Journal d'oncologie clinique et expérimentale

Demographic and Histopathological Differences of Oral Squamous Cell Carcinoma; Analysis of 4394 Cases from Sri Lanka

Siriwardena BSMS, Jayathilake DSY, Pitakotuwage TN, Illeperuma RP, Kumarasiri PVR, Attygalla AM, Peiris HRD and Tilakaratne WM

Demographic and Histopathological Differences of Oral Squamous Cell Carcinoma; Analysis of 4394 Cases from Sri Lanka

Head and neck cancer accounts for 6.5% cancer cases worldwide. In Southeast Asia it is higher and accounts for nearly 50% of malignancies. In Sri Lanka, studies of population based detailed analysis of head and neck cancer is scarce. Thus in this study we try to analyze data from 4394 cases obtained from the archives of the Department of Oral Pathology, Faculty of Dental Sciences, University of Peradeniya, Sri Lanka for a period of thirteen years from 1999 to 2011. This is an attempt to examine the histopathological variations of oral cancer and to correlate them with age, gender and site in order to identify changing patterns with time. Further, subgroup analysis was performed to elucidate the relationship between squamous cell carcinoma (SCC) with age, site and gender and also to identify the changing patterns with time. Literature review was carried out to compare our data with global trends. In this cohort, the overall cases of oral malignancies increased from 1999 (8%) to 2004 (18%). There was a steady decline after 2004 until 2007 (13%) and remained at an approximate 13% - 16% of new cases until 2011. The proportion of male-to-female was 3:1. Among all the cases, approximately 50% of the tumors were well differentiated SCC and the commonest site found to be buccal mucosa. 40.7% of the total cases were in the buccal mucosa while 16% of the cancers developed in the lateral border of the tongue. 7.3% of the tumors were found in the floor of the mouth and tumors of the other sites remained less than 5%. Nearly 60% of the total cases in this cohort were from the age groups of 51 yrs-60 yrs and 61 yrs-70 yrs. Among all the age groups SCC was the commonest type. When segregating data by tumor histology type, the commonest was SCC (87.9%) and least reported were the Adenosquamous carcinoma (0.2%) and the Spindle cell carcinoma (0.1%). Further there was no significant difference noted in tumor histology according to the gender. When considering the relationship between site and age, cancers of thebuccal mucosa and alveolar ridge significantly increased with age (P<0.05). Tongue involvement is very highly significant in younger population under the age of 40 years (P<0.0001). It is almost one third of the total oral cancers of this group. Interestingly, our data also showed significant increase of tongue cancers as a trend during 1999- 2011. This trend is in par with the global trend of increasing tonguecancers in younger populations which is attributed to HPV infection.In Sri Lanka, the reason for this trend is still obscure. Further study is necessary to analyze these tumors at molecular level to assess whether there is HPV infection similar to the global trend.