Clinical research on radiotherapy at different time for unresectable cervical cancer.

e16516 Background: Radiotherapy is one of the mainstay treatments for cervical cancer. Circadian rhythm can be associated with cancers. In this study, we focused on the therapeutic effects, acute radiation damages and expressions of circadian genes in unresectable cervical cancer irradiated at different time. Methods: A total of 67 patients of unresectable cervical cancer (stage IIB-IIIB) were randomized to morning (9:00-11:00am) and evening (9:00-11:00pm) irradiation groups. Patients were treated with external beam radiotherapy to the whole pelvis (50 Gy in 25 fractions) and brachytherapy (36-42 Gy in 6-7 fractions). Therapeutic effects and acute radiation toxicities were evaluated after radiotherapy. Samples analyzed by flow cytometry were obtained from cervix at 9:00-11:00am and 9:00-11:00pm before and after radiotherapy. Results: Of 65 patients, the overall and higher grade of diarrhea (III-IV) induced by radiation in patients after morning vs evening radiotherapy were 75.0% vs 57.6% (p = 0.138), 12.5...