Post-radiation changes in oral tissues - An analysis of cancer irradiation cases

Abstract

Introduction:Radiation, commonly employed as neoadjuvant, primary, and adjuvant therapy for head and neck cancer causes numerous epithelial and stromal changes, prominent among which is fibrosis with its early and late consequences. Very little is known about the true nature of the fibrosed tissue and the type of fibers accumulated. Radiotherapy affects the supporting tumor stroma often resulting in a worsening grade of tumor post-radiation.Aim:To study epithelial, neoplastic, stromal, and glandular changes in oral cavity induced by radiation therapy for oral squamous cell carcinoma (OSCC) using special stains.Materials and Methods:The study included 27 samples of recurrent OSCC following completion of radiotherapy (recurrence within an average span of 11 months), and 26 non-irradiated cases of OSCC. Patients with a history of combined radiotherapy and chemotherapy were not included in the study. The epithelial changes assessed included epithelial atrophy, apoptosis, necrosis, dysplasia, and neoplasia. The connective tissue was evaluated for amount of fibrosis, quality of fibers (using picrosirius red staining), fibrinous exudate, necrosis, pattern of invasion, vessel wall thickening, and salivary gland changes. The aforementioned changes were assessed using light and polarizing microscopy and tabulated.Statistical Analysis:Epithelial and connective tissue parameters were compared between the irradiated and non-irradiated cases using chi square and t-tests.Results:Epithelial and connective tissue parameters were found to be increased in irradiated patients. Pattern of invasion by tumor cells varied from strands and cords between the two groups studied. The effect of radiation was seen to reflect on the maturity of fibers and the regularity of their distribution.

Cancer-Associated Fibroblast Density, Prognostic Characteristics, and Recurrence in Head and Neck Squamous Cell Carcinoma: A Meta-Analysis

“…Recurrent malignancy after treatment with radiation exemplifies this phenotype. Orchestrated by CAFs, these recurrences are often exquisitely desmoplastic with extensive collagen cross linking and loss of microvascular structure (48,49). This modified environment is hypothesized to provide a physical barrier to immune surveillance, enabling unabated tumor growth (50).…”

Regulation of mucin 1 expression and its relationship with oral diseases

“…Oral cancer treatment involves various types of adjuvant and neoadjuvant therapies to combat the disease as well as avoiding dose-limiting, toxic side effects. Radiotherapy is associated with a significant increase in cure rates for many oral malignancies but inevitably involves exposure and damage to healthy surrounding tissues (Pandya et al, 2014). As a consequence, the oral mucosa, skin, maxilla, mandible and salivary glands undergo several undesirable reactions.…”

Morphology, Volume, and Density Characteristics of the Parotid Glands before and after Chemoradiation Therapy in Patients with Head and Neck Tumors

“…However, despite all the technological advances, it is a key challenge to maximize the radiation doses to cancer cells and at the same time to minimize damage to the surrounding healthy tissues [7]. RT destroys cancer cells by depositing high physical energy to the cells [6] and at the same time causing numerous epithelial and stromal changes (e.g., fibrosis) in the normal tissue surrounding the tumor leading to early and late adverse effects RT [8]. e radiation dose, the localization of the tumor, and the sensitivity of the normal tissue next to the tumor are all factors affecting the severity of adverse effects to RT [5].…”