New in Mathematica 9 › Survival Analysis

Experimental Drug Efficacy

Researchers interested in the effectiveness of a new tumor-suppression medication recorded time to tumor for cancer patients. Forty-three patients were treated with an older drug (A) and 76 were treated with the new drug (B).

In[1]:=

drugA = \!\(\*
TagBox[
RowBox[{"EventData", "[", 
PanelBox["43",
FrameMargins->Small], "]"}],
InterpretTemplate[EventData[Automatic, 
Map[Developer`ToPackedArray, {CompressedData["
1:eJxTTMoPSmVkYGDQZoCBH/YQmscBQguh0WJQWhGNVobSqlBaHUrrQ+gGAyht
BKXNobQVVB0LGs2Dg0Z3hxQaLUeAJuReTTRaG0rrotINpmi0GRptCaWtHQBA
rxg3
"], {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1,
          1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 
         1}, None}]]& ],
Editable->False,
SelectWithContents->True,
Selectable->True]\);
drugB = \!\(\*
TagBox[
RowBox[{"EventData", "[", 
PanelBox["76",
FrameMargins->Small], "]"}],
InterpretTemplate[EventData[Automatic, 
Map[Developer`ToPackedArray, {CompressedData["
1:eJxTTMoPSmVkYGDwYYCBB/ak0SwOqDQPlJaC0voO5JlLiP5BgEZ3Fy6ah0ha
CActRiQNCw85HLQiDloZjVbFQauj0ZoEaF1UusEAjTaC0sY4aBMobQalLaC0
JZS2QqNtHABGlzQi
"], {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
          1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 
         1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 
         1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1}, None}]]& ],
Editable->False,
SelectWithContents->True,
Selectable->True]\);

The survival functions cross.

In[2]:=

Out[2]=

LogRankTest does not detect a significant difference in the underlying hazard rates.

In[3]:=

Out[3]=

Suppose researchers expected that the new drug would be more effective at preventing late-developing tumors. The following Fleming-Harrington weights emphasize late survival times.

In[4]:=

Out[4]=

LogRankTest weighted for late survival detects a significant difference.

In[5]:=

Out[5]=