RCASPAR-package: A package for survival time prediction based on a piecewise...

Description Details Author(s) References Examples

Description

The package is the R-version of the C-based software CASPAR (Kaderali,2006). It is meant to help predict survival times in the presence of high-dimensional explanatory co-variates. The model is a piecewise baseline hazard Cox regression model with an Lq-norm based prior that selects for the most important regression coefficients, and in turn the most relevant co-variates for survival analysis. It was primarily tried on gene expression and aCGH data, but can be used on any other type of high-dimensional data and in disciplines other than biology and medicine.

Details

Package: RCASPAR
Type: Package
Version: 1.0
Date: 2010-08-23
License: GPL(>=3) LazyLoad: yes

Author(s)

Douaa Mugahid

Maintainer: Douaa Mugahid <mugahid@stud.uni-heidelberg.de>, Lars Kaderali <lars.kaderali@bioquant.uni-heidelberg.de>

References

The basic model is based on the Cox regression model as first introduced by Sir David Cox in: Cox,D.(1972).Regression models & life tables. Journal of the Royal Society of Statistics, 34(2), 187-220. The extension of the Cox model to its stepwise form was adapted from: Ibrahim, J.G, Chen, M.-H. & Sinha, D. (2005). Bayesian Survival Analysis (second ed.). NY: Springer. as well as Kaderali, Lars.(2006) A Heirarchial Bayesian Approach to Regression and its Application to Predicting Survival Times in Cancer Patients. Aachen: Shaker The prior on the regression coefficients was adopted from: Mazur, J., Ritter,D.,Reinelt, G. & Kaderali, L. (2009). Reconstructing Non-Linear dynamic Models of Gene Regulation using Stochastic Sampling. BMC Bioinformatics, 10(448).

Examples

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## Eg.(1): A simple example performed with a training and validation set:
data(Bergamaschi)
data(survData)
  ## Generate prediction:
result <- STpredictor_BLH(geDataS=Bergamaschi[1:27, 1:2], survDataS=survData[1:27, 9:10], geDataT=Bergamaschi[28:82, 1:2], survDataT=survData[28:82, 9:10], q = 1, s = 1, a = 1.558, b = 0.179
, cut.off=15, groups = 3, method = "CG", noprior = 1, extras = list(reltol=1))
 ## Plot a KM plot with both long and short survivors:
kmplt_svrl(long=result$long_survivors, short=result$short_survivors,title="KM plot of long and short survivors")
  ## Determine the area under the curve of AUROC curves vs. time to see the performance of the predictor given the chosen parameters and the current partitioning into training
  ## and validation sets:
survivAURC(Stime=result$predicted_STs$True_STs,status=result$predicted_STs$censored, marker=result$predicted_STs$Predicted_STs, time.max=20)
 ## Perform a log-rank test to see if the difference between the long and short survivors is significant:
logrnk(dataL=result$long_survivors, dataS=result$short_survivors)

## Eg.(2): A simple example performed with cross validation:
data(Bergamaschi)
data(survData)
  ## Generate prediction:
STpredictor_xvBLH(geData=Bergamaschi[1:40,1:2], survData=survData[1:40,9:10], k = 10, cut.off = 10, q = 1, s = 1, a = 1.558, b = 0.179, groups = 3, method = "BFGS", noprior = 1, extras = list(reltol=1))
 ## Plot a KM plot with both long and short survivors:
kmplt_svrl(long=result$long_survivors, short=result$short_survivors,title="KM plot of long and short survivors")
  ## Determine the area under the curve of AUROC curves vs. time to see the performance of the predictor given the chosen parameters and the current partitioning into training
  ## and validation sets:
survivAURC(Stime=result$predicted_STs$True_STs,status=result$predicted_STs$censored, marker=result$predicted_STs$Predicted_STs, time.max=20)
 ## Perform a log-rank test to see if the difference between the long and short survivors is significant:
logrnk(dataL=result$long_survivors, dataS=result$short_survivors)

Example output

---------------Optimizing------------------ 
...........................
$AUC
[1] 11.66154

$AUeachROC
 [1] 0.5076426 0.7127124 0.6375423 0.6095430 0.6095430 0.6095430 0.6095430
 [8] 0.6095430 0.6095430 0.6095430 0.6095430 0.6095430 0.6095430 0.6095430
[15] 0.6095430 0.6095430 0.6095430 0.6095430 0.6095430 0.6095430

