Comparison of Treatment Outcomes Between Squamous Cell Carcinoma and Adenocarcinoma of Cervix After Definitive Radiotherapy or Concurrent Chemoradiotherapy

Background: Concurrent chemoradiotherapy (CCRT) is effective in the treatment of locally advanced cervical squamous cell carcinoma (SCC). However, whether treatment outcomes of cervical adenocarcinoma are equivalent to SCC after CCRT has been a topic of debate.

Methods: Medical records of cervical cancer patients treated with definitive radiotherapy or CCRT in our institute from January 2011 to December 2014 were reviewed. Patients were treated with intensity modulated radiation therapy combined with intracavitary brachytherapy. Weekly cisplatin was the first line regimen of concurrent chemotherapy. The treatment outcomes of patients with SCC and adenocarcinoma were compared with a multivariate Cox regression model, and log-rank method before and after propensity score matching (1:1).

Results: A total of 815 patients with stage IB-IVA cervical cancer were included, with 744 patients in the SCC group and 71 patients in adenocarcinoma group. The median follow-up period was 36.2 months (range, 1.0-76.2 months). The 3-year overall survival (OS), disease-free survival (DFS), pelvic control and distant control rates of patients in the SCC group and adenocarcinoma group were 85.2 and 75.4% (p = 0.005), 77.5 and 57.3% (p < 0.001), 89.0 and 74.0% (p = 0.001) and 86.0 and 74.4% (p = 0.011), respectively. After multivariate analysis, histology was an independent factor of OS (p = 0.003), DFS (p < 0.001), pelvic control (p = 0.002) and distant control (p = 0.003). With propensity score matching, 71 pairs of patients were selected. After matching, the OS (p = 0.017), DFS (p = 0.001), pelvic control (p = 0.015) and distant control (p = 0.009) of patients with adenocarcinoma were poorer than those of patients with SCC. In subgroup analysis, patients with adenocarcinoma had significantly worse OS and DFS compared with patients with SCC, regardless of treatment with radiotherapy alone or CCRT.

Conclusion: The present study demonstrated that patients with adenocarcinoma of the cervix had poorer OS and DFS than patients with SCC, regardless of treatment with radiotherapy alone or CCRT. New treatment approaches should be considered for cervical adenocarcinoma.