My wife was also referred and eventually diagnosed with stage 3C ovarian cancer back on 1st February 2024 and her treatment started 54 days later on the 26th March. The NHS has an obligation that the time between referral and start a treatment is 62 days. I remember the agonising wait that I did think that treatment had needed to start a lot sooner but the oncologists need to first identify the grade of cancer through a biopsy and where it has spread and then they can determine the type of treatment that she would need (it sounds like from my own wife's experience that it was contained within a peritoneal cavity although was a lesion on the liver which was larger than 2 centimeters). However, the oncology doctor had identified that the secondary cancers were all the same type and hence when the chemotherapy started that it would dissolve and inactivate all the identical masses and a few weeks delay would not change the end outcome. It had so turned out that my wife was given a lot more chemotherapy that she would have needed to compensate for not having debulking surgery but what she had in her treatment had significantly shrunk the Cancer before inactivating at the end of the treatment. If it is the high grade serous carcinoma which is the most common type of ovarian cancer then that does respond well to treatment. They should also monitor her CA125 levels where if they are above 35 will be able to use that to monitor her treatment and these should start to come down as soon as the treatment starts. My wife was given Paclitaxol and Carboplatin which were the two main chemotherapy drugs where the first one stops the cancer cells dividing and the second one alters the DNA to stop the cancer cells forming in the first place. She had her chemotherapy on a three-week cycle where she would have the Paclitaxol on a weekly basis but would have the Carboplatin every three weeks. She was also having an immunotherapy drug called Avastin (also known as Bevacizumab) where her oncology doctor had told her that this enhances the effect of the chemotherapy during treatment but also captures proteins release by the cancer cells to stop them forming new blood vessels that would otherwise feed the cancer. The desired effect of this was to allow the cancer cells to die off and she had continued with Avastin to effectively mop up any cancer cells that had been missed in the body from the chemotherapy. Although she had inactivated all the cancer, unfortunately despite being given years to live, she would have to undergo monitoring and possible further treatment for the rest of her life has the oncology doctor had indicated that what she had was incurable but remains treatable. Additionally in the post treatment era, she would remain on their system and they would be able to identify long before she would have any further symptoms should the Cancer come back and undergo further treatment if necessary. However, my wife has suffered significant mental health issues in recent months and this might be something that your mother may have to also address once the initial cancer treatment is complete.