A phase III trial of adjuvant chemotherapy following chemoradiation as primary treatment for locally advanced cervical cancer compared to chemoradiation alone: The OUTBACK TRIAL.

TPS5116 Background: Cervical cancer is a global health problem and the most common cause of cancer-related death among women in developing nations. Despite the recently developed cervical cancer vaccine, many women will continue to die from cervical cancer for many decades unless existing treatments can be improved. Unscreened women often present with locally-advanced disease that has a 5 year overall survival (OS) rate of 60% or less following standard chemo-radiation. Although some evidence suggests that adjuvant chemotherapy following chemo-radiation may be of value, its role remains controversial. Methods: OUTBACK is a randomized phase III Gynecologic Cancer InterGroup (GCIG) trial designed and led by the Australia New Zealand Gynaecological Oncology Group (ANZGOG) in collaboration with the NHMRC Clinical Trials Centre. Participating countries (groups) include Australia and New Zealand (ANZGOG), India, the USA and Canada (GOG, RTOG). OUTBACK is suitable for women with locally advanced cervical cancer (FIGO stage IB 1 and node positive, IB 2 , II, IIIB or IVA). The primary objective is to determine if the addition of adjuvant chemotherapy to standard cisplatin-based chemo-radiation improves OS. Women are randomized to either A) standard cisplatin-based chemo-radiation or B) standard cisplatin-based chemo-radiation followed by 4 cycles of carboplatin and paclitaxel chemotherapy. Secondary objectives are to compare progression-free survival, treatment-related toxicity, patterns of disease recurrence, quality of life and psycho-sexual health, and the association between radiation protocol compliance and outcomes. Blood and tumour samples are collected from consenting patients for future translational studies. 780 women will be enrolled to determine if the addition of adjuvant chemotherapy can improve the 5-year OS rate by ≥ 10%. OUTBACK opened in Australia and New Zealand in 2011. In early 2012 the trial opened in the USA and activation of GOG sites is ongoing. 15 patients have been randomized. It is expected that RTOG and India will open the trial later this year with recruitment increasing substantially once all sites are activated.