Abnormal Nuclear Variations in Response to Radiotherapy- As a Tool in Treatment Planning and Assessment of Prognosis.

Abstract

The treatment approaches for oral squamous cell carcinoma (OSCC) include single management with surgery, radiotherapy, along with chemotherapy or various combinations of these modalities. The estimation of radio sensitivity of individual tumours is essential for planning the optimum radiation schedule for each patient. Assessment of radiation induced histo morphological changes in the nucleus is a known marker of radiosensitivity. The aim of this study was to establish the relationship between nuclear changes with radiation dose and to investigate the prospect of utilizing them as an assay to predict tumour response to radiotherapy in oral cancers. The present study included 50 patients (age range of 30-65yrs) with histopathologically confirmed squamous cell carcinoma of oral mucosa and being treated by radiotherapy alone with a radiation dose schedule of 4, 14, 24 and 60 Gy respectively at 2(nd), 7(th), 12(th) and 30(th) day. From the included patients, smear of the buccal mucosa was collected and was air dried and fixed with methanol. The Nuclear changes of Micronucleus (MN), Nuclear Budding (NB) and Multinucleation (MNU) were evaluated under the bright field microscopy after staining with Giemsa and May-Grunwald's stain. Out of the 50, 37(74%) were males and 13(26%) were females (Ratio 3:1). The mean percentage increase of MN and MNU were found to be statistically significant (p=0.001) when compared with pre-treatment day. Similar findings were seen with NB, except between pretreatment and after 14 Gy (p-0.110). In the present study the measurement of relative increment index done in respect to all nuclear abnormalities show a sustained increase with increasing dosage of radiation. The present study, was undertaken to explore the possibility of establishing a relationship between the frequencies of nuclear abnormalities in patients with oral cancer with applied dosage and duration of radiotherapy. The progressive increase in Micronucleus and Multinucleation indices with increasing dose of radiation proves that these parameters can be used as indicators for assessing the response of tumour for radiotherapy. These parameters can be used as prognostic indicator in oral carcinoma cases undergoing radiotherapy.