Radiation-induced morphological changes and radiocurability in squamous cell carcinoma of the head and neck region. A preliminary report.

Tissue samples taken from 22 patients before and during radical irradiation of squamous cell carcinomas in the head and neck region were studied by light and electron microscopy. The changes in keratinization pattern at the ultrastructural level seemed to be correlated with the outcome of the radiotherapy. The irradiation induced several cellular changes, of which nuclear atypia was the most prominent. This atypia was considered to be mainly due to cell death rather than to an aggressive nature of the tumor, because the number of mitoses decreased at the same time. The tumor invasion pattern remained unchanged. The keratinization pattern remained almost unchanged at the light microscopical level, but a slight increase of intracellular filaments and desmosomes was found in the electron microscopic study. The amount of intercellular filaments increased in three patients out of four with complete remission (CR), but in no case with tumor dissemination (n = 3) during radiotherapy. In patients with local persistent tumor or a local recurrence (LP + LR) (n = 15) the filaments either increased, decreased or remained unchanged. The number of desmosomes either increased or remained unchanged in three of four CR patients, in 13 of 15 LP + LR patients and in only one of three patients with tumor dissemination. They decreased in two patients with tumor dissemination, but only in one case with CR and in 2 cases with LP + LR. It is suggested that changes in cytoskeleton and desmosomes might be important in anchorage of tumor cells locally and might have value for prediction of the tumor response to radiotherapy. Further studies on larger materials are, however, needed before more definite conclusions can be drawn.