Summary Table 1

label levels all
age Mean (SD) 39.5 (15.4)
sex FEMALE 12 (24.0)
MALE 38 (76.0)
symptoms HEADACHE 28 (56.0)
MEMORY LOSS 2 (4.0)
SEIZURE 20 (40.0)
tos Mean (SD) 7.1 (10.5)
GFAP_preop Mean (SD) 0.0 (0.0)
GFAP_Postop Mean (SD) 0.0 (0.0)
GFAP_3m Mean (SD) 0.0 (0.0)
Grade 1 4 (8.0)
2 12 (24.0)
3 19 (38.0)
4 15 (30.0)
Tumor_Volume_Preop Mean (SD) 40.0 (10.0)
Tumor_Volume_Postop Mean (SD) 0.7 (0.2)
Tumor_Volume_3m Mean (SD) 5.6 (2.1)
category GBM 11 (22.0)
Non-GBM 39 (78.0)

Summary Table by Grade

label levels 1 2 3 4 p
age Mean (SD) 18.5 (0.6) 36.3 (10.7) 33.8 (10.7) 54.7 (12.9) <0.001
sex FEMALE 2 (50.0) 0 (0.0) 4 (21.1) 6 (40.0) 0.058
MALE 2 (50.0) 12 (100.0) 15 (78.9) 9 (60.0)
symptoms HEADACHE 2 (50.0) 11 (91.7) 3 (15.8) 12 (80.0) <0.001
MEMORY LOSS 0 (0.0) 0 (0.0) 0 (0.0) 2 (13.3)
SEIZURE 2 (50.0) 1 (8.3) 16 (84.2) 1 (6.7)
tos Mean (SD) 27.0 (24.2) 6.8 (6.3) 6.3 (8.5) 3.0 (1.4) 0.043
GFAP_preop Mean (SD) 0.0 (0.0) 0.0 (0.0) 0.0 (0.0) 0.1 (0.0) <0.001
GFAP_Postop Mean (SD) 0.1 (0.1) 0.0 (0.0) 0.0 (0.0) 0.0 (0.0) 0.062
GFAP_3m Mean (SD) 0.0 (0.0) 0.0 (0.0) 0.1 (0.1) 0.0 (0.0) <0.001
Tumor_Volume_Preop Mean (SD) 48.1 (5.4) 38.7 (10.3) 38.0 (11.7) 41.5 (7.5) 0.108
Tumor_Volume_Postop Mean (SD) 0.8 (0.1) 0.8 (0.2) 0.7 (0.2) 0.6 (0.2) 0.184
Tumor_Volume_3m Mean (SD) 7.5 (1.9) 5.2 (1.8) 6.3 (2.2) 4.4 (1.6) 0.021
category GBM 0 (0.0) 0 (0.0) 0 (0.0) 11 (73.3) <0.001
Non-GBM 4 (100.0) 12 (100.0) 19 (100.0) 4 (26.7)

Summary Table by GBM vs Non-GBM

label levels GBM Non-GBM p
age Mean (SD) 54.8 (15.1) 35.2 (12.6) <0.001
sex FEMALE 3 (27.3) 9 (23.1) 0.774
MALE 8 (72.7) 30 (76.9)
symptoms HEADACHE 8 (72.7) 20 (51.3) 0.004
MEMORY LOSS 2 (18.2) 0 (0.0)
SEIZURE 1 (9.1) 19 (48.7)
tos Mean (SD) 3.5 (1.2) 8.1 (11.7) 0.834
GFAP_preop Mean (SD) 0.1 (0.0) 0.0 (0.0) <0.001
GFAP_Postop Mean (SD) 0.0 (0.0) 0.0 (0.0) 0.034
GFAP_3m Mean (SD) 0.0 (0.0) 0.0 (0.0) 0.007
Grade 1 0 (0.0) 4 (10.3) <0.001
2 0 (0.0) 12 (30.8)
3 0 (0.0) 19 (48.7)
4 11 (100.0) 4 (10.3)
Tumor_Volume_Preop Mean (SD) 40.9 (8.0) 39.8 (10.6) 0.738
Tumor_Volume_Postop Mean (SD) 0.6 (0.1) 0.7 (0.2) 0.033
Tumor_Volume_3m Mean (SD) 4.3 (1.5) 6.0 (2.1) 0.021

