Impact of Adoption of Chemoradiotherapy on the Outcome of Cervical Cancer in Ontario: Results of a Population-Based Cohort Study

Abstract

Purpose To describe the adoption of concurrent cisplatin-based chemoradiotherapy (C-CRT), and to evaluate its impact on the outcome of cervical cancer in Ontario. Methods We used a population-based cancer registry to identify the 4,069 patients with invasive carcinoma of the cervix diagnosed in Ontario between 1992 and 2001. We linked electronic records of treatment to the registry. We described time trends in the use of C-CRT, and we compared survival before and after widespread adoption of C-CRT. Results Over the study period, the proportion of patients treated with primary radical radiotherapy (RT) remained constant at approximately 42%. Between 1992 and 1998, less than 10% of RT cases received chemotherapy. Early in 1999, there was rapid adoption of C-CRT. Between 1999 and 2001, more than 60% of RT cases received C-CRT. There was a contemporaneous increase in overall 3-year survival from 71.1% in the 1995 to 1998 cohort to 75.9% in the 1999 to 2001 cohort (P = .03). There was no change in survival in patients treated with surgery alone. However, there was a significant increase in 3-year survival from 58.6% in the 1995 to 1998 cohort to 69.8% in the 1999 to 2001 cohort (P < .01) in the subpopulation of patients treated with primary RT ± chemotherapy. Conclusion The adoption of C-CRT was associated with a significant improvement in overall survival of cervical cancer at the population level. The magnitude of the benefit of C-CRT in the general population was consistent with the results of the relevant clinical trials.