Effects of radiotherapy on oral epithelium. Quantitative cytology using light and scanning electron microscopy

To determine the short- and long-term morphologic and morphometric effects of radiotherapy on exfoliated oral squames.

Exfoliating squames were sampled from squamous carcinoma and contralateral clinically healthy sites from patients before and six weeks after radiotherapy and from patients who had received radiotherapy for oral squamous carcinoma five years previously. Morphologic and morphometric studies were undertaken using light and scanning electron microscopy (SEM).

Six weeks after radiotherapy, nuclear area was significantly increased in cells from both healed tumor and contralateral sites. No differences were detected in cells from previous tumor and contralateral sites five years after radiotherapy. SEM revealed bizarre microplications in cells from malignant sites, and microplication widths were significantly increased. Occasional cells with atypical patterns were identified six weeks and five years after radiotherapy, but microplication dimensions were comparable to those of cells from contralateral clinically healthy sites.

Radiotherapy produces a transient increase in nuclear area. Abnormal microplication patterns in cells from previous tumor sites five years after radiotherapy may reflect disordered maturation associated with radiation injury.