In this context, 'alternative' is simply another word for 'unproven'; if an alternative treatment had been proven to work, it would no longer be 'alternative'.
No, there are no alternative or natural cures for breast cancer, triple neg or otherwise, I'm sorry. If something had been proven to work in clinical trials it would be in use in hospitals.
Please be very wary in your search for alternative treatments; wherever there's cancer there's an unscrupulous charlatan eager to part desperate and vulnerable people from their cash in exchange for ineffective and sometimes dangerous 'treatments' and 'cures'.
And there are many people who mean well but know nothing about cancer; they just have a warm fuzzy feeling that natural is best and have a pet 'alternative cure' they found on the internet.
If you're tempted by any particular alternative, do a search on this site for real information before investing money, hope or (most dangerous of all for a cancer patient) time in it.
If you haven't found them already, the best sites for information are
As well as having a lot of information (especially the second one), they both have forums where you can talk to other women about their experiences and get information; both have a forum for triple neg breast cancer