Table 2.
Frequency of scanning, recurrence rates and timing of recurrences
| Study [ref] | N (GTR) |
Average follow-up years (range) | Average number of MRI scans by years | Rate of recurrence/progression: n (%) | Median time to recurrence/progression years (range) | Median time to recurrence years (range) | Timing of recurrence (years post-primary treatment) N (%) | |||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Year 1 | Year 2 | Year 3 | Year 4 | Year 5 | Years 1–5 | Total | Symp | Asymp | Symp | Asymp | Year 1 | Year 2 | Year 3 | Year 4 | Year 5 | > 5 years | ||||
| Low grade tumour studies | ||||||||||||||||||||
| Alford et al. [9] | 53 (41) |
6.1 (2.1–12.3) |
4 | 4 | 2 | 1 | 1 | 12 | 10 (19) |
NR | NR | GTR pts (n = 6): 0.64 (0.26–6.42) STR pts (n = 4): 0.42 (range NR) |
NR | NR | NR | NR | NR | NR | NR | NR |
| Dodgshun et al. [10]a | 67 (67) |
NR | NR | NR | NR | NR | NR | 12* | 3 (5) |
0(0) | 3 (100) |
1.9 (0.75–2.75) |
N/A | 1.9 (07.5 − 2.75) |
1 (33) |
– | 2 (67) |
– | – | – |
| Dorward et al. [11] | 40 (40) |
5.6 (2.1–9.8) |
2 | 1 | 1 | 1 | 1 | 6 | 11 (28) |
1 (9) |
10 (91) |
0.53 (0.17–4.02) |
NR | NR | 10 (91) |
– | – | 1 (9) |
– | – |
| Kim et al. [12] | 67 (67) |
6.6 (1.0–14.7) |
4 | 2 | 1 | 1 | 1 | 9 | 13 (19) |
0 (0) |
13 (100) |
1.0 (0.24–10.71) |
N/A | 1 (0.24–10.71) |
7 (54) |
– | 1 (8) |
1 (8) |
2 (15) |
2 (15) |
| Udaka et al. [13]b | 102 (38) |
NR | 3.4 | 3.4 | 3.4 | 3.4 | 3.4 | 17 | 46 (41) GTR:9 STR:35 |
16 (35) |
30 (65) |
2.28 (0.17–11)ϒ |
NR | NR | 21 (48) |
9 (20) |
8 (18) |
– | – | 6 (14) |
| Vassilyadi et al. [14] | 28 (19) |
PA: 6.0 (NR) Non-PA: 7.0 (NR) |
NR | NR | NR | NR | NR | 7–8 | 2 (7) STR |
0 (0) | 2 (100) STR |
0.33 (0.25–0.42) |
0 | 0.33 (0.25–0.42) |
2 (100) |
– | – | – | – | – |
| 357 | 98 (27) |
20 (23) |
68 (77) |
41 (56) |
9 (12) |
11 (16) |
2 (3) |
2 (3) |
8 (10) |
|||||||||||
| Mixed grade tumour studies | ||||||||||||||||||||
| Korones et al. [8]c | NR | NR | 2 | 2 | 2 | 2 | 2 | 10 | 13 | 3 (23) |
10 (77) |
2.33 (0.58–4.08) |
NR | NR | NR | NR | NR | NR | NR | NR |
Asymp. asymptomatic, GTR gross total resection, N/A not applicable, N number of patients in study, Non-PA non-pilocytic astrocytoma, nr not reached, NR not reported, PA pilocytic astrocytoma, STR sub-total resection, Symp. symptomatic, ϒ mean reported rather than median
aFor Dodgshun, the mean number of scans in years 1–5 (i.e. 12 scans (7–20)) is based on a sample of 33 pts with at least 5-years follow-up from diagnosis
bFor Udaka, reporting of timing is based on patients with known extent of resection (i.e. 44/46 pts)
cKorones is a mixed tumour study (n = 112) with a total of 46 recurrent pts, 13 of which were low-grade tumour recurrences; however the breakdown between pts with high and low-grade tumours at the beginning of the study is not reported