Abstract
Objectives: To analyze the different anatomical sites of oral cavity affected by the cancer in patients presenting to a tertiary care public sector hospital in Karachi, Pakistan.
Methodology: This retrospective observational study was conducted at the department of Ear, Nose and Throat (ENT), Head and Neck Surgery, Civil Hospital and Dow Medical College, Karachi, Pakistan from February 2015 to January 2016 and included 100 patients with biopsy-proven oral cavity cancer. Anatomical location was carefully noted for each patient and analyzed. Patients with premalignant oral conditions, patients with inconclusive histopathology reports and patients suffering from oropharyngeal carcinoma were excluded.
Results: The mean age of patients was 49.53±13.64 years (range 27 to 84). Out of 100 patients, 76 (76%) were male and 24 (24%) females. Male to female ratio was 3.1. Most of the patients belonged to low socio-economic group. A total of 142 cancer lesions were documented. In 18 patients, more than one site was involved, reflecting multiplicity and extension of the lesions. Buccal mucosa was the most commonly involved anatomical site. A total of 62 out of 100 patients (62%) had tumors localized to the buccal mucosa. Tongue was the second most commonly involved anatomical site with 30 cancers (30%) located in the oral tongue. In 10 (10%) patients, lips were involved. In 20(20%) patients, the disease was first discovered on the floor of the mouth. Gums and cheeks were involved by 10 tumors (10%) and hard palate by 10 tumors (10%).
Conclusion: The most common involved anatomical site in oral cancer was buccal mucosa. This pattern differs from the western world, where tongue is the most commonly involved anatomical site of the oral cavity. This may reflect different risk factors in our population.

Key words: Oral cancer, anatomical site, buccal mucosa, tongue, betel nut.