The results of the OUTBACK trial, a landmark multinational phase 3 trial investigating the efficacy of adjuvant chemotherapy in women with locally advanced cervical cancer, have been published in The Lancet Oncology 

The trial aimed to evaluate whether the addition of adjuvant chemotherapy following chemoradiation could improve survival compared to standard chemoradiation alone and recruited 926 women from 157 hospitals across seven countries, including the USA, Australia, New Zealand, Canada, China, Singapore, and Saudi Arabia.   

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Principal Investigator of the trial, Professor Linda Mileshkin, Director of Medical Oncology at Peter MacCallum Cancer Centre, said, “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. Although some oncologists have been giving adjuvant chemotherapy outside of trials while awaiting the results of OUTBACK, this practice should now stop. We need to find ways to improve the tolerability and completion of standard chemoradiation, as well as investigate other ways to improve survival rates for this group of women.”

Background of OUTBACK

Cervical cancer is one of the leading causes of cancer-related death in women worldwide, especially in areas without cervical screening programs. The standard treatment for locally advanced cervical cancer involves chemoradiation, however, several women with locally advanced cervical cancer experience a relapse and subsequently die from distant metastatic disease.

Carboplatin and paclitaxel chemotherapy, has been successfully used for treating metastatic or relapsed cervical cancer. The OUTBACK trial was a response to this clinical reality and aimed to determine the benefits of this treatment for women with locally advanced cervical cancer.

The study’s findings were immediately practice-changing internationally, answering an important question for patients with cervical cancer worldwide.


  • The key findings of the study revealed that adjuvant chemotherapy did not improve survival compared to standard chemoradiation alone in women with locally advanced cervical cancer.
  • The overall survival rates at 5 years were similar in both groups, with 72% of those assigned adjuvant chemotherapy versus 71% of those assigned standard chemoradiation alone. The rates of progression-free survival were also similar, with 63% versus 61% respectively. However, a higher percentage of women experienced severe side effects (grades 3-4) within a year of randomisation in the adjuvant chemotherapy group (81%) than in the standard chemoradiation group (62%).
  • Furthermore, the study highlighted that only 77% of women in each arm of the trial successfully completed all components of standard chemoradiation, including external beam radiotherapy, brachytherapy, and concurrent weekly chemotherapy with cisplatin.


ANZGOG carried out the OUTBACK trial in collaboration with the NHMRC Clinical Trials Centre at the University of Sydney and NRG Oncology under the sponsorship of the international Gynaecologic Cancer Intergroup (GCIG).

ANZGOG’s purpose is to improve the outcomes and quality of life for women with gynaecological cancers through conducting and promoting cooperative clinical trials and undertaking multidisciplinary research into causes, prevention and treatments of gynaecological cancer.

Learn more about ANZGOG’s trials