Our Australian Shepherd mix Bunny was diagnosed with histiocytic sarcoma in December of 2013. The tumor was localized to her right leg which we had amputated. She has been going through chemo and just finished her 6th treatment. The oncologist said that currently there are no signs of the cancer spreading. She also told us it was up to us if we go with 4 more CCNU treatments or if this sixth one is the last. My wife and I are trying to figure out what is best. We don't want to put her through 4 more treatments if it is not necessary, but we do not want to skip it and have another tumor show up. Our oncologist is not really giving us much advise either way so we were hoping there is someone out there who can help us.