Oncologic outcomes according to the level of disease burden in patients with metachronous distant metastases from uterine cervical cancer: a Korean Radiation Oncology Group study (KROG 18-10)

Objective: This study aimed to evaluate the oncologic outcomes according to disease burden in uterine cervical cancer patients with metachronous distant metastases. Methods: Between 2005 and 2015, 163 patients with metachronous distant metastases from uterine cervical cancer after receiving a definitive therapy were evaluated at seven institutions in Korea. Low metastatic burden was defined as less than 5 metastatic sites, whereas high metastatic burden was others. Each metastasis site was divided based on the lymph node (LN) and organs affected. The overall survival (OS) and progression-free survival (PFS) were assessed. Cox proportional hazards models, including other clinical variables, were used to evaluate the survival outcomes. Results: The median follow-up duration was 22.2 months (range: 0.3-174.8 months). Para aortic LNs (56.4%), lungs (26.4%), supraclavicular LNs (18.4%), and peritoneum (13.5%) were found to be the common metastasis sites. Among 37 patients with a single metastasis, 17 (45.9%) had LN metastases and 20 (54.1%) had organ metastases. The 1-and 2-year OS rates were 73.9% and 55.0%, respectively, whereas the PFS rates were 67.2% and 42.9%, respectively. SCC Ag after recurrence and high metastatic burden were significant factors affecting the OS (p=0.004 and p<0.001, respectively). Distant organ recurrence, short disease-free interval (<= 2 years), and high metastatic burden were unfavorable factors for PFS (p=0.003, p=0.011, and p=0.002, respectively). Conclusion: A favorable oncologic outcome can be expected by performing salvage treatments in selected patients with a long disease-free interval, low metastatic burden, and/ or lymphatic-only metastasis.