Adjuvant chemotherapy does not improve outcome in patients with locally advanced cervical cancer

The phase 3 OUTBACK trial results do not support the use of adjuvant chemotherapy after chemoradiation in women with locally advanced cervical cancer.

The use of adjuvant chemotherapy with carboplatin and paclitaxel is not supported by results

Results of the randomised, phase 3 OUTBACK trial do not support the use of adjuvant chemotherapy after chemoradiation in women with locally advanced cervical cancer. At 5 years, both overall and progression-free survival were similar in the respective treatment arms.

Standard treatment for locally advanced disease is chemoradiation. However, a significant percentage of women still relapse and die from the development of distant metastatic disease1. A randomised trial suggested additional benefit from the use of concurrent cisplatin-gemcitabine and radiation followed by 2 cycles of cisplatin-gemcitabine2.

The randomised, phase 3 OUTBACK trial (ACTRN12610000732088) was designed to determine the effects of giving adjuvant chemotherapy after chemoradiation on survival. Eligible women had locally advanced cervical cancer (FIGO 2008 stage IB1 and node positive, IB2, II, IIIB or IVA) that was suitable for primary treatment with chemoradiation with curative intent. A total of 919 women were randomised 1:1 to either standard cisplatin-based chemoradiation (control) or standard cisplatin-based chemoradiation followed by adjuvant chemotherapy with 4 cycles of carboplatin and paclitaxel.

No evidence of differences in adverse events between treatment groups

Adjuvant chemotherapy was started in 361 (78%) women assigned to receive it. Median follow-up was 60 months. The primary endpoint was overall survival at 5 years. Secondary endpoints included progression-free survival, adverse events, and patterns of disease recurrence.

Prof. Linda Mileshkin (Peter McCallum Cancer Center, Australia) presented the results3. Overall survival at 5 years was similar in both arms: 71% versus 72%. Progression-free survival was also similar: 63% versus 61%. Adverse events of grade 3-5 within a year of randomisation occurred in 81% who were assigned and received adjuvant chemotherapy versus 62% assigned control. There was no evidence of differences between treatment groups in adverse events beyond 1 year of randomisation. Global Health Quality of Life Scores were worse during adjuvant therapy and 3 to 6 months thereafter, but similar from months 12 to 36. Prof. Mileshkin concluded that these findings do not support the use of adjuvant chemotherapy with carboplatin and paclitaxel after chemoradiation with weekly cisplatin.

Sources:
1. Narayan K, et al. Int J Gynecol Cancer. 2009; 19(5): 912-918.
2. Dueñas-González A, et al. J Clin Oncol 2011; 29: 1678–1685.
3. Mileshkin LR, 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 2021 Virtual Meeting, abstract LBA3.