Summary table by most common tumors

label levels ANAPLASTIC ASTROCYTOMA ANAPLASTIC OLIGODENDROGLIOMA DIFFUSE ASTROCYTOMA GLIOBLASTOMA MULTIFORME Other p
age Mean (SD) 31.1 (11.5) 35.8 (10.1) 42.4 (9.4) 54.8 (15.1) 33.2 (15.7) <0.001
sex FEMALE 2 (25.0) 2 (18.2) 0 (0.0) 3 (27.3) 5 (38.5) 0.410
MALE 6 (75.0) 9 (81.8) 7 (100.0) 8 (72.7) 8 (61.5)
symptoms HEADACHE 2 (25.0) 1 (9.1) 6 (85.7) 8 (72.7) 11 (84.6) <0.001
MEMORY LOSS 0 (0.0) 0 (0.0) 0 (0.0) 2 (18.2) 0 (0.0)
SEIZURE 6 (75.0) 10 (90.9) 1 (14.3) 1 (9.1) 2 (15.4)
tos Mean (SD) 5.9 (4.1) 6.7 (10.9) 10.3 (6.0) 3.5 (1.2) 9.5 (17.2) 0.013
GFAP_preop Mean (SD) 0.0 (0.0) 0.0 (0.0) 0.0 (0.0) 0.1 (0.0) 0.0 (0.0) <0.001
GFAP_Postop Mean (SD) 0.0 (0.0) 0.0 (0.0) 0.0 (0.0) 0.0 (0.0) 0.1 (0.0) 0.005
GFAP_3m Mean (SD) 0.1 (0.0) 0.1 (0.1) 0.0 (0.0) 0.0 (0.0) 0.0 (0.0) <0.001
Grade 1 0 (0.0) 0 (0.0) 0 (0.0) 0 (0.0) 4 (30.8) <0.001
2 0 (0.0) 0 (0.0) 7 (100.0) 0 (0.0) 5 (38.5)
3 8 (100.0) 11 (100.0) 0 (0.0) 0 (0.0) 0 (0.0)
4 0 (0.0) 0 (0.0) 0 (0.0) 11 (100.0) 4 (30.8)
Tumor_Volume_Preop Mean (SD) 38.1 (10.1) 37.9 (13.2) 43.8 (6.5) 40.9 (8.0) 40.2 (10.7) 0.662
Tumor_Volume_Postop Mean (SD) 0.8 (0.1) 0.7 (0.2) 0.8 (0.2) 0.6 (0.1) 0.7 (0.3) 0.055
Tumor_Volume_3m Mean (SD) 7.3 (1.1) 5.7 (2.6) 5.4 (1.9) 4.3 (1.5) 5.7 (2.2) 0.034

Grade

The Flipped Bar- plot above shows Counts(X axis) and percentages(annotated within bar) of various categories. The top 2 sub-groups are as follows : 19/50(38 %) patients are in sub-group 3 15/50(30 %) patients are in sub-group 4 The Full details of distribution is in table below.

Group n total percentage Confidence_Interval
3 19 50 38 25.53% - 51.82%
4 15 50 30 18.69% - 43.55%
2 12 50 24 13.84% - 37.07%
1 4 50 8 2.76% - 17.91%

Diagnosis

The Flipped Bar- plot above shows Counts(X axis) and percentages(annotated within bar) of various categories. The top 2 sub-groups are as follows : 11/50(22 %) patients are in sub-group ANAPLASTIC OLIGODENDROGLIOMA 11/50(22 %) patients are in sub-group GLIOBLASTOMA MULTIFORME The Full details of distribution is in table below.

Group n total percentage Confidence_Interval
ANAPLASTIC OLIGODENDROGLIOMA 11 50 22 12.29% - 34.84%
GLIOBLASTOMA MULTIFORME 11 50 22 12.29% - 34.84%
ANAPLASTIC ASTROCYTOMA 8 50 16 7.87% - 27.93%
DIFFUSE ASTROCYTOMA 7 50 14 6.49% - 25.53%
OLIGODENDROGLIOMA 5 50 10 3.92% - 20.54%
B CELL LYMPHOMA 3 50 6 1.72% - 15.15%
GANGLIOGLIOMA 2 50 4 0.84% - 12.22%
PILOCYTIC ASTROCYTOMA 2 50 4 0.84% - 12.22%
ASTROCYTOMA 1 50 2 0.22% - 8.97%

Symptoms

The Flipped Bar- plot above shows Counts(X axis) and percentages(annotated within bar) of various categories. The top 2 sub-groups are as follows : 28/50(56 %) patients are in sub-group HEADACHE 20/50(40 %) patients are in sub-group SEIZURE The Full details of distribution is in table below.

