ASCO 2016

Intraperitoneal chemotherapy slows ovarian cancer progression

Dr Helen Mackay - Sunnybrook Research Institute, Toronto, Canada

I’m presenting a gynaecologic cancer inter-group study that was led by the Canadian cancer clinical trials group. The study is OV21/PETROC which is a pragmatic trial that looked at whether intraperitoneal chemotherapy benefitted women with epithelial ovarian cancer who had undergone neoadjuvant chemotherapy followed by an optimal cytoreductive surgical effort.

What kind of results did you see from this trial?

The primary endpoint of this clinical trial was the progressive disease rate at nine months following randomisation. 42.2% of patients in the intravenous arm had disease progression at that time, for the intraperitoneal arm with intraperitoneal carboplatin there was a 23.3% progressive disease rate, representing an 18.9% reduction in progression at that time point.

Those are pretty significant results.

Those are statistically significant, yes. The first stage of the clinical trial was designed to determine which of two experimental intraperitoneal chemotherapy regimens would move into a direct comparison with the standard of care intravenous treatment. In the first stage an intraperitoneal chemotherapy regimen containing carboplatin was selected to move forward over the more toxic intraperitoneal cisplatin containing regimen. The comparison between the intravenous chemotherapy and the intraperitoneal carboplatin containing regimen had as an endpoint progressive disease rate at nine months following randomisation. The progressive disease rate for the intravenous treatment was 43.3% and for the intraperitoneal carboplatin containing regimen 23.3%, an 18.9% reduction in progressive disease for the women who received intraperitoneal treatment.

Just a little bit of background – can you tell us about the patients concerned, how were they selected?

These women at the time of diagnosis had either clinical stage 2 or clinical stage 3 disease. Patients with stage 4 who had pleural effusions were also included. They underwent three, maximum four, cycles of neoadjuvant intravenous chemotherapy and then underwent optimal cytoreductive surgery. There was intraoperative randomisation of these patients, so if they previously consented to the study, and for those who were optimally cytoreduced at the time of surgery they could be randomised following the surgical procedure with an intraperitoneal catheter inserted by interventional radiology.

You mentioned that this was showing a significant reduction of cancer development. The c word is always on everyone’s mind and this seems like a significant step towards if not a cure then at least slowing down disease progression whilst other treatments are doing their thing.

This data adds to the literature on up front patients who undergo intraperitoneal chemotherapy and the benefits. It provides a treatment option for women who have undergone neoadjuvant chemotherapy. What we hope in the future is to be able to identify a predictive signature based on the biology of the cancer and we have collected tissue samples from women who participated in this study and we hope to have that data available at a later date.