The effect of adjuvant radiation on survival in early stage clear cell ovarian carcinoma.
OBJECTIVE
To assess the impact of adjuvant radiotherapy (RT) on survival in patients with stage I and II ovarian clear cell carcinoma (OCCC).


METHODS
Data collection and analysis of stage I and II OCCC patients treated at two tertiary centers in Toronto, between 1995 and 2014, was performed. Descriptive statistics and Kaplan-Meier survival probability estimates were completed. The log-rank test was used to compare survival curves.


RESULTS
163 patients were eligible. 44 (27%) patients were treated with adjuvant RT: 37 of them received adjuvant chemotherapy (CT), and 7 had RT only. In the no-RT group, there were 119 patients: 83 patients received adjuvant CT and 36 had no adjuvant treatment. The 10year progression free survival (PFS) was 65% for patients treated with RT, and 59% no-RT patients. There were a total of 41 (25%) recurrences in the cohort: 12 (27.2%) patients in RT group and 29 (24.3%) in the no-RT group. On multivariable analysis, adjuvant RT was not significantly associated with an increased PFS (0.85 (0.44-1.63) p=0.63) or overall survival (OS) (0.84 (0.39-1.82) p=0.66). In the subset of 59 patients defined as high-risk: stage IC with positive cytology and/or surface involvement and stage II: RT was not found to be associated with a better PFS (HR 1.18 (95% CI: 0.55-2.54) or O S(HR 1.04 (95% CI: 0.40-2.69)).


CONCLUSIONS
Adjuvant RT was not found to be associated with a survival benefit in patients with stage I and II ovarian clear cell carcinoma or in a high risk subset of patients including stage IC cytology positive/surface involvement and stage II patients.
Division of Gynecologic Oncology, Department of Obstetrics and Gynecology, University of Toronto, Toronto, Ontario, Canada.
Liat
L
Hogen
Department of Radiation Oncology, Odette Cancer Centre, Toronto, Ontario, Canada.
Gillian
G
Thomas
Division of Gynecologic Oncology, Department of Obstetrics and Gynecology, University of Toronto, Toronto, Ontario, Canada; Division of Gynecologic Oncology, Princess Margaret Cancer Centre, University Health Network, University of Toronto, Toronto, Ontario, Canada.
Marcus
M
Bernardini
Department of Anatomic Pathology, Sunnybrook Health Sciences Center, Toronto, Ontario, Canada.
Dina
D
Bassiouny
Division of Gynecologic Oncology, Department of Obstetrics and Gynecology, University of Toronto, Toronto, Ontario, Canada.
Harinder
H
Brar
Division of Gynecologic Oncology, Department of Obstetrics and Gynecology, University of Toronto, Toronto, Ontario, Canada; Division of Gynecologic Oncology, Odette Cancer Centre, Toronto, Ontario, Canada.
Lilian T
LT
Gien
Division of Gynecologic Oncology, Department of Obstetrics and Gynecology, University of Toronto, Toronto, Ontario, Canada; Division of Gynecologic Oncology, Princess Margaret Cancer Centre, University Health Network, University of Toronto, Toronto, Ontario, Canada.
Barry
B
Rosen
Department of Biostatistics, Princess Margaret Cancer Center, Toronto, Ontario, Canada.
Lisa
L
Le
Division of Gynecologic Oncology, Department of Obstetrics and Gynecology, University of Toronto, Toronto, Ontario, Canada; Division of Gynecologic Oncology, Odette Cancer Centre, Toronto, Ontario, Canada. Electronic address: danielle.vicus@sunnybrook.ca.
Danielle
D
Vicus
D018262:Adenocarcinoma, Clear Cell / Q000401:mortality / Q000473:pathology / Q000532:radiotherapy*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D008875:Middle Aged; D009367:Neoplasm Staging; D010051:Ovarian Neoplasms / Q000401:mortality / Q000473:pathology / Q000532:radiotherapy*; D018714:Radiotherapy, Adjuvant
Clear cell carcinoma; Early stage; Ovarian cancer; Radiotherapy; Survival