Weekly chemotherapy no better than 3-weekly chemotherapy for women with ovarian cancer

08 Sep 2017

The results of the ICON8 trial show that for women with ovarian cancer, fallopian tube cancer or primary peritoneal cancer, having chemotherapy weekly is no better than having chemotherapy once every three weeks. These results were presented earlier today at the European Society for Medical Oncology annual meeting in Madrid.

Ovarian cancer, fallopian tube cancer and primary peritoneal cancer are usually treated with both surgery and chemotherapy. The chemotherapy used is normally a combination of two drugs; carboplatin and paclitaxel (also known as Taxol) are given together once every 3 weeks, for 6 cycles. Research carried out in Japan had suggested that having a lower dose of the paclitaxel chemotherapy more frequently (once a week), rather than a higher single dose once every three weeks, might increase how long women with these cancers live, but also increase side-effects. ICON8 tested whether once-weekly chemotherapy would lead to the same improvement in ovarian cancer treatment for women from outside of Japan that had been seen previously in Japanese women.

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

  • Standard chemotherapy with carboplatin and paclitaxel once every three weeks, for a total of 18 weeks
  • Weekly chemotherapy with carboplatin given once every three weeks and paclitaxel 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 took place either after surgery, or was given for nine weeks (three cycles) before and nine weeks after surgery.

The trial recruited 1,566 women between 2011 and 2014. These women were followed up for an average of 35 months. The trial found no difference between the three groups in how long it took for the disease to get worse. There did seem to be more side-effects among the women who had weekly chemotherapy. However, these side-effects were mostly a temporary reduction in the numbers of a type of white blood cell, found via blood tests, rather than clinical symptoms.

These results suggest that there is no benefit to weekly chemotherapy for these women in terms of delaying the disease getting worse. The researchers are continuing to follow-up these women to see if there is any difference in how long women in any of these groups live.

Dr Andrew Clamp, the Chief Investigator of the trial, from the Christie NHS Foundation Trust and the University of Manchester, said "The results clearly demonstrate that, although well-tolerated, using weekly scheduling as part of the first-line treatment of ovarian cancer does not delay the disease getting worse. Therefore, this approach cannot be recommended as a standard-of-care treatment option for this population [non-Japanese women with ovarian cancer]."

The ICON8 trial was carried out in hospitals around the UK, and in South Korea, Republic of Ireland, Mexico and Australia. The trial was funded by Cancer Research UK.

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