[Probably not for the squeamish.]

If cancer causes unwanted tissue to grow and leprosy eats tissue away,
what happens when cancer meets leprosy?

I'm just curious, but it's not a flippant question.  It seems like
there ought to be some sort of medical possibility to explore there.
But even if not...I'm curious.

Thank you,
Apteryx

the effects of leprosy (which is an infection caused by a
mycobacterium,  the type of organism that also causes TB) are
extremely slow; tissue injury takes place over months and years.
Cancer grows very fast; in addition, there's no way to target the
organism specifically to cancerous tissues. It's an interesting idea,
but it doesn't work that way.  While I don't know for sure, I'd be
certain many people with leprosy have died of cancer; because cancer
is common enough and leprosy is indolent enough, and there are enough
people over the years that have had leprosy that some would get
cancer. And they'd be treated in the same way as anyone else, with the
same results. Interestingly, trials have been done with a vaccine
called BCG, used (with limited effectiveness) to treat TB, to see if 
such stimulation of the immune system would cause reactivity to
cancer. It hasn't had success. Nor, so far as I'm aware, is there
evidence that people with leprosy have reduced incidence of cancer.
Since there are around 13 million people with leprosy currently, one
would expect such a trend to have been noticed were it true.

well, leprosy "eats tissue" by killing the little nerves that go to
that part of the tissue which eventually destroys blood flow and it's
kind of "dry rot".

Angiogenesis inhibitors [factors that stop the growth of new blood
vessels ] may have a role in the treatment of cancer. They arbeing
studied intensively. Tumors produce signalers that cause new blood
vessels to grow into them. If they could be blocked, the cancer cells
would die.

Maybe go into medical research?   ; )

Bill

Thanks, surgeon and heybill, for your willingness to entertain my
admittedly off-the-wall notion and comment on it.  I don't think I'm
likely to get more of an answer than that after two weeks, so I'll
close it.

Apteryx