Documents are very important starting with your doctor's assessment of your condition.  You will be given forms for your doctor to fill out describing your condition. Your doctor can invoice Veterans Affairs Canada (VAC) for this service.

If you undergo a radical prostatectomy you should include your pathology report.

If you can a letter from someone who can verify that you used Carbon Tetrachloride while in the service will help make the connection between your cancer and your service.

Research documents connecting Carbon Tetrachloride to cancer are important to include. You will find some of these on this website.

The bottom line is whether your submitting your first claim or your appeal
the more evidence you can get that ties your cancer to your service the better.