Ovarian cancer recurrence, multiple abdominal metastases, allergic to carboplatin, resistant to cisplatin, ineffective with olaparib, niraparib, and bevacizumab, what to do?

I. Brief Introduction of the Condition#

Female, 76 years old, discovered a large pelvic mass 6 years ago, sought medical attention for abdominal distension.
Pathological puncture confirmed ovarian cancer with multiple peritoneal metastases and a large amount of ascites.

Not suitable for surgery at the moment, chemotherapy was initiated first.
Carboplatin and paclitaxel-based chemotherapy for 5 cycles, each cycle lasting 21 days.
After chemotherapy, single-agent olaparib was taken orally twice a day for maintenance over 5 years.
During this period, CA125 was tested monthly, and enhanced CT scans were conducted every six months.

CT in April 2024 indicated recurrence, with abnormal elevation of CA125.
Continued with carboplatin, paclitaxel, and bevacizumab for 4 cycles of chemotherapy.
In the 5th cycle, there was an allergy to carboplatin, leading to a pause in carboplatin chemotherapy (this is a hidden danger).
In the 6th and 7th cycles, although carboplatin was replaced with cisplatin for continued chemotherapy, CA125 continued to rise.
Chemotherapy ended in August 2024, continued oral olaparib, but CA125 still kept rising.
On New Year's Day 2025, olaparib was stopped, and an attempt was made to maintain with oral letrozole.
In April 2025, an attempt was made to add niraparib for maintenance, with CA125 exceeding 1000.

General physical condition is average, RBC 3.0, HB 97, PLT 104.
Recently experienced irregular lower gastrointestinal bleeding, with a significant amount on May 24.
Economic condition is average; what treatment plan should be used next?
Is intraperitoneal hyperthermic perfusion therapy possible?
If hyperthermic perfusion is possible, will cisplatin be ineffective like in the 6th and 7th cycles of chemotherapy?
Seeking guidance from industry experts.