My Mom Is Suffering From Ovarian Cancer, Please Help

My mom is suffering from ovarian cancer 2 years she got operated got 6 cycles of chemotherapy aftr a year of operation..she had 2 small cysts in the ovary they wer neutral afr 3 or 4 months one of the cysts got disappeared but one exseted latr now developed in to cancerous cyst its size was of 40\40 mm got increased to 75\75 mm after 2nd phase of chemotherapy...that cyst got reduced back to 40/40mm now doctors said that the cyst should be reduced completely...but it didnt even aftr complete 6 cycles of chemotherapy for 2nd phase. can we conduct a operation now as even cancerous r no more. remove that cyst ? because that cyst might later develop back to cancerous as it happened last time doctors said that the neutral crst is ok in the human body, but I read in the internet that even a normal cyst shouldnt be kept inthe body not more than 8 weeks. so i feel doctors neglected at that point 7 yet kept the cyst in the body which now had turned back to cancerous. what can be the perfect solution now to treat?? plz..i need asnwer for this .. thanks