 (21) | 0.69 |
| Poor differentiation | 304 (49) | 19 (15) | 75 (51) | 68 (58) | 67 (65) | 75 (64) | <0.001b |
| Undifferentiated | 25 (4) | 2 (2) | 7 (5) | 4 (3) | 7 (7) | 5 (4) | 0.42 |
| Anterior chamber tumour seeds | 45 (7) | 8 (6) | 8 (5) | 5 (4) | 7 (7) | 17 (14) | 0.05 |
| Iris infiltration | 28 (5) | 2 (2) | 5 (3) | 4 (3) | 6 (6) | 11 (9) | 0.06 |
| Ciliary body infiltration | 29 (5) | 4 (3) | 5 (3) | 2 (2) | 7 (7) | 11 (9) | 0.06 |
| Choroidal invasion | 186 (30) | 31 (24) | 49 (33) | 32 (27) | 37 (36) | 37 (31) | 0.64 |
| Minor (<3 mm) | 66 (11) | 19 (15) | 14 (9) | 10 (9) | 8 (8) | 15 (13) | 0.45 |
| Massive (≥3 mm) | 120 (19) | 12 (9) | 35 (23) | 22 (19) | 29 (28) | 22 (19) | 0.04c |
| Optic nerve infiltration | 279 (45) | 51 (40) | 74 (50) | 55 (47) | 47 (45) | 52 (44) | 0.89 |
| Pre-laminar | 60 (10) | 16 (13) | 15 (10) | 9 (8) | 9 (9) | 11 (9) | 0.83 |
| Laminar | 105 (17) | 26 (20) | 24 (16) | 22 (19) | 15 (14) | 18 (15) | 0.83 |
| Post-laminar | 103 (17) | 8 (6) | 34 (23) | 20 (17) | 21 (20) | 20 (17) | 0.02d |
| Optic nerve transection | 11 (2) | 1 (<1) | 1 (<1) | 4 (3) | 2 (2) | 3 (3) | 0.43 |
| Combination of pre-laminar/laminar optic nerve and non-massive choroidal involvement | 27 (4) | 9 (7) | 3 (2) | 4 (3) | 3 (3) | 8 (7) | 0.20 |
| Scleral infiltration | 30 (5) | 2 (2) | 11 (7) | 7 (6) | 5 (5) | 5 (4) | 0.29 |
| Extrascleral involvement | 10 (2) | 1 (<1) | 4 (3) | 4 (3) | 1 (<1) | 0 (0) | 0.20 |
| High-risk features of retinoblastoma | 237 (38) | 31 (24) | 62 (42) | 40 (34) | 47 (45) | 57 (48) | 0.06 |
| Number of high-risk features Mean (median, range) | 2 (1, 1–7) | 2 (1, 1–6) | 2 (1, 1–5) | 2 (1, 1–7) | 2 (1, 1–7) | 2 (1, 1–6) | 0.85 |
| 1 | 150 (24) | 23 (18) | 40 (27) | 24 (21) | 29 (28) | 34 (29) | 0.42 |
| 2 | 43 (7) | 4 (3) | 9 (6) | 8 (7) | 11 (11) | 11 (9) | 0.25 |
| 3 | 24 (4) | 2 (2) | 6 (4) | 3 (3) | 3 (3) | 10 (8) | 0.08 |
| 4 | 11 (2) | 1 (<1) | 5 (3) | 4 (3) | 1 (<1) | 0 (0) | 0.14 |
| 5 | 5 (<1) | 0 (0) | 2 (1) | 0 (0) | 2 (2) | 1 (1) | 0.40 |
| 6 | 2 (<1) | 1 (<1) | 0 (0) | 0 (0) | 0 (0) | 1 (1) | 0.56 |
| 7 | 2 (<1) | 0 (0) | 0 (0) | 1 (<1) | 1 (<1) | 0 (0) | 0.47 |
aPost-hoc analysis (Chi-square test with Bonferroni correction) showed that only age ≤1 year was significantly different from all the other groups (all p < 0.001)
bPost-hoc analysis (Chi-square test with Bonferroni correction) showed that only age ≤1 year was significantly different from all the other groups (all p < 0.001)
cPost-hoc analysis (Chi-square test with Bonferroni correction) showed that only age ≤1 year was significantly different from ages 1–2 years (p = 0.008) and ages 3–4 years (p = 0.002)
dPost-hoc analysis (Chi-square test with Bonferroni correction) showed that only age ≤1 year was significantly different from 1–2 years (p = 0.001) and 3–4 years (p = 0.005)