2021 ASCO OUTBACK study: locally advanced cervical cancer adjuvant chemotherapy does not benefit

The 2021 American Society of Clinical Oncology (ASCO) annual meeting will be held online from June 4th to 8th.
As one of the largest and most popular events in oncology, the ASCO annual meeting will show scholars from all walks of life the latest cutting-edge progress
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In the Plenary Session, OUTBACK research was released
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The results show that adding adjuvant chemotherapy to standard radiotherapy and chemotherapy cannot improve the survival outcome of patients with locally advanced cervical cancer, and the incidence of adverse events is higher
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Research background Concurrent radiotherapy and chemotherapy (CTRT) is the standard treatment for locally advanced cervical cancer
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However, a large proportion of patients will still experience recurrence or metastasis
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The purpose of the OUTBACK study is to clarify the impact of adjuvant chemotherapy after radiotherapy and chemotherapy on survival
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Research method The Phase III OUTBACK study initiated by the United States Gynecological Oncology Group (GOG) aims to evaluate whether 4 cycles of carboplatin combined with paclitaxel chemotherapy after concurrent radiotherapy and chemotherapy can improve the survival of cervical cancer patients compared with radiotherapy and chemotherapy alone
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The enrolled patients were patients with locally advanced cervical cancer (FIGO 2008 IB1 stage & lymph node positive, IB2, II, IIIB or IVA)
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After stratifying lymph node status, participating location, FIGO stage, age, and planned expanded field radiotherapy, the patients were randomly assigned to the standard cisplatin radiotherapy and chemotherapy group (control) or standard cisplatin radiotherapy and chemotherapy + carboplatin/paclitaxel adjuvant chemotherapy (ACT) 4 cycle groups
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The primary endpoint is the 5-year overall survival rate (OS)
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Secondary endpoints include progression-free survival (PFS), adverse events (AE), and disease recurrence patterns
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Results of the study From April 2011 to June 2017, a total of 926 patients were recruited.
919 patients met the enrollment conditions and were included in the preliminary analysis: 463 patients in the ACT group and 456 patients in the control group
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In the ACT group, 361 cases (78%) received ACT treatment with a median follow-up time of 60 months (IQR 45-65 months)
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The 5-year OS rate between the ACT group and the control group was similar (72% and 71%, difference <1%, 95% CI -6% ~ +7%, P = 0.
91), and the OS risk ratio was 0.
91 (95% CI 0.
70 ~ 1.
18)
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The 5-year PFS rate was similar (63% and 61%, 2% difference, 95% CI -5% ~ +9%, P = 0.
61), and the PFS risk ratio was 0.
87 (95% CI 0.
70 ~ 1.
08)
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Within 1 year after randomization, 81% of patients treated with ACT in the ACT group had grade 3 to 5 AEs, compared to 62% in the control group
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After randomization for more than 1 year, there is no evidence that there is a difference in AE between the two groups
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The disease recurrence patterns of the two groups of patients were similar
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Research conclusions: Patients with locally advanced cervical cancer receiving adjuvant chemotherapy after standard cisplatin radiotherapy and chemotherapy cannot improve OS or PFS
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References: Linda R.
Mileshkin, et al.
Adjuvant chemotherapy following chemoradiation as primary treatment for locally advanced cervical cancer compared to chemoradiation alone: ​​The randomized phase III OUTBACK Trial (ANZGOG 0902, RTOG 1174, NRG 0274).
ASCO Annual Meeting 2021.
Abstract LBA3.