Ultrastructural study of clinically radioresponsive oral carcinoma: is it a true regression?

ABSTRACT

Thirteen patients presented with oral SCC were of clinical stages; I, II, and III, biopsied before and 6-7 weeks, after irradiation therapy, for ultra-structural examination. Post irradiated subjects, were selected to be seven, of whom complete regression of the tumour lesions were clinically proved. Post irradiation, light microscopic examination of semi-thin sections were correlated to the clinical picture, as reepithelization was almost normal, stromal fibrosis was obvious with absence of malignant cells. Utrastructural examination revealed comparable alterations in the epithelium, basal almina discontinuity and invasion of epithelial cells to the underlying connective tissue stroma. These cells showed similarity to the preexisting epithelial malignant cells, on the ultrastructural level. Recovery of these cells to regain their capacity for proliferation, might be considered, as signs expecting recurrence. Presence of some inflammatory cells; mast cells, histocytes and active lymphocytes, might have a role in initiating radioresponsiveness. Mast cell might have a harmful influence, initiated by irradiation, so further study was recommended to reveal its role. From the present study it can be concluded that 1. Clinical regression of irradiated oral SCC and its light microscopic examination were unsatisfactory measures for reporting complete curability. 2. Electron microscopy could detect minute residual invading epithelial cells which were not observed by other measures. 3. Electron microscopy, might be a valid tool in early detection of asymptomatic oral SCC whether denovo or recurrence, however a suggested easier method of exfoliative cytology, on the ultrastructural level, might be of value. 4. Irradiation therapy even for small tumour lesions of oral carcinoma, seemed to be unsatisfactory for compete treatment. Adjuvant treatment modalities, reconsiderations and close follow up of such patients were considerably needed. 5. Further study was needed to investigate clearly, the role of mast cell in radiation response of oral SCC