Response to radiotherapy in carcinoma cervix - clinical, spectroscopic, and radiobiological correlation

A substantial number of patients still have some form of residual disease at the end of the treatment with radiotherapy for carcinoma of cervix. Therefore there is an existing need for developing some form of diagnostic modality that can help predict tumor response in the early phases of the treatment. To identify the possible markers from protein profiles and DNA based assays for prediction of tumor response to radiotherapy. We estimated the serum glutathione (GSH) levels using CNDB method utilizing 23 serum samples taken before and 24 hours after 2nd fraction of radiotherapy and in 43 samples taken before start of treatment, and after 24 hours after 5th fraction. 18 normal serum samples were also taken. We also evaluated the extent of DNA damage using Komet imaging software (Kinetic imaging Ltd.) in 36 malignant biopsy samples. The same samples were also analysed using RAMAN spectroscopy. The serum GSH levels of normal samples ranged from 145-216 μg/ml. The serum GSH values of malignant (pretreatment) ranged from 142-176 μg/ml. 2-RT GSH levels of complete response (CR), partial response (PR) and no response (NR) were 110.67 ± 13.78 μg/ml (n =18), 144.56 ± 6.45 μg/ml (n =3) and 162.43 ± 9.99 μg/ml (n =4) respectively. Mean and standard deviation of olive tail movements (OTM) values of CR, PR and NR were 34.8±12.0 (n = 27), 22.9±6.56 (n = 7) and 18.0±2.19 (n = 2) respectively. These levels obtained were compared with the earlier verified Raman spectroscopy data and with clinical assessment one month after the completion of radiotherapy and showed good correlation. From the present study we conclude that serum GSH, DNA assays and spectra from Raman laser can be used as a predictor of tumor response in early phases of radiotherapy in carcinoma of cervix. (author)