Comparison of clinical outcomes of squamous cell carcinoma, adenocarcinoma, and adenosquamous carcinoma of the uterine cervix after definitive radiotherapy: a population-based analysis

Purpose To evaluate the clinical outcomes in patients with International Federation of Gynecology and Obstetrics (FIGO) stage I to IVA squamous cell carcinoma (SCC), adenocarcinoma (AC), and adenosquamous carcinoma (ASC) of the uterine cervix after definitive radiotherapy. Methods Patients with a primary diagnosis of FIGO stage I-IVA SCC, AC, and ASC of the uterine cervix who had undergone definitive beam radiation with implants or isotopes between 1988 and 2013 were identified using the Surveillance, Epidemiology, and End Results database. Univariate and multivariate Cox regression analyses were performed to analyze the effect of histologic subtype on cause-specific survival (CSS) and overall survival (OS). Results A total of 8751 were identified, and 86.0, 10.6, and 3.4 % of patients were SCC, AC, and ASC, respectively. AC patients were more often well differentiated, while more patients were poorly/undifferentiated in ASC subtype. A higher percentage of AC and ASC patients were stage I, and fewer had stage III compared to SCC. Univariate and multivariate Cox analyses showed that histologic subtype was an independent prognostic factor for CSS and OS. SCC subtype had a better CSS and OS compared to AC and ASC subtype. The survival between AC and ASC had no significant difference. The impact of the histologic subtype on CSS and OS was not affected by FIGO stage and the year of diagnosis. Conclusion AC and ASC subtypes are independent prognostic factors for cervical cancer patients treated with definitive radiotherapy. AC and ASC subtypes are associated with poor survival outcomes than those with SCC.