235P - The efficacy of radiation therapy in ovarian carcinoma: A propensity score analysis of a population-based study

Background

Radiation therapy (RT) is not a standard treatment for ovarian cancer (OC). However, it can be used as an adjunctive therapy to control the local recurrent disease. We aimed to investigate whether OC patients could benefit from RT.

Methods

From 2004 to 2013, the incidence, survival, treatment, and end results data from the SEER were analyzed for cases diagnosed with OC. We examined cause-specific survival (CSS) and overall survival (OS) with 95% confidence intervals (CIs) to estimate the effect of RT from multivariate Cox regression analysis. Performed propensity score matching (PSM) method was used for OC patients who received radiotherapy versus those who did not.

Results

A total of 11140 cases were enrolled for analysis. The aggregated HR of univariate survival analysis suggested that radiotherapy had unfavorable effects on overall survival (HR 1.315, 95% CI 0.994–1.739, P = 0.055) and cancer-specific survival (HR 1.732, 95% CI 1.285–2.334, P < 0.001), but there is no significant difference in multivariate analysis (OS HR 1.315, 95% CI 0.994–1.739, P = 0.055; CSS HR 1.222, 95% CI 0.905–1.651, P = 0.191). After PSM by 1:4, 655 patients were included. Both of the effect of radiotherapy in overall survival (HR 1.341, 95% CI 0.977–1.84, P = 0.070) and cancer-specific survival (HR 1.309, 95% CI 0.931–1.838, P = 0.121) were not significant ever in univariate analysis. Multivariate analysis also found the same results (OS HR 1.232, 95% CI 0.894–1.699, P = 0.202; CSS HR 1.187, 95% CI 0.841–1.674, P = 0.330). Radiotherapy seems to have a reverse effect in regionally spread patients in stage II patients (before PMS HR 3.154, 95% CI 1.709-5.821, p < 0.01; after PMS HR = 3.543, 95% CI 1.603-7.834, p < 0.01) and non-epithelial OC patients (before PMS HR 1.748, 95% CI 1.219-2.507, p = 0.002; after PMS HR = 1.5422, 95% CI 1.021-2.329, p = 0.04).

Conclusions

In OC patients, RT does not have a proven benefit on CSS and OS overall, and it is especially not suitable for early-stage patients and non-epithelial OC patients. However, further confirmation is needed from well-designed and large-scale RCTs in the future to identify its effect in certain types of epithelial OC patients after the developed techniques.

Clinical trial identification

Editorial acknowledgement

Legal entity responsible for the study

The authors.

Funding

Has not received any funding.

Disclosure

All authors have declared no conflicts of interest.