Who does this research impact?

• People with suspected or diagnosed cancer of the ovary, the fallopian tube or the peritoneum.

How were the participants treated?

• This international study included 688 people with confirmed newly diagnosed cancer that spread to the abdomen and/or chest, FIGO stage IIIB, IIIC, IVA and IVB and who were not previously treated for this disease.
• Study participants were randomly assigned to receive either primary cytoreductive surgery followed by standard systemic therapy (345 participants) or three cycles of neoadjuvant chemotherapy, then interval cytoreductive surgery, followed by three additional cycles of chemotherapy (343 participants).
• All participants were treated with standard chemotherapy. This included carboplatin and paclitaxel. Bevacizumab and PARP-inhibitors were also given if indicated. The type of systemic therapy was selected by the doctor treating the patient.
• All participating study centers had to pass a rigorous qualification process, to allow for transparent and adequate surgical quality.
  This was a central part of the TRUST study.

What did the study find? What does this mean for patients right now?

• The study found that the timing of surgery, either prior to systemic therapy or after three cycles of neoadjuvant chemotherapy, did not make a big difference in survival, but surgery prior to chemotherapy delayed tumor regrowth and prolonged remission as compared to neoadjuvant chemotherapy.
• Especially for participants with cancer confined to the abdomen (FIGO stage III), a long term benefit was seen for primary surgery over interval surgery. After 5 years, 23% of the participants in the primary surgery group were still in remission, as compared to 11% in the interval surgery group.
• A benefit of surgery was mainly seen for participants where all visible tumor could be removed during the surgery. Primary surgery prolonged remission 6 months more than interval surgery, and participants lived an average of 1 year longer after primary surgery as compared to interval surgery. The result of surgery is however only known after it was performed, so this information is not known in each individual when making the decision to start primary surgery or neoadjuvant chemotherapy.
• Serious complications after surgery were generally low. Primary surgery took the surgeons about 1 hour longer than interval surgery (5 ½ hours compared to 4 ½ hours) and had slightly more complications.
• Quality of life of the participants did not differ between the two groups.
• The high rate of successful surgery, together with low complication rates and subsequent long survival in both treatment groups demonstrates also, that centralized patient care and surgery in centers with surgical quality assurance programs play an important role to survive cancer of the ovary, fallopian tube or peritoneum.