# stagec: Stage C Prostate Cancer In rpart: Recursive Partitioning and Regression Trees

## Description

A set of 146 patients with stage C prostate cancer, from a study exploring the prognostic value of flow cytometry.

## Usage

 `1` ```data(stagec) ```

## Format

A data frame with 146 observations on the following 8 variables.

`pgtime`

Time to progression or last follow-up (years)

`pgstat`

1 = progression observed, 0 = censored

`age`

age in years

`eet`

early endocrine therapy, 1 = no, 2 = yes

`g2`

percent of cells in G2 phase, as found by flow cytometry

`grade`

grade of the tumor, Farrow system

`gleason`

grade of the tumor, Gleason system

`ploidy`

the ploidy status of the tumor, from flow cytometry. Values are diploid, tetraploid, and aneuploid

## Details

A tumor is called diploid (normal complement of dividing cells) if the fraction of cells in G2 phase was determined to be 13% or less. Aneuploid cells have a measurable fraction with a chromosome count that is neither 24 nor 48, for these the G2 percent is difficult or impossible to measure.

## Examples

 ```1 2``` ```require(survival) rpart(Surv(pgtime, pgstat) ~ ., stagec) ```

### Example output

```Loading required package: survival
n= 146

node), split, n, deviance, yval
* denotes terminal node

1) root 146 192.111100 1.0000000
2) grade< 2.5 61  44.799010 0.3634439
4) g2< 11.36 33   9.117405 0.1229835 *
5) g2>=11.36 28  27.602190 0.7345610
10) gleason< 5.5 20  14.297110 0.5304115 *
11) gleason>=5.5 8  11.094650 1.3069940 *
6) age>=56.5 75 103.062900 1.4255040
12) gleason< 7.5 50  66.119800 1.1407320
24) g2< 13.475 24  27.197170 0.8007306 *
25) g2>=13.475 26  36.790960 1.4570210
50) g2>=17.915 15  20.332740 0.9789825 *
51) g2< 17.915 11  13.459010 2.1714480 *
13) gleason>=7.5 25  33.487250 2.0307290
26) g2>=15.29 10  11.588480 1.2156230 *
27) g2< 15.29 15  18.939150 2.7053610 *
7) age< 56.5 10  13.769010 3.1822320 *
```

rpart documentation built on Feb. 23, 2018, 9:01 a.m.