International OUTBACK trial results released

04 Jun 2021

The international OUTBACK study is a phase III clinical trial focused on the treatment of cervical cancer, led by ANZGOG and the NHMRC Clinical Trials Centre at the University of Sydney.

The full trial results will be presented at the 2021 American Society of Clinical Oncology (ASCO) Annual Meeting.

OUTBACK was conducted with the purpose of finding ways to improve standard of chemoradiation, its effects on patients, and explore alternative ways to improve survival rates for women with cervical cancer. 

Currently, the standard treatment for locally advanced cervical cancer is chemoradiation over a 6 to 8 week period. Unfortunately, this form of treatment is resulting in 1 in 3 women dying after developing distant metastatic disease. This observation is where the OUTBACK study originated.

The study involved a total of 926 women from seven countries, and aimed to show whether the addition of adjuvant chemotherapy after chemoradiation could improve survival.

OUTBACK is an academic collaboration of the Australia New Zealand Gynaecological Oncology Group (ANZGOG), NHMRC Clinical Trials Centre at the University of Sydney, and NRG Oncology under the auspices of the international Gynecologic Cancer Intergroup (GCIG).

After much anticipation, the trial results have been finalised.

“The OUTBACK results confirm that chemoradiation alone is currently our best standard treatment for women with locally advanced cervical cancer. The addition of adjuvant chemotherapy did not improve 5-year survival rates, but it did add significant side effects" Principle Investigator of the trial, Professor Linda Mileshkin

Some oncologists have begun administering adjuvant chemotherapy in lieu of the trial results being released, Professor Mileshkin has advised that this practice should now stop.

This study, whilst unfortunately not a positive result for women, is 'immediately practice-changing' and will help to improve future treatment for women with cervical cancer.

“This trial provides clear evidence that the addition of chemotherapy after chemoradiation does not extend survival. The results are immediately practice-changing, showing that this approach should not be used to treat locally advanced cervical cancer. We can now spare our patients the side effects and toxicity that comes with additional chemotherapy said ASCO President Lori J. Pierce, MD, FASTRO, FASCO.

OUTBACK produced significant trial findings, which is why it was selected to be presented at the 2021 ASCO Plenary Session, arguably the premiere session of ASCO. ASCO is the world’s leading organisation of its kind, representing more than 45,000 oncology professionals who care for people living with cancer. ASCO works to conquer cancer through research and education, and promotes the highest quality of patient care.

“OUTBACK has been a fantastic effort from investigators and trial units around the world. This global effort has culminated in a high-quality, rigorously-conducted clinical trial, producing robust results that answer an important question for women with cervical cancer. Great credit is due to Principal Investigator Professor Linda Mileshkin for her pivotal role together with ANZGOG and our collaborators in generating these important results. Our heartfelt thanks go to the women, and their families, who participated in this trial, enabling us to move forward and test new ideas to improve the outcomes of women affected by cervical cancer” Associate Professor Philip Beale, Chair of ANZGOG

To find out more about ANZGOG's clinical trials, click here.