Comparison of survival outcomes of locally advanced cervical cancer by histopathological types in the surveillance, epidemiology, and end results (SEER) database: a propensity score matching study

BACKGROUND: There has been limited research on the comparison of squamous cell carcinoma (SCC) and adenocarcinoma (AC) of cervical cancer and that lack of information may have significant bearing on the treatment of patients. We compared survival outcomes between squamous cell carcinoma and adenocarcinoma in locally advanced cervical cancer patients and examined factors related to the prognosis of cervical cancer. METHODS: We identified 4131 patients with stage IB2-IVA cervical cancer patients diagnosed between 2010 and 2015 by using the Surveillance, Epidemiology, and End Results (SEER) database. Variables related to the prognosis of cervical cancer were compared using both univariate and multivariate Cox models and log-rank method before and after propensity score matching. We compared the efficacy of radiotherapy alone to radiotherapy combined with chemotherapy or/and surgery in overall survival of SCC and AC. RESULTS: Our sample included 3385 patients with SCC (81.9%) and 746 patients with AC (18.1%). The 5-year overall survival on comparing the squamous cell carcinoma group and adenocarcinoma group was not significant (P > 0.05). Using propensity score matching, 676 pairs of patients were selected. The 5-year overall survival of matched patients did not differ significantly (P > 0.05). Histology was not independently associated with overall survival in multivariate Cox model (P > 0.05). Factors affecting overall survival included FIGO stage IVA (P < 0.05), chemotherapy (P < 0.05), and external radiation combined with brachytherapy (P < 0.05). Patients with SCC that were treated with radiation alone had significantly worse OS than AC patients receiving radiation only (P < 0.05). CONCLUSIONS: The OS in AC of the cervix is similar to that SCC in when treated with radiotherapy combined with chemotherapy and/or surgery but better when treated with radiation alone.