Introduction
Methods
Search strategy
Study selection
Data extraction and risk of bias assessment
Statistical analysis
Results
Quantity of the research
Quality of the research
Description of included studies
Study (year) [ref] Location Years of study Study design | Aim | Population | Intervention | Outcomes reported |
---|---|---|---|---|
Alford et al. [9] USA 2000–2013 Retrospective case series | To test hypothesis that PA pts without residual tumour after surgery and with > 2 consecutive, negative surveillance MRI scans, are unlikely to suffer a recurrence thereafter and that therefore further surveillance imaging is unnecessary | Included: Pts with cerebellar PA (WHO grade 1) without brainstem involvement and at least 2 years postoperative MRI follow-up Excluded: pilomyxoid astrocytoma (WHO grade 2), pts with NF1 and those without preoperative imaging N = 53 (43% male) Tumour location: cerebellum (posterior fossa) Median age at diagnosis: 6.69 years (range 1.50–18.99) Median follow-up: 6.05 years (2.07–12.28)
Previous treatments:
GTR/indeterminate: n = 41 (77%) STR: n = 12 (23%) | Surveillance MRI: 1.5T (pre-2005) and 1.5T/3T (post-2005) magnets; Diffusion-weighted imaging using spin-echo sequence Image sequences: T1-weighted, FLAIR and T2-weighted; Gd-enhanced T1 weighted and FLAIR Average frequency of imaging: every 3 months for first 2 years, every 6 months in 3rd year and every 12 months thereafter Median number of images per pt: n = 9 (GTR/indeterminate pts only) | Median no. of surveillance images per pt (GTR pts only) Median time to recurrence/progression Recurrence rate Diagnostic yield of MRI |
Dodgshun et al. (2016) [10] Australia 1996–2013 Retrospective case series | To determine the optimal management in paediatric pilocytic astrocytoma post-surgery, with a view to proposing a restricted schedule of MRI surveillance resulting in time and cost savings | Included: pts with PA (grade unspecified) who underwent GTR Excluded: pts who underwent adjunctive therapy post-resection N = 67 (55% male) Median age at diagnosis: 6.9 years (range 1–16) Average follow-up: NR although 33 patients (49%) had at least 5 years from diagnosis
Tumour location:
Posterior fossa: n = 58 (87%) Supratentorial: n = 9 (13%)
Previous treatments:
GTR: n = 67 (100%) | Surveillance MRI: details of MRI scanner and image sequences NR
Average frequency of Imaging: NR
Average number of MRI images per pt
NR for whole cohort for study period 12 (mean; range 7–20 scans) based on 33 pts with minimum 5 years follow-up | Mean time to recurrence/progression from diagnosis Recurrence rate Changes in pt treatment post-recurrence OS EFS |
Dorward et al. (2010) [11] USA NR Retrospective case series | To create a post-operative surveillance imaging strategy that both emphasizes the initial postoperative MRI as a baseline and incorporates histopathological variables for determining the optimal surveillance imaging interval for posterior fossa pilocytic astrocytoma | Included: pts with PA (WHO grade 1) located in the posterior fossa with clinical and > 2 years radiographic follow-up Excluded: pts with NF1 N = 40 (45% male) Mean age at diagnosis: 8 years (range 1.4–19.9) Mean follow-up: 5.6 years (2.1–19.8) Previous treatments: GTR: n = 40 (100%) | Surveillance MRI: 1.5T magnet Image sequences T1- and T2-weighted (± Gd contrast) Average frequency of imaging: every 3–6 months post-surgery, then at 1-year intervals post-surgery for duration of follow-up Average number of images per pt: NR | Median time to recurrence RFS by evidence of nodular enhancement on initial surveillance MRI |
