Introduction: The cancer of uterine cervix is one of the leading sites of primary cancers in women around the world. External beam radiotherapy along with Brachytherapy may be routinely administered to cervical cancer patients – stages I B2 to IVA in a curative fashion. Proctitis, a radiotherapy associated toxicity in pelvic irradiation is the main cause of treatment interruptions and discontinuation of treatment. Aim: To evaluate any relationship between the severity of acute gastrointestinal mucositis and the time of radiation during a day with respect to circadian rhythm in patients of cervical carcinoma on pelvic EBRT. Materials and methods: Prospective randomized 2 arm comparative study. Total of 50 patients were included in the study. Patients with squamous cell carcinoma of the uterine cervix stages IB2 to IVA were randomly allocated to 2 groups-group A and group B. Group A patients received radiation in the morning (8.00-10.00AM) and patients in group B received radiation in the evening (6.00-8.00PM) Each patient was informed about the technique and informed consent was obtained. All patients underwent CT-simulation and 3D conformal treatment planning. Results: Incidence and severity of intestinal mucositis is more in the morning arm than in the evening arm. There is no difference in the tumour response rates between the morning and evening arm. Haematological toxicity showed very high significant occurrence (p < 0.001) in the CRT arm compared to ART arm. Nausea, dermatological side effects, fever, vaginal discharge and bladder irritation showed no statistically significant difference.

Conclusion: The final conclusion of this study is there is more incidence and severity of intestinal mucositis in patients receiving RT in the morning indirectly indicating the role of circadian cycle which is most active during early hours on the cell cycle  

Keywords: Cervical Carcinoma; Radiotherapy.