Weekly chemotherapy does not improve ovarian cancer survival compared to three-weekly chemotherapy

22 Sep 2020

Long-term follow-up results of the ICON8 trial have shown that having chemotherapy every week does not improve survival for women with ovarian cancer compared to having it once every three weeks, as has been standard for some years. These results were presented yesterday at the European Society of Medical Oncology Virtual Congress.

ICON8 was a large international trial looking at whether having smaller doses of chemotherapy more often could offer additional benefit for women with epithelial ovarian, fallopian tube, or primary peritoneal cancer. These women are usually treated with two chemotherapy drugs, which are given once every three weeks.

These latest results are in line with previous results from ICON8, which showed that weekly chemotherapy was no better at preventing the cancer returning or getting worse than having it every three weeks.

Women who agreed to take part in ICON8 were allocated at random to one of three groups:

  • Standard chemotherapy with the drugs carboplatin and paclitaxel, given once every three weeks, for a total of 18 weeks
  • Weekly chemotherapy, with carboplatin still given every three weeks, but with paclitaxel given once a week (at a lower dose), for a total of 18 weeks
  • Weekly chemotherapy, with both carboplatin and paclitaxel given once a week (at a lower dose), for a total of 18 weeks

The chemotherapy was given either after surgery, or for nine weeks before and nine weeks after surgery.

A total of 1566 women took part in the study, joining between June 2011 and November 2014. Most of the women were from the UK, but some women from South Korea, the Republic of Ireland, Mexico, Australia and New Zealand also took part. Women in the trial have now been followed up for at least 5 years.

On average, women in the trial lived for around four years from randomisation, with no evidence of a difference between the groups. This is more than a year longer than the forecasted average survival time when the trial was designed, probably reflecting general improvements in standards of care. Having smaller doses of chemotherapy weekly did not reduce side-effects compared to having bigger doses once every three weeks.

These results will not change the way that future patients are treated. But they help doctors to understand more about how chemotherapy should be given to women with ovarian cancer. This may help them find other, better ways to treat ovarian cancer in the future.

A follow-on trial is now running called ICON8B. ICON8B is looking at whether weekly chemotherapy is better than three-weekly chemotherapy for women who are receiving the drug bevacizumab (also known as Avastin) in addition to chemotherapy. ICON8B has now finished recruiting patients, and is following them up to see how they do. We expect to know the ICON8B results in 2023.

The ICON8 trial was funded by Cancer Research UK.

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