Kim et al. (2014) [12] USA 1993–2003 Retrospective case series | To employ MRI imaging to evaluate how often tumours recur and to determine if recurrences are associated with any clinical symptoms in children with conclusive evidence GTR; to propose guidelines regarding the frequency of post-surgery surveillance MRI imaging; to estimate the financial costs of imaging | Included: Pts with WHO Grade 1 glial and glioneuronal tumours with GTR and follow-up clinical and MRI data Excluded: NR N = 67 (42% male) Mean age at surgery: 9.1 years (range 1–21.5) Mean follow-up: 6.6 years (1-14.7) Tumour type: PA: n = 46 (69%) Ganglioglioma: n = 14 (21%) DNET: n = 6 (9%) Glioneuronal: 1% Tumour location: Cerebellum: n = 41 (61%) Temporal: n = 16 (24%) Parietal: n = 4 (6%) Frontal: n = 2 (3%) Brainstem: n = 2 (3%) Occipital: n = 2 (3%) Previous treatments: GTR: n = 67 (100%) | Surveillance MRI: details of magnet and image sequences NR Average frequency of imaging: Immediately in the postoperative period, every 3 months in year 1, every 6 months in year 2, yearly until 5 years post-surgery, and then every 2–3 years thereafter
Average number of MRI images per pt
8.6 scans (mean) 9 scans (median; range 2–20 scans) | Median time to recurrence Recurrence rate by tumour type and location RFS post-resection (2- and 5-year) for whole cohort and by tumour type Changes in pt treatment post-recurrence |
Udaka et al. (2013) [13] USA 1994–2010 Retrospective case series | To determine the clinical and radiographic characteristics associated with recurrent/progressive disease in children with LGG and to address the role and optimal frequency of surveillance MRI imaging in asymptomatic cases of paediatric LGG based on an evaluation of the timing of recurrence/progression | Included: pts with pathologically proven LGG (WHO Grade 1 or 2) Excluded: Pts with NF1/NF2, tuberous sclerosis complex, optic pathway glioma or brainstem glioma for which no pathological diagnosis was obtained N = 102 (52% male) Median age at diagnosis: 7 years (range 0.08 to 17) Average follow-up: NR Tumour type: PA: n = 76 (75%) Ganglioglioma: n = 8 (8%) Optic glioma: n = 7 (7%) DFA: n = 5 (5%) Oligodendroglioma: n = 3 (3%) Other astrocytoma: n = 3 (3%) Tumour location Posterior fossa: n = 49 (48%) Cortical: n = 15 (15%) Multifocal: n = 14 (14%) Basal ganglia/thalamus/hypothalamus n = 7 (7%) Optic tract/chiasmatic: n = 6 (6%) Tectal: n = 4 (4%) Other: n = 7 (7%) Previous treatments: Surgery only: n = 61 (59%) Surgery + ChemT: n = 20 (20%) Surgery + RT: n = 10 (10%) Surgery + ChemT + RT: n = 11 (11%) Details of Surgery: GTR: n = 38 (37%) STR/biopsy: n = 64 (63%) | Surveillance MRI: 1.5T magnet Image sequences: T1-weighted pre- and post-Gd, T2-weighted pre-Gd and diffusion-weighted Average frequency of imaging (n = 46 recurrent pts) 1 scan every 3.5 months (asymptomatic pts only) 1 scan every 3.6 months (asymptomatic pts only)
Average number of images per pt
3.4 per year (irrespective of symptomatic status at recurrence) | Mean time to recurrence/progression OS PFS |
Vassilyadi et al. (2009) [14] Canada 1987–2007 Retrospective case series | To evaluate the utility of ‘MRI surveillance strategy to detect recurrence or progression in children with pilocytic and non-pilocytic cerebellar astrocytoma | Included: pts with a histopathological diagnosis of a posterior fossa brain tumour (i.e. PA or non-PA cerebellar astrocytoma) Excluded: pts with incomplete chart information precluding collection of any follow-up information N = 28 (47% male) Median age at surgery: PA (n = 15): 7 ± 4 years (range 2–13) Non-PA (n = 13): 7 ± 5 years (range 1–15) GTR (n = 19): 7 ± 4 years STR (n = 9): 8 ± 4 years Average follow-up: PA (n = 15): 6 ± 3 years Non-PA (n = 13): 7 ± 5 years GTR (n = 19): 7 years STR (n = 9): 4.4 years Tumour type: PA: n = 15 (54%) Non-PA (diffuse fibrillary astrocytoma): n = 13 (46%) Previous treatments: GTR: n = 19 (68%) PA: n = 11 (58%) Non-PA: n = 8 (42%) STR: n = 9 (32%) PA: n = 4 (44%) Non-PA: n = 5 (56%) | Surveillance MRI: Details of magnet NR Image sequences: T1, T1 with Gd Average frequency of imaging: GTR pts (n = 19): 1 every 11 months STR pts (n = 9): 1 every 6 months
Average number of images per pt
PA: 7 ± 2 GTR: 7 ± 2 (42% with general anaesthetic) STR: 7 ± 2 (55% with general anaesthetic) Non-PA: 8 ± 4 GTR: 8 ± 5 (47% with general anaesthetic) STR: 9 ± 4 (47% with general anaesthetic) | Average number of images per pt by tumour type and extent of resection Average time to progression Recurrence rate Frequency of MRI-detected recurrence |
