Histomorphology of chemoradiotherapy-induced oral mucositis in patients with gastrointestinal cancer

Objective: To study the histomorphological changes of oral mucosa by observing the sections of lip buccal mucosae from patients with gastrointestinal cancer. Methods: Oral mucosae from 15 patients aged 61-80 years old who died of gastrointestinal cancer were sampled. Group A (n=10) had received high-dose chemoradiotherapy. Group B (n=10) were divided two subgroups. Group B1 (n=5) had gastrointestinal cancer (before chemoradiotherapy), and Group B2 (n=5) consisted of healthy adult subjects. Oral mucosa (1 cm × 3 cm) was collected, prepared into 5-7 μm-thick paraffin sections, stained with haematoxylin-eosin, and observed under a light microscope. Meanwhile, indirect immunoperoxidase reaction was performed. Results: No. 5 sample in Group A showed the atrophy rate of mucosal epithelial cells was 100%. No. 6 sample showed that the autologous mucosal layer was attenuated, and the hypodermal mucosa was loosened and arranged in deposited fibers. Besides, 75% of No. 3 and 9 samples showed moderate focal or diffusive inflammatory infiltrations of lymphocytes-macrophages in the basal layer of oral mucosa. The nerve fibers and muscles in 20% of No. 2 sample underwent dystrophy. Conclusion: The oral mucosae of patients receiving chemoradiotherapy suffered from atrophy of epithelial cells and infiltration of numerous cells. In deeper layers, there was relaxation of the hypodermal mucosa as well as dystrophy of nerve fibers and muscles. The deep submucosa exhibited atrophic muscle fibers. In the meantime, the neuromodulation system was injured, especially in nonhyperplastic and hyperplastic muscle fiber bundles.