Prognostic factors and the role of locoregional treatment in patients with distantly metastatic hypopharyngeal cancer: a retrospective cohort study based on SEER database

Background: There is increasing evidence that locoregional treatment (LRT, surgery or/and radiotherapy) for the primary tumor can improve survival in some cancers with systemic dissemination. This study aimed to investigate the survival benefit of LRT and prognostic factors in patients with hypopharyngeal cancer with distant metastasis. Methods: A retrospective population-based analysis was performed using the Surveillance, Epidemiology, and End Results database. Cox regression analysis was used to account for the imbalance of baseline covariates. The Kaplan-Meier method, log-rank test, and competing risk analysis were used to compare survival outcomes between treatment patterns. Results: Four hundred and sixty-three eligible patients were included in the analysis with a median overall survival of 7 months. LRT plus systemic therapy was the most common treatment modality (47%) and was associated with the most prolonged survival compared with other treatment methods (log-rank test, P<0.001). In multivariate analysis, bone metastasis, liver metastasis, and treatment were identified as independent prognostic factors for survival. Patients receiving LRT and systemic therapy had a 35% reduced risk of death compared with patients receiving systemic therapy (HR = 0.65, 95% CI: 0.39-0.92, P=0.028). Further subgroup analysis and competing risk analysis also confirmed this survival trend favoring LRT and systemic therapy. Interestingly, interaction analysis revealed that only age variable affected the treatment effect and younger patients (<65 years) were more likely to benefit from LRT plus systemic therapy. Conclusions: Our results suggest that bone metastasis, liver metastasis, and treatment were prognostic factors for the survival of patients with metastatic hypopharyngeal cancer. Patients with distant metastasis are often treated with systemic therapy for a palliative intention. In our work, LRT plus systemic therapy was associated with improved survival compared with systemic therapy alone in selected patients. Particularly, patients younger than 65 years may be the potential subpopulation that can benefit from LRT with improved survival.