$Xsq
[1] 0.7582287

$pValue
[1] 0.3838834

Progress for group 1 
---------------Optimizing------------------ 
.......
Progress for group 2 
---------------Optimizing------------------ 
.......
Progress for group 3 
---------------Optimizing------------------ 
...............................
Progress for group 4 
---------------Optimizing------------------ 
........
Progress for group 5 
---------------Optimizing------------------ 
.......
Progress for group 6 
---------------Optimizing------------------ 
........
Progress for group 7 
---------------Optimizing------------------ 
.......
Progress for group 8 
---------------Optimizing------------------ 
.........................
Progress for group 9 
---------------Optimizing------------------ 
........
Progress for group 10 
---------------Optimizing------------------ 
.......
$predicted_STs
   PatientOrderValidation  True_STs Predicted_STs Absolute_Error censored
1                       1 1.4166667     39.030772      37.614106        0
2                       2 2.7500000     36.001739      33.251739        1
3                       3 2.4166667     25.560606      23.143939        1
4                       4 2.5833333     24.695553      22.112220        1
5                       5 2.1666667     12.251305      10.084638        1
6                       6 2.5000000     15.373521      12.873521        0
7                       7 2.5000000     20.606804      18.106804        1
8                       8 1.8333333     26.136561      24.303228        1
9                       9 1.2500000     12.255812      11.005812        0
10                     10 0.6666667     12.652276      11.985610        1
11                     11 1.0000000     12.987651      11.987651        0
12                     12 6.5833333     12.484618       5.901284        1
13                     13 6.5000000     13.403160       6.903160        1
14                     14 6.6666667     12.327331       5.660664        1
15                     15 2.7500000     13.853202      11.103202        1
16                     16 1.6666667     11.243977       9.577311        0
17                     17 1.1666667     30.689279      29.522612        0
18                     18 2.8333333     54.970975      52.137642        0
19                     19 3.5833333     34.620992      31.037659        0
20                     20 6.1666667     22.431978      16.265311        1
21                     21 6.1666667     16.295538      10.128871        1
22                     22 3.4166667     10.827320       7.410654        1
23                     23 6.0833333     14.276327       8.192993        1
24                     24 1.8333333      8.800746       6.967413        0
25                     25 5.5833333     38.834027      33.250694        1
26                     26 0.7500000      8.678266       7.928266        0
27                     27 5.7500000     12.938162       7.188162        1
28                     28 5.5000000     15.990608      10.490608        1
29                     29 0.5833333     21.979914      21.396580        0
30                     30 7.6666667     23.486206      15.819540        1
31                     31 5.0000000     30.704349      25.704349        1
32                     32 2.8333333     27.046630      24.213296        0
33                     33 1.3333333     12.677999      11.344665        0
34                     34 5.0833333     13.168304       8.084970        1
35                     35 0.8333333     11.593089      10.759756        0
36                     36 1.5000000     11.072555       9.572555        0
37                     37 4.7500000     23.131348      18.381348        1
38                     38 3.4166667      9.911739       6.495072        0
39                     39 4.6666667     65.929331      61.262664        1
40                     40 1.9166667     29.703152      27.786485        0

$short_survivors
   PatientOrderValidation  True_STs Predicted_STs Absolute_Error censored group
2                       2 2.7500000     36.001739      33.251739        1     S
6                       6 2.5000000     15.373521      12.873521        0     S
10                     10 0.6666667     12.652276      11.985610        1     S
14                     14 6.6666667     12.327331       5.660664        1     S
18                     18 2.8333333     54.970975      52.137642        0     S
22                     22 3.4166667     10.827320       7.410654        1     S
26                     26 0.7500000      8.678266       7.928266        0     S
30                     30 7.6666667     23.486206      15.819540        1     S
34                     34 5.0833333     13.168304       8.084970        1     S
38                     38 3.4166667      9.911739       6.495072        0     S

$long_survivors
   PatientOrderValidation  True_STs Predicted_STs Absolute_Error censored group
1                       1 1.4166667     39.030772      37.614106        0     L
3                       3 2.4166667     25.560606      23.143939        1     L
4                       4 2.5833333     24.695553      22.112220        1     L
5                       5 2.1666667     12.251305      10.084638        1     L
7                       7 2.5000000     20.606804      18.106804        1     L
8                       8 1.8333333     26.136561      24.303228        1     L
9                       9 1.2500000     12.255812      11.005812        0     L
11                     11 1.0000000     12.987651      11.987651        0     L
12                     12 6.5833333     12.484618       5.901284        1     L
13                     13 6.5000000     13.403160       6.903160        1     L
15                     15 2.7500000     13.853202      11.103202        1     L
16                     16 1.6666667     11.243977       9.577311        0     L
17                     17 1.1666667     30.689279      29.522612        0     L
19                     19 3.5833333     34.620992      31.037659        0     L
20                     20 6.1666667     22.431978      16.265311        1     L
21                     21 6.1666667     16.295538      10.128871        1     L
23                     23 6.0833333     14.276327       8.192993        1     L
24                     24 1.8333333      8.800746       6.967413        0     L
25                     25 5.5833333     38.834027      33.250694        1     L
27                     27 5.7500000     12.938162       7.188162        1     L
28                     28 5.5000000     15.990608      10.490608        1     L
29                     29 0.5833333     21.979914      21.396580        0     L
31                     31 5.0000000     30.704349      25.704349        1     L
32                     32 2.8333333     27.046630      24.213296        0     L
33                     33 1.3333333     12.677999      11.344665        0     L
35                     35 0.8333333     11.593089      10.759756        0     L
36                     36 1.5000000     11.072555       9.572555        0     L
37                     37 4.7500000     23.131348      18.381348        1     L
39                     39 4.6666667     65.929331      61.262664        1     L
40                     40 1.9166667     29.703152      27.786485        0     L

$weights
[1] -0.4492131  0.4886046

$baselineHs
[1] 0.2499189 0.0998820 0.0998820

$AUC
[1] 11.66154

$AUeachROC
 [1] 0.5076426 0.7127124 0.6375423 0.6095430 0.6095430 0.6095430 0.6095430
 [8] 0.6095430 0.6095430 0.6095430 0.6095430 0.6095430 0.6095430 0.6095430
[15] 0.6095430 0.6095430 0.6095430 0.6095430 0.6095430 0.6095430

$Xsq
[1] 0.7582287

$pValue
[1] 0.3838834

RCASPAR documentation built on Nov. 8, 2020, 6:56 p.m.