Impact on survival with adjuvant radiotherapy for clear cell, mucinous, and endometriod ovarian cancer: the SEER experience from 2004 to 2011

Objective: Evaluate the impact of radiotherapy on cause specific survival (CSS) and overall survival (OS) for stage (I-III) clear cell, mucinous, and endometriod ovarian cancer. Methods: We analyzed incidence, survival, and treatments from the Surveillance, Epidemiology, and End Results (SEER) Program from 2004 to 2011 for clear cell, mucinous, and endometriod histologies of the ovary for stages (I-III). We examined CSS and OS for all three histologies combined and each histology with relation to the use of adjuvant radiation therapy (RT). Survival analysis was calculated by Kaplan-Meier and log-rank analysis. Results: CSS was higher in individuals not receiving RT at 5 years (81% vs. 74%) and 10 years (74% vs. 65%, p=0.003). OS was higher in individuals not receiving RT at 5 years (76% vs. 73%) and 10 years (64% vs. 59%, p=0.039). Stage III patients receiving RT had a higher OS at 5 years (54% vs. 44%) and 10 year intervals (36% vs. 30%, p=0.037). Stage III patients with mucinous histology receiving RT had a higher OS at 5 years (50% vs. 36%) and 10 years (45% vs. 26%, p=0.052). Conclusion: Those receiving RT had a lower CSS and OS at 5 and 10 years. However, subgroup analysis revealed a benefit of RT in terms of OS for all stage III patients and for stage III patients with mucinous histology.