Hello Gavin,
There's lots of theories about what might (or might not) help various
cancers.
The theories are tested on cells, then on special mice or rats, bred for
that purpose.
Then, if "looks promising" are put into clinical trials.
There's different types and phases of trials
http://clinicaltrials.gov/ct/info/resources
Phase I measures for toxicity,
Phase II for toxicity and efficacy
Phase III larger cohort of patients - more toxicity and efficacy.
In Phase IV trials, post marketing studies delineate additional
information including the drug's risks, benefits, and optimal use.
There's one for cannabis and pain
http://clinicaltrials.gov/ct/show/NCT00046709?order=2

Nothing at the complementary cliinical trail website
http://nccam.nih.gov/clinicaltrials/

So I searched the archives and the www and found the following.
First it was tried in rats.
Then in 2 persons.
Now it's being tried in 5 persons.
http://www.medicalnewstoday.com/medicalnews.php?newsid=12088
Two persons "the patients experienced reduced VEGF levels in the tumor as
a result of treatment with cannabinoids"
I don't know how that translates into improved (or worsened) symptoms or
prolonged survival, it's not mentioned there.

This is what UK says
http://www.cancerhelp.org.uk/help/default.asp?page=9977
"As far as we know, this is the only trial of its kind at the moment.
Further trials may take place if this current research is successful.
There are already several other anti VEGF inhibitors in clinical
development for several types of cancers.  It is all very early research
and it may be many years before we know for sure how safe and effective
anti VEGF treatment really is for people with cancer."

A friend of mine, smoked cannabis quite a bit. It never helped her lung
cancer.
There's several on alt.support.cancer (probably more, over the years)
who've tried it for pain or appetite..
Didn't change their cancer or change the outcome.

There's no way, at the moment, for us to know the dose or  the delivery
system currently being tested on those 5 patients.

What do your wife's doctors say about treatments, if any?

Alayne's on alt.support.cancer. She's in UK. Her husband had glioblastoma.

If you'd like to, come over and join us there.
J