The prognostic significance of histology and treatment modality in stage IB1 squamous cell carcinoma, adenocarcinoma, and adenosquamous cell carcinoma of the uterine cervix: SEER study 2004–2008

Objective: To determine the significance of histology and treatment modality on overall survival and cause-specific survival in stage IB1 cervical carcinoma. Methods: Cases of stage IB1 squamous cell carcinoma, adenocarcinoma, and adenosquamous cell carcinoma of the uterine cervix managed with either radical hysterectomy, definitive radiation therapy which may include external beam radiation therapy and/or vaginal brachytherapy, or total abdominal hysterectomy with adjuvant radiation therapy which may include external beam radiation therapy plus/minus vaginal brachytherapy were abstracted from the SEER database (2004–2008). Cause-specific survival was calculated using Kaplan–Meier, log-rank, and multivariable Cox regression analyses. Results: Five-year cause-specific survival for squamous cell carcinoma, adenocarcinoma, and adenosquamous cell carcinoma were 94.4%, 97.3%, and 85.7%, respectively (p = 0.001 by log-rank test). On multivariable Cox regression analysis, patients with squamous cell carcinoma were not more likely to die of cervical cancer than patients with adenocarcinoma (hazard ratio = 1.12, 95% confidence interval = 0.53–2.39); but patients with adenosquamous cell carcinoma were more likely to die of cervical cancer than patients with adenocarcinoma (hazard ratio = 3.65, 95% confidence interval = 1.41–9.44). Five-year cause-specific survival was 96.9%, 80.0%, and 92.4% for patients receiving radical hysterectomy, definitive radiation therapy, and total abdominal hysterectomy plus radiation therapy, respectively (p < 0.0001 by log-rank test). On multivariable Cox regression analysis, patients who received definitive radiation therapy and patients who received total abdominal hysterectomy plus radiation therapy were more likely to die of cervical cancer than patients who received radical hysterectomy. Conclusion: In patients with stage IB1 cervical cancer, on multivariable Cox regression analysis, patients with squamous cell carcinoma were not more likely to die of cervical cancer than patients with adenocarcinoma; patients with adenosquamous cell carcinoma were more likely to die of cervical cancer than patients with adenocarcinoma. Patients who received either definitive radiation therapy or total abdominal hysterectomy plus radiation therapy were more likely to die of cervical cancer than patients who received radical hysterectomy