Mixed grade tumour studies
| ||||
Korones et al. (2001) [8] USA 1990–1999 Retrospective case series | To determine the frequency of detection of recurrent/progressive brain tumours in asymptomatic children are detected by surveillance MRI scans, and to compare the survival of children with asymptomatic recurrence compared to those whose recurrences are detected by symptoms | Included: pts with brain tumour aged < 21 at diagnosis and for which neuro-imaging surveillance was performed exclusively by MRI Excluded: pts with spinal cord tumours or children followed by CT scans N = 112 [although paper focuses exclusively on the 46 recurrent pts (67% male)] Median age at diagnosis: (n = 46) 6.5 years (0.25–21) Average follow-up: NR Tumour type: both low- and high-grade tumours, including 13 (28%) low-grade tumours pts Astrocytoma (WHO grade unspecified) n = 11 (24%) Ganglioglioma: n = 2 (4%) Tumour location: NR Previous treatments: NR | Surveillance MRI: details of magnet and image sequences NR Average frequency of imaging: 1 scan every 5.3 months (range 1/2.3 to 1/11.8 months) Average number of images per pt: NR for low-grade tumour pts only | Median time to recurrence by tumour grade Recurrence rate by symptomatic status Median OS by symptomatic status at recurrence 2-year OS from time of recurrence by symptomatic status at recurrence |
Korones [8]
MRI protocols
Imaging schedules/frequency of imaging
Rates of recurrence
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 |
Recurrence rates by tumour type
Study [ref] | N of pts | Patients with recurrent/progressive disease: n (%) | Median time to recurrence: years (range) | Median time to recurrence: years (range) | |||
---|---|---|---|---|---|---|---|
Total | Symp | Asympt | Sympt | Asympt | |||
(a) Low-grade tumour studies
| |||||||
Pilocytic astrocytoma | |||||||
Alford et al. [9] | 53 | 10 (19) | NR | NR | GTR pts (n = 6) 0.64 (0.26–6.42) STR pts (n = 4) 5.23 (range NR) | NR | NR |
Dodgshun et al. [10] | 67 | 3 (5) | 0 (0) | 3 (100) | 1.9 (0.75–2.75) | 0 | 1.9 (07.5–2.75) |
Dorward et al. [11] | 40 | 11 (28) | 1 (9) | 10 (91) | 0.53 (0.17–4.02) | NR | NR |
Kim et al. [12] | 46 | 9 (20) | 0 (0) | 9 (100) | NR | NR | NR |
Udaka et al. [13] | 76 | 36 (47) | NR | NR | NR | NR | NR |
Vassilyadi et al. [14] | 15 | 1 (7) | 0 (0) | 1 (100) | 0.25 | 0 | 0.25 |
Totals | 297 | 70 (24) | 1 (4) | 23 (96) | |||
Diffuse fibrillary astrocytoma | |||||||
Vassilyadi et al. [14] | 13 | 1 (8) | 0 (0) | 1 (100) | 0.42 | 0 | 0.42 |
Other astrocytoma (WHO grade not specified) | |||||||
Udaka et al. [13] | 3 | 8 (267) | NR | NR | NR | NR | NR |
Ganglioglioma | |||||||
Kim et al. [12] | 14 | 3 (21) | 0 | 3 (100) | NR | NR | NR |
Udaka et al. [13] | 8 | 2 (25) | NR | NR | NR | NR | NR |
Totals | 22 | 5 (23) | 0 | 3 (100) | |||
Dysembryoplastic neuroepithelial tumours (DNET) | |||||||
Kim et al. [12] | 6 | 1 (17) | 0 | 1 (100) | NR | NR | NR |
(b) Mixed-grade tumour study (Korones)
| |||||||
Other astrocytoma (WHO grade not specified) | 11a | 2 (18) | 9 (82) | NR | NR | NR | |
Ganglioglioma | 2 | 1 (50) | 1 (50) | NR | NR | NR |
Recurrence rates by tumour site
Recurrence rates by extent of resection
Author (year) [ref] | N | Rec N | GTR n (%) | STR n (%) | N/A | ||
---|---|---|---|---|---|---|---|
All pts | Rec pts | All pts | Rec pts | ||||
GTR pts only
| |||||||
Dodgshun et al. (2016) [10] | 67 | 3 | 67 (100) | 3 (4) | N/A | N/A | N/A |
Dorward et al. (2010) [11] | 40 | 11 | 40 (100) | 11 (28) | N/A | N/A | N/A |
Kim et al. (2014) [12] | 67 | 13 | 67 (100) | 13 (19) | N/A | N/A | N/A |
GTR and STR pts
| |||||||
Alford et al. (2016) [9] | 53 | 10 | 41a (77) | 6 (15) | 12 (23) | 4 (33) | N/A |
Korones et al. (2014) [8] | NR | – | NR | NR | NR | NR | NR |
Udaka et al. (2013) [13] | 102 | 46 | 38 (37) | 9 (24) | 64 (63) | 35 (55) | 2 (4) |
Vassilyadi et al. (2009) [14] | 28 | 2 | 19 (68) | 0 (0) | 9 (32) | 2 (22) | N/A |
Totals | 357 | 85 | 272 (76) | 42 (15) | 85 (24) | 41 (48) | 2 (3) |