How long can a body take treatment before ineffective?

My mother Lisa, is a carrier of the BRCA 1 mutation and has been on the battle grounds with cancer for awhile now.

About six years ago(2009) she was diagnosed with Stage 3 breast cancer. After some radiation and Chemo, she underwent a double mastectomy and was in remission for short bit.

Being that her cancer was genetic(BRCA1), she under went a 'routine' surgery to remove her ovaries as a preventative measure. While they had her opened up they discovered cancer on multiple organs and ended up performing a hysterectomy, as well as an extensive scraping of the peritoneal lining that was also housing some cancer cells. She followed up with an extensive chemo regimen (mostly taxol) and she fell into remission for a staggering 5 year stint.

Last April (2015) she went in for her semi-annual checkup and her tests were off the chart suggesting the cancer has returned. After more scans, they verified that the cancer was once again on the peritoneal lining and she underwent 5 more rounds of chemo. As of October her counts were back to normal. Just a couple days age she went in for her follow up, and it appears that the cancer is back. I think everyone is a little worried that the cancer didn't respond to the chemo as well as it has in the past. Even the Oncologist at Mayo was expecting 2 years of remission before the cancer reared its ugly head again.

So now we are in a little holding pattern until she returns next month for some more conclusive testing. We are hoping that PARP inhibitor studies bring some promising treatment alternatives to the traditional options, but also wanted to get some insight on homeopathic options or any success stories out there? Any info you could share about your experience would be very appreciated as we are at a fork in the road and wonder how long someones body can take aggressive treatment? Thank you for your help!

-Inquiring daughter