Utilization and outcomes of adjuvant systemic chemotherapy alone in high risk, early stage cervical cancer in the United States.

OBJECTIVE

To examine trends and outcomes related to adjuvant systemic chemotherapy alone for high risk, early stage cervical cancer.

METHODS

This retrospective observational study queried the National Cancer Institute's Surveillance, Epidemiology, and End Results Program from 2000 to 2016. Surgically treated women with American Joint Commission on Cancer stages T1-2 cervical cancer who had high risk factors (nodal metastasis and/or parametrial invasion) and received additional therapy were examined. Propensity score inverse probability of treatment weighting was used to assess the survival estimates for systemic chemotherapy versus external beam radiotherapy with chemotherapy.

RESULTS

Among 2462 patients with high risk factors, 185 (7.5%) received systemic chemotherapy without external beam radiotherapy, of which the utilization significantly increased over time in multivariable analysis (adjusted odds ratio per 1 year increment 1.06, 95% confidence interval (CI) 1.02 to 1.09). In weighted models, adjuvant chemotherapy and combination therapy (external beam radiotherapy and chemotherapy) had comparable overall survival among patients aged <40 years (hazard ratio (HR) 0.73, 95% CI 0.41 to 1.33), in adenocarcinoma or adenosquamous histologies (HR 0.90, 95% CI 0.62 to 1.32), and in those with nodal metastasis alone without parametrial tumor invasion (HR 1.17, 95% CI 0.84 to 1.62). In contrast, systemic chemotherapy alone was associated with increased all cause mortality compared with combination therapy in patients aged ≥40 years (HR 1.57, 95% CI 1.19 to 2.06), with squamous histology (HR 1.63, 95% CI 1.19 to 2.22), and with parametrial invasion alone (HR 1.87, 95% CI 1.09 to 3.20) or parametrial invasion with nodal metastasis (HR 1.64, 95% CI 1.06 to 2.52).

CONCLUSION

Utilization of adjuvant systemic chemotherapy alone for high risk, early stage cervical cancer is increasing in the United States in the recent years. Our study suggests that survival effects of adjuvant systemic chemotherapy may vary based on patient and tumor factors. External beam radiotherapy with chemotherapy remains the standard for high risk, early stage cervical cancer, and use of adjuvant systemic chemotherapy without external beam radiotherapy should be considered with caution.