(2015) Impact on Survival With Adjuvant Radiation Therapy for Clear Cell, Mucinous, and Endometriod Ovarian Cancer (SEER)

Blogger's Note:  this abstract does not indicate what form of RT (eg. targeted/WAR); it also does not discuss longterm side effects/complications/adverse effects (eg. vs OS)

abstract:
Impact on Survival With Adjuvant Radiation Therapy for Clear Cell, Mucinous, and Endometriod Ovarian Cancer: The SEER Experience From 2004 to 2011 - International Journal of Radiation Oncology • Biology • Physics
 

Purpose/Objective(s)

To evaluate the impact of radiation therapy (RT) on cause-specific and overall survival for stage I-III clear cell, mucinous, and endometrial ovarian cancer.

Materials/Methods

We analyzed incidence, survival, and treatment data from the Surveillance, Epidemiology, and End Results (SEER) Program from 2004 to 2011 for clear cell, mucinous, and endometrial histologies of the ovary for stages I-III. We examined cause-specific survival (CSS) and overall survival (OS) for all 3 histologies combined and for each histology with relation to the use of adjuvant RT. Survival analysis was calculated by Kaplan-Meier and log-rank analysis.

Results

There was a total of 13,313 cases of which 13,024 received no RT and 289 received RT. CSS was higher in individuals who did not receive RT at 5 years (81% vs 74%) and 10 years (74% vs 65%), P=.003. Similarly, OS was higher in individuals who did not receive RT at 5 years (76% vs 73%) and 10 years (64% vs 59%), P=.04. However, stage III patients who received RT had a higher OS at 5- (54% vs 44%) and 10-year intervals (36% vs 30%), P=.04. For clear cell histology, there were a total of 3467 cases of which 68 received RT. OS was higher in individuals who received no RT compared to those who received RT both at 5 years (71% vs 41%) and 10 years (61% vs 40%), P<.0001. For mucinous histology, there were a total of 4369 cases of which 68 received RT. OS was higher in individuals who received no RT at 5 years (76% vs 70%) and 10 years (65% vs 49%), P=.037. In contrast, stage III patients with mucinous histology who received RT had a higher OS at 5- (50% vs 36%) and 10-year intervals (45% vs 26%), P<.05. For endometriod histology, there were a total of 7993 cases of which 314 received RT. OS was similar in these patients regardless of their RT status at 5 years (78% vs 81%) and similar at 10 years (65% vs 65%), P=.97.

Conclusion

Over 2004 to 2011, only 2% of all clear cell, endometriod, and mucinous ovarian cancer cases were treated with adjuvant RT. Those treated with RT had a lower CSS and OS at 5-year and 10-year intervals. However, further subgroup analysis revealed a benefit of RT in terms of OS for all stage III patients and for stage III patients with mucinous histology. These findings together with previous studies that demonstrated a potential survival benefit of adjuvant RT for stage I and II patients in these histologies suggest a role of RT. Therefore, further investigation should be performed in the indication for RT, dose and volume treated, RT techniques and delivery, treatment compliance, and the patient’s functional status for non-metastatic clear cell, mucinous, and endometriod ovarian cancer.