Group n total percentage Confidence_Interval
HEADACHE 28 50 56 42.23% - 69.1%
SEIZURE 20 50 40 27.3% - 53.83%
MEMORY LOSS 2 50 4 0.84% - 12.22%

Sex

The Flipped Bar- plot above shows Counts(X axis) and percentages(annotated within bar) of various categories. The top 2 sub-groups are as follows : 38/50(76 %) patients are in sub-group MALE 12/50(24 %) patients are in sub-group FEMALE The Full details of distribution is in table below.

Group n total percentage Confidence_Interval
MALE 38 50 76 62.93% - 86.16%
FEMALE 12 50 24 13.84% - 37.07%

Duration Of Symptoms

The plot above shows a flipped bar plot of Counts(X axis) and percentages(annotated within bar) of various categories. The top 2 tos categories are as follows : 20/50(40%) patients are in group 3 - 6 . 13/50(26%) patients are in group < 3 . The Full details of distribution is in table below.

Duration.Of.Symptoms.Months. n percentage
< 3 13 26
3 - 6 20 40
7-12 11 22
13 - 48 6 12

Age Distribution

we found a Significant association between category and age_grp. The chi-square statistic was 30.61 . The degree of freedom was 5 and P value was <0.001 .Contingency and Proportion table are shown below

we found a Significant association between category and age_grp. The chi-square statistic was 30.61 . The degree of freedom was 5 and P value was <0.001 .Contingency and Proportion table are shown below

In this Figure we see Box plot of age in 2 sub-groups of category : Non-GBM and GBM respectively .The individual jittered data points of age are overlaid over transparent Boxplot for better visualisation. We see distribution of data in individual sub-groups of category based on these box-plots. The lower edge of box plot represents -first quartile (Q1), Horizontal bar represents the median, Upper edge represnts third quartile (Q3), Two black lines (whiskers) emanating from box-plots signify range of non-outlier data for the particular sub-group. Lower whisker represents minimum(Q1- 1.5 interquartile range) non-outlier limit of age and upper whisker represnts maximum(Q1+1.5interquartile range) of age .Any data beyond whiskers of box-plots represents outliers in the sub-groups The big brown point in the box-plots represents mean age of 2 groups and it has been annotated in the figure itself Summary Statistics of the groups is presented in table below

The mean in Group GBM [ 54.82 ± 15.13 ] was significantly higher than Group Non- GBM [ 35.15 ± 12.56 ] . The mean difference was 19.66 and 95 % confidence interval of the difference was ( 8.98 - 30.35 ) . The p value was <0.001 . The t statistic was 3.94 and degree of freedom of the Welch unpaired two-sample t test was 14.12 .In Formal statistical notation this result is expressed as : t(14.12) = 3.94, p= <0.001.

Group n Mean SD Median Minimum Maximum
GBM 11 54.818 15.132 62 26 68
Non-GBM 39 35.154 12.556 40 16 56

Gender distribution

we found a Non-significant association between category and sex. The chi-square statistic was 0.28 . The degree of freedom was 1 and P value was 0.6 .Contingency and Proportion table are shown below

category sex n value 95 % Confidence Interval
GBM FEMALE 3 3/11 ( 27.27 %) 8.35% - 56.51%
GBM MALE 8 8/11 ( 72.73 %) 43.49% - 91.65%
Non-GBM FEMALE 9 9/39 ( 23.08 %) 12.08% - 37.9%
Non-GBM MALE 30 30/39 ( 76.92 %) 62.1% - 87.92%

GFAP as prognostic marker

This is a trace-plot of variation in GFAP (on Y axis) with passage of of time on X-axis , GFAP across various time are connected by distinct colored trace-line . Individual readings have been plotted on graph and points have been jittered for better clarity . The raw data points representing two groups have different shapes as indicated in the legend. The points across the trace represent the mean readings in two groups and whiskers represent Standard error of measurements.

we can clearly see a negative trend/slope indicating a fall in GFAP with passage of Time.we decided to explore this intuitive graphical relationship with formal statistical tests.

