My two cents
My two cents:
I think that the physical toll from long term mental distress could provide an invitation for cancer - but in no way will I ever believe that trauma and stress alone cause cancer.
Neither do I agree that we know the cause of cancer unless you wish to determine cancer as a cellular defense mechanism brought on by irritation/inflammation due to a number of items such as chemical contamination, bacteria, virus, heavy metals, etc.
Most people who have been diagnosed with cancer are not in the healing phase in my opinion - their cancer cells and tumors are continuing to multiply and halting the growth of the actual cancer cells AND the eliminating the root causes that led to cancer manifesting itself are both vital for survival.
Eliminating stress and addressing mental conflicts can be important measures to help achieve success, and failure to do so could make success much more difficult. Like Essiac tea or a juice diet, such measures just might result in the elimination of the cancer, but I would not bet my life on it because in most instances much more is needed.
To be succint, I think that "stress (or trauma) causes cancer" is in the same category as "cancer is a fungus", "cancer is caused by a fluke", "cancer is caused by myco-toxins", and any other number of universal causes, or universal cures for that matter. It sounds good and sells lots of books and products, but it is not valid when presented as a universal cause.
DQ