Yes, you can.

Basically, a Custom Test is a test type that you create yourself.  Audiqueen can also come qith a couple of built in custom tests, such as ABR, OAE, etc.  Custom Tests typically work with software connectors such as Audiqueen Easy File Fetcher, Multimedia Capture for Win10, Audiqueen Text Editor, etc.

You can create synopsis parameters, as explained here.

You can assign one of these synopsis variables as index.  For this, go to Format, then select one of the synospis parameters and click on the 'use as index' button.

This index now appears in the grid and in the evolution graph.  For the latter, use the right-mouse button to click on the background of the graph, or check the Show Evolution Chart box in the Format window of the test type.

A synopsis parameter Volume is created to enter the tumor volume as measured on MRI.  
It is then set as Index and the checkbox 'Show Evolution Chart' is checked.

Audiqueen now shows the time evolution of the synopsis parameter 'Volume'.

The vertical axis can be inverted by double clicking on it.

This feature is not available in the webviewer.