Effect df MSE F ges p.value
key 1.97, 96.60 0.00 0.13 .001 .87

On Formal Statistical analysis there is a non-significant fall on repeated measures Anova. Adjusted pairwise differences are given in table below.

contrast estimate SE df t.ratio p.value
GFAP_preop - GFAP_Postop 0.001 0.005 98 0.266 0.962
GFAP_preop - GFAP_3m 0.002 0.005 98 0.519 0.862
GFAP_Postop - GFAP_3m 0.001 0.005 98 0.252 0.966
Group n mean median sd min max
GFAP_3m 50 0.044 0.030 0.036 0.020 0.240
GFAP_Postop 50 0.045 0.040 0.027 0.020 0.150
GFAP_preop 50 0.046 0.039 0.025 0.009 0.149

Variation Of tumor Volume with Time

This is a trace-plot of variation in Tumor volume (on Y axis) with passage of of time on X-axis , Tumor Volume across various times are connected by distinct colored trace-line . Individual readings have been plotted on graph and points have been jittered for better clarity . The raw data points representing two groups have different shapes as indicated in the legend. The points across the trace represent the mean readings in two groups and whiskers represent Standard error of measurements.

we can clearly see an initial fall post surgery followed by a rise at 3 months .we decided to explore this intuitive graphical relationship with formal statistical tests.

Effect df MSE F ges p.value
key 1.06, 52.18 62.41 690.13 *** .90 <.0001

On Formal Statistical analysis there is a significant fall on repeated measures Anova. Adjusted pairwise differences are given in table below.

contrast estimate SE df t.ratio p.value
Tumor_Volume_Preop - Tumor_Volume_Postop 39.3 1.153 98 34.088 0
Tumor_Volume_Preop - Tumor_Volume_3m 34.4 1.153 98 29.838 0
Tumor_Volume_Postop - Tumor_Volume_3m -4.9 1.153 98 -4.250 0
Group n mean median sd min max
Tumor_Volume_3m 50 5.6 5.465 2.100 1.65 10.11
Tumor_Volume_Postop 50 0.7 0.705 0.199 0.24 1.28
Tumor_Volume_Preop 50 40.0 41.295 10.000 17.19 65.57

GFAP as diagnostic marker

The scatter plots above show relationship between Tumour Grade on X axis and GFAP_preop on Y axis. Graphically, we see that as Grade increases, GFAP_preop also increases . On a formal statistical linear regression analysis, we that line of best fit (blue line signifying line with least square difference) also has a positive slope implying a positive correlation. The gray shaded error around blue line signifies 95% confidence interval of linear regression line of best fit. The correlation between two variables is Significant . The Pearson’s correlation between Grade and GFAP_preop is 0.56 with 95% Confidence Interval of 0.33 to 0.72. the t statistic is 4.63 The p value is <0.001 .The degree of freedom is 48. In formal statistical notation this expressed as t(48)= 4.63, P= <0.001. r(Pearson) = 0.56 95% C.I. [0.33-0.72]. n= 50. The correlation is summmarised in table below

variable n Mean SD Median Minimum Maximum
GFAP_preop 50 0.046 0.025 0.039 0.009 0.149
Grade 50 2.900 0.931 3.000 1.000 4.000
Grade n mean median sd min max
1 4 0.014 0.014 0.004 0.009 0.019
2 12 0.038 0.039 0.006 0.019 0.039
3 19 0.044 0.029 0.029 0.029 0.149
4 15 0.064 0.059 0.017 0.019 0.089

Discriminating Value of GFAP in GBM vs non GBM tumours

The ridgeplot above shows density distribution of Preoperative GFAP in GBM group and Non -GBM tumours. We see most of GBM tumours have GFAP greater than 0.05

cutpoint sensitivity specificity Accuracy AUC method
0.049 1 0.846 0.88 0.923 Youden

Thus cut off 0.049 has best combination of sensitivity (100%) and specifcity (84.6%) for GBM detection with AUC of 0.923

cut off >0.05

         
          FALSE TRUE
  GBM         2    9
  Non-GBM    33    6
category n mean median sd min max
GBM 11 0.069 0.069 0.013 0.049 0.089
Non-GBM 39 0.039 0.039 0.023 0.009 0.149

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