title: Post-radiation changes in oral tissues - An analysis of cancer irradiation cases.
abstract: BACKGROUND
  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.
  
  
  OBJECTIVE
  To study epithelial, neoplastic, stromal, and glandular changes in oral cavity induced by radiation therapy for oral squamous cell carcinoma (OSCC) using special stains.
  
  
  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.
  
  
  METHODS
  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.
authors.affiliation: Department of Oral Pathology and Microbiology, Manipal College of Dental Sciences, Mangalore, Manipal University, Karnataka, India.
authors.forename: Jay Ashokkumar
authors.initials: JA
authors.lastname: Pandya
authors.affiliation: Department of Oral Pathology and Microbiology, Manipal College of Dental Sciences, Mangalore, Manipal University, Karnataka, India.
authors.forename: N
authors.initials: N
authors.lastname: Srikant
authors.affiliation: Department of Oral Pathology and Microbiology, Manipal College of Dental Sciences, Mangalore, Manipal University, Karnataka, India.
authors.forename: Karen
authors.initials: K
authors.lastname: Boaz
authors.affiliation: Department of Oral Pathology and Microbiology, Manipal College of Dental Sciences, Mangalore, Manipal University, Karnataka, India.
authors.forename: Nidhi
authors.initials: N
authors.lastname: Manaktala
authors.affiliation: Department of Oral Pathology and Microbiology, Manipal College of Dental Sciences, Mangalore, Manipal University, Karnataka, India.
authors.forename: Supriya Nikita
authors.initials: SN
authors.lastname: Kapila
authors.affiliation: Department of Oral Pathology and Microbiology, Manipal College of Dental Sciences, Mangalore, Manipal University, Karnataka, India.
authors.forename: Shanmukha Raviteja
authors.initials: SR
authors.lastname: Yinti
keywords: Fibrosis; oral squamous cell carcinoma; pattern of invasion; radiation-induced changes