OUTBACK results confirm that chemoradiation alone is currently the 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. The results are immediately practice-changing, showing that this approach should not be used to treat locally advanced cervical cancer. 



OUTBACK originated from observations that while standard chemoradiation for women with cervical cancer was working well to cure many, 1 in 3 women died due to later developing distant metastatic disease. The trial aimed to show whether the addition of adjuvant chemotherapy after chemoradiation could improve survival. 


OUTBACK is a phase 3 trial of adjuvant chemotherapy following chemoradiation as primary treatment for locally advanced cervical cancer compared with chemoradiation alone (ANZGOG 0902, RTOG 1174, NRG 0274).  OUTBACK is an international trial led by ANZGOG and the NHMRC Clinical Trials Centre at the University of Sydney. OUTBACK included 926 women from the USA, Australia, New Zealand, Canada, China, Singapore, and Saudi Arabia. The trial had financial support in Australia and New Zealand from the NHMRC Project Grant (APP1044349) and through the National Cancer Institute for the US sites. Hospira provided paclitaxel in Australia and New Zealand. 


The phase 3 OUTBACK trial showed that the addition of adjuvant chemotherapy following chemoradiation did not improve survival compared to standard chemoradiation alone in women with locally advanced cervical cancer. At 5 years, overall survival was similar in the two treatment groups — 72% among those assigned adjuvant chemotherapy after chemoradiation versus 71% among those assigned standard chemoradiation alone. Rates of progression-free survival at 5 years were also similar (63% versus 61%, respectively). Patterns of disease recurrence were also similar in the two treatment groups. Severe side effects (grades 3-4) within a year of randomisation were experienced by more women assigned adjuvant chemotherapy than standard chemoradiation alone (81% versus 62%). The trial also found that only 77% of women in each arm successfully completed all components of standard chemoradiation (including external beam radiotherapy, brachytherapy, and concurrent weekly chemotherapy with cisplatin). 


Conceived, designed, and conducted in collaboration with ANZGOG, the NHMRC Clinical Trials Centre team was able to attract independent funding and successfully complete an investigator-initiated trial recruiting over 900 participants from more than 160 sites in 7 countries.

OUTBACK incorporated patient-reported outcomes, translational research, and innovative statistical methods to focus on important long-term outcomes and better inform clinical practice and future research. 


2011 - 2022


Australia New Zealand Gynaecological Oncology Group (ANZGOG), Gynecologic Cancer Intergroup (GCIG), NRG Oncology


926 women from 7 countries, +160 sites 

  • ANZ – 168  
  • USA – 715  
  • CANADA – 28  
  • CHINA – 9  
  • SINGAPORE – 1   


OUTBACK Trial Among the Most Important Cervical Cancer Research Advances in the Past Year, ANZGOG press release 3 June 2021

OUTBACK study published by the Journal of Clinical Oncology

ASCO Daily News OUTBACK article