Prognostic factors for radiation responses in patients with cervical cancer: A nested case-control study

Background: The radiation response of cervical cancer is believed to be enhanced by the levels of melatonin because of its roles in the circadian cycle and cancer growth. However, several other factors can affect the radiation response, such as haemoglobin (Hb) levels and tumour size. This study examined the role of circadian rhythms and melatonin levels as prognostic factors for predicting the radiation response in patients with cervical cancer.Methods: In this nested case-control study, good and poor radiation responses were assessed in patients treated with radiotherapy. Data on tumour size and other biological parameters were collected and analysed with the binary logistic regression using SPSS for Windows version 20.Results: Among the 56 examined patients, most subjects had good radiation responses. Other common features of the patients were as follows: <50 years old, initial weight >50 kg, no pain before radiation, low erythrocyte sedimentation rates, normal IVP, moderate or well differentiation on pathology and non-keratinised histopathology. The combination of the time of day of radiation as a surrogate of the circadian cycle (morning vs afternoon), the initial Hb level and the clinical tumour size significantly predicted the radiation response in multivariate analysis.Conclusion: The circadian cycle, tumour size and Hb levels may affect the radiation response in patients with cervical cancer. Further research is needed to identify more suitable prognostic factors using different radiotherapy techniques.